key: cord- -oguse gt authors: kelly, l.; clark, k. title: the effectiveness of training and taste testing when using respirator masks date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: oguse gt nan weeks at room temperature and c. furthermore, swirling the swabs in the broth for a few seconds was easier, quicker and gave comparable results to the current practice of breaking the swabs in broth. these features of smb enabled us to introduce the use of smb in the hospital. the nursing staff swirl screening swabs from various sites into a single smb that is labelled with the patient's identification details. this precludes the need to label several swabs and saves time. the broths are incubated for - h in the laboratory and the results of negative tests are available within h. mrsa-positive specimens take up to h because smb has to be subcultured and the presence of mrsa has to be confirmed because of the relatively low specificity of smb. the user survey showed that the majority of nurses preferred smb to sending swabs to the laboratory. smb was also considerably cheaper ( pence) than salt-broth-based screening (£ . ) for mrsa-negative screens. this was mainly due to saved labour costs. the principal limitation of smb is that it can only detect those strains of mrsa that are resistant to ciprofloxacin. we conclude that swirling of screening swabs directly into smb is a sensitive, cost-effective and convenient method to screen for ciprofloxacinresistant mrsa in hospitals. the effectiveness of training and taste testing when using respirator masks recent concerns about severe acute respiratory syndrome (sars), influenza and multidrug-resistant tuberculosis have highlighted the need for the use of respirator masks of adequate design and construction. however, it is equally important to ensure that healthcare personnel are using these masks correctly. in november , members of staff on our respiratory ward were trained on the correct method for putting on respirator masks (tecnol fluid n particulate filter, kimberly clark); they were asked to cascade this training on to remaining staff on the ward. in february , with help from the suppliers, we returned to test the adequacy of mask fitting by staff. this involved staff putting on a mask using their normal method and then wearing a plastic hood into which a saccharin solution was aerosolized. they were then asked to read a paragraph of text and any tasting of saccharin during this time was regarded as a mask-fit failure, demonstrating to staff that this left them exposed to infectious agents. the results are shown in table i . the majority of staff who had not been trained failed the test. although there was a greater degree of success amongst those formally trained, they still failed to comply with the manufacturer's instructions in all aspects, which suggests that their future success may be haphazard. using the test hoods, we also looked at staff in the accident and emergency department and the intensive care unit who had not received any formal training in mask fitting but who were expected to follow the manufacturer's instructions. only three out of clinical staff passed the fit test; / nurses and all medical staff, including nine consultants, failed. subsequently, the correct method of mask use was demonstrated followed by testing; the effectiveness of the mask was demonstrated for every individual using the hood and all passed the fit test. this experience has highlighted several areas. in particular, it re-emphasizes that just because a piece of equipment is technically sufficient for purpose does not mean that it will provide the required protection when called upon in practice. it also suggests that training may be of limited value if the relevance to the individual is not clearly demonstrated. we have changed our practice and now recommend that staff working in high-risk areas receive training on mask fitting at induction and pass a fit test. we also recommend that staff in these areas are tested annually. we have found that these tests not only give us assurance regarding performance, but they have given every member of staff real confidence in these relatively simple masks and brought home to them what failure might represent. sir, clostridium-difficile-associated diarrhoea (cdad) recently became subject to mandatory surveillance in england. this initiative was supported by standardization of diagnostic procedures that had previously varied widely and rendered figures from different laboratories difficult to compare. briefly, since january , laboratories have been asked to test all diarrhoeal specimens from patients aged years and over for c. difficile toxins (cdt) a and b, and not to test non-diarrhoeal specimens. the scheme ignores results from repeat specimens submitted within four weeks of an included positive assay, and does not apply to patients younger than years of age. laboratories are at liberty to formulate their own testing algorithms for these patients. this laboratory's previous strategy was to perform cdt testing only (and always) on request, in effect relying upon clinicians' judgment to optimize the predictive value of the investigation. for ourselves, as for most others, the new standards have entailed testing specimens that we would not previously have tested while rejecting specimens that we would previously have tested. this communication reports the impact of the changes on laboratory workload and diagnosis of cdad in sunderland. the first requests of were analysed. in previous years, these requests would have generated tests. under the new standards, however, ( . %) of the specimens were judged not to be diarrhoeal and were therefore not processed, while in the same period, unrequested tests were three strategies in the control of staphylococci including methicillin-resistant staphylococcus aureus revised guidelines for control of mrsa: applying appropriately-based recommendations shea guideline for preventing nosocomial transmission of multidrug-resistant strains of staphylococcus aureus and enterococcus screening for methicillin-resistant staphylococcus aureus in the endemic hospital: what have we learned? is it time to stop searching for mrsa? stop the ritual of tracing colonised people a novel selective medium for the detection of methicillinresistant staphylococcus aureus enabling result reporting in under h i would like to thank mr kevin reece, universal hospital supplies, for all the valuable discussions and his help with mask testing. key: cord- - nz wdlo authors: kelly, s.; hardwick, r.; wong, j.; gopal rao, g. title: laboratory evaluation of selective mannitol broth for mrsa screening date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: nz wdlo nan laboratory evaluation of selective mannitol broth for mrsa screening screening for methicillin-resistant staphylococcus aureus (mrsa) carriage in patients admitted to hospital features prominently in strategies for control of mrsa. , the society for healthcare epidemiology of america recently commissioned a critical review of the reasons for the failure to control the spread of mrsa in hospitals despite the existence of guidelines for over three decades. the review concluded that active surveillance cultures are essential to identify the reservoir for spread of mrsa infections, and make control possible using the center for disease control's long-recommended contact precautions. similarly, rubinovitch and pittet found that the best way to detect occult mrsa reservoirs is by screening, but this can be expensive. as a result, many hospitals either do not screen or only do limited screening. this letter describes our evaluation and use of a recently described selective mannitol broth (smb) for rapid ciprofloxacin-resistant mrsa screening. selective mannitol broth was prepared as described previously and poured in -ml aliquots. smb was made by adding mannitol ( g/l), trehalose ( g/l), sodium chloride ( g/l), aztreonam ( mg/l), ciprofloxacin ( mg/l), colistin sulphate ( u/l) and % phenol red ( ml) to l of nutrient broth. growth of mrsa produces a colour change from red to yellow after overnight incubation at c in air. smb was evaluated in the laboratory for its ability to detect low concentrations of mrsa. ten-fold serial dilutions (range k - k ) of an overnight broth culture were made of mrsa (nctc , ciprofloxacin resistant) and clinical isolates of mrsa (ciprofloxacin resistant). fifty microlitres of each dilution was added to separate aliquots of smb. the broths were incubated for - h at c in air. in addition, ml of each of the dilutions of the overnight broth of mrsa was cultured on % horse blood agar and incubated for - h at c in air to determine the concentration of mrsa in each dilution. the shelf life of smb at room temperature and c was determined. aliquots of smb were prepared as described earlier. each week, separate aliquots of the broth were inoculated with -fold serial dilutions (range k - k ) of an overnight broth culture of mrsa (nctc ), and undiluted and k dilution of overnight broth culture of escherichia coli (nctc ). the broths were incubated for - h at c in air. non-inoculated aliquots of smb were incubated at room temperature and c. all tests were performed in duplicate. we compared the current technique of breaking the screening swabs into smb with swirling the swabs (without breaking) in the broth. ten-fold serial dilutions (range k - k ) of an overnight broth culture of mrsa (nctc , ciprofloxacin resistant) were made. two swabs were dipped into each dilution. one swab was broken into smb and the other swab was swirled into a separate aliquot of smb for s. the broths were incubated for - h at c in air. material and labour costs of screening using the conventional method of salt broth enrichment followed by subculture were compared with those using smb. following introduction of smb and the swirling technique, we conducted a user-satisfaction survey. our results show that smb can detect - cfu/ml of mrsa (table i) and that it has a shelf life of three y, yellow; o, orange; r, red. yellow or orange indicated growth, and red indicated no growth. dilution to k z - cfu on % blood agar. weeks at room temperature and c. furthermore, swirling the swabs in the broth for a few seconds was easier, quicker and gave comparable results to the current practice of breaking the swabs in broth. these features of smb enabled us to introduce the use of smb in the hospital. the nursing staff swirl screening swabs from various sites into a single smb that is labelled with the patient's identification details. this precludes the need to label several swabs and saves time. the broths are incubated for - h in the laboratory and the results of negative tests are available within h. mrsa-positive specimens take up to h because smb has to be subcultured and the presence of mrsa has to be confirmed because of the relatively low specificity of smb. the user survey showed that the majority of nurses preferred smb to sending swabs to the laboratory. smb was also considerably cheaper ( pence) than salt-broth-based screening (£ . ) for mrsa-negative screens. this was mainly due to saved labour costs. the principal limitation of smb is that it can only detect those strains of mrsa that are resistant to ciprofloxacin. we conclude that swirling of screening swabs directly into smb is a sensitive, cost-effective and convenient method to screen for ciprofloxacinresistant mrsa in hospitals. the effectiveness of training and taste testing when using respirator masks recent concerns about severe acute respiratory syndrome (sars), influenza and multidrug-resistant tuberculosis have highlighted the need for the use of respirator masks of adequate design and construction. however, it is equally important to ensure that healthcare personnel are using these masks correctly. in november , members of staff on our respiratory ward were trained on the correct method for putting on respirator masks (tecnol fluid n particulate filter, kimberly clark); they were asked to cascade this training on to remaining staff on the ward. in february , with help from the suppliers, we returned to test the adequacy of mask fitting by staff. this involved staff putting on a mask using their normal method and then wearing a plastic hood into which a saccharin solution was aerosolized. they were then asked to read a paragraph of text and any tasting of saccharin during this time was regarded as a mask-fit failure, demonstrating to staff that this left them exposed to infectious agents. the results are shown in table i . the majority of staff who had not been trained failed the test. although there was a greater degree of success amongst those formally trained, they still failed to comply with the manufacturer's instructions in all aspects, which suggests that their future success may be haphazard. using the test hoods, we also looked at staff in the accident and emergency department and the intensive care unit who had not received any formal training in mask fitting but who were expected to follow the manufacturer's instructions. only three out of clinical staff passed the fit test; / nurses and all medical staff, including nine consultants, failed. subsequently, the correct method of mask use was demonstrated followed by testing; the effectiveness of the mask was demonstrated for every individual using the hood and all passed the fit test. three strategies in the control of staphylococci including methicillin-resistant staphylococcus aureus revised guidelines for control of mrsa: applying appropriately-based recommendations shea guideline for preventing nosocomial transmission of multidrug-resistant strains of staphylococcus aureus and enterococcus screening for methicillin-resistant staphylococcus aureus in the endemic hospital: what have we learned? is it time to stop searching for mrsa? stop the ritual of tracing colonised people a novel selective medium for the detection of methicillinresistant staphylococcus aureus enabling result reporting in under h key: cord- -gexh wtd authors: prescott, k.; baxter, e.; lynch, c.; jassal, s.; bashir, a.; gray, j. title: covid- : how prepared are front-line healthcare workers in england? date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: gexh wtd national efforts are underway to prepare the uk national health service (nhs) for the covid- pandemic; however, the efficacy of these interventions is unknown. in view of this, a cross-sectional survey of front-line healthcare workers (hcws) at two large acute nhs hospital trusts in england was undertaken to assess their confidence and perceived level of preparedness for the virus. the survey found that there has been moderate success in readying hcws to manage covid- , but that more still needs to be done, particularly in relation to educating hcws about laboratory diagnostics. on st december the world health organisation (who) was notified of unusual cases of pneumonia linked to a seafood whole sale market in huanan, in the chinese province of wuhan [ , ] . by early january the causative agent was identified as a novel betacoronavirus with greater than % identity with a bat sars-cov genome [ ] . the new virus has been named sars-cov- and the disease covid- [ ] . coronaviruses are enveloped rna viruses which can infect both animals and humans and are capable of zoonotic spread. most present as mild coryzal illnesses but those of zoonotic spread such as severe acute respiratory syndrome (sars-cov) and middle east respiratory syndrome (mers-cov) can manifest with fatal respiratory illnesses [ ] . with human-to-human transmission covid- has spread globally and was declared a public health emergency of international concern on th january [ , ] internationally, the who, and nationally public health england (phe), have issued guidance on the infection prevention and control of covid- (see websites for details). hcw need to be able to identify patients at risk of covid- , and respond appropriately to any risk, in order to protect themselves and others from this infection. levels of hcw confidence and feelings of preparedness are unknown. as such we carried out an online cross sectional questionnaire based survey of front line hcw at two large acute nhs hospital trusts in england to ascertain how prepared they felt to manage covid- . the timing of the survey coincided with a national direction to all acute nhs hospital trusts that they establish priority assessment pods for patients concerned about covid- . thus hcw should have been prepared to encounter cases. we designed an online cross-sectional questionnaire-based survey using online surveys (formerly bos) to ascertain how confident and prepared front line hcw felt in managing potential covid- cases. the survey comprised of questions and was anonymised by name and place of work. the first questions ascertained the respondent's profession and for how many years they had been qualified. the subsequent questions assessed on a rating scale how confident the hcw felt in various management aspects of covid- . the eighth question asked respondents where, if at all, they had sought information about the virus, with a free text option for additional responses. the final question allowed free text for respondents to express anything else they wanted to highlight in terms of how prepared they felt. the online survey was live from thursday th february at : am until pm monday th february. it was sent to front line hcw at nottingham university hospitals nhs trust and birmingham women's & children's nhs foundation trust. those considered to be front line hcw were doctors, nurses and advanced clinical practitioners (acp) working in areas most likely to encounter early cases of covid- . across the hospital trusts this included those working in the emergency departments, intensive care units, designated covid- paediatric admission areas and infectious diseases. the survey was sent to a key person in each of these areas to disseminate, with reminders sent out once the survey was live to encourage participation. at the time the survey went live work in both hospital trusts had already begun to prepare front line hcw for covid- . as the survey was anonymised by name and place of work no ethical approval was required. between th and th february respondents completed the survey. as it was disseminated via a key person in each area it was not possible to calculate the response rate as these figures are unknown. the results of questions - are displayed in figure . question allowed respondents to select more than one answer and had a free text option to enable them to elaborate on where they had sought information on the virus. responses included colleagues in infectious diseases, local infection control teams (ipc) and internet/media sources. question was a free text question asking respondents if there was anything else they wanted to mention about how prepared they felt for covid- . in total there were responses. the major themes covered were to do with clarity surrounding ppe, the desire for more information/communications, concerns regarding lack of capacity to manage cases and lack of preparation in certain areas, lack of guidance around staff travel and safety to work and a request for simulations to help staff preparedness. during the last decade there have been a number of emerging infectious diseases posing a global threat to human health. hcw surveyed during these times demonstrated a lack of knowledge surrounding these pathogens and a need for further education/training [ , ] . outbreaks of novel pathogens can be extremely stressful and detrimental to hcw; but this stress can be lessened by clear guidelines from hospitals and ipc teams [ ] . healthcare systems must ensure all hcw feel equipped to manage new and emerging threats. as the threat of covid- grows, we wanted to assess how confident our front line hcw felt to manage possible cases. to the best of our knowledge this is the first such survey to gauge hcw feelings of preparedness in england. almost two thirds of respondents had been qualified for over years, suggesting many will have been practising during the emergence of mers-cov in and ebola virus in and possibly sars-cov in / and influenza a h n in . as such this cohort is likely to have some experience in preparing for novel infectious diseases. during the containment phase of a possible pandemic, healthcare systems are required to ready themselves to manage possible cases. this preparation generally starts by focussing on key front line areas and then expanding efforts throughout organisations. an important component of these preparations is providing staff with the knowledge they require to identify and manage cases. at the time this survey went live there was already formal guidance on covid- issued by the who and phe. in addition, the hospital trusts surveyed were actively working with front line hcw in the participating areas to equip them with the knowledge and skills needed. neither hospital trust had yet encountered a positive case of covid- . this survey demonstrates only moderate success with these interventions with % of respondents feeling somewhat confident or greater in their knowledge of covid- . however, if there is to be success in managing this pandemic, levels of hcw knowledge must rapidly increase. in view of the rapidly evolving nature of pandemics and the frequency with which information changes it is vital that hcw know where to go for up to date guidance. . % of respondents felt at least somewhat confident in knowing where to go for covid- guidance. healthcare organisations must ensure their staff know where to access key guidance in order to reduce their anxiety and optimise their performance. it is crucial that relevant personnel are informed of possible cases of covid- so that these patients are managed effectively, other patients are not put at risk and that the flow of the organisation is not unduly compromised. % of respondents felt at least somewhat confident of who to inform of a possible case. the hopes of containment of covid- rely on swift and effective identification of those possibly infected. this survey found that % of respondents felt somewhat confident or greater in their knowledge of the criteria for identifying those at risk. a delay in identifying possible cases may have a detrimental effect on the patient, and with a reported r of . put other patients and hcw at risk [ ] . strategies must be implemented to enable all hcw to recognise those who may be harbouring the virus. containment of the virus also relies heavily on ipc interventions. % of respondents felt at least somewhat confident in how to isolate a suspected case and . % of what ppe (personal protective equipment) to use. however, . % had the same level of confidence in how to don and doff the ppe. this must be addressed as any lapse in ipc will place other patients and hcw at risk and could hinder containment of the virus. as shown in previous studies this can be extremely anxiety provoking for hcw [ ] . this survey identified laboratory diagnostics as the area where hcw had the least confidence. only % of respondents were somewhat confident or greater in their knowledge of how to collect/handle laboratory samples; almost % were not at all confident. this may in part be because neither hospital trust had had to perform diagnostic testing at that time. in addition, whilst there was published guidance from phe on the collection and handling of diagnostic samples, local variation in laboratory testing methods, may have added to the uncertainty felt by hcw. diagnostics is a vital part of managing a pandemic, allowing early detection and isolation of cases and freeing up of resources following identification of negatives. this survey suggests hospital trusts should focus on educating hcw on the laboratory diagnostics of covid- through integration of guidance from laboratories and the ipc team. . % of respondents had used local training/guidance to gain knowledge on covid- . . % had referred to phe guidance and % who guidance. . % had not sought information from any additional sources and % had used social media. whilst employers have a responsibility to provide employees with the knowledge they require to carry out their roles, individual hcw also have an obligation to their patients to ensure they keep up to date with current guidance. in our survey respondents highlighted areas where they would like additional information and areas where they had concerns. hospital trusts should have mechanisms in place to seek out and address employees concerns to keep anxiety to a minimum and performance at its best. there are a number of limitations in this survey that should be considered when interpreting this data. it is a snap shot in time, at an early stage of preparations. the relatively small number of hospital trusts surveyed means the results may not be generalizable across england and only a small proportion of hcw in each hospital trust were surveyed. a larger scale study would be useful to add to the findings of our study. finally, this survey was assessing levels of hcw confidence not competence and there may not be a direct correlation between the two. in conclusion this survey has demonstrated that hospital trusts and individual hcw alike have acted quickly and with moderate success to make preparations for covid- . however, more still needs to be done if they are to feel confident and prepared to tackle this global threat. in particular, we identified a lack of confidence in the collection and handling of diagnostic samples. early transmission dynamics in wuhan, china, of novel coronavirus-infected pneumonia a novel coronavirus from patients with pneumonia in china the novel coronavirus: a bird's eye view r: a language and environment for statistical computing. r foundation for statistical computing welcome to the tidyverse cowplot: streamlined plot theme and plot annotations for 'ggplot knowledge and attitude towards the middle east respiratory syndrome coronavirus among healthcare personnel in the southern region of saudi arabia attitudes and behaviours of healthcare workers in the kingdom of saudi arabia to mers coronavirus and other emerging infectious diseases healthcare workers emotions, perceived stressors and coping strategies during a mers-cov outbreak the authors of this manuscript would like to acknowledge the two hospital trusts and individual hcw who participated in this study. the authors of this manuscript declare no conflicts of interest. no funding was required for this study. key: cord- - znb authors: omrani, a.s.; shalhoub, s. title: middle east respiratory syndrome coronavirus (mers-cov): what lessons can we learn? date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: znb the middle east respiratory coronavirus (mers-cov) was first isolated from a patient who died with severe pneumonia in june . as of june , a total of , mers-cov infections have been notified to the world health organization (who). clinical illness associated with mers-cov ranges from mild upper respiratory symptoms to rapidly progressive pneumonia and multi-organ failure. a significant proportion of patients present with non-respiratory symptoms such as headache, myalgia, vomiting and diarrhoea. a few potential therapeutic agents have been identified but none have been conclusively shown to be clinically effective. human to human transmission is well documented, but the epidemic potential of mers-cov remains limited at present. healthcare-associated clusters of mers-cov have been responsible for the majority of reported cases. the largest outbreaks have been driven by delayed diagnosis, overcrowding and poor infection control practices. however, chains of mers-cov transmission can be readily interrupted with implementation of appropriate control measures. as with any emerging infectious disease, guidelines for mers-cov case identification and surveillance evolved as new data became available. sound clinical judgment is required to identify unusual presentations and trigger appropriate control precautions. evidence from multiple sources implicates dromedary camels as natural hosts of mers-cov. camel to human transmission has been demonstrated, but the exact mechanism of infection remains uncertain. the ubiquitously available social media have facilitated communication and networking amongst healthcare professionals and eventually proved to be important channels for presenting the public with factual material, timely updates and relevant advice. the middle east respiratory syndrome coronavirus (mers-cov) was first identified in september . as of june , a total of , mers-cov infections have been reported to the world health organization (who). despite an accumulation of clinical experience and scientific knowledge, new mers-cov infections continue to be reported almost on daily basis. what lessons can we learn after three years of clinical experience and scientific research? lesson one: no substitute for continuous vigilance a -year-old man was admitted on june th, , to a hospital in jeddah, saudi arabia, with severe pneumonia and multi-organ failure. the patient died after days of hospitalization. indirect immunofluorescence assays and real-time polymerase chain reaction (pcr) for widely occurring respiratory viruses failed to identify an infective aetiology. interestingly, cytopathic changes consistent with viral replication were noted in llc-mk and vero cell cultures of the patient's respiratory samples. slides of the infected cell cultures reacted strongly with the patient's serum but not with any of control sera stored in the same hospital. however, pancoronavirus pcr yielded positive results. the pcr fragments were sequenced at the erasmus medical centre in rotterdam, the netherlands, and phylogenetic analysis showed that the novel coronavirus belonged to lineage c of the genus betacoronavirus. , on september , an email was posted on program for monitoring emerging diseases mail (promed-mail) announcing the discovery of a novel human coronavirus. meanwhile, a critically ill -year-old qatari man was transferred by air ambulance on september th, , to a hospital in england. he had developed respiratory symptoms on september rd followed by multi-organ failure. his upper and lower respiratory tract samples were negative for influenza a/b, parainfluenza e , rsv a/b, human metapneumovirus, enterovirus, rhinovirus, adenovirus, human bocavirus, and the human coronaviruses (nl , e, oc , hku ). on september st, , one day after the above promed-mail posting, the patient's respiratory samples tested positive by pancoronavirus pcr. once sequenced, a base-pair fragment from this isolate showed . % homology with the erasmus medical centre's isolate. the third patient was a -year-old man who presented to a hospital in riyadh, saudi arabia, on october th, , with severe pneumonia and renal failure. mers-cov was detected in samples from the patient's upper and lower respiratory tract. prior to all of this, an outbreak of respiratory illness was reported in april from an intensive care unit in a hospital in zarqa, jordan. a retrospective epidemiological investigation in november identified probable cases, two of whom had died. mers-cov was detected by reverse transcription (rt)epcr in stored samples from the two deceased patients. seven more were subsequently confirmed by serological testing. a pattern began to emerge, characterized by severe pneumonia, multi-organ failure, and an epidemiological link to a country in the middle east. in may , the virus, which had been initially known as human coronaviruseerasmus medical centre (hcov-emc), was named the middle east respiratory syndrome coronavirus (mers-cov). notably, phylogenetic analysis of the first five available mers-cov sequences suggested a common ancestor dating back to mid- . furthermore, anti-mers-cov antibodies were detected in out of , serum samples [ . %; % confidence interval (ci): . e . %] obtained between december and december from provinces in saudi arabia. the authors extrapolated that just fewer than , individuals ( , ; % ci: , e , ) in saudi arabia could be seropositive for mers-cov. it is therefore reasonable to assume that human mers-cov infections had taken place in the region for some considerable time before it was identified. it is possible that the identification of the virus might have been delayed even more, had it not been for the meticulous investigation by a single virologist, dr a.m. zaki, of the first reported case of mers-cov. the first lesson one has to learn from mers-cov and its discovery is that continuous vigilance and perseverance with diagnostic investigation of undiagnosed infectious diseases are essential to identify emerging pathogens. lesson two: yet again, prevention is better than cure clinically, mers-cov infection may range from an asymptomatic or mild upper respiratory illness to a rapidly progressive and fatal disease. e the majority of hospitalized patients with mers-cov infection present with fever and respiratory symptoms including cough and shortness of breath with clinical and radiological evidence of pneumonia. , fatigue, myalgia, headache, and gastrointestinal symptoms such as vomiting and diarrhoea are also frequent. , respiratory and renal failure are frequent complications of severe mers-cov infection, in addition to acute liver injury, cardiac dysrhythmias, and coagulopathy. e overall mortality is around . %, but exceeds % in critically ill patients and in those with significant comorbidities. , e for reasons yet to be understood, mers-cov infection is rare in children. , in-vitro studies have identified numerous agents with anti-mers-cov activity including interferon, ribavirin, mycophenolate, cyclosporine and lopinavir. the combination of interferon and ribavirin showed promising results in experimentally infected macaques. however, in retrospective clinical studies the combination was not associated with significantly improved overall survival. , treatment of patients with mers-cov infections remains largely dependent on supportive measures. diagnosis is confirmed by detection of mers-cov rna in respiratory samples by real-time pcr targeting the upe and orf b genes. samples obtained from the lower respiratory tract have higher viral loads and better diagnostic yield than those obtained from the throat or nasopharynx. , , moreover, viral shedding is considerably prolonged in symptomatic and severely ill mers-cov patients compared with asymptomatic infected contacts. interestingly, detection of mers-cov in blood has been associated with worse clinical outcome. , mers-cov may also be detected in stool for up days and in urine for up to days from disease onset. under certain conditions, mers-cov can survive on plastic and steel surfaces for up to h. in the absence of appropriate precautions, the environment surrounding a symptomatic mers-cov patient can therefore become extensively contaminated with viable, potentially infectious virus. human-to-human transmission of mers-cov has been well documented in family clusters, community settings and more often in healthcare settings. e , , , common denominators in the largest hospital outbreaks have been overcrowding, especially in emergency departments, and poor adherence to infection control standards. , , , however, mers-cov continues to have relatively limited infectiousness. for example, screening identified secondary mers-cov infections in only % of close family contacts and % of healthcare contacts. , moreover, no secondary cases were identified following extensive epidemiological investigations of imported cases in the uk, germany, france, greece, the netherlands, and the usa. e it has been phylogenetically demonstrated that mers-cov transmission chains have not extended beyond two to three months and that the virus has remained genetically stable over the past three years. , given an effective reproduction number (r ) of less than one, human-to-human mers-cov could be readily interrupted with effective preventive interventions. , indeed, even the most explosive hospital outbreaks of mers-cov infection, such those that occurred in jeddah and riyadh in april to may , were brought under control through a strategy based on early case detection and implementation of appropriate infection prevention and control measures; namely contact and droplet precautions for general care in addition to airborne precautions for aerosolgenerating procedures such as intubation and respiratory tract suctioning. e the poor prognosis associated with mers-cov, especially in patients with multiple comorbidities, and the lack of effective anti-viral therapy make appropriate infection prevention and control all-important. just as is true for most infectious diseases, mers-cov reminds us again that prevention is better than cure. the initial case definitions for mers-cov case finding and reporting focused on patients who are hospitalized, had evidence of acute pulmonary disease with an epidemiological link to confirmed cases or to countries in the middle east. , as more clinical experience and epidemiological data became available, updated definitions removed the requirement for hospitalization. the reporting of several community and hospital clusters during the first half of the year , often without identifiable human or animal sources, led to speculation that individuals with no or only mild respiratory symptoms might have a role in mers-cov transmissions. , , this was reflected in the who revised interim definition published in july where patients with acute febrile illness of any severity were included; in addition to a recommendation to proactively test asymptomatic close contacts of confirmed mers-cov infections. memish et al. later showed that mers-cov was detectable for up to days in % of asymptomatic contacts. in another report, an asymptomatic healthcare worker had detectable mers-cov for more than five weeks. although mers-cov transmission from an asymptomatic individual remains a strong probability, this has never been documented. , in the meantime, clinicians were becoming increasingly aware that mers-cov infections were being diagnosed in patients whose clinical presentations did not conform to those definitions, including the absence of fever, lack of respiratory involvement and the predominance of gastrointestinal or nonspecific generalized symptoms. , , in the aftermath of the surge of mers-cov infection in jeddah and riyadh in april and may , the ministry of health in saudi arabia revised its case definition and surveillance guidance to recommend mers-cov testing in any of four patient categories: e patients with clinical or radiological evidence of community-acquired pneumonia; e patients with clinical or radiological evidence of healthcare-associated pneumonia; e patients with acute febrile illness and myalgia, headache, diarrhoea, nausea, or vomiting, and unexplained leucopenia or thrombocytopenia; e contacts of individuals with confirmed or probable mers-cov infection who develop upper or lower respiratory symptoms within two weeks of exposure. as better understanding of the epidemiology of mers-cov developed, it became obvious that a considerable proportion of cases were probably missed. , during the steep learning curve of an emerging infectious disease, regularly updated guidelines are important. such guidelines are inevitably based on incomplete evidence and hence may not be comprehensive or applicable in all situations. clinical acumen and heightened medical awareness are essential for early detection of unusual mers-cov cases and to prevent delays in diagnosis and to mitigate additional exposures. a zoonotic origin was suspected soon after the identification of mers-cov. bats are known natural hosts for several coronaviruses and hence were the initial target for investigation. , more than faecal samples were collected from wild bats in the area around where the first mers-cov patient lived. a -nucleotide fragment of mers-cov rna was detected in one faecal pellet from an egyptian tomb bat. the sequenced amplification product was genetically identical to the mers-cov sequence obtained from the index human case. more recently, a closely related coronavirus was isolated from bats in south africa, suggesting that mers-cov ancestors might exist in old world bats. , to date, no further evidence is available to confirm the role of bats as natural hosts or reservoirs for mers-cov. on the other hand, the evidence implicating dromedary camels in mers-cov epidemiology is more consistent. a role for dromedary camels is supported by the following observations: À neutralizing mers-cov antibodies are highly prevalent in dromedary camels from across the arabian peninsula, north africa, and eastern africa. e mers-cov antibodies were detected in stored camel sera dating as far back as the early s. e the prevalence of mers-cov seropositivity is significantly higher in camels aged more than two years than in juvenile camels. , , À several groups have reported the detection of mers-cov by rtepcr in nasal and faecal samples from dromedary camels in the arabian peninsula. , , e one study reported mers-cov positivity in more than % of lung tissue samples obtained from dromedary camel carcasses. rtepcr was positive in camels that had prior evidence of mers-cov seropositivity, indicating that animal reinfection is possible. interestingly, the prevalence of mers-cov rna is significantly higher in juvenile than in adult camels. , , furthermore, all mers-cov strains obtained from dromedary camels are phylogenetically clustered within human isolates, supporting possible animalehuman intertransmission. it is important to note, however, that mers-cov seroprevalence studies in individuals with close contact with camels have yielded inconsistent results. a national serosurvey in saudi arabia found prevalence of mers-cov antibodies that was times higher in camel shepherds (p ¼ . ) and times higher in slaughterhouse workers (p < . ), compared with the general population. similarly, mers-cov serology was positive in individuals who had occupational exposure to dromedary camels in qatar but not in those without such exposure. on the other hand, mers-cov antibodies were not detected in sera obtained from individuals who had close contact with camels that had documented mers-cov infection two to three months earlier. likewise, screened slaughterhouse workers and other animal workers in western and southern saudi arabia were all seronegative for mers-cov antibodies. , collectively, the available data strongly suggest that mers-cov is highly prevalent in dromedary camels in the arabian peninsula and that transmission of infection from camels to humans, although inefficient, does occur. however, the exact mechanism and route of infection it is still unclear. infections. , , , one pertinent cause for concern has been the potential global spread of mers-cov during the annual hajj pilgrimage when millions of muslims from around the world gather in mecca, saudi arabia. e though those concerns are well founded, several surveillance studies over the past three years have not identified any mers-cov infections among hajj pilgrims while they are in saudi arabia or after their return to their home countries. e the situation was entirely different in the recent outbreak in south korea where a single imported case resulted in a total of laboratory-confirmed cases of mers-cov infection, including deaths. the index patient was a -year-old man who developed respiratory symptoms seven days after returning to seoul from a two-week visit to bahrain, saudi arabia, united arab emirates, and qatar. he sought medical care in several hospitals before he was diagnosed with mers-cov infection. , a combination of late recognition, overcrowding in emergency departments and hospital wards, multiple incidents of patient movement between different healthcare facilities, and delayed implementation of adequate infection control precautions culminated in the largest single outbreak of mers-cov infection. , , e the outbreak involved patients, visitors, care-givers and healthcare workers, and spanned across six different hospitals in three south korean cities. , notably, phylogenetic analysis of mers-cov strains from south korea revealed no significant biological changes compared to previously sequenced viruses. the outbreak in south korea was eventually controlled through a series of measures including aggressive contact identification, screening and strict isolation, and rigorous infection control precautions. , , within a few weeks, south korea went from a country with no reported mers-cov cases to one that has the second largest number in the world. , with air travel becoming readily accessible and affordable, the south korean experience demonstrates vividly that in the context of an infectious respiratory illness, there is simply no room for complacency. adequate assessment of patients presenting with febrile illness must include their recent travel history to enable early application of proper control measures and to expedite laboratory confirmation and appropriate clinical management. the past decade has witnessed an exponential rise in internet-based social media sites such as facebook, twitter, and youtube. healthcare professionals are increasingly using social media applications to follow medical developments and emerging scientific literature and to share their own research findings, observations, and opinion. the general public often uses these tools as news outlets to seek and share medical and scientific information. however, in the context of mers-cov, social media have been a double-edged sword. for example, social media were at some point rife with inaccurate information that included rumours of hospitals closed due to mers-cov outbreaks and certain social events being nodes for mers-cov transmission. the authors are aware of examples of information and photos shared on social media resulting in patients losing their right to privacy and confidentiality. patients often cancelled their clinic appointments or scheduled surgical procedures for fear of acquiring mers-cov while in hospital. some avoided attending emergency departments despite having acute problems that required medical attention. some individuals posted videos and messages challenging the suggestion that camels may be a source of mers-cov infection. scepticism and mistrust in governmental agencies and the medical community were sometimes promoted and propagated. on the other hand, various government agencies, scientific organizations and healthcare professionals used social media to enhance networking and facilitate communication of epidemiological, medical and scientific developments; in addition to presenting the public with factual material, timely updates, and relevant advice. the saudi ministry of health, for example, posts daily updates on its website and through social media outlining details of current mers-cov cases. the korean ministry of health and welfare did the same during their mers-cov outbreak. such steps are important to gain the public's trust and to remove barriers to appropriate sources of information. taking on board the surging role of social media and using them effectively to disseminate appropriate information turns them into invaluable tools for controlling an emerging infectious disease such as mers-cov. mers-cov is an emerging infectious disease of probable animal origin. sustained human-to-human infection has not occurred and its potential for causing widespread epidemic remains limited. vigilance, early recognition, and institution of appropriate protective measures are the most effective control measures. none declared. middle east respiratory syndrome coronavirus (mers-cov); summary of current situation, literature update and risk assessment isolation of a novel coronavirus from a man with pneumonia in saudi arabia genomic characterization of a newly discovered coronavirus associated with acute respiratory distress syndrome in humans novel coronavirus e saudi arabia: human isolate. archive number severe respiratory illness caused by a novel coronavirus first cases of middle east respiratory syndrome coronavirus (mers-cov) investigations and implications for the prevention of human-to-human transmission a case of imported middle east respiratory syndrome coronavirus infection and public health response middle east respiratory 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respiratory symptoms lack of mers coronavirus but prevalence of influenza virus in french pilgrims after prevalence of mers-cov nasal carriage and compliance with the saudi health recommendations among pilgrims attending the hajj from the hajj: it's the flu, idiot high prevalence of common respiratory viruses and no evidence of middle east respiratory syndrome coronavirus in hajj pilgrims returning to ghana circulation of respiratory viruses among pilgrims during the hajj pilgrimage saudi arabia, south korea preliminary epidemiological assessment of mers-cov outbreak in south korea lessons to learn from mers-cov outbreak in south korea spread of mers to south korea and china list of hospitals with known mers exposure preliminary data from sequencing of viruses in the republic of korea and the people's republic of china. mers-cov situation assessment world health organization. managing contacts in the mers-cov outbreak in the republic of korea geneva: who. available at middle east respiratory syndrome coronavirus (mers-cov): summary and risk assessment of current situation in the republic of korea and china e as of korean society for healthcare-associated infection control and prevention. an unexpected outbreak of middle east respiratory syndrome coronavirus infection in the republic of korea dangers and opportunities for social media in medicine social media and health care professionals: benefits, risks, and best practices social media and clinical care: ethical, professional, and social implications middle east respiratory syndrome: an emerging coronavirus infection tracked by the crowd key: cord- -xag e h authors: dharamsi, a.; hayman, k.; yi, s.; chow, r.; yee, c.; gaylord, e.; tawadrous, d.; chartier, l.b.; landes, m. title: enhancing departmental preparedness for covid- using rapid cycle in situ simulation date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: xag e h in response to covid- , we developed a rapid-cycle in situ simulation (iss) programme to facilitate identification and resolution of systems-based latent safety threats. the simulation involved a possible covid- case in respiratory failure, using a manikin modified to aerosolize phosphorescent secretions. individuals participated in and observed five iss sessions over six weeks. debriefing identified latent safety threats from four domains: personnel, ppe, supply/environment, and communication. these threats were addressed and resolved in later iterations. % of participants felt more prepared to care for a potential covid- patient after the iss. in early , the world health organization declared a public health emergency of international concern in regard to an emerging novel respiratory pathogen, known as covid- . covid- is among the family of zoonotic coronaviruses, from which severe acute respiratory syndrome (sars) and middle east respiratory syndrome (mers) have emerged. while much still remains unclear as to the transmission dynamics of this novel coronavirus, it does appear that it may spread via aerosolization during procedures [ ] . as with previous novel respiratory pathogens, such as sars and mers, the spread of this virus is anxiety provoking and tests our health care system's agility to protect both our patients and our health care workers. the first documented case of covid- in canada created a sense of urgency locally to ensure preparedness for more potential cases [ ] . in situ simulation (iss) is a process in which simulation exercises are conducted in the clinical workspace, by care providers who are on clinical duty, using equipment and resources in that workspace [ , ] . such exercises can aid clinical units in improving team functioning, identifying latent safety threats, informing processes, as well as guiding clinical protocols and care [ ] [ ] [ ] . rapid cycle simulation has been described previously in medical education as a way of providing real time feedback and opportunities for learners to practice [ ] , and there are examples of in situ simulation being used in an iterative fashion to find solutions to latent safety threats over months to years [ , ] . we present a hybrid of these two methods, a rapid-cycle iss programme, developed for emergency departments (eds) in the wake of an emerging respiratory pathogen. we evaluated this programme's ability to uncover and address departmental, organizational, and system gaps that present latent safety threats to both patients and providers in an urgent and timesensitive fashion. leaders of the physician, nursing, and respiratory therapist staff were familiar with the iss programme at our institution and highly supportive of utilizing this novel iss programme to test our ed preparedness, particularly since toronto has historically been a potential area of spread of pathogens from china as was evidenced by the sars epidemic [ ] . the study was conducted at an academic, tertiary care academic centre in toronto, canada which includes two eds, collectively seeing over , patients per year. simulations were conducted in the ed negative pressure rooms. the iss team includes three physician simulationists, a simulation education specialist, as well as the nurse educators and nurse managers from each site. the case was created using aggregate data from previous febrile respiratory illness outbreaks, namely local data captured from the sars outbreak [ ] . given our experience from sars, our iss team understood that the highest risk of this emerging respiratory pathogen would be in the case of a critically-ill patient presenting to triage and ultimately requiring aerosol-generating procedures in the ed [ , ] . the rapid-cycle iss programme was created to identify latent safety threats (lst) to staff and mitigate these with innovative solutions that could subsequently be tested in the next simulation. although there is no established frequency of simulations to be considered a "rapid cycle", previous iterative iss studies have been completed on much longer timelines (months to years) [ , ] . we planned to facilitate one session per week, with time between sessions dedicated to solution generation and implementation. the case features a febrile, haemodynamically unstable patient in severe respiratory distress, who screens positive at triage for potential covid- exposure based on travel history. a manikin was modified to aerosolize phosphorescent droplet secretions. at the end of the case, these secretions were visualized on providers using black light. full details of the case, including the phosphorescent moulage, are published on emsimcases [ ] . simulation sessions were conducted in standard negative pressure rooms, congruent with institutionally established full personal protective equipment (ppe) (eye protection, n mask, gown, gloves) and isolation protocols (airborne, droplet and contact) for a critically ill covid- patient. the simulations were conducted in real time with clinical staff on duty that day. in accordance with infection control guidelines to minimize team size in potential covid- cases, one physician, one registered nurse, and one respiratory therapist participated. key stakeholders contributed to subsequent formalization and improvement of existing ed processes, including infection prevention and control, infectious diseases, anesthesia, and the iss team. following each session, an iss physician team member facilitated a -minute debriefing session. a second iss team member took notes during the debriefing session, which were utilized to drive solutions between sessions. each participant also completed a brief mixedmethods survey via a google form. participants were asked to identify key safety threats, major learning points, and outstanding questions via open-ended short answer questions. the survey also included likert-type questions about perceived preparedness and attitudes towards the iss programme. two investigators (ef, kh) independently coded and thematically analyzed openended survey responses and facilitator debriefing notes to identify emerging themes. these themes were organized by simulation session date to identify persistence and/or resolution of safety threats. we planned to continue the iss sessions until no new major modifiable safety threats were identified, and thematic saturation was reached. this quality improvement initiative received an exemption from the research ethics board at our institution. between january th and march th, five covid- iss sessions were completed in a rapid cycle format as the epidemic was emerging. people participated in the simulation and evaluation, representing a broad team of hospital-wide stakeholders informing guidelines and addressing latent safety threats that were identified after each simulation. an additional individuals observed the session but did not fully participate in the debrief or complete the survey. infographics, email notifications, video recording of the simulation and invitations to participate as observers helped broaden the reach of these simulations. results were also presented at two monthly ed team meetings, as well as at morning safety huddles. after the march th session, investigators reached a consensus that thematic saturation had been achieved, with no new safety threats identified. this also coincided with a marked increase in patients in our department requiring isolation precautions, given concern about imminent community circulation of covid- in toronto. the first critically ill suspected covid- case arrived at our institution less than one week after the most recent iss. the team believed that iss had adequately prepared them to care for the patient without breaching ppe. participants rated the iss process very positively. % of participants agreed the simulation was relevant to their practice and % felt more prepared to care for a potential covid- patient. only % of participants believe that the simulation distracted from patient care. debriefing identified latent safety threats from four domains: ppe, personnel, supply/environment, and communication. the identified safety threats and iterative solutions are detailed in table i . while asked separately, the responses to the three open-ended survey questions were highly similar, thus were thematically analyzed together. the majority of survey results reflected common themes identified in the debriefing sessions. the survey demonstrated that most safety threats were adequately addressed by later iterations, as early issues did not reemerge in subsequent surveys. ppe remained a concern for participants across sessions, but evolved from general (e.g., order of donning/doffing) to specific (e.g., wearing shoe covers) over time. only one respondent remarked explicitly on the emotional response to a novel risk such as covid- , yet provider concern about the specifics of personal protection was a dominant theme in debriefing and the survey. safety threats in the ppe domain generally required only a single session to resolve after identification. survey responses highlighted the specific value of practicing in interprofessional teams, for example, by identifying different standard operating procedures between the respiratory therapy group and the nursing staff for the same task. team-based strategies to address threats were identified in both the debriefings and survey, for example pre-selection of a specific staff member to gather any additional supplies for the team inside the isolation room. latent safety threats in this domain were largely resolved with improved signage and preparation of materials (see appendix for materials signage). the stakeholder analysis for our simulation was an iterative process, and some team members (e.g., housekeeping staff) were invited to participate later in the process, which led to identification of and solutions for new safety threats after several sessions had already occurred. safety threats in this domain required multiple iterations to address. several of the solutions trialed posed large new issues, for example, contamination of the user with a portable phone. the team members found the baby monitor (hands-free communication system) provided sufficient clarity of communication with minimal risk of contamination. iss allows users to design context and location-specific scenarios that address specific behaviours (i.e., teamwork, communication), identify system vulnerabilities and implementation challenges, and shape processes of care [ ] . our model of rapid-cycle iss was particularly helpful as it allowed us to iteratively modify the simulation based on feedback and evolving guidelines, which allowed for incremental improvements over a very short period of time. as new solutions were implemented, we were able to quickly disseminate updates to the group via infographics, emails, morning departmental safety huddles, and team meetings. as these solutions were trialed in clinical care, we were also able to ascertain feedback from the group, inform further iterative changes in subsequent simulations. the systemization of these changes provide a structure for other sites to navigate changes to their departmental infrastructure and practices. this structure can aid in not only implementing changes, but also rationalizing the specific solutions to the care team. demonstrating how and why these changes have been implemented has aided in the uptake and acceptance of these innovations into clinical practice. personal safety, maintained primarily through proper ppe, was a major theme of this case. the phosphorescent aerosol moulage changed providers' perception of their risk during the resuscitative scenario and led to high commitment to maintaining infection prevention precautions in the simulated exercise. this high commitment likely uncovered latent safety threats more quickly than a lower commitment from stakeholders, and we may have had very different results without this critical component of the simulation. iss in a team environment, rather than performing preparedness drills, led to key improvements particularly in the communication domain. this finding emphasizes the strength and agility of an interprofessional training environment. while our sample size is relatively small, we met our endpoint of thematic saturation/no major new safety threats identified in our final iss session. knowledge translation in iss can be challenging owing to the low ratio of participants to overall care providers in the group, yet we were able to disseminate findings to stakeholders rapidly. continued sessions may yield new or different results; we balanced this with the relative urgency to share our findings in an expedited fashion. the timing of these iss was expedited while allowing for procurement of supplies and within limitations of scheduling the various facilitators and sessions; however, preparedness for covid- could have been further accelerated and condensed over a shorter time period. this rapid-cycle iss programme provides an opportunity to identify and iteratively address latent safety threats in caring for patients with possible covid- in a time-sensitive fashion. rapidcycle iss is a valuable model to augment departmental preparedness in the wake of emerging epidemics. e m a i l u h n s i m c o m @ g m a i l . c o m s c r e e n i n g t o o l c l i n i c a l n o t e s a n d a c o d e b l u e r e s u s r e c o r d ( i n a p l a s t i c c o v e r ) l n s i v a n d b l o o d w o r practical recommendations for critical care and anesthesiology teams caring for novel coronavirus ( -ncov) patients. can j anesth can anesth first imported case of novel coronavirus in canada, presenting as mild pneumonia. the lancet in situ simulation in emergency medicine: moving beyond the simulation lab: in situ simulation in emergency medicine using simulation to improve patient safety: dawn of a new era detecting latent safety threats in an interprofessional training that combines in situ simulation with task training in an emergency department quality improvement utilizing in-situ simulation for a dual-hospital pediatric code response team situ simulated cardiac arrest exercises to detect system vulnerabilities sars: a local public health perspective illness in intensive care staff after brief exposure to severe acute respiratory syndrome the authors would like to acknowledge the efforts of dr. peng yinhua, who alerted the world to the potential dangers of covid- , and ultimately succumbed to the disease. we would also like to thank kathy bates, deborah davies, elayna fremes, and camilla parpia for their assistance in propelling this project forward. this research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. none to declare. key: cord- -b tsjmfs authors: thampi, n.; longtin, y.; peters, a.; pittet, d.; overy, k. title: it’s in our hands: a rapid, international initiative to translate a hand hygiene song during the covid- pandemic date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: b tsjmfs nan sir, the novel coronavirus disease- (covid- ) continues to affect the global community deeply and rapidly, with more than countries impacted at the time of writing (may , ). in order to manage the extent of this pandemic, there is a need to develop, disseminate and implement infection prevention and control strategies in both healthcare settings and the community. early on in the outbreak, there were general recommendations to frequently wash hands to reduce the spread of infection. with the current, relentless global scale of covid- , international compliance with handwashing frequency and technique is more important than ever. a prominent strategy to improve hand hygiene, developed by the world health organization (who), includes an effective six-step handwashing technique and has led to broad uptake through the use of a multimodal approach; however encouraging consistent compliance can be challenging [ ] . in addition to needing to remember all six steps of the technique and needing to wash hands for the required duration of time, there can be a lack of awareness regarding the importance of handwashing technique on reducing the microbial burden on hands. this lack of awareness may not be surprising, as most hand hygiene promotion campaigns focus on indications for action ("when to clean hands") rather than on technique ("how to clean hands") [ ] . thus, continuing to promote correct handwashing technique is currently of utmost importance to the world population, especially given the disproportionate burden of covid- on older adults, and emerging evidence of asymptomatic shedding [ , ] . in order to assist children with remembering the effective six-step technique, we recently published a musical mnemonic to the tune of the well-known nursery rhyme frère jacques, or brother john [ , ] . this memory aid reinforces inclusion of all six handwashing steps using self-instruction, via engaging with the familiar melody and singing (or imagining singing) the lyrics ( figure a ). in the context of the / evolving covid- pandemic, the near-ubiquitous melody of brother john provided an opportunity for international, interdisciplinary collaboration to translate and rapidly disseminate the musical mnemonic globally. on th march, drawing on our combined network of music neuroscience researchers, music education specialists and healthcare professionals, we invited approximately international colleagues to create a new version of the handwashing song that a) included all six who handwashing steps; b) worked musically in the new language; and c) had been checked by a healthcare professional for accuracy. each translator was also invited to submit an audio or video file of the translated song. we brother john is an ideal tune to use in this context: it is widely known across cultures; the melody involves very simple, repeating patterns; the vocal range centres around a small interval of a sixth (e.g. middle c to a), which is easy to sing even by non-musically trained individuals; and the duration, when sung at a steady tempo, is between and seconds. singing is a highly sequential, structured activity and has been used throughout history to remember text or coordinate movement, from ballads and religious scriptures to work songs and children's action songs. experimentally, music has been shown to facilitate verbal and motor learning in a variety of contexts, likely using neural resources shared between music, language and motor networks [ ] [ ] [ ] . in practice, we have observed that, once the handwashing song becomes highly familiar through repetition and rehearsal, a missed step is immediately noticed, leading to important self-correcting behavior. a clear advantage of this six-step handwashing song is that it highlights the importance of correct technique, in addition to the recommended -second duration (such as singing "happy birthday" twice, another popular approach). a demonstration, prior to introducing the song, will ensure full understanding of each step. in launching these translated songs during a pandemic that underlines our global interconnectedness, and to highlight world hand hygiene day on th may, we have made these songs available at www.cleanhandssavelives.org/hand-washing-song/, hoping this mnemonic will inspire individuals to take matters into their own hands and reduce their risk of acquiring or spreading covid- . music is known to have the capacity to entertain, bring joy and be a powerful, positive shared experience; the languages included here allow access to this musical mnemonic to more than half of the world's population in their native language. global implementation of who's multimodal strategy for improvement of hand hygiene: a quasi-experimental study hygiene: why, how & when? in: who characteristics of and important lessons from the coronavirus disease (covid- ) outbreak in china: summary of a report of cases from the chinese center for disease control and prevention virological assessment of hospitalized patients with covid- longtin y wash your hands cognitive and neural mechanisms underlying the mnemonic effect of songs after stroke singing can facilitate foreign language learning schaefer rs auditory rhythmic cueing in movement rehabilitation: findings and possible mechanisms figure : who six-step handwashing technique and handwashing song lyrics, set to the tune of brother john. (a) visual handwashing aid, lyrics and musical notes for each step. figure (b) translations of the handwashing song additional thanks go to tom howey for the figures and to giuliano avanzini and maria majno for sparking and facilitating this initiative, respectively. a b key: cord- -z wujlo authors: cheng, v.c.c.; wong, s-c.; kwan, g.s.w.; hui, w-t.; yuen, k-y. title: disinfection of n respirators by ionized hydrogen peroxide during pandemic coronavirus disease (covid- ) due to sars-cov- date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: z wujlo nan letter to the editor disinfection of n respirators by ionized hydrogen peroxide during pandemic coronavirus disease (covid- ) due to sars-cov- coronavirus disease (covid- ) due to sars-cov- has been spreading globally, and the world health organization declared a pandemic on th march [ ] . the number of confirmed cases was , with , ( . %) deaths as of th march . the overwhelming number of infected cases not only paralyses the healthcare system, but also poses a significant risk to healthcare workers (hcws). in hong kong, we adopted a proactive infection control approach, escalating the response according to the rapidly evolving epidemiology to minimize the risk of nosocomial transmission [ , ] . however, limited supply of personal protective equipment (ppe), especially n respirators, remains a great challenge. although we have already adopted extended use of n respirators in accordance with the us centers for disease control and prevention (cdc) [ ] , we have to prepare for the worst-case scenario of lacking a supply of n respirators. therefore, we attempted to disinfect n respirators using steramist binary ionization technology solution delivered through a steramist surface unit, registered with the us environmental protection agency [ ] . the main constituent is . % h o solution, which is converted to ionized h o (ihp) after passing through a cold plasma arc, and moves like a gas over the surfaces of n respirators. the by-product of ihp is oxygen and water in the form of humidity. the experiment was conducted in a well-ventilated room with six air changes per hour inside a biosafety level microbiology laboratory, with the operator wearing a coverall protective gown. four n respirators (two m þ and two m s) were hung horizontally (facing outer and inner surfaces), and each was inoculated with ml of three different concentrations of influenza a virus subtype h n [ , , % of tissue culture infectious dose (tcid ) ml À , , tcid ml À and , tcid ml À ] in the presence of % fetal calf serum to mimic organic soil contamination in the clinical setting to the outer and inner surfaces (i.e. , tcid , tcid and tcid per spot). ihp was sprayed three times in a 'to-and-fro' manner at a distance of inches for a total of appropriately s. the viruses were also applied in a similar manner to a cover glass that served as the control on a non-porous surface. n respirators inoculated with influenza a virus without disinfection were used as the positive control. one hour later, the pieces of n respirators with viral inoculation were cut out. the virus was eluted from the n respirators for viral culture in madin-darby canine kidney (mdck) cells. cytopathic changes of mdck cells were observed daily for days by light microscopy. none of the ihptreated pieces of n respirators demonstrated cytopathic changes suggesting the presence of live influenza a virus ( table i) . the samples were subcultured again on mdck cells for a further days, and no cytopathic changes were observed; this was confirmed by lack of detection of influenza a antigen following immunofluorescence staining. this experiment showed that ihp could kill influenza a virus at moderate to high levels of inoculum. influenza a virus was chosen for this study because it is an enveloped rna virus that has similar virological characteristics as coronaviruses. disinfection of disposable ppe can be attempted whenever the supply is limited during pandemics [ , ] . reuse of n respirators has been proposed by cdc [ ] , but this carries a risk of contamination and infection of hcws. disinfection of n respirators may provide an alternative option. the disinfection process is faster using steramist, a hand-held device, than the conventional platform, which uses a higher concentration of h o vapour ( % e %) and requires concealment of the air ventilation system and longer cycle times. ultraviolet germicidal irradiation has also been used for the disinfection of n respirators, but it has been shown to degrade polymers, leading to a small increase in particle penetration [ ] . it is important to test the particulate filtration efficiency of n respirators to determine the maximum number of disinfection cycles regardless of the method of disinfection. hcws should be reminded not to reuse n respirators immediately after disinfection. in this study, the level of h o on the inner surface of n respirators was . ppm (below the safety limit of < ppm) at h and undetectable at h. the speed of h o release from n respirators may be variable and affected by the air current. more importantly, hcws should be well informed regarding the potential risk of exposure to other chemicals or inert ingredients which may persist in the porous material of n respirators. this may pose a dilemma to hcws who need to balance the risk and benefit of reusing n respirators with or without disinfection. further investigation into the disinfection of n respirators is warranted. situation report . geneva: who; preparedness and proactive infection control measures against the emerging novel coronavirus in china escalating infection control response to the rapidly evolving epidemiology of the coronavirus disease (covid- ) due to sars-cov- in hong kong national institute for occupational safety and health. recommended guidance for extended use and limited reuse of n filtering facepiece respirators in healthcare settings evaluation of five decontamination methods for filtering facepiece respirators final report for the bioquell hydrogen peroxide vapor (hpv) decontamination for reuse of n respirators effects of ultraviolet germicidal irradiation (uvgi) on n respirator filtration performance and structural integrity the authors wish to thank dr h. shane for sharing the disinfection protocol, and mr b. chan for providing steramist binary ionization technology solution and the steramist surface unit. none declared. none. key: cord- -zi q lj authors: liu, yongjian; li, tianyi; deng, yongqiang; liu, siyang; zhang, dong; li, hanping; wang, xiaolin; jia, lei; han, jingwan; bei, zhuchun; li, lin; li, jingyun title: stability of sars-cov- on environmental surfaces and in human excreta date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: zi q lj nan at the end of , a novel human coronavirus, severe acute respiratory syndrome coronavirus (sars-cov- ), emerged and rapidly spread throughout the world. although close exposure to respiratory droplets from an infected patient is the main transmission route of sars-cov- , touching contaminated surfaces and objects might also contribute to transmission of this virus. in addition, the evidence for gastrointestinal infection of sars-cov- and the presence of sars-cov- rna in faecal specimens raised a question of a fecal-oral transmission route [ , ] . here, we provide a report of our study of the stability of sars-cov- on various environmental surfaces and in human excreta (feces and urine). these data has great importance for our understanding the transmission of this virus. nine different objects representing a variety of household and hospital situations were collected and cut into small pieces with the area about × cm. sars-cov- betacov/beijing/amms / was the strain used. fifty microliters of virus stock with the infectious titer of % tissue culture infectious dose (tcid ) per milliliter was deposited on each surface and left at room temperature. at predefined time points, the viruses were recovered by adding μl of viral transport medium. the infectivity of residual virus was titrated in quadruplicate on -well plates containing μl of vero cells ( × cells/ml). the plates were incubated in % co at °c. on the fifth day, the cytopathic effect (cpe) was observed under a microscope, and the tcid for each sample at a different time was calculated with reed-muench method. all experiments were repeated three times. sars-cov- was stable on plastic, stainless steel, glass, ceramics, wood, latex gloves, and surgical mask, and remained viable for seven days on these surfaces. as is shown in figure a , the virus titer declined slowly on these seven surfaces. however, no infectious virus could be recovered from cotton clothes after days and from paper after days. the specimens of feces and urine were collected from three healthy donors, including two adults and one seven-year-old child. a % suspension of each faecal specimen j o u r n a l p r e -p r o o f was prepared in pbs (ph, . ) as described previously [ ] . a total of . ml of each filtered faecal suspension and urine sample was inoculated with . ml of virus stock and left at room temperature for days. at desired time points, μl of each sample was taken and virus titer was determined with the same method described above. figure b shows the duration of sars-cov- survival in three feces. in the first adult faecal specimen, no viable sars-cov- was measured after hours, and in the second adult faecal specimen, no virus remained viable after hours. however, the virus survived for days in the child feces. sars-cov- was more stable in urine than in feces, and infectious virus was detected up to days in two adult urine and days in one child urine. prior to our study, two research teams had just reported the stability of sars-cov- on different material surfaces [ , ] . in comparison with the above two studies, our data displayed a prolonged survival time of this virus on environmental surfaces. in general, the stability of virus in environments was derived from simulated experiments, which were influenced by many factors. the titer of virus stock and the volume of virus inoculation were related with the final results. compared with van doremalen's experiments, we used the same volume of inoculation, but the titer of virus stock was one log unit higher. in chin's study, a five microliters of virus stock with the infectious titer of . tcid /ml was deposited on the surface. therefore, evidence for gastrointestinal infection of sars-cov- prolonged presence of sars-cov- viral rna in faecal samples survival of severe acute respiratory syndrome coronavirus stability of sars-cov- in different environmental conditions aerosol and surface stability of sars-cov- as compared with sars-cov- detection of novel coronavirus by rt-pcr in stool specimen from asymptomatic child patient-derived mutations impact pathogenicity of sars-cov- key: cord- -woyycghi authors: basso, trude; nordbø, svein arne; sundqvist, erik; martinsen, tom christian; witsø, eivind; wik, tina s. title: transmission of infection from non-isolated patients with covid- to health care workers date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: woyycghi insufficiently protected health care workers (hcws) defined as high-risk contacts of patients with covid- are routinely quarantined. this study evaluated transmission of infection from a symptomatic patient with covid- to hcws exposed ≤ m for ≥ minutes, or during aerosol generating procedures. following ≥ unique high-risk contacts, none of the hcws tested positive for sars-cov- rna or had developed antibodies. the hcws reported adherence to basic infection control procedures. these results were in accordance with other reports and should reassure hcws and further stimulate a broader evaluation of the foundation for the current practice of home-quarantine of non-symptomatic hcws. during the coronavirus disease- (covid- ) pandemic, the proportion of health care workers (hcws) amongst verified, infected individuals, has been reported somewhere between and % [ , ] . in addition, a considerable proportion of hcws with covid- self-report to have been infected at work [ , ] . an objective evaluation of the risk for hcws contracting the new coronavirus (sars-cov- ) compared to the general population is difficult since test criteria for hcws differ from that of the general population. an increasing number of reports indicate low rates of sars-cov- -transmission from non-isolated patients to hcws [ ] [ ] [ ] [ ] [ ] [ ] . it is interesting that the incidence of asymptomatic cases amongst hcws in a hospital showed the same trend of virus transmission as the general community and dropped following social distancing despite the hospital remaining full of patients with covid- [ ] . our level trauma center received transfer of a middle-aged patient with a pelvic injury from a hospital in a region with a low prevalence of covid- . the patient had mild hypoxia (sato % on l o ), but no obvious airway symptoms. the patient was placed in a single occupancy room in a regular ward. the patient was not isolated, but social distancing measures were enforced due to the ongoing pandemic. hence, mingling with other patients, such as during meals, was prohibited. the room had fresh-air ventilation with three air changes per hour, a hand sink with soap and disinfectants on both sides of the door and once daily cleaning including disinfection of all contact surfaces. the hospital provides clothing which is changed at least once a day for all hcws. hcws or patients in our hospital did not, and still at time of writing, do not wear masks on a general basis. from the day of admittance, the patient experienced intermittent fever and diarrhoea in addition to mild hypoxia (table i) . on day four the fever increased, and the patient developed a cough with purulent sputum. the patient was isolated the following morning, and two consecutive tests showed high viral loads (ct values . and . ) of sars-cov- . by then, the patient had undergone two operations under combined general-and epidural anesthesia in an operating theatre with laminar air flow and air-changes per hour. hcws were quarantined for two weeks due to participation in aerosol-generating procedures (agps) with insufficient personal protective equipment (ppe), or close-contact viral exposure defined as ≤ meters for ≥ minutes. the transmission-risk of sars-cov- from patients to hcws is a highly relevant issue. it affects not only hcws, but also how hospitals plan health care services during this pandemic. the aim of this study was to evaluate the extent of sars-cov- transmission from a symptomatic, non-isolated patient to hcws in a hospital with adequate capacity. the study was approved by the regional committee for medical and health research ethics in mid-norway (rek / ). quarantined hcws were invited to participate under informed written consent. the participants were tested for sars-cov- rna approximately two weeks after virus exposure. samples were taken from the retro-tonsillar pharynx according to procedure in a specialized covid- outpatient clinic for hospital employees. rna was extracted from the samples using an easymag extractor (biomérieux) and analyzed with in-house real-time rt-pcr assay targeting the e-gene of sars-cov- [ ] . to evaluate if any of the exposed hcws had undergone covid- infection, sera were collected approximately three weeks following exposure for the detection of antibodies against sars-cov- . edi novel coronavirus covid- lgg and igm elisa (epitope diagnostics, inc.) was used for initial testing, and supplemented with tests from diasorin (liaison® sars-cov- s /s igg test), abbott (alinity i sars-cov- igg), roche (elecsys anti-sars-cov- ) and wantai (wantai sars-cov- ab elisa). all participants completed a questionnaire to map the type and extent of virus exposure, symptoms while in quarantine, and self-evaluation of adherence to procedures on hand hygiene. this included hand wash with soap and water or disinfectant, prior to and following procedures in a patient room and direct or indirect contact with a patient. fifty-eight out of -quarantined hcws consented to participate in the study. two hcws could not be reached in time for testing. one hcw withdrew from the study following the throat swab and all data was excluded, leaving participants for analyses. fifty-seven hcws completed an rna-test, antibody testing and answered the questionnaire. all participants tested negative for sars-cov- rna and sars-cov- igm. in addition, all of them tested negative for igg and total antibodies with tests from out of manufacturers. discrepant test results are presented in table ii. these discrepant, positive, results were reproducible. twenty-two hcws ( %) experienced some airway symptoms during the quarantine, of which a sore throat was most frequently reported (n= ). none of the responders experienced loss of taste and smell. fifteen hcws had already been tested during their quarantine because of symptoms, and all tested negative at both test points. there were ≥ unique contacts of ≥ minutes of ≤ m, or during agps, between hcws and the nonisolated covid- patient. nurses on the ward had ≥ unique close contacts that also included oral hygiene. twelve hcws had been exposed during agps: during in-and/ or extubation at ≤ meters from the patient's head, and another five at > meters. hcws were present during open surgery involving power drilling, electrocautery and pulsed lavage. half of the affected hcws (n= ) had not used any kind of ppe while exposed. surgical masks were used by / , and by / of the nurses on the ward. disposable gloves were used by / and visor / glasses by / . one hcw reported close contact with the patient during extubation without wearing a surgical mask. the majority (n= , %) were certain they had adhered to the hand hygiene procedure and were quite certain (total %). one hcw reported that it was unlikely that he / she had performed proper hand hygiene. in this study we found that ≥ unique close contact exposures, including contacts during agps with a nonisolated patient with covid- , resulted in no sars-cov- transmissions from patient to hcws. with one exception, all included hcws were certain or quite certain that their adherence to the hand hygiene procedure had been proper at the time of exposure. ideally, and according to common practice, samples for pcr-testing should have been collected on day seven and repeated at day following exposure. however, since this study required ethical approval and written j o u r n a l p r e -p r o o f consent it was not possible to organize the study in time for testing during the first week. nevertheless, this study is, to our knowledge, the first to complement throat swabs with antibody-testing in a prospective study of symptomatic and non-symptomatic hcws. it must be stressed, however, that even antibody-tests do not seem to reveal all individuals who have been previously infected with covid- . our test results illustrate that antibody tests may give false-positive reactions in a low-prevalence setting and retesting with alternative assays may be required to draw a conclusion. to our knowledge, six other reports on disease transmission from non-isolated covid- patients to hcws have been published (table iii) . out of a total of hcws, five hcws tested positive for sars-cov- rna. two out of hcws ( %) that had been exposed during agps without wearing a particulate respirator, contracted covid- . all these seven reports were from hospitals with seemingly good infection prevention practices. there were suboptimal covid- screenings both before transfer and upon admission of our patient. the procedure for patient transfer between hospitals was consequently changed from per phone oral clarification, to strict documentation by written questionnaires. the affected ward normally serves as a unit for revision arthroplasties and spinal surgery. at the time of the incident, elective surgeries had been reduced to a minimum and the ward then hosted a broad range of orthopedic patients. abrupt changes in established means of organizing care of patients, must be considered a risk factor for impaired patient safety. it is likely that the reorganization for the covid- pandemic contributed to the delay in diagnosing this very disease and sending hcw into quarantine. there is seemingly a low risk of virus transmission from non-isolated covid- patients to hcws in hospitals with adequate capacity and with hcws who adhere to basic measures to prevent infectious disease transmission. our results should reassure hcws and further stimulate a broader evaluation of the foundation for the current practice of home-quarantine of non-symptomatic hcws. this research did not receive any specific grant from funding agencies in the public, commercial, or not-forprofit sectors. the study was approved by the regional committee for medical and health research ethics in mid-norway (rek / ). characteristics of health care personnel with covid- -united states survey of covid- disease among orthopaedic surgeons in wuhan, people's republic of china transmission risk of sars-cov- to healthcare workers -observational results of a primary care hospital contact tracing transmission of covid- to health care personnel during exposures to a hospitalized patient first known person-to-person transmission of severe acute respiratory syndrome coronavirus (sars-cov- ) in the usa escalating infection control response to the rapidly evolving epidemiology of the coronavirus disease (covid- ) due to sars-cov- in hong kong covid- and the risk to health care workers: a case report covid- infections among hcws exposed to a patient with a delayed diagnosis of covid- infection control & hospital epidemiology covid- : pcr screening of asymptomatic health-care workers at london hospital detection of novel coronavirus ( -ncov) by real-time rt-pcr j o u r n a l p r e -p r o o f key: cord- -mdkr qo authors: russell, c.d.; koch, o.; laurenson, i.f.; o'shea, d.t.; sutherland, r.; mackintosh, c.l. title: diagnosis and features of hospital-acquired pneumonia: a retrospective cohort study date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: mdkr qo background: hospital-acquired pneumonia (hap) is defined as radiologically confirmed pneumonia occurring ≥ h after hospitalization, in non-intubated patients. empirical treatment regimens use broad-spectrum antimicrobials. aim: to evaluate the accuracy of the diagnosis of hap and to describe the demographic and microbiological features of patients with hap. methods: medical and surgical inpatients receiving intravenous antimicrobials for a clinical diagnosis of hap at a uk tertiary care hospital between april and were identified. demographic and clinical details were recorded. findings: a total of adult patients with a clinical diagnosis of hap were identified. broad-spectrum antimicrobials were prescribed, primarily piperacillin–tazobactam ( . %) and co-amoxiclav ( . %). sputum from . % of patients was obtained for culture. sixty-five percent of patients had radiological evidence of new/progressive infiltrate at the time of hap treatment, therefore meeting hap diagnostic criteria ( american thoracic society/infectious diseases society of america guidelines). radiologically confirmed hap was associated with higher levels of inflammatory markers and sputum culture positivity. previous surgery and/or endotracheal intubation were associated with radiologically confirmed hap. a bacterial pathogen was identified from / sputum samples from radiologically confirmed hap patients. these were gram-negative bacilli (n = ) or staphylococcus aureus (n = ). gram-negative bacteria tended to be resistant to co-amoxiclav, but susceptible to ciprofloxacin, piperacillin–tazobactam and meropenem. five of the six s. aureus isolates were meticillin susceptible and all were susceptible to doxycycline. conclusion: in ward-level hospital practice ‘hap’ is an over-used diagnosis that may be inaccurate in % of cases when objective radiological criteria are applied. radiologically confirmed hap represents a distinct clinical and microbiological phenotype. potential risk factors were identified that could represent targets for preventive interventions. the syndrome of hospital-acquired pneumonia (hap) is defined as pneumonia occurring in non-intubated patients ! h after hospitalization, and therefore not incubating at the time of admission. this is distinct from ventilator-associated pneumonia (vap), which is defined as pneumonia occurring after e h of mechanical ventilation in an intubated patient. hap may be suspected if a patient develops new symptoms and signs consistent with respiratory tract infection (fever, abnormal chest examination, purulent sputum, tachypnoea, impaired oxygenation) and laboratory results consistent with inflammation (raised white cell count and creactive protein). however, the diagnosis of hap also requires radiological demonstration of a new or progressive lung infiltrate. american thoracic society/infectious diseases society of america (ats/idsa) guidelines for the management of hap highlight gram-negative bacilli as frequently occurring pathogens in hap and staphylococcus aureus as an emerging cause. much of the literature that has been used to describe the aetiology of hap relates to vap, nosocomial pneumonia occurring specifically in the intensive care unit (icu) or nursinghome-acquired pneumonia. e overall, more is known about the pathogenesis and microbiology of vap, facilitated by the ease of obtaining deep respiratory samples by bronchoalveolar lavage in intubated patients. importantly, there are evidencebased 'care bundles' to prevent vap, but not hap. empirical treatment of hap aims to include cover for nosocomial pathogens, especially gram negative bacteria, therefore it necessitates using broad-spectrum agents such as coamoxiclav and piperacillinetazobactam, with the attendant risks of antibiotic-associated diarrhoea, c. difficile infection, selection for antimicrobial resistance in patient and environmental flora and also high costs. an accurate diagnosis of hap is therefore essential to ensure appropriate use of these antimicrobials. the aim of this study was to retrospectively evaluate the accuracy of the diagnosis of hap in inpatients on acute internal medicine and general surgical wards receiving intravenous antimicrobials for a clinical diagnosis of hap made by the patient's team. the demographic and microbiological features of patients with radiologically confirmed hap will be described. this was a retrospective observational cohort study of medical and surgical inpatients receiving intravenous antimicrobials for a clinical diagnosis of hap at a tertiary care hospital in edinburgh, uk. data were collected as part of a large prospective audit of antimicrobial prescribing in all inpatients within acute internal medicine and general surgery wards of the royal infirmary of edinburgh (rie) over months, between april and april . all patients treated with intravenous antimicrobials for ! h for any indication were identified and reviewed by a consultant infectious disease physician and an antimicrobial pharmacist. to be included in the current study, a patient from this cohort had to be receiving intravenous antimicrobials for a documented clinical diagnosis of hap, excluding vap and cap. demographic data, medical history, admission details (including death during admission), clinical diagnosis (as deduced by the primary clinical team), microbiological sampling, and radiological investigations were collected. antimicrobial susceptibility testing was carried out using the european committee on antimicrobial susceptibility testing (eucast) methodology. the presence of signs and/or symptoms consistent with respiratory tract infection was assumed based on the clinical diagnosis of hap made by the patient's clinicians ! h after admission to hospital. to be classified as radiologically confirmed hap in this study, chest x-ray evidence of a new or progressive lung infiltrate was required (reported by a radiologist), consistent with the ats/idsa guidelines. fisher's exact test was used to compare categorical variables if one cell contained five or fewer subjects; chi-square test was used if all cells contained more than five subjects. the shapiroewilk w-test for non-normality was used to assess the distribution of continuous data and the mannewhitney u-test was used for data not in a normal distribution. data were analysed using statsdirect software version . . (statsdirect, altrincham, uk). p < . was considered statistically significant. outcomes icu admission ( . %) ( . %) . intubation and ventilation ( . %) ( . %) . over the -month time-period, a total of , admissions to eight wards in the rie were reviewed. overall of these adult inpatients received ! h of intravenous antimicrobials ( . %). of these, were treated for a clinical diagnosis of hap ( . % of patients on intravenous antimicrobials) ( table i) . the cohort of patients was elderly, with a median age of . years. the majority of patients were aged ! years ( . %) and were male ( . %); . % of patients had been admitted to a medical ward, and . % to a surgical ward. comorbidities, for example chronic obstructive pulmonary disease, heart failure and cardio-/cerebrovascular disease, were widespread in the cohort, reflected in an inpatient mortality of . % (table ii) . median number of comorbidities was with . % of patients having > . of the patients treated for hap, . % underwent a surgical procedure under general anaesthetic prior to diagnosis and treatment (table ii) . a slightly higher percentage ( . %) had previously undergone endotracheal intubation during the admission, reflecting some patients requiring intubation for airway management or mechanical ventilation in the icu, over and above those intubated for general anaesthesia. six patients treated for a clinical diagnosis of hap required icu admission and mechanical ventilation following clinical diagnosis of hap. the majority of patients had clear lung fields reported by a radiologist on their admission chest x-ray. nine percent of patients had consolidation reported on admission, representing an initial presentation with community-acquired pneumonia or aspiration pneumonia before suspicion of and treatment for hap arising ! h after admission. in accordance with local guidelines for the treatment of hap, piperacillinetazobactam was the most frequently used antimicrobial, prescribed to . % of included patients (table ii) . co-amoxiclav was the second most widely prescribed antimicrobial, used in . % of cases. in . %, chest imaging found no evidence of a new or progressive infiltrate. no chest imaging was performed for four patients, and these patients were excluded from the following analyses. radiologically confirmed hap appeared to represent a distinct clinical phenotype, with significantly higher levels of inflammatory markers (white cell count, neutrophils, and creactive protein; p < . for all) in these patients (table iii) . patients with radiologically confirmed hap were more likely to have a white cell count greater than the upper limit of the local reference range [odds ratio (or): . ; % confidence interval (ci): . e . ; p ¼ . ]. leucopenia was only observed in one patient from each group. when the total duration of intravenous antimicrobial therapy was considered, patients with radiologically confirmed hap had a longer median minimum duration of treatment ( . days vs days; p ¼ . ; table ii ) further suggesting that the two groups were clinically different. there was no significant difference in the use of piperacillinetazobactam, co-amoxiclav, vancomycin, ciprofloxacin or meropenem between patients with and without radiological confirmation of hap. the mortality rate during admission for patients with radiologically confirmed hap was . %, with . % of patients requiring admission to the icu and mechanical ventilation following hap diagnosis. in the group without radiological confirmation, no patients went on to require icu admission and the mortality rate during admission was . % (p ¼ . ). demographics associated with radiologically confirmed hap patient characteristics and admission details were compared between patients treated for hap with and without radiological confirmation of a new/progressive infiltrate (tables i and ii) . being admitted to a surgical ward (or: . , % ci: . e . ; p ¼ . ), undergoing surgery (requiring general anaesthesia and intubation) ( . ; . e . ; p ¼ . ) or endotracheal intubation for any indication ( . ; . e . ; p ¼ . ) were all associated with radiologically confirmed hap. in surgical patients, there was no difference between emergency/elective admissions. patients from both groups had a median of two medical comorbidities, and aside from ckd no comorbidity was associated with radiologically confirmed hap. rates of microbiological sampling in patients with radiologically confirmed hap were similar to the overall population of patients treated for clinical suspicion of hap. a bacterial pathogen was identified from of sputum samples from patients with radiologically confirmed hap ( . %; table iv ). the majority of bacterial species identified in sputum samples were gram-negative bacilli (n ¼ ) and s. aureus (n ¼ ). sputum samples were obtained from six patients without radiologically confirmed hap and none of these yielded growth of a bacterial pathogen. blood cultures were drawn in . % of patients with radiologically confirmed hap and bacteraemia was infrequent, occurring in only four patients (sputum cultures were not obtained from any of the patients with bacteraemia). gramnegative bacteria were responsible for two of these bloodstream infections, and mrsa and s. pneumoniae accounted for one each. the patient with s. pneumoniae bacteraemia associated with hap had clear lung fields on admission chest x-ray. a throat swab for qpcr testing for respiratory pathogens was obtained from . % of patients and was negative in all cases. mrsa was found in only five of mrsa screens (taken any time during admission) and was identified from one sputum sample and one blood culture (from different patients). both of these patients had a positive mrsa screen. an antibiogram of the antimicrobial susceptibilities of bacteria isolated from sputum samples is shown in supplementary table i . overall, gram-negative bacteria tended to be resistant to amoxicillin and co-amoxiclav, but susceptible to ciprofloxacin, gentamicin, piperacillinetazobactam, and meropenem. five out of six s. aureus isolates were susceptible to flucloxacillin and all six were susceptible to doxycycline (including the one mrsa isolate). the mrsa sputum isolate was susceptible to vancomycin. we have retrospectively evaluated a cohort of medical and surgical inpatients treated for a clinical diagnosis of hap. applying the ats/idsa hap guidelines to these patients, we identified that only . % of patients had radiologically confirmed hap; therefore it appears that in ward-level hospital practice at our institution 'hap' is an over-used diagnosis that may be inaccurate in more than one-third of cases. surgical ward admission, undergoing surgery with general anaesthesia, or endotracheal intubation for any indication were associated with radiologically confirmed hap. the ats/idsa guidelines describe intubation and mechanical ventilation as a risk factor for developing nosocomial pneumonia, but the literature cited to support this statement describes vap, i.e. the development of pneumonia in patients during mechanical ventilation. hypothesis-generating univariate analysis on our data suggests that intubation and ventilation, especially when associated with surgery, may be a continuing risk factor for pneumonia even following extubation and is therefore a relevant factor when assessing nonintubated patients with new respiratory signs and symptoms in hospital. the pathogenesis of hap may therefore often be related to microaspiration of oropharyngeal contents around the cuff of an endotracheal (et) tube in paralysed intubated patients during surgery, without necessarily a prolonged period of mechanical ventilation such as during critical illness (i.e. vap). in a systematic literature review of airway management strategies to reduce the incidence of vap in critically ill ventilated patients in the icu, interventions including continuous aspiration of subglottic secretions using a special et tube (vs standard et tubes) and the use of heat and moisture exchangers have been shown to lower vap rates. in a separate study, persistent et tube cuff pressure of < cmh o was also associated with risk of vap. such interventions could also be evaluated in intubated patients undergoing surgery. similarly, in critically ill ventilated patients, oral hygiene with chlorhexidine mouthwash has been shown to reduce rates of vap, and has been included as a component of a successfully evaluated 'vap care bundle'. , chlorhexidine mouthwash would be an inexpensive measure for use in the immediate pre-and postoperative period for surgical patients. oral care (chlorhexidine mouthwash or mechanical cleaning) was shown to be associated with a reduced relative risk of pneumonia in a metaanalysis incorporating non-ventilated hospital inpatients and nursing home residents (though there was a high risk of bias in included studies). other postoperative factors likely to be important in development of hap include being bed-bound, having reduced chest wall movement (and therefore reduced clearance of secretions) due to pain or being drowsy secondary to opiate analgesics. in approximately one-third of patients treated for suspected hap in this study, a chest x-ray or computed tomography (ct) excluded a pneumonic infiltrate, therefore an alternative diagnosis may have been missed. a phenotype has been described in ventilated icu patients with respiratory signs but no infiltrate on chest imaging, labelled nosocomial tracheobronchitis. this has been associated with longer icu admission and ventilation times but prospective data describing the necessity for antimicrobials are lacking. further study of this phenotype in non-intubated patients may be valuable and it may account for some of the cases in this study without radiological changes consistent with hap. non-infective alternatives include atelectasis, pulmonary embolism, and underlying lung disease, such as chronic obstructive pulmonary disease (present in . % of patients treated for hap in this study) and asthma. unwell patients labelled as 'hap' may have a subdiaphragmatic cause of sepsis resulting in the clinical findings. given the demonstrated difficulty in reaching a reliable clinical diagnosis of hap, microbiological testing to confirm an infective aetiology becomes even more important, but a sputum sample was obtained from only . % of patients treated for hap. this low rate may reflect the difficulty in obtaining a suitable deep specimen from non-intubated patients with a degree of respiratory distress or weakness. in such patients biomarkers of pulmonary infection would be helpful in establishing the likelihood of an infective aetiology and justifying the use of empirical antimicrobials prior to culture results. in comparison to community-acquired pneumonia, where the culture-positive rate of sputum samples at our institution has been reported as %, a bacterial pathogen was identified from of ( . %) samples from patients with radiologically confirmed hap and therefore has greater potential to influence management. in our study, gram-negative bacilli ( / ) and s. aureus ( / ) were the identified pathogens, with no frequently occurring cap pathogens isolated. in the remainder of cases where a sputum sample was obtained, the result was 'no growth', 'respiratory commensals' or 'yeasts'. antimicrobial resistance was significant, with most gram-negative isolates displaying resistance to amoxicillin and co-amoxiclav, but susceptibility to piperacillinetazobactam. however, the overall number of sputum cultures obtained from patients was low, reducing the utility of these data in describing the microbiology of hap. in addition, we recognize the potential for contamination of sputum samples with oropharyngeal colonizers. this is an important issue, especially considering the prescription of broad-spectrum antimicrobials to cover the susceptibility pattern of these pathogens, but pragmatically one would aim to cover these species if they were identified in a sputum sample from a patient with hap. as discussed above, the inability to routinely obtain deep respiratory tract specimens (e.g. bal) from non-intubated patients hinders microbiological diagnosis in hap. the largest report on the microbiology of hap comes from a retrospective cohort study of a us inpatient database of patients with culture-positive pneumonia, including patients with hap. here, s. aureus accounted for . % of cases, pseudomonas spp. . %, klebsiella spp. . %, haemophilus spp. . %, e. coli . %, enterobacter spp. . %, and acinetobacter spp. . %. overall, gram-negative pathogens were isolated from . % of hap cases. a complicating factor in conventional culture-based testing of samples from patients with suspected hap is the fact they will most likely already have received antimicrobials prior to sampling, impairing sensitivity of pathogen detection using culture-based techniques. a qpcr test for detection and quantification of eight key bacterial causes of pneumonia (including s. aureus, e. coli and p. aeruginosa) from sputum samples has recently been described and could represent a useful tool for the investigation of suspected hap. only six ( . %) patients with hap had throat swabs obtained for qpcr respiratory virus and m. pneumoniae testing and in all cases these were negative. nosocomial influenza can account for a significant proportion of influenza cases ( . % in a canadian surveillance programme). using admission to critical care wards as a marker, the / influenza season in scotland was similar to the preceding year with no significant increase in cases. however, the lack of consistent testing for influenza virus in patients with hap precludes any conclusions about the incidence of nosocomial influenza causing hap during the study period, or the utility of respiratory virus/mycoplasma testing in the work-up of suspected hap. a limitation of this study is that radiological confirmation of hap is primarily derived from the results of chest x-rays (only of the patients underwent ct) which may lead to underdetection of pulmonary infiltrates compared to ct. e in a study of patients presenting to the emergency department with respiratory symptoms who underwent both chest xray and ct, it has been demonstrated that x-ray has poor sensitivity in detecting pulmonary infiltrates in comparison to ct (sensitivity . %). the timing of ct scan was not specified in this study, therefore a confounding factor may be that a possible delay between x-ray and ct allows development of a detectable infiltrate. in cases where hap is suspected clinically but the chest x-ray does not show a new/progressive lung infiltrate, there may be a role for ct scanning. in addition, there is emerging evidence for the role of lung ultrasound for the detection of pulmonary infiltrates in cap, with some data suggesting superiority over chest x-ray when compared to ct as a gold standard. , a further limitation lies in the casee control analysis performed, which should be repeated in the future with a control cohort of hospital inpatients with no clinical suspicion of hap. furthermore, this study only identified patients receiving intravenous antimicrobials, thereby selecting for patients perceived to have more severe illness. when cases were identified during the antimicrobial prescribing audit, a recommendation was made to the parent team regarding further antimicrobial management. whereas this occurred after the clinical diagnosis of hap had been made by the patient's team and would have had no influence on this, it may have altered subsequent management. this could therefore confound the mortality data presented here, although no significant difference was observed between patients with and without radiologically confirmed hap. this study has described the features of radiologically confirmed hap in a cohort of uk inpatients. potential risk factors have been identified through a hypothesis-generating caseecontrol analysis using patients treated for suspicion of hap but without consistent radiology. previous surgery and/or endotracheal intubation were found to be associated with radiologically confirmed hap. significantly, the clinical diagnosis of hap may have been inaccurate in more than one-third of cases, where there were no consistent changes on chest imaging. we have also highlighted a lack of microbiological sampling in patients receiving broad-spectrum antimicrobials for a clinical diagnosis of hap. directions for further work on hap are highlighted in supplementary table ii . improved accuracy of hap diagnosis is essential, since around one-third of patients in our cohort were exposed to broad-spectrum antimicrobials potentially unnecessarily and may have had an alternative diagnosis requiring different investigation and management. infectious diseases society of america. guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia ventilator-associated pneumonia incidence of anaerobes in ventilator-associated pneumonia with use of a protected specimen brush etiology of severe pneumonia in the very elderly impact of invasive strategy on management of antimicrobial treatment failure in institutionalized older people with severe pneumonia a prospective comparison of nursing home acquired pneumonia with community acquired pneumonia reducing ventilatorassociated pneumonia in intensive care: impact of implementing a care bundle influence of airway management on ventilator-associated pneumonia: evidence from randomized trials pneumonia in intubated patients: role of respiratory airway care oral hygiene care for critically ill patients to prevent ventilator-associated pneumonia prevention of healthcareassociated pneumonia with oral care in individuals without mechanical ventilation: a systematic review and meta-analysis of randomized controlled trials nosocomial tracheobronchitis in mechanically ventilated patients: incidence, aetiology and outcome epidemiology, antibiotic therapy, and clinical outcomes in health care associated pneumonia: a uk cohort study epidemiology and outcomes of health-care-associated pneumonia: results from a large us database of culture-positive pneumonia development of two real-time multiplex pcr assays for the detection and quantification of eight key bacterial pathogens in lower respiratory tract infection healthcare-associated influenza in canadian hospitals from surveillance of influenza and other respiratory viruses in the united kingdom: winter / diagnostic value of chest radiographs in bedridden patients suspected of having pneumonia chest radiograph vs. computed tomography scan in the evaluation for pneumonia high discordance of chest x-ray and computed tomography for detection of pulmonary opacities in ed patients: implications for diagnosing pneumonia lung ultrasound in the diagnosis and follow-up of community-acquired pneumonia: a prospective, multicenter, diagnostic accuracy study accuracy of lung ultrasonography versus chest radiography for the diagnosis of adult communityacquired pneumonia: review of the literature and meta-analysis we gratefully acknowledge the assistance of a. cockburn, l. shaw, c. philip, and d. reekie (antimicrobial pharmacists), e. fletcher (antimicrobial team data analyst) and l. robertson (data entry). none declared. none. supplementary data related to this article can be found at http://dx.doi.org/ . /j.jhin. . . . key: cord- -belkwihy authors: peters, alexandra; parneix, pierre; otter, jon; pittet, didier title: putting some context to the aerosolization debate around sars-cov- date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: belkwihy nan didier pittet works with who in the context of the who initiative 'private organizations for patient safety -hand hygiene'. the aim of this who initiative is to harness industry strengths to align and improve implementation of who recommendations for hand hygiene in health care indifferent parts of the world, including in least developed countries. in this instance, companies/industry with a focus on hand hygiene and infection control related advancement have the specific aim of improving access to affordable hand hygiene products as well as through education and research. all listed authors declare no financial support, grants, financial interests or consultancy that could lead to conflicts of interest. the authors alone are responsible for the views expressed in this article and they do not necessarily represent the views, decisions or policies of the institutions with which they are affiliated. who takes no responsibility for the information provided or the views expressed in this paper. a letter to the editor entitled "aerosol and surface stability of sars-cov- as compared with sars-cov- " was recently published in in the new england journal of medicine. the experiments reported in this letter compared the stability of sars-cov- and sars-cov- in aerosols and on a number of different surfaces. the usefulness of such a comparison is without argument, and knowing the relative tenacity of sars-cov- versus sars-cov- in the healthcare environment will no doubt help put the sars-cov- virus in perspective, and help guide protocols for environmental hygiene. the work showed that "sars-cov- remained viable in aerosols throughout the duration of (the) experiment ( hours), with a reduction in infectious titer from . to . tcid per liter of air. this reduction was similar to that observed with sars-cov- ". nonetheless, this perfectly solid article has inadvertently become the source of a great deal of misinformation in the mainstream media. there is a large number of sources including reuters, the new york times, and the bbc, which argue that sars-cov- is an airborne disease. [ ] [ ] [ ] these media articles' assertions include that sars-co v- can last "three hours after being coughed out into the air", and that the van doremalen et al. study "attempted to mimic the virus deposited from an infected person onto everyday surfaces in a household or hospital setting, such as through coughing or touching objects". the media even went as far as suggesting that the aerosols generated by the three-jet collison nebulizer "duplicated the microscopic droplets created in a cough or a sneeze". , this is not what the authors of the original letter said at all. exactly here lies the main issue: there is a lack of understanding of the media concerning the difference between test conditions and clinical conditions. the general assumption that is made is that the particles created when a virus is artificially nebulized are the same as when someone coughs or sneezes. in reality, the collision nebulizer that the study used, is know for creating very small droplets that can hold viruses far longer than other types of nebulizers that mimic conditions closer to those generated by humans. the media also assumed that conditions for the survival of viruses in droplets in ambient air are similar to those in a goldberg drum like the one used in the experiment. this is an inaccurate assumption-droplets that are coughed behave differently in the open air. some are large and fall to the ground, some linger for a bit close to where they were disseminated, and some tiny ones evaporate very fast. if we look at the example of sars-cov- , there was evidence of nosocomial spread even with the use of n masks. air and surface samples were taken, and the virus was only found on surfaces. the study by van doremalen et al. measures how long sars-cov- stays viable in aerosol in very specific experimental conditions. it should not be interpreted as giving information on when and how aerosols are generated in clinical conditions, nor whether the virus remains viable or, more importantly, transmissible in those conditions or not. it is for these reasons that the who and infection prevention specialists continue to support assertion that transmission of sars-cov- is primarily through droplets and contact (including indirect contact with contaminated surfaces). , aerosols are likely to be generated through a small number of clinical procedures, but that these are not the main way the virus spreads in the community. aerosol and surface stability of sars-cov- as compared with sars-cov- coronavirus can persist in air for hours and on surfaces for days: study how long will coronavirus live on surfaces or in the air around you? covid- : how long does the coronavirus last on surfaces characterization and deposition of respirable large-and small-particle bioaerosols the size and concentration of droplets generated by coughing in human subjects respiratory virus shedding in exhaled breath and efficacy of face masks modes of transmission of virus causing covid- : implications for ipc precaution recommendations key: cord- - iv ezg authors: maltezou, helena c.; dedoukou, xanthi; tsonou, paraskevi; tseroni, maria; raftopoulos, vasilios; pavli, androula; papadima, kalliopi; chrysochoou, anastasios; randou, efthalia; adamis, georgios; kostis, evangelos; pefanis, angelos; gogos, charalambos; sipsas, nikolaos v. title: hospital factors associated with sars-cov- infection among healthcare personnel in greece date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: iv ezg healthcare personnel (hcp) constitute a high-risk group for sars-cov- infection. we estimated their risk of infection per hospital characteristics. factors significantly associated with an increased risk for sars-cov- infection were: working in a non-referral hospital compared to a covid- referral hospital, working in a hospital with a high number of employees, and working in a hospital with an increased number of covid- patients. our study revealed gaps in infection control in the non-referral hospitals. there is an urgent need for continuous training in infection control practices. compliance of hcp with the use of personal protective equipment should also be addressed. triage for prompt detection of patients with covid- was implemented in all hospitals. a surgical mask was administered to symptomatic patients upon entering any hospital. the following personal protective equipment (ppe) was recommended for hcp caring for suspected or laboratory-confirmed covid- cases: filtering face piece respirator (ffp)- , non-sterilized single-use gloves, goggles or face shield, and gown resistant to fluid penetration. an ffp respirator was recommended for hcp performing aerosol-generating procedures [ ] . in case of shortages, surgical masks were recommended for hcp caring for patients in order to preserve respirators for aerosol-generating procedures. contact tracing and risk assessment of exposed hcp were performed by the infection control committee of each hospital. exposures were categorized as highrisk, moderate-risk or low-risk and managed accordingly [ ] . hcp with high-risk exposure were excluded from work for isolation purposes for seven days. exposed hcp were tested for sars-cov- infection by reverse-transcriptase polymerase chain reaction (rt-pcr) in case of onset of symptoms. although testing of asymptomatic hcp was officially recommended only for hcp working in high-risk settings (transplantation units, hematology-oncology units, intensive care units), this was a common practice in many hospitals, regardless of exposure-risk category or working setting [ ] . the study period extended from february (first covid- case detected in healthcare-associated sars-cov- infection was defined as a case of sars-cov- infection in a hcp following occupational exposure. j o u r n a l p r e -p r o o f written consent was not required, given that the data were collected within the frame of epidemiological surveillance. data were managed in accordance with the national and european union laws. all the items were coded and scored, and were included in the data analysis set. ibm spss was used to analyze the data. the t-test was used to assess whether the means of two groups were statistically different. p-values < . were considered statistically significant. in as expected, the designated covid- referral hospitals significantly outnumbered the non-referral hospitals in terms of number of hospitalized patients with covid- . nevertheless, the current study showed that the ratio of sars-cov-to hcp working in covid- units [ . % ( / ) versus . % ( / ); p-value= . ] [ ] . in another study of ours we found that approximately half of , hcp with a history of occupational exposure to covid- had been exposed to another hcp with covid- ; we also found that administrative employees were more likely to get infected in-hospital than other profession categories, suggesting that the former either did not comply with infection control guidelines or were less trained for ppe use [ ] . these findings underscore the need for continuous education of hcp in order to achieve high compliance rates with infection control guidelines, regardless of direct care of covid- patients. the introduction of an integrated infection control strategy in a sars-designated hospital in taiwan with no negative pressure isolation rooms during the sars epidemic, was associated with a significant reduction of the incidence rate of hcp who contracted sars, compared to hospitals that did not use the infection control strategy ( . cases/bed compared to . cases/bed; p-value= . ) [ ] . beyond triage of patients and extensive installation of alcohol dispensers, the strategy included reinforcement for hcp to comply with infection control procedures, especially hand washing [ ] . in addition, in the current study hcp working in hospitals with large number of employees were more likely to get infected with sars-cov- , which points out to the challenges to efficiently train hcp in large hospitals. another possible explanation is the difficulty to respect social distancing in large hospitals especially during coffee breaks and meals at the selfservice restaurant. hcp often consider masks and other ppe uncomfortable to use [ ] . yet, studies indicate that a workplace culture supporting training of all hcp categories, communication of guidelines, and good patient care practices could improve their compliance to guidelines [ ] . in response to the increasing number of hcp with a limitation of the current study is the fact that only public hospitals were studied. however, the overwhelming majority of covid- patients in greece were cared for in public hospitals. a clear advantage is the large number of consecutively diagnosed patients and hcp with sars-cov- infection retrieved from the national surveillance database. in conclusion, our study confirms that hcp constitute a high-risk group for sars-cov- infection. it also shows that there are gaps in infection control in non-referral hospitals. given the ongoing epidemic in greece and globally and the increasing potential for infected cases to seek healthcare in any healthcare facility, there is a need to raise infection control capacity and to address issues of hcp compliance with the use of ppe in all healthcare facilities. j o u r n a l p r e -p r o o f world health organization. coronavirus disease (covid- ) pandemic sars-cov- infection in healthcare personnel with high-risk occupational exposure: evaluation of seven-day exclusion from work policy online ahead of print transmission of covid- to health care personnel during exposures to a hospitalized patient first experience of covid- screening of health-care workers in england using an integrated infection control strategy during outbreak control to minimize nosocomial infection of severe acute respiratory syndrome among healthcare workers middle east respiratory syndrome coronavirus: implications for health care facilities nosocomial outbreak of covid- pneumonia in wuhan, china airborne transmission of severe acute respiratory syndrome coronavirus- to healthcare workers: a narrative review sars-cov- infection: advocacy for training and social distancing in healthcare settings barriers and facilitators to healthcare workers' adherence with infection prevention and control guidelines for respiratory infectious diseases: a rapid we thank the infection control committees of all hospitals for their assistance. we also thank sophia poufta for technical assistance. the opinions presented in this article are those of the authors, and do not necessarily represent those of their institutions.j o u r n a l p r e -p r o o f key: cord- -nb j k h authors: loveday, h.p.; wilson, j.a.; pratt, r.j.; golsorkhi, m.; tingle, a.; bak, a.; browne, j.; prieto, j.; wilcox, m. title: epic : national evidence-based guidelines for preventing healthcare-associated infections in nhs hospitals in england date: - - journal: j hosp infect doi: . /s - ( ) - sha: doc_id: cord_uid: nb j k h national evidence-based guidelines for preventing healthcare-associated infections (hcai) in national health service (nhs) hospitals in england were originally commissioned by the department of health and developed during – by a nurse-led multi-professional team of researchers and specialist clinicians. following extensive consultation, they were first published in january ( ) and updated in .( ) a cardinal feature of evidence-based guidelines is that they are subject to timely review in order that new research evidence and technological advances can be identified, appraised and, if shown to be effective for the prevention of hcai, incorporated into amended guidelines. periodically updating the evidence base and guideline recommendations is essential in order to maintain their validity and authority. the department of health commissioned a review of new evidence and we have updated the evidence base for making infection prevention and control recommendations. a critical assessment of the updated evidence indicated that the epic guidelines published in remain robust, relevant and appropriate, but some guideline recommendations required adjustments to enhance clarity and a number of new recommendations were required. these have been clearly identified in the text. in addition, the synopses of evidence underpinning the guideline recommendations have been updated. these guidelines (epic ) provide comprehensive recommendations for preventing hcai in hospital and other acute care settings based on the best currently available evidence. national evidence-based guidelines are broad principles of best practice that need to be integrated into local practice guidelines and audited to reduce variation in practice and maintain patient safety. clinically effective infection prevention and control practice is an essential feature of patient protection. by incorporating these guidelines into routine daily clinical practice, patient safety can be enhanced and the risk of patients acquiring an infection during episodes of health care in nhs hospitals in england can be minimised. we would like to acknowledge the assistance of the infection prevention society, british infection association and the healthcare infection society for their input into the development of these guidelines; and other associations, learned societies, professional organisations, royal colleges and patient groups who took an active role in the external review of the guidelines. we would also like to acknowledge the support received from professor brian duerden cbe in chairing the guideline development advisory group, and carole fry in the chief medical ofÀ cer's team at the department of health (england). the department of health (england). this guidance is based on the best critically appraised evidence currently available. the type and class of supporting evidence explicitly linked to each recommendation is described. some recommendations from the previous guide lines have been revised to improve clarity; where a new recom mendation has been made, this is indicated in the text. these recommendations are not detailed procedural protocols, and need to be incorporated into local guidelines. none are regarded as optional. standard infection control precautions need to be applied by all healthcare practitioners to the care of all patients (i.e. adults, children and neonates). the recommendations are divided into À ve distinct interventions: • hospital environmental hygiene; • hand hygiene; • use of personal protective equipment (ppe); • safe use and disposal of sharps; and • principles of asepsis. these guidelines do not address the additional infection control requirements of specialist settings, such as the operating department or outbreak situations. the hospital environment must be visibly clean; free from non-essential items and equipment, dust and dirt; and acceptable to patients, visitors and staff. sp levels of cleaning should be increased in cases of infection and/ or colonisation when a suspected or known pathogen can survive in the environment, and environmental contamination may contribute to the spread of infection. the use of disinfectants should be considered for cases of infection and/ or colonisation when a suspected or known pathogen can survive in the environment, and environmental contamination may contribute to the spread of infection. sp shared pieces of equipment used in the delivery of patient care must be cleaned and decontaminated after each use with products recommended by the manufacturer. all healthcare workers need to be educated about the importance of maintaining a clean and safe care environment for patients. every healthcare worker needs to know their speciÀ c responsibilities for cleaning and decontaminating the clinical environment and the equipment used in patient care. hand hygiene sp hands must be decontaminated: • immediately before each episode of direct patient contact or care, including clean/aseptic procedures; • immediately after each episode of direct patient contact or care; • immediately after contact with body Á uids, mucous membranes and non-intact skin; • immediately after other activities or contact with objects and equipment in the immediate patient environment that may result in the hands becoming contaminated; and • immediately after the removal of gloves. use an alcohol-based hand rub for decontamination of hands before and after direct patient contact and clinical care, except in the following situations when soap and water must be used: • when hands are visibly soiled or potentially contaminated with body Á uids; and • when caring for patients with vomiting or diarrhoeal illness, regardless of whether or not gloves have been worn. class a healthcare workers should ensure that their hands can be decontaminated effectively by: • removing all wrist and hand jewellery; • wearing short-sleeved clothing when delivering patient care; • making sure that À ngernails are short, clean, and free from false nails and nail polish; and • covering cuts and abrasions with waterproof dressings. effective handwashing technique involves three stages: preparation, washing and rinsing, and drying. • preparation: wet hands under tepid running water before applying the recommended amount of liquid soap or an antimicrobial preparation. • washing: the handwash solution must come into contact with all of the surfaces of the hand. the hands should be rubbed together vigorously for a minimum of - s, paying particular attention to the tips of the À ngers, the thumbs and the areas between the À ngers. hands should be rinsed thoroughly. • drying: use good-quality paper towels to dry the hands thoroughly. when decontaminating hands using an alcohol-based hand rub, hands should be free of dirt and organic material, and: • hand rub solution must come into contact with all surfaces of the hand; and • hands should be rubbed together vigorously, paying particular attention to the tips of the À ngers, the thumbs and the areas between the À ngers, until the solution has evaporated and the hands are dry. clinical staff should be made aware of the potentially damaging effects of hand decontamination products, and encouraged to use an emollient hand cream regularly to maintain the integrity of the skin. consult the occupational health team or a general practitioner if a particular liquid soap, antiseptic handwash or alcohol-based hand rub causes skin irritation. alcohol-based hand rub should be made available at the point of care in all healthcare facilities. hand hygiene resources and healthcare worker adherence to hand hygiene guidelines should be audited at regular intervals, and the results should be fed back to healthcare workers to improve and sustain high levels of compliance. healthcare organisations must provide regular training in risk assessment, effective hand hygiene and glove use for all healthcare workers. local programmes of education, social marketing, and audit and feedback should be refreshed regularly and promoted by senior managers and clinicians to maintain focus, engage staff and produce sustainable levels of compliance. patients and relatives should be provided with information about the need for hand hygiene and how to keep their own hands clean. patients should be offered the opportunity to clean their hands before meals; after using the toilet, commode or bedpan/urinal; and at other times as appropriate. products available should be tailored to patient needs and may include alcohol-based hand rub, hand wipes and access to handwash basins. selection of personal protective equipment must be based on an assessment of the: • risk of transmission of microorganisms to the patient or carer; • risk of contamination of healthcare practitioners' clothing and skin by patients' blood or body Á uids; and • suitability of the equipment for proposed use. healthcare workers should be educated and their competence assessed in the: • assessment of risk; • selection and use of personal protective equipment; and • use of standard precautions. supplies of personal protective equipment should be made available wherever care is delivered and risk assessment indicates a requirement. gloves must be worn for: • invasive procedures; • contact with sterile sites and nonintact skin or mucous membranes; • all activities that have been assessed as carrying a risk of exposure to blood or body Á uids; and • when handling sharps or contaminated devices. gloves must be: • worn as single-use items; • put on immediately before an episode of patient contact or treatment; • removed as soon as the episode is completed; • changed between caring for different patients; and • disposed of into the appropriate waste stream in accordance with local policies for waste management. hands must be decontaminated immediately after gloves have been removed. a range of ce-marked medical and protective gloves that are acceptable to healthcare personnel and suitable for the task must be available in all clinical areas. sensitivity to natural rubber latex in patients, carers and healthcare workers must be documented, and alternatives to natural rubber latex gloves must be available. disposable plastic aprons must be worn when close contact with the patient, materials or equipment pose a risk that clothing may become contaminated with pathogenic microorganisms, blood or body Á uids. full-body Á uid-repellent gowns must be worn where there is a risk of extensive splashing of blood or body Á uids on to the skin or clothing of healthcare workers. plastic aprons/Á uid-repellent gowns should be worn as single-use items for one procedure or episode of patient care, and disposed of into the appropriate waste stream in accordance with local policies for waste management. when used, nondisposable protective clothing should be sent for laundering. sp fluid-repellent surgical face masks and eye protection must be worn where there is a risk of blood or body Á uids splashing into the face and eyes. appropriate respiratory protective equipment should be selected according to a risk assessment that takes account of the infective microorganism, the anticipated activity and the duration of exposure. respiratory protective equipment must À t the user correctly and they must be trained in how to use and adjust it in accordance with health and safety regulations. personal protective equipment should be removed in the following sequence to minimise the risk of cross/self-contamination: • gloves; • apron; • eye protection (when worn); and • mask/respirator (when worn). hands must be decontaminated following the removal of personal protective equipment. sharps must not be passed directly from hand to hand, and handling should be kept to a minimum. sp needles must not be recapped, bent or disassembled after use. used sharps must be discarded at the point of use by the person generating the waste. all sharps containers must: • conform to current national and international standards; • be positioned safely, away from public areas and out of the reach of children, and at a height that enables safe disposal by all members of staff; • be secured to avoid spillage; • be temporarily closed when not in use; • not be À lled above the À ll line; and • be disposed of when the À ll line is reached. all clinical and non-clinical staff must be educated about the safe use and disposal of sharps and the action to be taken in the event of an injury. sp use safer sharps devices where assessment indicates that they will provide safe systems of working for healthcare workers. organisations should involve end-users in evaluating safer sharps devices to determine their effectiveness, acceptability to practitioners, impact on patient care and cost benefi t prior to widespread introduction. organisations should provide education to ensure that healthcare workers are trained and competent in performing the aseptic technique. the aseptic technique should be used for any procedure that breaches the body's natural defences, including: • insertion and maintenance of invasive devices; • infusion of sterile fl uids and medication; and • care of wounds and surgical incisions. this guidance is based on the best critically appraised evidence currently available. the type and class of supporting evidence explicitly linked to each recommendation is described. some recommendations from the previous guidelines have been revised to improve clarity; where a new recommen dation has been made, this is indicated in the text. these recommendations are not detailed procedural protocols, and need to be incorporated into local guidelines. none are regarded as optional. these guidelines apply to adults and children aged ≥ year who require a short-term indwelling urethral catheter (≤ days), and should be read in conjunction with the guidance on standard principles. the recommendations are divided into six distinct interventions: • assessing the need for catheterisation; • selection of catheter type and system; • catheter insertion; • catheter maintenance; • education of patients, relatives and healthcare workers; and • system interventions for reducing the risk of infection. only use a short-term indwelling urethral catheter in patients for whom it is clinically indicated, following assessment of alternative methods and discussion with the patient. class d/gpp uc document the clinical indication(s) for catheterisation, date of insertion, expected duration, type of catheter and drainage system, and planned date of removal. uc assess and record the reasons for catheterisation every day. remove the catheter when no longer clinically indicated. assess patient's needs prior to catheterisation in terms of: • latex allergy; • length of catheter (standard, female, paediatric); • type of sterile drainage bag and sampling port (urometer, -l bag, leg bag) or catheter valve; and • comfort and dignity. select a catheter that minimises urethral trauma, irritation and patient discomfort, and is appropriate for the anticipated duration of catheterisation. uc select the smallest gauge catheter that will allow urinary outfl ow and use a -ml retention balloon in adults (follow manufacturer's instructions for paediatric catheters). urological patients may require larger gauge sizes and balloons. uc ensure patients, relatives and carers are given information regarding the reason for the catheter and the plan for review and removal. if discharged with a catheter, the patient should be given written information and shown how to: • manage the catheter and drainage system; • minimise the risk of urinary tract infection; and • obtain additional supplies suitable for individual needs. uc use quality improvement systems to support the appropriate use and management of short-term urethral catheters and ensure their timely removal. these may include: • protocols for catheter insertion; • use of bladder ultrasound scanners to assess and manage urinary retention; • reminders to review the continuing use or prompt the removal of catheters; • audit and feedback of compliance with practice guidelines; and • continuing professional education this guidance is based on the best critically appraised evidence currently available. the type and class of supporting evidence explicitly linked to each recommendation is described. some recommendations from the previous guidelines have been revised to improve clarity; where a new recommendation has been made, this is indicated in the text. these recommendations are not detailed procedural protocols, and need to be incorporated into local guidelines. none are regarded as optional. ivad healthcare workers caring for patients with intravascular catheters should be trained and assessed as competent in using and consistently adhering to practices for the prevention of catheter-related bloodstream infection. ivad healthcare workers should be aware of the manufacturer's advice relating to individual catheters, connection and administration set dwell time, and compatibility with antiseptics and other Á uids to ensure the safe use of devices. ivad before discharge from hospital, patients with intravascular catheters and their carers should be taught any techniques they may need to use to prevent infection and manage their device. ivad hands must be decontaminated, with an alcohol-based hand rub or by washing with liquid soap and water if soiled or potentially contaminated with blood or body Á uids, before and after any contact with the intravascular catheter or insertion site. ivad use the aseptic technique for the insertion and care of an intravascular access device and when administering intravenous medication. ivad use a catheter with the minimum number of ports or lumens essential for management of the patient. ivad preferably use a designated singlelumen catheter to administer lipidcontaining parenteral nutrition or other lipid-based solutions. ivad use a tunnelled or implanted central venous access device with a subcutaneous port for patients in whom long-term vascular access is required. ivad use a peripherally inserted central catheter for patients in whom mediumterm intermittent access is required. ivad use an antimicrobial-impregnated central venous access device for adult patients whose central venous catheter is expected to remain in place for > days if catheter-related bloodstream infection rates remain above the locally agreed benchmark, despite the implementation of a comprehensive strategy to reduce catheter-related bloodstream infection. ivad in selecting an appropriate intravascular insertion site, assess the risks for infection against the risks of mechanical complications and patient comfort. ivad use the upper extremity for nontunnelled catheter placement unless medically contraindicated. ivad use maximal sterile barrier precautions for the insertion of central venous access devices. ivad when safer sharps devices are used, healthcare workers should ensure that all components of the system are compatible and secured to minimise leaks and breaks in the system. ivad administration sets in continuous use do not need to be replaced more frequently than every h, unless device-speciÀ c recommendations from the manufacturer indicate otherwise, they become disconnected or the intravascular access device is replaced. ivad administration sets for blood and blood components should be changed when the transfusion episode is complete or every h (whichever is sooner). ivad administration sets used for lipidcontaining parenteral nutrition should be changed every h. ivad use quality improvement interventions to support the appropriate use and management of intravascular access devices (central and peripheral venous catheters) and ensure their timely removal. these may include: • protocols for device insertion and maintenance; • reminders to review the continuing use or prompt the removal of intravascular devices; • audit and feedback of compliance with practice guidelines; and • continuing professional education. these are systematically developed broad statements (principles) of good practice. they are driven by practice need, based on evidence and subject to multi-professional debate, timely and frequent review, and modiÀ cation. national guidelines are intended to inform the development of detailed operational protocols at local level, and can be used to ensure that these incorporate the most important principles for preventing hcai in the nhs and other acute healthcare settings. during the past two decades, hcai have become a signiÀ cant threat to patient safety. the technological advances made in the treatment of many diseases and disorders are often undermined by the transmission of infections within healthcare settings, particularly those caused by antimicrobial-resistant strains of disease-causing microorganisms that are now endemic in many healthcare environments. the À nancial and personal costs of these infections, in terms of the economic consequences to the nhs and the physical, social and psychological costs to patients and their relatives, have increased both government and public awareness of the risks associated with healthcare interventions, especially the risk of acquiring a new infection. many, although not all, hcai can be prevented. clinical effectiveness (i.e. using prevention measures that are based on reliable evidence of efÀ cacy) is a core component of an effective strategy designed to protect patients from the risk of infection, and when combined with quality improvement methods can account for signiÀ cant reductions in hcai such as meticillin-resistant staphylococcus aureus (mrsa) and clostridium difÀ cile. these guidelines describe clinically effective measures that are used by healthcare workers for preventing infections in hospital and other acute healthcare settings. three sets of guidelines were developed originally and have now been updated. they include: • standard infection control principles: including best practice recommendations for hospital environmental hygiene, effective hand hygiene, the appropriate use of ppe, the safe use and disposal of sharps, and the principles of asepsis; • guidelines for preventing infections associated with the use of short-term indwelling urethral catheters; and • guidelines for preventing infections associated with the use of intravascular access devices. the evidence for these guidelines was identiÀ ed by multiple systematic reviews of peer-reviewed research. in addition, evidence from expert opinion as reÁ ected in systematically identiÀ ed professional, national and international guidelines was considered following formal assessment using a validated appraisal tool. all evidence was critically appraised for its methodological rigour and clinical practice applicability, and the best-available evidence inÁ uenced the guideline recommendations. a team of specialist infection prevention and control researchers and clinical specialists and a guideline development advisory group, comprising lay members and specialist clinical practitioners, developed the epic guidelines (see sections . and . ). these guidelines can be appropriately adapted and used by all hospital practitioners. this will inform the development of more detailed local protocols and ensure that important standard principles for infection prevention are incorporated. consequently, they are aimed at hospital managers, members of hospital infection prevention and control teams, and individual healthcare practitioners. at an individual level, they are intended to inÁ uence the quality and clinical effectiveness of infection prevention decision-making. the dissemination of these guidelines will also help patients and carers/relatives to understand the standard infection prevention precautions they can expect all healthcare workers to implement to protect them from hcai. each set of guidelines follows an identical format, which consists of: • a brief introduction; • the intervention heading; • a headline statement describing the key issues being addressed; • a synthesis of the related evidence; and • guideline recommendation(s) classiÀ ed according to the strength of the underpinning evidence. a cardinal feature of evidence-based guidelines is that they are subject to timely review in order that new research evidence and technological advances can be identiÀ ed, appraised and, if shown to be effective for the prevention of hcai, incorporated into amended guidelines. the evidence base for these guidelines will be reviewed in years ( ) and the guidelines will be considered for updating approximately years after publication ( ). following publication the dh will ask the advisory group on antimicrobial resistance and healthcare associated infection to advise whether the s h. p. loveday et al. / journal of hospital infection s ( ) s -s evidence base has progressed signiÀ cantly to alter the guideline recommendations and warrant an update. in addition to informing the development of detailed local operational protocols, these guidelines can be used as a benchmark for determining appropriate infection prevention decisions and, as part of reÁ ective practice, to assess clinical effectiveness. they also provide a baseline for clinical audit, evaluation and education, and facilitate on-going quality improvements. there are a number of audit tools available locally, nationally and internationally that can be used to audit compliance with guidance including high-impact intervention tools for auditing care bundles. signiÀ cant additional costs are not anticipated in implement ing these guidelines. however, where current equipment or resources do not facilitate the implementation of the guidelines or where staff levels of adherence to current guidance are poor, there may be an associated increase in costs. given the social and economic costs of hcai, the consequences associated with not implementing these guidelines would be unacceptable to both patients and healthcare professionals. the guidelines were developed using a systematic review process (appendix a. ). in each set of guidelines, a summary of the relevant guideline development methodology is provided. electronic databases were searched for national and international guidelines and research studies published during the periods identiÀ ed for each search question. a two-stage search process was used. for each set of epic guidelines, an electronic search was conducted for systematic reviews of randomised controlled trials (rcts) and current national and international guidelines. international and national guidelines were retrieved and subjected to critical appraisal using the agree ii instrument, an evaluation method used internationally for assessing the methodological quality of clinical guidelines. following appraisal, accepted guidelines were included as part of the evidence base supporting guideline development and, where appropriate, for delineating search limits. they were also used to verify professional consensus and, in some instances, as the primary source of evidence. review questions for the systematic reviews of the literature were developed for each set of epic guideline topics following recommendations from scientiÀ c advisors and the guideline development advisory group. searches were constructed using relevant mesh (medical subject headings) and free-text terms. the following databases were searched: • medline; • cumulated index of nursing and allied health literature; • embase; • the cochrane library; and • psycinfo (only searched for hand hygiene). search results were downloaded into a refworks™ database, and titles and abstracts were printed for review. titles and abstracts were assessed independently by two reviewers, and studies were retrieved where the title or abstract: addressed one or more of the review questions; identiÀ ed primary research or systematically conducted secondary research; or indicated a theoretical/clinical/in-use study. where no abstract was available and the title indicated one or more of the above criteria, the study was retrieved. due to the limited resources available for this review, foreign language studies were not identiÀ ed for retrieval. full-text studies were retrieved and read in detail by two experienced reviewers; those meeting the study inclusion criteria were independently quality assessed for inclusion in the systematic review. included studies were appraised using tools based on systems developed by the scottish intercollegiate guideline network (sign) for study quality assessment. studies were appraised independently by two reviewers and data were extracted by one experienced reviewer. any disagreement between reviewers was resolved through discussion. evidence tables were constructed from the quality assessments, and the studies were summarised in adapted considered judgement forms. the evidence was classiÀ ed using methods from sign, and adapted to include interrupted time series design and controlled before-after studies using criteria developed by the cochrane effective practice and organisation of care (epoc) group (table ) . , this system is similar that used in the previous epic guidelines. the evidence tables and considered judgement reports were presented to the guideline development advisory group for discussion. the guidelines were drafted after extensive discussion. factors inÁ uencing the guideline recommendations included: • the nature of the evidence; • the applicability of the evidence to practice; • patient preference and acceptability; and • costs and knowledge of healthcare systems. the classiÀ cation scheme adopted by sign was used to deÀ ne the strength of recommendation ( these guidelines have been subject to extensive external consultation with key stakeholders, including royal colleges, professional societies and organisations, patients and trade unions (appendix a. ). comments were requested on: • format; • content; • practice applicability of the guidelines; • patient preference and acceptability; and • speciÀ c sections or recommendations. all the comments were collated and sent to the scientiÀ c advisors and the guideline development advisory group for consideration prior to virtual meetings for discussion and agreement on any changes in the light of comments. final agreement was sought from the scientiÀ c advisors and the guideline development advisory group following revision. high-quality meta-analyses, systematic reviews of rcts or rcts with a very low risk of bias + well-conducted meta-analyses, systematic reviews or rcts with a low risk of bias -meta-analyses, systematic reviews or rcts with a high risk of bias* ++ high-quality systematic reviews of case-control or cohort studies. high-quality case-control or cohort studies with a very low risk of confounding or bias and a high probability that the relationship is causal. interrupted time series with a control group: (i) there is a clearly deÀ ned point in time when the intervention occurred; and (ii) at least three data points before and three data points after the intervention + well-conducted case-control or cohort studies with a low risk of confounding or bias and a moderate probability that the relationship is causal. controlled before-after studies with two or more intervention and control sites -case-control or cohort studies with a high risk of confounding or bias and a signiÀ cant risk that the relationship is not causal. interrupted time series without a parallel control group: (i) there is a clearly deÀ ned point in time when the intervention occurred; and (ii) at least three data points before and three data points after the intervention. controlled before-after studies with one intervention and one control site non-analytic studies (e.g. uncontrolled before-after studies, case reports, case series) expert opinion. legislation *studies with an evidence level of ' -' and ' -' should not be used as a basis for making a recommendation. rct, randomised controlled trial. this guidance is based on the best critically appraised evidence currently available. the type and class of supporting evidence explicitly linked to each recommendation is described. some recommendations from the previous guidelines have been revised to improve clarity; where a new recommendation has been made, this is indicated in the text. these recommendations are not detailed procedural protocols, and need to be incorporated into local guidelines. none are regarded as optional. standard infection control precautions need to be applied by all healthcare practitioners to the care of all patients (i.e. adults, children and neonates). the recommendations are divided into À ve distinct interventions: • hospital environmental hygiene; • hand hygiene; • use of ppe; • safe use and disposal of sharps; and • principles of asepsis. these guidelines do not address the additional infection control requirements of specialist settings, such as the operating department or outbreak situations. this section discusses the evidence upon which recommendations for hospital environmental hygiene are based. the evidence identiÀ ed in the previous systematic review was used as the basis for updating the searches, and searches were conducted for new evidence published since . hospital environmental hygiene encompasses a wide range of routine activities. guidelines are provided here for: • cleaning the general hospital environment; • cleaning items of shared equipment; and • education and training of staff. current legislation, regulatory frameworks and quality standards emphasise the importance of the healthcare environment and shared clinical equipment being clean and properly decontaminated to minimise the risk of transmission of hcai and to maintain public conÀ dence. [ ] [ ] [ ] [ ] [ ] patients and their relatives expect the healthcare environment to be clean and infection hazards to be controlled adequately. the term 'cleaning' is used to describe the physical removal of soil, dirt or dust from surfaces. conventionally, this is achieved in healthcare settings using cloths and mops. dust may be removed using dry dust-control mops/cloths. detergent and water is used for cleaning of soiled or contaminated surfaces, although microÀ bre cloths and water can also be used for surface cleaning. enhanced cleaning describes the use of methods in addition to standard cleaning speciÀ cations. these may include increased cleaning frequency for all or some surfaces, or the use of additional cleaning equipment. enhanced cleaning may be applied to all areas of the healthcare environment or in speciÀ c circumstances, such as cleaning of rooms or bed spaces following the transfer or discharge of patients who are colonised or infected with a pathogenic microorganism. this is sometimes referred to as 'terminal cleaning'. disinfection is the use of chemical or physical methods to reduce the number of pathogenic microorganisms on surfaces. these methods need to be used in combination with cleaning as they have limited ability to penetrate organic material. the term 'decontamination' is used for the process that results in the removal of hazardous substances (e.g. microorganisms, chemicals) and therefore may apply to cleaning or disinfection. research evidence in this À eld remains largely limited to ecological studies and weak quasi-experimental and observational study designs. there is evidence from outbreak reports and observational research which demonstrates that the hospital environment becomes contaminated with microorganisms responsible for hcai. pathogens may be recovered from a variety of surfaces in clinical environments, including those near to the patient that are touched frequently by healthcare workers. [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] however, no studies have provided high-quality evidence of direct transmission of the same strain of microorganisms found in the environment to those found in colonised or infected patients. we identiÀ ed one prospective cohort study that found a signiÀ cant independent association between acquisition of two multi-drug-resistant pathogens and a prior room occupant with the same organism [multi-drug-resistant pseudomonas aeruginosa odds ratio (or) . , % conÀ dence interval (ci) . - . , p= . ; multi-drug-resistant acinetobacter baumanii or . , % ci . - . , p= . ] after adjustment for severity of underlying illness, comorbidities, antimicrobial exposure and some other risk factors. a further study reported an association between mrsa and vancomycin-resistant enterococcus (vre), but conclusions that can be drawn from the À ndings are limited by the retrospective study design and lack of adjustment for severity of underlying illness, colonisation pressure and antibiotic exposure. similarly, another retrospective cohort study found an association between acquisition of c. difÀ cile and prior room occupant with the same infection; however, this was based solely on clinical diagnosis rather than active surveillance. many microorganisms recovered from the hospital environment do not cause hcai. cleaning will not completely eliminate microorganisms from environmental surfaces, and reductions in their numbers will be transient. there is some evidence that enhanced cleaning regimens are associated with the control of outbreaks of hcai; however, these study designs do not provide robust evidence of cause and effect. enhanced cleaning has been recommended, particularly 'terminal cleaning', after a bed area has been used by a patient colonised or infected with an hcai. we searched for robust evidence from studies conducted in the healthcare environment which demonstrated cleaning interventions that were associated with reductions in both environmental contamination and hcai. a randomised crossover study of daily enhanced cleaning of high-touch surfaces in an intensive care unit (icu) demonstrated a reduction in the daily number of s sites in a bed area contaminated with mrsa (or . , % ci . - . , p= . ), and the aerobic colony count in communal areas (or . , % ci . - . , p= . ). although the reduction in mrsa in the environment was associated with a large reduction in mrsa contaminating doctors' hands (or . , % ci . - . , p= . ), there was no effect on the incidence of mrsa acquisition by patients (or . , % ci . - . , p= . ). disinfectants have been recommended for cleaning the hospital environment; , however, a systematic review failed to conÀ rm a link between disinfection and the prevention of hcai, although contamination of detergent and inadequate disinfection strength could have been an important confounder. whilst subsequent studies may have demonstrated a link between disinfection and reduced environmental contamination, and sometimes the acquisition of hcai, the study designs are weak with no control groups or randomisation of intervention, and/or the introduction of multiple interventions at the same time. this makes it difÀ cult to draw deÀ nitive conclusions about the speciÀ c effect of disinfection or cleaning. new technologies for cleaning and decontaminating the healthcare environment have become available over the past years, including hydrogen peroxide, and others are in the early stages of development. whilst hydrogen peroxide has been used for decontamination of selected rooms in a us hospital following use by patients with a multi-drug-resistant organism or c. difÀ cile, this study found that it was not possible to use hydrogen peroxide routinely for this purpose. the effectiveness, cost-effectiveness and practicality of this and other new technologies in terms of reducing hcai and routine use in the variety of facilities in uk hospitals has yet to be demonstrated. we identiÀ ed three studies conducted in patient care environments that provided evidence for the effectiveness of different products, containing chemical or other disinfection agents, on environmental contamination but not reductions in hcai. a prospective randomised crossover study provided evidence for the effectiveness of daily cleaning of high-touch surfaces with microÀ bre/copper-impregnated cloths on the reduction of mrsa, as discussed above. an rct demonstrated the efÀ cacy of daily high-touch surface cleaning with peracetic acid on mrsa and c. difÀ cile contamination of the environment, with a signiÀ cant reduction in mrsa and c. difÀ cile isolated from samples taken from surfaces with gloved hands (p< . ) and the hands of healthcare workers ( / in peractic acid group vs / in standard cleaning group, p= . ). a nonrandomised controlled trial (nrct) in two wards at a single hospital provided evidence that an additional cleaner was associated with a . % reduction in environmental microbial contamination of hand-touch sites ( % ci . - . , p< . ) and . % reduction in acquisition of mrsa infection ( % ci . - . , p= . ), although the infection types were not speciÀ ed. hydrogen peroxide has been used as a method of decontamination of the environment in situations where wards/ beds can be closed or left unused for the required period of time [ ] [ ] [ ] we identiÀ ed a prospective, randomised beforeafter study that compared the efÀ cacy of hypochlorite and a hydrogen peroxide decontamination system for terminal cleaning of rooms used by a patient with c. difÀ cile infection in reducing environmental contamination with c. difÀ cile. although both methods reduced environmental contamination signiÀ cantly compared with cleaning alone, hydrogen peroxide achieved a signiÀ cantly greater reduction ( % vs % decrease in proportion of samples with c. difÀ cile, p< . ). a prospective cohort study provided evidence for the efÀ cacy of hydrogen peroxide when used for terminal decontamination after standard cleaning in signiÀ cantly reducing the acquisition of multi-drug-resistant organisms in patients subsequently admitted to the rooms (adjusted incidence rate ratio . , % ci . - . ). however, the effect was mainly driven by reduction in acquisition of vre, and the results could have been confounded by the concurrent implementation of chlorhexidine baths, incomplete surveillance data and nonrandom assignment of rooms to the intervention. the efÀ cacy of antimicrobial surfaces in the clinical environment in reducing surface contamination and hcai is an area of emerging research. four non-randomised, experimental studies, conducted in clinical environments, demonstrated signiÀ cant reductions in microbial burden of between % and % on high-touch surfaces coated with metallic copper and/or its alloys compared with similar noncopper surfaces. [ ] [ ] [ ] [ ] one rct conducted in three icus reported a signiÀ cantly lower acquisition of hcai in patients allocated to rooms with six high-touch copper-coated surfaces ( . % vs . %, p= . ). a multi-variate analysis suggested that both severity of underlying illness and room assignment were independently associated with the acquisition of hcai or colonisation. however, these À ndings may have been biased by poor discrimination of patients colonised on admission because of limited surveillance cultures, poor agreement in deÀ ning cases of hcai, and incomplete adjustment for confounders in the multi-variate analysis. evidence of the effectiveness and cost-effectiveness of these technologies and their contribution to reductions in hcai is therefore not currently available. indicators of cleanliness based on levels of microbial or adenosine triphosphate (atp) contamination have been recommended; however, relationships between atp and aerobic colony counts are not consistent, and neither method distinguishes normal environmental Á ora and pathogens responsible for hcai. , benchmark values of between and relative light units have been proposed as a more objective measure of assessing the efÀ cacy of cleaning than visual assessment, although these are based on arbitrary standards of acceptable contamination that have not been shown to be associated with reductions in hcai. [ ] [ ] [ ] we identiÀ ed a number of uncontrolled before-after studies that used atp in various forms to highlight the extent of contamination of the healthcare environment. in addition, some studies described the use of atp monitoring as an intervention to improve cleaning, but the lack of a control group in the study design precluded their inclusion in this review. as cleaning will only have a transient effect on the numbers of microorganisms, regular cleaning or disinfection of hospital surfaces will not guarantee a pathogenfree environment. preventing the transfer of pathogens from the environment to patients therefore still depends on ensuring that hands are decontaminated prior to patient contact. the hospital environment must be visibly clean; free from non-essential items and equipment, dust and dirt; and acceptable to patients, visitors and staff. sp levels of cleaning should be increased in cases of infection and/ or colonisation when a suspected or known pathogen can survive in the environment, and environmental contamination may contribute to the spread of infection. the use of disinfectants should be considered for cases of infection and/ or colonisation when a suspected or known pathogen can survive in the environment, and environmental contamination may contribute to the spread of infection. shared clinical equipment used to deliver care in the clinical environment comes into contact with intact skin and is therefore unlikely to introduce infection directly. however, it can act as a vehicle by which microorganisms are transferred between patients, which may subsequently result in infection. equipment should therefore be cleaned and decontaminated after each use with cleaning agents compatible with the piece of equipment being cleaned. in some outbreak situations, the use of chlorine-releasing agents and detergent should be considered. [ ] [ ] [ ] [ ] sp shared pieces of equipment used in the delivery of patient care must be cleaned and decontaminated after each use with products recommended by the manufacturer. in a systematic review of healthcare workers' knowledge about mrsa and/or frequency of cleaning practices, three studies indicated that staff were not using appropriate cleaning practices with sufÀ cient frequency to ensure minimisation of mrsa contamination of personal equipment. staff education was lacking on optimal cleaning practices in the clinical areas. the À nding of the review is reinforced by a later observational study, which noted that lapses in adherence to the cleaning protocol were linked with an increase in environmental contamination with isolates of a. baumannii. a second systematic review of four cohort studies that compared the use of detergents and disinfectants on microbial-contaminated hospital environmental surfaces suggested that a lack of effectiveness was, in many instances, due to inadequate strengths of disinfectants, probably resulting from a lack of knowledge. we identiÀ ed no new, robust research studies of education or system interventions for this review. however, creating a culture of responsibility for maintaining a clean environment and increasing knowledge about how to decontaminate equipment and high-touch surfaces effectively requires education and training of both healthcare cleaning professionals and clinical staff. all healthcare workers need to be educated about the importance of maintaining a clean and safe care environment for patients. every healthcare worker needs to know their speciÀ c responsibilities for cleaning and decontaminating the clinical environment and the equipment used in patient care. total number of articles located = abstract indicates that the article: relates to infections associated with hospital hygiene; is written in english; is primary research, a systematic review or a meta-analysis; and appears to inform one or more of the review questions. total number of articles retrieved from sift = full text conÀ rms that the article: relates to infections associated with hospital hygiene; is written in english; is primary research (randomised controlled trials, prospective cohort, interrupted time series, controlled before-after, quasi-experimental, experimental studies answering speciÀ c questions), a systematic review or a meta-analysis including the above designs; and informs one or more of the review questions. total number of studies selected for appraisal during sift = all articles that described primary research, a systematic review or a meta-analysis and met the sift criteria were independently critically appraised by two appraisers using sign and epoc criteria. consensus and grading was achieved through discussion. total number of studies accepted after critical appraisal = total number of studies rejected after critical appraisal = this section discusses the evidence for recommendations concerning hand hygiene practice. designing and conducting robust, ethical rcts in the À eld of hand hygiene is challenging, meaning that recommendations are based on evidence from nrcts, quasi-experimental studies, observational studies and laboratory studies with volunteers. in addition, expert opinion derived from systematically retrieved and appraised professional, national and international guidelines is used. the areas discussed in this section include: • assessment of the need to decontaminate hands; • efÀ cacy of hand decontamination agents and preparations; • rationale for choice of hand decontamination practice; • technique for hand decontamination; • care required to protect hands from the adverse effects of hand decontamination practice; • promoting adherence to hand hygiene guidelines; and • involving patients and carers in hand hygiene. the transfer of organisms between humans can occur directly via hands, or indirectly via an environmental source (e.g. commode or wash basin). epidemiological evidence indicates that hand-mediated transmission is a major contributing factor in the acquisition and spread of infection in hospitals. , , the hands are colonised by two categories of microbial Á ora. the resident Á ora are found on the surface, just below the uppermost layer of skin, are adapted to survive in the local conditions and are generally of low pathogenicity, although some, such as stapylococcus epidermidis, may cause infection if transferred on to a susceptible site such as an invasive device. the transient Á ora are made up of microorganisms acquired by touching contaminated surfaces such as the environment, patients or other people, and are readily transferred to the next person or object touched. they may include a range of antimicrobial-resistant pathogens such as mrsa, acinetobacter or other multi-resistant gram-negative bacteria. if transferred into susceptible sites such as invasive devices or wounds, these microorganisms can cause life-threatening infections. transmission to non-vulnerable sites may leave a patient colonised with pathogenic and antibiotic-resistant organisms, which may result in an hcai at some point in the future. outbreak reports and observational studies of the dynamics of bacterial hand contamination have demonstrated an association between patient care activities that involve direct patient contact and hand contamination. , [ ] [ ] [ ] [ ] the association between hand decontamination, using liquid soap and water and waterless alcohol-base hand rub (abhr), and reductions in infection have been conÀ rmed by clinically-based nonrandomised trials , and observational studies. , current national and international guidance has consistently identiÀ ed that effective hand decontamination results in signiÀ cant reductions in the carriage of potential pathogens on the hands, and therefore it is logical that the incidence of preventable hcai is decreased, leading to a reduction in patient morbidity and mortality. patients are put at risk of developing an hcai when informal carers or healthcare workers caring for them have contaminated hands. decontamination refers to a process for the physical removal of dirt, blood and body Á uids, and the removal or destruction of microorganisms from the hands. the world health organization's (who) 'five moments for hand hygiene' provides a framework for training healthcare workers, audit and feedback of hand hygiene practice, and has been adopted without modiÀ cation in many countries and adapted in others (e.g. canada). hands must be decontaminated at critical points before, during and after patient care activity to prevent crosstransmission of microorganisms. , , , evidence considered by the national institute for health and clinical excellence (nice) indicated increases in hand decontamination compliance before and after patient contact associated with implementation of the who 'five moments' and us centers for disease control and prevention guidelines, but no difference in compliance after contact with patient surroundings. the following recommendations are derived from the who framework and nice guidelines, and include additional points of emphasis. hands must be decontaminated: • immediately before each episode of direct patient contact or care, including clean/aseptic procedures; • immediately after each episode of direct patient contact or care; • immediately after contact with body Á uids, mucous membranes and non-intact skin; • immediately after other activities or contact with objects and equipment in the immediate patient environment that may result in the hands becoming contaminated; and • immediately after the removal of gloves. current national and international guidelines , , consider the efÀ cacy of various preparations for the decontamination of hands using liquid soap and water, antiseptic handwash agents and abhr in laboratory studies and their effectiveness in clinical use. overall, there is no compelling evidence to favour the general use of antiseptic handwashing agents over liquid soap or one antiseptic agent over another. , , , all hand hygiene products for use in clinical care must comply with current british standards. many studies have been conducted during the past years to compare hand hygiene preparations, including abhr and gels, antiseptic handwash and liquid soap. rcts and other quasiexperimental studies have generally demonstrated alcoholbased preparations to be more effective hand hygiene agents than non-medicated soap and antiseptic handwashing agents, although a small number of studies reported no statistically signiÀ cant difference. [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] many of these studies involved the use of abhr as part of a number of interventions, or multimodal campaigns, to improve hand hygiene practice, and had methodological Á aws that weaken the causal relationship between the introduction of abhr and reductions in hcai. we identiÀ ed one multi-variate, interrupted time series which suggested that the amount of abhr used per patientday was the only factor associated with a reduction in mrsa incidence density (p= . ) in a neonatal icu in japan. incidence density fell over a -year period from an average of per patient-days, with a peak of per patientdays in august , to per patient-days in october and was sustained to july (average incidence density . per patient-days). the supporting evidence from laboratory studies of the efÀ cacy of abhr indicates that these products are highly effective at reducing hand carriage, whilst overcoming some of the recognised barriers to handwashing; most importantly, the ease of use at the point of patient care. these studies underpin a continuing trend to adopt abhr for routine use in clinical practice. however, some studies highlight the need for continued evaluation of the use of abhr within the clinical environment to ensure staff adherence to guidelines and effective hand decontamination technique. , choosing the method of hand decontamination will depend upon the assessment of what is appropriate for the episode of care, the availability of resources at or near the point of care, what is practically possible and, to some degree, personal preferences based on the acceptability of preparations or materials. in general, effective handwashing with liquid soap and water or the effective use of abhr will remove transient microorganisms and render the hands socially clean. the effective use of abhr will also substantially reduce resident microorganisms. this level of decontamination is sufÀ cient for general social contact and most clinical care activities. , , liquid soap preparations that contain an antiseptic affect both transient microorganisms and resident Á ora, and some exert a residual effect. the use of preparations containing an antiseptic is required in situations where prolonged reduction in microbial Á ora on the skin is necessary (e.g. surgery, some invasive procedures or in outbreak situations). , , abhr is not effective against all microorganisms (e.g. some viruses such as norovirus and spore-forming microorganisms such as c. difÀ cile). it will not remove dirt and organic material, and may not be effective in some outbreak situations. , we identiÀ ed two laboratory studies which demonstrated that abhr was not effective in removing c. difÀ cile spores from hands. , in the À rst study, a comparison of liquid soap and water, chlorhexidine gluconate (chg) soap and water, antiseptic hand wipes and abhr resulted in all the soap and water protocols yielding greater mean colony-forming unit (cfu) reductions, followed by the antiseptic hand wipes, than abhr. abhr was equivalent to no intervention ( . log cfu/ml, % ci - . to . log cfu/ml). in the second study, three abhr preparations with a minimum % alcohol s concentration were compared with antiseptic (chg) soap and water. antiseptic soap and water reduced spore counts signiÀ cantly compared with each of the abhrs (chg vs isagel, p= . ; chg vs endure, p= . ; chg vs purell, p= . ). in addition, % of the residual spores were readily transferred by handshake following the use of abhr. recent evidence from a laboratory study that compared the efÀ cacy of liquid soap and water and abhr with and without chg against h n inÁ uenza virus demonstrated that all the hand hygiene protocols were effective in reducing virus copies. a further study that compared the use of liquid soap and water and % ethanol hand sanitisers for the removal of rhinovirus indicated that the hand sanitisers were more effective than soap and water. two economic evaluations from the usa, included in recent nice primary care guidelines, suggest that non-compliance with hand hygiene guidelines results in increased infection-related costs. although compliance increases procurement costs of hand hygiene products, even a small increase in compliance is likely to result in reduced infection costs. we identiÀ ed a further economic analysis of a hand hygiene programme based on the introduction of point-of-use abhr and associated implementation materials. this demonstrated a reduction in episodes of hcai and a saving of $ . for every $ spent on the programme when future costs were considered. sensitivity analyses showed that the programme remained cost saving in all alternative scenarios. abhr is likely to be less costly and result in greater compliance. national and international guidelines suggest that the acceptability of agents and techniques is an essential criterion for the selection of preparations for hand hygiene. , , acceptability of preparations is dependent upon the ease with which the preparation can be used in terms of time and access, together with their dermatological effects. abhr is preferable for routine use due to its efÀ cacy, availability at the point of care and acceptability to healthcare workers. however, abhr does not remove organic matter and is ineffective against some microorganisms; therefore, handwashing is required. use an alcohol-based hand rub for decontamination of hands before and after direct patient contact and clinical care, except in the following situations when soap and water must be used: • when hands are visibly soiled or potentially contaminated with body Á uids; and • when caring for patients with vomiting or diarrhoeal illness, regardless of whether or not gloves have been worn. investigations of technique for hand decontamination are limited and generally laboratory-based or small-scale observational designs. hand hygiene technique involves both the preparation and the physical process of decontamination. , , hands and wrists need to be fully exposed to the hand hygiene product and therefore should be free from jewellery and long-sleeved clothing. a number of small-scale observational studies have demonstrated that wearing rings and false nails is associated with increased carriage of microorganisms and, in some cases, linked to the carriage of outbreak strains. department of health guidance on uniforms and work wear and nice guidelines indicate that healthcare workers should remove rings and wrist jewellery, and wear short-sleeved clothing whilst delivering patient care. , evidence for the duration of hand decontamination has been considered in previous systematic reviews underpinning guidelines, and suggests that different durations of handwashing and hand rubbing do not signiÀ cantly affect the reduction of bacteria. , the who guidelines indicate that decontamination using abhr should take - s for a seven-step process, and that handwashing should take - s for a nine-step process. we identiÀ ed one recent rct in a single hospital which demonstrated that allowing staff to decontaminate their hands 'in no particular order' took less time and was as effective as using the who seven-step technique using abhr or liquid antimicrobial soap and water (p= . and p< . , respectively). all three of the protocols tested in this study were effective in reducing hand bacterial load (p< . ). a similar result was reported by authors of a laboratory study that tested the en six-step technique against a range of other protocols. they reported that allowing volunteers to use their own 'responsible application' or a new À ve-step technique resulted in better coverage of the hands during hand decontamination. a number of laboratory-based studies that investigated methods of hand drying suggested that there is no signiÀ cant difference in the efÀ cacy of different methods of drying hands, but that good-quality paper towels dry hands efÀ ciently and remove bacteria effectively. , current guidance on infection control in the built environment suggests that air and jet driers are not appropriate for use in clinical areas. we identiÀ ed one systematic review of studies on hand drying that failed to meet the quality criteria for inclusion. due to the methodological limitations of studies, evidence recommendations are based on national and international guidelines which state that the duration of hand decontamination, the exposure of all aspects of the hands and wrists to the preparation being used, the use of vigorous rubbing to create friction, thorough rinsing in the case of handwashing, and ensuring that hands are completely dry are key factors in effective hand hygiene and the maintenance of skin integrity. healthcare workers should ensure that their hands can be decontaminated effectively by: • removing all wrist and hand jewellery; • wearing short-sleeved clothing when delivering patient care; • making sure that À ngernails are short, clean, and free from false nails and nail polish; and • covering cuts and abrasions with waterproof dressings. effective handwashing technique involves three stages: preparation, washing and rinsing, and drying. • preparation: wet hands under tepid running water before applying the recommended amount of liquid soap or an antimicrobial preparation. • washing: the handwash solution must come into contact with all of the surfaces of the hand. the hands should be rubbed together vigorously for a minimum of - s, paying particular attention to the tips of the À ngers, the thumbs and the areas between the À ngers. hands should be rinsed thoroughly. • drying: use good-quality paper towels to dry the hands thoroughly. when decontaminating hands using an alcohol-based hand rub, hands should be free of dirt and organic material and: • hand rub solution must come into contact with all surfaces of the hand; and • hands should be rubbed together vigorously, paying particular attention to the tips of the À ngers, the thumbs and the areas between the À ngers, until the solution has evaporated and the hands are dry. expert opinion suggests that skin damage is generally associated with the detergent base of the preparation and/or poor handwashing technique. , , , in addition, the frequent use of some hand hygiene agents may cause damage to the skin and alter normal hand Á ora. sore hands are associated with increased colonisation by potentially pathogenic microorganisms and increase the risk of transmission. , , , the irritant and drying effects of liquid soap and antiseptic soap preparations have been identiÀ ed as one of the reasons why healthcare practitioners fail to adhere to hand hygiene guidelines. , , , , in addition, washing hands regularly with liquid soap and water before or after the use of abhr is associated with dermatitis and is not necessary. systematic reviews conducted to underpin national guidelines , , , , have identiÀ ed a range of studies that compared the use of alcohol-based preparations with liquid soap and water using self-assessment of skin condition by nurses. these studies found that abhr was associated with less skin irritation than liquid soap and water. , , , , [ ] [ ] [ ] in addition, a longitudinal study of the introduction and subsequent use of abhr over a -year period observed no reports of irritant and contact dermatitis associated with the use of abhr. we identiÀ ed a recent study which suggested that two abhr preparations containing a glycerol emollient were more acceptable to staff (p< . ). hand moisturisers/ emollients that are for shared use are more likely to become contaminated, and have been associated with an outbreak of infection in a neonatal unit. current national and international guidance suggests that skin care, through the appropriate use of hand lotion or moisturisers added to hand hygiene preparations, is an important factor in maintaining skin integrity, encouraging adherence to hand decontamination practices and assuring the health and safety of healthcare practitioners. , , clinical staff should be made aware of the potentially damaging effects of hand decontamination products, and encouraged to use an emollient hand cream regularly to maintain the integrity of the skin. consult the occupational health team or a general practitioner if a particular liquid soap, antiseptic handwash or alcohol-based hand rub causes skin irritation. national and international guidelines emphasise the importance of adherence to hand hygiene guidance, and provide an overview of the barriers and factors that inÁ uence hand hygiene compliance. , , , the use of multi-modal approaches to improving hand hygiene practice and behaviour has been advocated for over years. observational studies have consistently reported an association between multi-modal interventions involving the introduction of near-patient abhr, audit and feedback, reminders and education, and greater compliance by healthcare staff. , [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] an early systematic review of studies involving interventions to improve hand hygiene compliance concludes that: • single interventions have a short-term inÁ uence on hand hygiene; • reminders have a modest but sustained effect; • feedback increases rates of hand hygiene but must be regular; • near-patient alcohol-based preparations improve the frequency with which healthcare workers clean their hands; and • multi-faceted approaches have a more marked effect on hand hygiene and rates of hcai. h. p. loveday et al. / journal of hospital infection s ( ) s -s national hand hygiene campaigns have been modelled on the multi-modal approach and implemented across the world. , , , in england and wales, the national patient safety agency's 'cleanyourhands campaign' was piloted and implemented between and with the aim of creating sustainable change in hand hygiene compliance. the campaign comprised the use of near-patient abhr, national poster materials, audit and feedback, and materials for patient engagement. recent cochrane reviews of randomised and controlled clinical trials, interrupted time series and controlled before-after studies have suggested that the majority of studies conducted in this À eld have methodological biases that exclude them from this review. , we identiÀ ed four systematic reviews of interventions to improve hand hygiene compliance. , [ ] [ ] [ ] the most recent cochrane review identiÀ ed studies published after for potential inclusion, but only four studies (one rct, two interrupted time series and one controlled before-after study) were included following detailed quality assessment. the heterogeneity of interventions and methods precluded the pooling and meta-analysis of results, and it was concluded that multi-faceted campaigns that include social marketing or staff engagement may be more effective than campaigns without these components, and that education or product substitution alone were less effective. an integrative systematic review of studies that reported a wide range of interventions, including multi-modal interventions and hand hygiene product changes, only scored nine of the included studies as having limited or no fatal Á aws. the authors concluded that design limitations made it difÀ cult to generalise the study results or isolate the speciÀ c effects of hand hygiene (or other interventions) on reductions in hcai. an earlier systematic review of 'bundled' behavioural intervention studies that reported hcai or rates of colonisation as the primary outcome identiÀ ed potential studies for inclusion; of these, only four had quality scores > %. again, due to the heterogeneity of study interventions and outcomes, the results were narratively synthesised. the authors concluded that the formation of multi-disciplinary quality improvement teams and educational interventions might be effective strategies to improve hand hygiene and reduce rates of hcai. the À nal systematic review focused speciÀ cally on educational interventions to improve hand hygiene compliance and competence in hospital settings, and included all study designs that reported at least one outcome measure of hand hygiene competence and had a follow-up of at least months. thirty studies met the inclusion criteria for the review, but it was not possible to separate competence from compliance. educational interventions taught or re-taught the correct methods for hand hygiene and then assessed compliance. the authors concluded that educational interventions had a greater impact if compliance with hand hygiene was low. multiple interventions were better than single interventions in sustaining behaviour change, as were continuous, rather than one-off, interventions. however, it was not possible to determine the duration or sustainability of behaviour change in these studies. we identiÀ ed six new studies in our systematic review: one cluster rct and process evaluation, , one step-wedge cluster rct, two interrupted time series studies , and one controlled before-after study that evaluated multi-modal interventions with varying components. in a cluster rct that also included a process evaluation, the authors tested a set of core elements in a 'state-of-the-art strategy' (sas) against a team-leader-directed strategy (tds) at baseline (t ), immediately following the intervention (t ) and months later (t ) to ascertain the additional beneÀ ts of leadership and staff engagement components. , in the intention-to-treat analysis (itt), an or of . ( % ci . - . , p< . ) in favour of the tds between t and t suggested that engaging ward leadership and the involvement of teams in setting norms and targets resulted in greater compliance with hand hygiene. however, there was no signiÀ cant difference between the groups' compliance at t in the itt (p= . ), with the sas also having a sustained effect. the process evaluation examined the extent to which the content, dosage and coverage of the intervention had been delivered. an as-treated analysis demonstrated a greater effect size for the tds at t with a signiÀ cant difference in hand hygiene compliance (p< . ). the process evaluation also suggested that feedback about individual hand hygiene performance at t and t (p< . and p< . , respectively), challenging colleagues on undesirable hand hygiene practice (p< . ), and support from colleagues in performing hand hygiene (p< . ) were positively correlated with changes in nurses' hand hygiene compliance. the second cluster rct used a step-wedge design to assess a behavioural feedback intervention in intensive therapy units (itus) and acute care of the elderly (ace) wards at sites participating in the 'cleanyourhands campaign'. the primary and secondary outcome measures were hand hygiene compliance measured by covert direct observation for h every weeks, and soap and abhr procurement, respectively. sixty wards were recruited, of which implemented the intervention. the itt analysis ( wards) showed a signiÀ cant effect of the intervention in the itus but not the ace wards, equating to a - % increase in compliance, with estimated or of . ( % ci . - . , p=< . ) in itus and estimated or of . ( % ci . - . , p= . ) in ace wards. the perprotocol analysis ( wards) showed a signiÀ cant increase in compliance in both ace wards and itus of - % and - %, respectively, with estimated or of . ( % ci . - . , p . ) in ace wards and estimated or of . ( % ci . - . , p . ) in itus. the authors concluded that individual feedback and team action planning resulted in moderate but sustained improvements in hand hygiene adherence. the difÀ culties in implementing this intervention point to the problems that might be faced in a non-trial context. two interrupted time series studies of the -year national 'cleanyourhands campaign' in england and a -year hospitalwide programme in taiwan demonstrated increased hand hygiene compliance (measured by procurement of abhr and liquid soap) and reductions in hcai [mrsa and c. difÀ cile, and mrsa and extensively-drug-resistant acinetobacter (xdrab)]. , in the national study, increased procurement of soap was independently associated with reductions in c. difÀ cile infection (adjusted incidence rate ratio for -ml increase per patient-bed-day . , % ci . - . , p< . ) and mrsa in the last four quarters of the study (adjusted incidence rate ratio for -ml increase per patient-bed-day . , % ci . - . , p< . ). the 'cleanyourhands campaign' was not independent of other national programmes to reduce analysis also identiÀ ed that the publication of the health act and the department of health improvement team visits were associated with reductions in mrsa and c.difÀ cile. in the hospital-wide study, the authors demonstrated a decrease in the cumulative incidence of hcai caused by mrsa (change in level, p= . ; change in trend, p= . ) and xdrab (change in level, p= . ; change in trend, p< . ) during the intervention period. hand hygiene compliance was signiÀ cantly correlated with increased consumption of abhr, and improved overall from . % in to . % in (p< . ). hand hygiene compliance was also signiÀ cantly correlated with professional categories of healthcare workers (p< . ) in both general wards and icus (p< . ). the controlled before-after study of a range of patient safety interventions in england, including hand hygiene, as measured by abhr and soap consumption in non-specialist acute hospitals, reported no signiÀ cant differences in the rate of increase in consumption of abhr (p= . favouring controls and p= . favouring intervention) and non-signiÀ cant decreases in c. difÀ cile (p= . ) and mrsa (p= . ). alcohol-based hand rub should be made available at the point of care in all healthcare facilities. hand hygiene resources and healthcare worker adherence to hand hygiene guidelines should be audited at regular intervals, and the results should be fed back to healthcare workers to improve and sustain high levels of compliance. healthcare organisations must provide regular training in risk assessment, effective hand hygiene and glove use for all healthcare workers. local programmes of education, social marketing, and audit and feedback should be refreshed regularly and promoted by senior managers and clinicians to maintain focus, engage staff and produce sustainable levels of compliance. patient involvement in multi-modal strategies to improve hand hygiene among healthcare workers is established, and includes making it acceptable for patients and carers to request that healthcare workers clean their hands. however, research suggests that many patients and carers do not feel empowered to challenge staff, particularly doctors. , , , many nhs trusts have promoted hand hygiene among visitors by placing abhr at the entrances to wards and patient rooms, but there is no evidence that this reduces hcai. despite being highlighted as an important gap in research, the role of patients' hands in the cross-transmission of microorganisms has not been investigated systematically, other than in ecologic studies that describe hand or skin contamination [ ] [ ] [ ] or observations of non-use of hand hygiene products. studies of effective interventions to enable patients to clean their hands remain small scale and descriptive in nature. [ ] [ ] [ ] [ ] we identiÀ ed three studies that described interventions to improve patient hand hygiene: one in an outbreak situation, one uncontrolled before-after study of parent education in a single paediatric icu, and one as part of a prospective observational study in a community hospital. none of these studies met the quality criteria for inclusion in this systematic review. [ ] [ ] [ ] however, all of these studies suggested that improving patient/carer hand hygiene had some effect on crosstransmission of microorganisms and hand hygiene technique. national guidelines indicate that it is important to educate patients and carers about the importance of hand hygiene, and inform them about the availability of hand hygiene facilities and their role in maintaining standards of healthcare workers' hand hygiene. patients and relatives should be provided with information about the need for hand hygiene and how to keep their own hands clean. patients should be offered the opportunity to clean their hands before meals; after using the toilet, commode or bedpan/urinal; and at other times as appropriate. products available should be tailored to patient needs and may include alcohol-based hand rub, hand wipes and access to handwash basins. total number of articles located = abstract indicates that the article: relates to infections associated with hand hygiene; is written in english; is primary research, a systematic review or a meta-analysis; and appears to inform one or more of the review questions. total number of articles retrieved from sift = full text conÀ rms that the article: relates to infections associated with hand hygiene; is written in english; is primary research (randomised controlled trials, prospective cohort, interrupted time series, controlled before-after, quasi-experimental, experimental studies answering speciÀ c questions), a systematic review or a meta-analysis including the above designs; and informs one or more of the review questions. total number of studies selected for appraisal during sift = all articles that described primary research, a systematic review or a meta-analysis and met the sift criteria were independently critically appraised by two appraisers using sign and epoc criteria. consensus and grading was achieved through discussion. total number of studies accepted after critical appraisal = total number of studies rejected after critical appraisal = this section discusses the evidence and associated recommendations for the use of ppe by healthcare workers in acute care settings and includes the use of aprons, gowns, gloves, eye protection and face masks/respirators to prevent potential transmission of pathogenic microorganisms to staff, patients and the healthcare environment. the use of gloves for other purposes does not form part of these guidelines. where health and safety legislation underpins a recommendation, this is indicated by 'health & safety (h&s)' in addition to the classiÀ cation of any clinical evidence underpinning the recommendations. the primary roles of ppe are to protect staff and reduce opportunities for cross-transmission of microorganisms in hospitals. , , there is no evidence that uniforms or work clothing are associated with hcai. however, there is a public expectation that healthcare workers will wear work and protective clothing to minimise any potential risk to patients and themselves. , the decision to use or wear ppe must be based upon an assessment of the level of risk associated with a speciÀ c patient care activity or intervention, and take account of current health and safety legislation. [ ] [ ] [ ] [ ] there is evidence that both a lack of knowledge of guidelines and non-adherence to guideline recommendations are common, and that regular in-service education and training is required. , [ ] [ ] [ ] [ ] selection of personal protective equipment must be based on an assessment of the: • risk of transmission of microorganisms to the patient or carer; • risk of contamination of healthcare practitioners' clothing and skin by patients' blood or body Á uids; and • suitability of the equipment for proposed use. healthcare workers should be educated and their competence assessed in the: • assessment of risk; • selection and use of personal protective equipment; and • use of standard precautions. supplies of personal protective equipment should be made available wherever care is delivered and risk assessment indicates a requirement. the use of gloves as an element of ppe and contact precautions is an everyday part of clinical practice for healthcare workers. , , there are other indications unrelated to preventing the cross-transmission of infection that require gloves to be worn (e.g. the use of some chemicals or medications). the two main indications for the use of gloves in the prevention of hcai are: • to protect hands from contamination with organic matter and microorganisms; and • to reduce the risk of cross-transmission of microorganisms to staff and patients. gloves should be selected on the basis of a risk assessment, and should be suitable for the proposed task and the materials being handled. [ ] [ ] [ ] gloves are categorised as medical gloves (examination and surgical) and protective gloves. examination gloves are available as sterile or non-sterile for use by healthcare workers during clinical care to prevent contamination with microorganisms, blood and body Á uids. surgical gloves are available as sterile for use by healthcare workers during surgical and other invasive procedures. protective gloves are used to protect healthcare workers from chemical hazards. gloves should not be worn as a substitute for hand hygiene. their prolonged and unnecessary use may cause adverse reactions and skin sensitivity, and may lead to crosscontamination of the patient environment. , the need to wear gloves and the selection of appropriate glove materials requires careful assessment of the task to be performed and its related risks to patients and healthcare workers. , , , , risk assessment should include consideration of: • who is at risk (patient or healthcare worker) and whether sterile or non-sterile gloves are required; • potential for exposure to blood, body Á uids, secretions and excretions; • contact with non-intact skin or mucous membranes during care and invasive procedures; and • healthcare worker and patient sensitivity to glove materials. we identiÀ ed four observational studies which suggested that clinical gloves are not used in line with current guidance, and that glove use impacts negatively on hand hygiene. [ ] [ ] [ ] [ ] in addition, a cluster rct of screening and enhanced contact precautions for patients colonised with mrsa or vre found no reduction in transmission, but also found that adherence to contact precautions was less than ideal. gloves must be removed immediately following each care activity for which they have been worn, and hands must be decontaminated in order to prevent the cross-transmission of microorganisms to other susceptible sites in that individual or to other patients. gloves should not be washed or decontaminated with abhr as a substitute for changing gloves between care activities. there is evidence that hands become contaminated when clinical gloves are worn, even when the integrity of the glove appears undamaged. , , in terms of leakage, gloves made from natural rubber latex (nrl) perform better than vinyl gloves in laboratory test conditions. , standards for the manufacture of medical gloves for single use require gloves to perform to european standards. [ ] [ ] [ ] [ ] [ ] however, the integrity of gloves cannot be guaranteed, and hands may become contaminated during the removal of gloves. , , , the appropriate use of medical gloves provides barrier protection and reduces the risk of hand contamination from blood, body Á uids, secretions and excretions, but does not eliminate the risk. hands cannot be considered to be clean because gloves have been worn, and should be decontaminated following the removal of gloves. used gloves must be disposed of in accordance with the requirements of current legislation and local policy for waste management. gloves must be worn for: • invasive procedures; • contact with sterile sites and nonintact skin or mucous membranes; • all activities that have been assessed as carrying a risk of exposure to blood or body Á uids; and • when handling sharps or contaminated devices. gloves must be: • worn as single-use items; • put on immediately before an episode of patient contact or treatment; • removed as soon as the episode is completed; • changed between caring for different patients; and • disposed of into the appropriate waste stream in accordance with local policies for waste management. hands must be decontaminated immediately after gloves have been removed. clinical gloves should be used by healthcare workers to prevent the risk of hand contamination with blood, body Á uids, secretions and excretions, and to protect patients from potential cross-contamination of susceptible body sites or invasive devices. having decided that gloves should be used for a healthcare activity, the healthcare worker must make a choice between the use of: • sterile or non-sterile gloves, based on contact with susceptible sites or clinical devices; and • surgical or examination gloves, based on the aspect of care or treatment to be undertaken. healthcare organisations must provide gloves that conform to european standards (en - , - , - ), and which are acceptable to healthcare practitioners. [ ] [ ] [ ] medical gloves are available in a range of materials, the most common being nrl, which remains the material of choice due to its efÀ cacy in protecting against bloodborne viruses and properties that enable the wearer to maintain dexterity. , patient or healthcare practitioner sensitivity to nrl proteins must also be taken into account when deciding on glove materials. synthetic gloves are generally more expensive than nrl gloves and may not be suitable for all purposes. nitrile gloves have the same chemical range as nrl gloves and may also lead to sensitivity problems in healthcare workers and patients. polythene gloves are not suitable for clinical use due to their permeability and tendency to damage easily. a study that compared the performance of nitrile, latex, copolymer and vinyl gloves under stressed and unstressed conditions found that nitrile gloves had the lowest failure rate, suggesting that nitrile gloves are a suitable alternative to nrl gloves, provided that there are no sensitivity issues. importantly, the study noted variation in performance of the same type of glove produced by different manufacturers. the health and safety executive (hse) also provide a guide-to-glove selection for employers. a range of ce-marked medical and protective gloves that are acceptable to healthcare personnel and suitable for the task must be available in all clinical areas. sensitivity to natural rubber latex in patients, carers and healthcare workers must be documented, and alternatives to natural rubber latex gloves must be available. national and international guidelines recommend that ppe should be worn by all healthcare workers when close contact with the patient, materials or equipment may lead to contamination of uniforms or other clothing with microorganisms, or when there is a risk of contamination with blood or body Á uids. , , disposable plastic aprons are recommended for general clinical use. full-body gowns need only be used where there is the possibility of extensive splashing of blood or body Á uids, and should be Á uid repellent. , we identiÀ ed a systematic review of the evidence that microbial contaminants found on the work clothing of healthcare practitioners are a signiÀ cant factor in cases of hcai. the reviewers identiÀ ed seven small-scale studies that described the progressive contamination of work clothing during clinical care, and a further three studies that suggested a link with microbial contamination and infection. , [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] one of the three studies was conducted in a simulated scenario and demonstrated that it was possible to transfer s. aureus from nurses' gowns to patients' bed sheets, but this was not associated with clinical infection. a further pair of linked studies, associated with an outbreak of bacillus cereus, showed an epidemiological link between contaminated clothing and hcai, but this occurred when surgical scrub suits became highly contaminated in an industrial laundry, rather than as a result of clinical care. , a further study demonstrated high levels of contamination of gowns, gloves and stethoscopes with vre following examination of patients known to be infected. a systematic review of eight studies that assessed the effects of gowning by attendants and visitors found no evidence to suggest that over-gowns are effective in reducing mortality, clinical infection or bacterial colonisation in infants admitted to newborn nurseries. one quasi-experimental study investigated the use of gowns and gloves as opposed to gloves alone for prevention of acquisition of vre in a medical icu setting. a further prospective observational study investigated the use of a similar intervention in a medical icu. these studies suggested that the use of gloves and gowns may minimise the transmission of vre when colonisation pressure is high. disposable plastic aprons must be worn when close contact with the patient, materials or equipment pose a risk that clothing may become contaminated with pathogenic microorganisms, blood or body Á uids. full-body Á uid-repellent gowns must be worn where there is a risk of extensive splashing of blood or body Á uids on to the skin or clothing of healthcare workers. plastic aprons/Á uid-repellent gowns should worn as single-use items for one procedure or episode of patient care, and disposed of into the appropriate waste stream in accordance with local policies for waste management. when used, non-disposable protective clothing should be sent for laundering. healthcare workers (and sometimes patients) may use standard, Á uid-repellent surgical face masks to prevent respiratory droplets from the mouth and nose being expelled into the environment. face masks are also used, often in conjunction with eye protection, to protect the mucous membranes of the wearer from exposure to blood and/or body Á uids when splashing may occur. our previous systematic reviews failed to reveal any robust experimental studies that demonstrated that healthcare workers wearing surgical face masks protected patients from hcai during routine ward procedures, such as wound dressing or invasive medical procedures. , face masks are also used to protect the wearer from inhaling aerosolised droplet nuclei expelled from the respiratory tract. as surgical face masks are not effective at À ltering out such particles, specialised respiratory protective equipment (respirators) may be recommended for the care of patients with certain respiratory diseases [e.g. active multiple drugresistant pulmonary tuberculosis, severe acute respiratory syndrome (sars) and pandemic inÁ uenza]. the À ltration efÀ ciency of these respirators will protect the wearer from inhaling small respiratory particles, but to be effective, they must À t closely to the face to minimise leakage around the mask. , , the selection of the most appropriate respiratory protective equipment (rpe) should be based on a suitable risk assessment that includes the task being undertaken, the characteristics of the biological agent to which there is a risk of exposure, as well as the duration of the task and the local environment. where the activity involves procedures likely to generate aerosols of biological agents transmitted by an airborne route (e.g. intubation), rpe with an assigned protection factor (apf) of (equivalent to ffp ) should be used. in other circumstances, such as where the agent is transmitted via droplet rather than aerosol or where the level of aerosol exposure is low, the risk assessment may conclude that other forms of rpe (e.g. apf / ffp ) or a physical barrier (e.g. surgical face mask) may be appropriate, such as when caring for patients with inÁ uenza. where rpe is required, it must À t the user properly and the user must be fully trained in how to wear and adjust it. we identiÀ ed four systematic reviews of the use of facial protection, all of which had been undertaken in the aftermath of the sars outbreak and in response to the h n inÁ uenza pandemic. a range of study designs were considered in each of the reviews, including cluster rcts, rcts, cohort studies and descriptive before-after studies. overall, many studies were poorly controlled, with no accounting for confounders, such as poor compliance in the weaker studies. the authors of each of the reviews concluded that there was no strong evidence that masks/respirators alone are effective for the prevention of respiratory viral infections. masks/respirators should be used together with other protective measures to reduce transmission. [ ] [ ] [ ] [ ] our previous systematic review indicated that different protective eyewear offered protection against physical splashing of infected substances into the eyes (although not on all occasions), but that compliance was poor. expert opinion recommends that face and eye protection reduce the risk of occupational exposure of healthcare workers to splashes of blood or body Á uids. , , , sp fluid-repellent surgical face masks and eye protection must be worn where there is a risk of blood or body Á uids splashing into the face and eyes. appropriate respiratory protective equipment should be selected according to a risk assessment that takes account of the infective microorganism, the anticipated activity and the duration of exposure. respiratory protective equipment must À t the user correctly and they must be trained in how to use and adjust it in accordance with health and safety regulations. personal protective equipment should be removed in the following sequence to minimise the risk of cross/self-contamination: • gloves; • apron; • eye protection (when worn); and • mask/respirator (when worn). hands must be decontaminated following the removal of personal protective equipment. total number of articles located = ag ( ), fp ( ) abstract indicates that the article: relates to infections associated with protective clothing; is written in english; is primary research, a systematic review or a meta-analysis; and appears to inform one or more of the review questions. total number of articles retrieved from sift = ag ( ), fp ( ) full text conÀ rms that the article: relates to infections associated with protective clothing; is written in english; is primary research (randomised controlled trials, prospective cohort, interrupted time series, controlled before-after, quasi-experimental), a systematic review or a meta-analysis including the above designs; and informs one or more of the review questions. total number of studies selected for appraisal during sift = ag ( ), fp ( ) all articles that described primary research, a systematic review or a meta-analysis and met the sift criteria were independently critically appraised by two appraisers using sign and epoc criteria. consensus and grading was achieved through discussion. total number of studies accepted after critical appraisal = ag ( ), fp ( ) total number of studies rejected after critical appraisal = ag ( ), fp ( ) this section discusses the evidence and associated recommendations for the safe use and disposal of sharps in general care settings. this includes minimising the potential infection risks associated with sharps use and disposal, and the use of needle protection devices. the use and disposal of sharps is subject to the health and safety at work act and several elements of health and safety legislation including: where health and safety legislation underpins a recommendation, this is indicated by 'h&s' in addition to the classiÀ cation of any clinical evidence underpinning the recommendations. the hse deÀ ne a sharp as a needle, blade or other medical instrument capable of cutting or piercing the skin. similarly, a sharps injury is an incident that causes a needle, blade or other medical instrument to penetrate the skin (percutaneous injury). the safe handling and disposal of needles and other sharp instruments forms part of an overall strategy of clinical waste disposal to protect staff, patients and visitors from exposure to bloodborne pathogens. the national audit ofÀ ce identiÀ ed that needlestick and sharps injuries ranked alongside moving and handling, falls, trips and exposure to hazardous substances as the main types of accidents experienced by nhs staff. a later royal college of nursing survey of nurses found that almost half ( %) had, at some point in their career, sustained a sharps injury from a device that had previously been used on a patient. a similar number ( %) reported fearing sharps injuries, and nearly half ( %) reported that they had not received training from their employer on safe needle use. the 'eye of the needle' report from the health protection agency conÀ rms that healthcare workers continue to be exposed to bloodborne virus infections, even though such exposures are largely preventable. the average risk of transmission of bloodborne viruses following a single percutaneous exposure from an infected person, in the absence of appropriate post-exposure prophylaxis, has been estimated to be: , , • hepatitis b virus, one in three; • hepatitis c virus, one in ; and • human immunodeÀ ciency virus, one in . national and international guidelines are consistent in their recommendations for the safe use and disposal of sharp instruments and needles, and the management of healthcare workers who are exposed to potential infection from bloodborne viruses. , [ ] [ ] [ ] as with many infection prevention and control policies, the assessment and management of the risks associated with the use of sharps is paramount, and safe systems of work and engineering controls must be in place to minimise any identiÀ ed risks. national and european union legislation requires the uk and all eu member states to provide protection for all healthcare workers exposed to the risk of sharps injuries. in summary, the health and safety (sharp instruments in healthcare) regulations require all employers, under existing health and safety law, to: • conduct risk assessments; • avoid unnecessary use of sharps and, where this is not possible, use safer sharps that incorporate protection mechanisms; • prevent the recapping of needles; • ensure safe disposal by placing secure sharps containers close to the point of use; • provide employees with adequate information and training on the safe use and disposal of sharps, what to do in the event of a sharps injury and the arrangements for testing, immunisation and post-exposure prophylaxis, where appropriate; • record and investigate sharps incidents; and • provide employees who have been injured with access to medical advice, and offer testing, immunisation, post-exposure prophylaxis and counselling, where appropriate. , legislation also includes a duty for employees who receive a sharps injury whilst undertaking their work to inform their employer as soon as is practicable. , all healthcare workers must be aware of their responsibility in avoiding sharps injuries. we identiÀ ed a systematic review which included studies that focused on education and training interventions to minimise the incidence of occupational injuries involving sharps devices. the authors identiÀ ed À ve primary beforeafter studies that demonstrated a consistent reduction in the incidence of percutaneous injuries when other safety initiatives (e.g. training) were implemented before and during the introduction of safer sharps devices. [ ] [ ] [ ] [ ] [ ] these studies used a range of interventions in one setting and are not generalisable. however, education is essential in ensuring that staff understand safe ways of working and how to use safer sharps devices. this should form a part of induction programmes for new staff and on-going in-service education. the introduction of new devices should include an appropriate training programme as part of staff introduction. sharps must not be passed directly from hand to hand, and handling should be kept to a minimum. needles must not be recapped, bent or disassembled after use. used sharps must be discarded at the point of use by the person generating the waste. all sharps containers must: • conform to current national and international standards; • be positioned safely, away from public areas and out of the reach of children, and at a height that enables safe disposal by all members of staff; • be secured to avoid spillage; • be temporarily closed when not in use; • not be À lled above the À ll line; and • be disposed of when the À ll line is reached. all clinical and non-clinical staff must be educated about the safe use and disposal of sharps and the action to be taken in the event of an injury. to improve patient and staff safety, legislation and the department of health require healthcare providers and their employees to pursue safer methods of working through risk assessment to eliminate the use of sharps and, where this is not possible, the use of safer sharps. , , the incidence of sharps injuries has led to the development of safety devices in many different product groups. they are designed to minimise the risk of operator injury during sharps use, as well as 'downstream' injuries that occur after disposal, often involving the housekeeping or portering staff responsible for the collection of sharps disposal units. the lack of well-designed, controlled intervention studies means that evidence to show whether or not safety devices are effective in reducing rates of infection is limited. however, a small number of studies have shown signiÀ cant reductions in injuries associated with the use of safety devices in cannulation, , phlebotomy - and injections. it is logical that where needle-free or other safety devices are used, there is a resulting reduction in sharps injuries. a review of needlestick injuries in scotland suggested that % of injuries would 'probably' or 'deÀ nitely' have been prevented if a safety device had been used. however, some studies have identiÀ ed a range of barriers to the expected reduction in injuries, including staff resistance to using new devices, complexity of device operation or improper use, and poor training. a comprehensive report and product review s conducted in the usa provides background information and guidance on the need for and use of needlestick-prevention devices, but also gives advice on establishing and evaluating a sharps injury prevention programme. it reported that all devices have limitations in relation to cost, applicability and/or effectiveness. some of the devices available are more expensive than standard devices, may not be compatible with existing equipment, and may be associated with an increase in bloodstream infection rates if used incorrectly. nice identiÀ ed three rcts that compared safety cannulae with standard cannulae. the studies were all in hospital settings and of low/very-low quality. the quality of evidence for safety needle devices was low, with no rcts identiÀ ed and the À ve before-after implementation studies being of very-low quality. the quality of evidence for training was similarly low, with the type of training varying across the À ve observational studies identiÀ ed. we identiÀ ed a systematic review undertaken by the hse which reviewed studies that provided evidence for reductions in the incidence of occupational sharps injuries associated with use of sharps safety devices, education and training, and the acceptability of sharps safety devices. thirteen studies, predominantly with observational designs, demonstrated that safer sharps devices were associated with a signiÀ cant reduction in the incidence of healthcare worker needlestick injury. , , [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] however, safety devices were not the total solution to reducing occupational injury. the beneÀ cial outcome of consulting with end-users of safer sharps devices before they are introduced was demonstrated in À ve studies identiÀ ed in this review. , , [ ] [ ] [ ] [ ] in the usa, the occupational safety health administration and the national institute for occupational safety and health suggest that a thorough evaluation of any device is essential before purchasing decisions are made. , similarly, the hse suggests that the end-users of any safer sharps device should be involved in the assessment of user acceptability and clinical applicability of any needle safety devices. the evaluation should ensure that the safety feature works effectively and reliably, that the device is acceptable to healthcare practitioners and that it does not have an adverse effect on patient care. use safer sharps devices where assessment indicates that they will provide safe systems of working for healthcare workers. organisations should involve end-users in evaluating safer sharps devices to determine their effectiveness, acceptability to practitioners, impact on patient care and cost beneÀ t prior to widespread introduction. systematic review questions total number of articles located = abstract indicates that the article: relates to infections associated with sharps; is written in english, is primary research, a systematic review or a meta-analysis; and appears to inform one or more of the review questions. total number of articles retrieved from sift = full text conÀ rms that the article: relates to infections associated with sharps; is written in english; is primary research (randomised controlled trials, prospective cohort, interrupted time series, controlled before-after, quasi-experimental), a systematic review or a meta-analysis including the above designs; and informs one or more of the review questions. total number of studies selected for appraisal during sift = all articles that described primary research, a systematic review or a meta-analysis and met the sift criteria were independently critically appraised by two appraisers using sign and epoc criteria. consensus and grading was achieved through discussion. the term 'asepsis' means the absence of potentially pathogenic microorganisms. asepsis applies to both medical and surgical procedures. medical asepsis aims to minimise the risk of contamination by microorganisms, and prevent their transmission by applying standard principles of infection prevention, including decontaminating hands, use of ppe, maintaining an aseptic area, and not touching susceptible sites or the surface of invasive devices. surgical asepsis is a more complex process, including procedures to eliminate microorganisms from an area (thus creating an aseptic environment), and is practised in operating theatres and for invasive procedures, such as the insertion of a central venous catheter (cvc). 'aseptic technique' is a term applied to a set of specifi c practices and procedures used to assure asepsis and prevent the transfer of potentially pathogenic microorganisms to a susceptible site on the body (e.g. an open wound or insertion site for an invasive medical device) or to sterile equipment/devices. it involves ensuring that susceptible body sites and the sterile parts of devices in contact with a susceptible site are not contaminated during the procedure. the aseptic technique is an essential element of the prevention of hcai, particularly when the body's natural defence mechanisms are compromised. however, similar to nice, we identifi ed no clinical or economic evidence that any one approach to the aseptic technique is more clinically or cost-effective than another. thus, all recommendations here are class d/gpp. no studies that met the inclusion criteria and compared education interventions for improving the aseptic technique generally were identifi ed. we identifi ed one systematic review that assessed education interventions to improve competence in the aseptic insertion and maintenance of cvcs. the review included studies of educational interventions that were designed to change staff behaviour related to: general asepsis, maximal sterile barrier (msb) precautions during insertion, cutaneous antisepsis, and other aspects of insertion and maintenance practice. the studies all described multi-modal education approaches alone or combined with demonstration, simulation, video and self-study. only one of these studies reported improvements in competence with performing the aseptic technique as a discrete outcome, and nine studies measured overall compliance with the total insertion bundle. variations in terminology are used in the literature to describe the aseptic technique. inconsistencies in the use of terms and application of the principles of asepsis in clinical practice have been addressed in a framework referred to as 'aseptic non-touch technique'. this provides a practice structure and educational materials aimed at minimising variation and developing competence in practice. however, no comparative evidence indicating the effi cacy of this approach was identifi ed. organisations should provide education to ensure that healthcare workers are trained and competent in performing the aseptic technique. the aseptic technique should be used for any procedure that breaches the body's natural defences, including the: • insertion and maintenance of invasive devices; • infusion of sterile fl uids and medication; and • care of wounds and surgical incisions. abstract indicates that the article: relates to infections associated with asepsis; is written in english; is primary research, a systematic review or a meta-analysis; and appears to inform one or more of the review questions. full text conÀ rms that the article: relates to infections associated with asepsis; is written in english; is primary research (randomised controlled trialsrct), prospective cohort, interrupted time series, controlled before-after, quasi-experimental), a systematic review or a meta-analysis including the above designs; and informs one or more of the review questions. total number of studies selected for appraisal during sift = all articles that described primary research, a systematic review or a meta-analysis and met the sift criteria were independently critically appraised by two appraisers using sign and epoc criteria. consensus and grading was achieved through discussion. total number of studies accepted after critical appraisal = total number of studies rejected after critical appraisal = this guidance is based on the best critically appraised evidence currently available. the type and class of supporting evidence explicitly linked to each recommendation is described. evidence identiÀ ed in the healthcare infection control practices advisory committee (hicpac) systematic review was used to support the recommendations in these guidelines. some recommendations from the previous guidelines have been revised to improve clarity; where a new recommendation has been made, this is indicated in the text. these recommendations are not detailed procedural protocols, and need to be incorporated into local guidelines. none are regarded as optional. these guidelines apply to adults and children aged year who require a short-term indwelling urethral catheter ( days), and should be read in conjunction with the guidance on standard principles. the recommendations are divided into six distinct interventions: • assessing the need for catheterisation; • selection of catheter type and system; • catheter insertion; • catheter maintenance; • education of patients, relatives and healthcare workers; and • system interventions for reducing the risk of infection. urinary tract infection (uti) is the most common infection acquired as a result of health care, accounting for % of hcai, with between % and % of utis associated with a urethral catheter. , catheters predispose to infection because microorganisms are able to bypass natural host mechanisms, such as the urethra and micturition, and gain entry to the bladder. most microorganisms causing catheterassociated uti (cauti) gain access to the urinary tract either extraluminally or intraluminally. extraluminal contamination may occur as the catheter is inserted, by contamination of the catheter from healthcare workers' hands or from the patient's own perineal Á ora. extraluminal contamination is also thought to occur from microorganisms ascending from the perineum. intraluminal contamination occurs by reÁ ux of microorganisms from a contaminated urine drainage bag. the bladder is normally sterile; in the non-catheterised patient, a uti is usually identiÀ ed from the symptoms of dysuria and frequency of urination. patients who develop a uti with a short-term indwelling urethral catheter in place may not experience these symptoms, and diagnosis may be based on other signs, such as fever or suprapubic or loin tenderness. after a few days of catheterisation, microorganisms may be isolated from urine and, in the absence of any symptoms of uti, this is called 'bacteriuria'. the duration of catheterisation is the dominant risk factor for cauti, and virtually all catheterised patients develop bacteriuria within month. for the purpose of these guidelines, a duration of catheterisation of days is considered to be a short-term catheterisation. several factors contribute to the potential development of cauti, including the formation of bioÀ lms and encrustation of the catheter. bacteria on the catheter surface and drainage bag multiply rapidly, adhering to the surface by excreting extracellular polysaccharides and forming a layer known as a 'bioÀ lm'. bacteria within the bioÀ lm are morphologically and physiologically different from free-living planktonic bacteria in the urine, and have considerable survival advantages as they are protected from the action of antibiotic therapy. whilst bioÀ lms commonly form on devices inserted into the body, they can cause additional problems on urethral catheters if the bacteria produce the enzyme urease, such as proteus mirabilis. this enzyme causes the urine to become alkaline, inducing crystallisation of calcium and magnesium phosphate within the urine. these crystals are incorporated into the bioÀ lm and, over time, result in encrustation of the catheter. encrustation is generally associated with long-term catheterisation, as it has a direct relationship with the length of catheterisation. urinary catheterisation is a frequent intervention during clinical care in hospital, affecting a signiÀ cant number of patients. it has been estimated that - % of hospitalised patients have a urinary catheter inserted during their stay. [ ] [ ] [ ] [ ] this number is much higher in icus. the risk of infection is associated with the method and duration of catheterisation, the quality of catheter care and patient susceptibility. bacteriuria develops in approximately % of catheterised patients after - days, and % ( % ci - %) of these will develop symptoms of cauti. approximately . % ( % ci . - . %) of those with cauti develop life-threatening secondary infections, such as bacteraemia or sepsis, where mortality rates range from % to %. , cauti is associated with prolonged hospitalisation, re-admission and increased mortality. patients at particular risk are those who are immunocompromised, the elderly and patients with diabetes. physical and psychological discomfort associated with insertion, removal and the catheter in situ are common. complications such as inÁ ammation, urethral strictures, mechanical trauma, bladder calculi and other infections of the renal system also occur. , [ ] [ ] [ ] urine retention after catheter removal is also a frequent occurrence. in some instances, especially in older people, cauti may contribute to falls and delirium. the treatment of both cauti and other infection sequelae contribute to the emerging problem of antibiotic resistance in hospitals, and uropathogens are a major source of infections caused by antimicrobial-resistant organisms. cauti also increases the cost of health care due to delayed discharge from hospital, antimicrobial treatment and staff resources. the À nancial burden of cauti on the nhs has been estimated as £ million per year, with an estimated cost per episode of £ . , however, there are no robust economic assessments of the cost of cauti. there is a strong association between the duration of catheterisation and the risk of infection (i.e. the longer the catheter is in place, the higher the incidence of uti). , , in acute care facilities, the risk of developing bacteriuria increases % for each day of catheterisation. approximately % of bacteriuric patients will develop cauti, and of these, up to % develop a severe secondary infection such as bloodstream infection. current best practice emphasises the importance of documenting all procedures involving the catheter or drainage system in the patient's records, and providing patients with adequate information in relation to the need for catheterisation, details of the insertion, catheter and drainage system, maintenance procedures and plan for removal of the catheter. , there is some evidence to suggest that computer management systems improve documentation and are associated with reduced duration of catheterisation. using a short-term indwelling urethral catheter only when necessary after considering alternatives and ensuring the catheter is removed as soon as possible are simple and effective methods to prevent cauti. the use of a short-term indwelling urethral catheter may be appropriate in patients with acute urinary retention or obstruction, those who require precise urine output measures to monitor an underlying condition, and patients undergoing certain surgical procedures (especially urological procedures and those of prolonged duration). a short-term indwelling urethral catheter may also be appropriate to minimise discomfort or distress (e.g. during end-of-life care or in the management of open sacral or perineal wounds when the patient is incontinent). however, short-term indwelling urethral catheterisation should not be used as a method of managing urinary incontinence. while the use of a short-term indwelling urethral catheter is sometimes unavoidable, there is evidence that catheters are inserted without a clear clinical indication, clinicians are not always aware they are in situ, and they are not removed promptly when no longer required. , interventions that prompt or facilitate the removal of unnecessary catheters may, therefore, reduce the risk of cauti. these interventions have been categorised as reminder systems which prompt clinicians that the catheter is in place and removal should be considered, or stop orders, which indicate that catheters should be removed after a set period of time or when deÀ ned clinical criteria have been met. , [ ] [ ] [ ] a systematic review of studies (one rct, one nrct, three controlled before-after studies and nine uncontrolled beforeafter studies) on reminder and stop order systems found that these interventions signiÀ cantly decreased the rate of cauti and did not increase the need for re-catheterisation, although, as some of the studies were not controlled, they were susceptible to bias in favour of the intervention. a second systematic review identiÀ ed a number of uncontrolled before-after studies that used ultrasound bladder scanners to assess for urinary retention and support appropriate catheterisation. when used in combination with guidelines, insertion checklist/kit, education, audit and feedback, and reminder/stop orders, ultrasound bladder scanners were found to decrease the use of urethral catheters by - %. only use a short-term indwelling urethral catheter in patients for whom it is clinically indicated, following assessment of alternative methods and discussion with the patient. uc document the clinical indication(s) for catheterisation, date of insertion, expected duration, type of catheter and drainage system, and planned date of removal. assess and record the reasons for catheterisation every day. remove the catheter when no longer clinically indicated. evidence from best practice indicates that the incidence of cauti in patients catheterised for a short time (up to week) is not inÁ uenced by any particular type of catheter material. , however, many practitioners have strong preferences for one type of catheter over another. this preference is often based on clinical experience, patient assessment and materials that induce the least allergic response. smaller gauge catheters with a -ml balloon minimise urethral trauma, mucosal irritation and residual urine in the bladder; all factors that predispose to cauti. , there is also a risk of urethral trauma associated with using a female length catheter in a male patient, and systems should be in place to ensure that this does not occur. however, in adults that have recently undergone urological surgery, larger gauge catheters may be indicated to allow for the passage of blood clots. our previous evidence-based guidelines identiÀ ed three experimental studies that compared the use of latex with silicone catheters, which found no signiÀ cant difference in the incidence of bacteriuria. , , we identiÀ ed one new systematic review which included three trials that compared different types of standard (nonantiseptic-/non-antimicrobial-impregnated) catheters. these studies did not provide sufÀ cient evidence to suggest that one type of catheter may be more effective than another for the prevention of bacteriuria. [ ] [ ] [ ] [ ] in our previous systematic review, we found evidence related to the efÀ cacy of using short-term indwelling urethral catheters coated or impregnated with antiseptic or antimicrobial agents from four systematic reviews and one meta-analysis. in general, all of these À ve studies suggested that antiseptic-impregnated or antimicrobial-coated shortterm indwelling urethral catheters can signiÀ cantly prevent or delay the onset of cauti compared with standard untreated urinary catheters. , [ ] [ ] [ ] [ ] the consensus in these À ve reviews of evidence, however, is that the individual studies reviewed are generally of poor quality; for instance, in one case, only eight studies out of met the inclusion criteria, and in another, of the six reports describing seven trials included, only one scored À ve in the quality assessment. the other À ve reports only scored one. the studies included in these reviews investigated a wide range of coated or impregnated catheters, including catheters coated or impregnated with: silver alloy, , , [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] silver oxide, gendine, gentamicin, silverhydrogel, - minocycline, rifampicin, chlorhexidinesilver-sulfadiazine, chlorhexideine-sulfadiazine-triclosan, nitrofurazone and nitrofuroxone. four studies compared the use of silver-coated (silver alloy or silver oxide) catheters with silicone, hydrogel or teÁ on ® latex. - a systematic review and meta-analysis of these and other studies found that silver-alloy-coated (but not silver-oxide-coated) catheters were associated with a lower incidence of bacteriuria. , despite their unit cost, these devices may provide a costeffective option if overall numbers of infections are reduced signiÀ cantly through their use. however, the few studies that have explored the cost-beneÀ t/cost-effectiveness of using these devices have been inconclusive. , , , we identiÀ ed two new systematic reviews of the efÀ cacy of silver-coated or antimicrobial-impregnated catheters for the prevention of cauti. , the À rst systematic review included rcts, as well as one nrct, and concluded that silver-coated (alloy or oxide) short-term indwelling urethral catheters reduced the risk of bacteriuria but did not demonstrate an effect on cauti. catheters impregnated with antimicrobial agents (minocycline, rifampicin or nitrofurazone) were found to reduce the rate of bacteriuria during the À rst week of catheterisation, but not for catheter durations exceeding week. although antimicrobial-impregnated catheters reduced the risk of cauti, the number of cases was too small to demonstrate a signiÀ cant effect. the second systematic review, which included nine rcts and three quasi-experimental studies, concluded that, compared with standard catheters, both nitrofurazone-impregnated and silver-alloy-coated catheters can prevent and delay the onset of bacteriuria during short-term use. however, there were no data on the risk of cauti. we identiÀ ed one multi-centre rct that compared silveralloy-coated and nitrofurazone-impregnated catheters with standard teÁ on-coated latex for short-term catheterisation. although the nitrofurazone-impregnated and silver-alloycoated catheters were associated with a reduced risk of cauti compared with the teÁ on-coated latex, the effect was not considered to be clinically effective (adjusted or . , % ci . - . and adjusted or . , % ci . - . , respectively). the nitrofurazone-impregnated catheter, but not the silver-alloy-coated catheter, was associated with a signiÀ cantly lower incidence of bacteriuria (or . , % ci . - . , p= . ). however, the nitrofurazone-impregnated catheter was associated with increased discomfort during the period the catheter was in place. a major limitation of this study was that the median duration of catheterisation was s h. p. loveday et al. / journal of hospital infection s ( ) s -s days (range - days) and the risk of cauti associated with this short period is correspondingly low. also, utis developing up to weeks post randomisation were included in the outcome measurement, even though they may not have been directly associated with catheterisation. the economic analysis suggested that nitrofurazone-impregnated catheters, but not silver-alloy-coated catheters, may be cost-effective, but the measures of cost were associated with a large amount of uncertainty. overall, the evidence suggests that silver-coated urethral catheters reduce the risk of bacteriuria, but there is insufÀ cient evidence to indicate whether they reduce the risk of cauti in short-term catheterised patients. assess patient's needs prior to catheterisation in terms of: • latex allergy; • length of catheter (standard, female, paediatric); • type of sterile drainage bag and sampling port (urometer, -l bag, leg bag) or catheter valve; and • comfort and dignity. select a catheter that minimises urethral trauma, irritation and patient discomfort, and is appropriate for the anticipated duration of catheterisation. uc select the smallest gauge catheter that will allow urinary outÁ ow and use a -ml retention balloon in adults (follow manufacturer's instructions for paediatric catheters). urological patients may require larger gauge sizes and balloons. in our previous review, we found evidence from one systematic review which suggested that the use of the aseptic technique has not demonstrated a reduction in the rate of cauti. however, principles of good practice, clinical guidance , and expert opinion, , , [ ] [ ] [ ] [ ] [ ] together with À ndings from another systematic review, agree that shortterm indwelling urethral catheters must be inserted using sterile equipment and the aseptic technique. expert opinion indicates that there is no advantage in using antiseptic preparations for cleansing the urethral meatus prior to catheter insertion. , , , whilst there is low-quality evidence to suggest that pre-lubrication of the catheter decreases the risk of bacteriuria, it is also important to use lubricant or anaesthetic gel in order to minimise urethral trauma and discomfort. there is no evidence suggesting a general beneÀ t of securing the catheter in terms of preventing the risk of cauti, but it is important in order to minimise patient discomfort. ensuring healthcare practitioners are trained and competent in the insertion of short-term indwelling urethral catheters will minimise trauma, discomfort and the potential for cauti. , , , neither we nor hicpac identiÀ ed any additional evidence of acceptable quality whilst updating our systematic review. catheterisation is an aseptic procedure and should only be undertaken by healthcare workers trained and competent in this procedure. uc clean the urethral meatus with sterile, normal saline prior to the insertion of the catheter. uc use lubricant from a sterile singleuse container to minimise urethral discomfort, trauma and the risk of infection. ensure the catheter is secured comfortably. maintaining a sterile, continuously closed urinary drainage system is central to the prevention of cauti. , , , , , the risk of infection reduces from % with an open system to - % when a sterile closed system is employed. , , breaches in the closed system, such as unnecessary emptying, changing of the urinary drainage bag or taking a urine sample, will increase the risk of cauti and therefore should be avoided. , , hands must be decontaminated, and clean and non-sterile gloves should be worn before manipulation of the catheter or the closed system, including drainage taps. a systematic review has suggested that sealed (e.g. taped, pre-sealed) drainage systems contribute to preventing bacteriuria. however, there is limited evidence regarding how often catheter bags should be changed. one study showed that higher rates of symptomatic and asymptomatic cauti were associated with a -day urinary drainage bag change regimen compared with no routine change regimen. best practice suggests that drainage bags should only be changed when necessary (i.e. according either to the manufacturer's recommendations or the patient's clinical need). , reÁ ux of urine is associated with infection and, consequently, drainage bags should be positioned in a way that ensures the free Á ow of urine and prevents back-Á ow. , it is also recommended that urinary drainage bags should be hung on an appropriate stand that prevents contact with the Á oor. a number of studies have investigated the addition of disinfectants and antimicrobials to drainage bags as a way of preventing cauti. three acceptable studies - from our original systematic review demonstrated no reduction in the incidence of bacteriuria following the addition of hydrogen peroxide or chlorhexidine to urinary drainage bags. these À ndings are supported by a further systematic review, which suggested that adding bacterial solutions to drainage bags had no effect on catheter-associated infection. neither we nor hicpac identiÀ ed any additional evidence of acceptable quality whilst updating our systematic review. uc connect a short-term indwelling urethral catheter to a sterile closed urinary drainage system with a sampling port. uc do not break the connection between the catheter and the urinary drainage system unless clinically indicated. uc change short-term indwelling urethral catheters and/or drainage bags when clinically indicated and in line with the manufacturer's recommendations. uc decontaminate hands and wear a new pair of clean non-sterile gloves before manipulating each patient's catheter. decontaminate hands immediately following the removal of gloves. uc use the sampling port and the aseptic technique to obtain a catheter sample of urine. uc position the urinary drainage bag below the level of the bladder on a stand that prevents contact with the Á oor. uc do not allow the urinary drainage bag to À ll beyond three-quarters full. uc use a separate, clean container for each patient and avoid contact between the urinary drainage tap and the container when emptying the drainage bag. uc do not add antiseptic or antimicrobial solutions to urinary drainage bags. our previous systematic reviews , found eight acceptable studies that compared meatal cleansing with a variety of antiseptic/antimicrobial agents or soap and water. no reduction in bacteriuria was demonstrated when using any of these preparations for meatal/peri-urethral hygiene compared with routine bathing or showering. , [ ] [ ] [ ] [ ] [ ] [ ] [ ] expert opinion and other systematic reviews support the view that active meatal cleansing is not necessary and may increase the risk of infection. , , , , , daily routine bathing or showering is all that is needed in order to maintain patient comfort. neither we nor hicpac identiÀ ed any additional evidence of acceptable quality whilst updating our systematic review. uc routine daily personal hygiene is all that is required for meatal cleansing. evidence from our previous systematic review did not demonstrate any beneÀ cial effect of bladder irrigation, instillation or washout with a variety of antiseptic or antimicrobial agents for the prevention of cauti. , , [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] evidence from best practice supports these À ndings of no beneÀ cial effect, and indicates that the introduction of such bladder maintenance solutions may have local toxic effects and contribute to the development of resistant microorganisms. however, continuous or intermittent bladder irrigation may be required for other urological or catheter management indications. given the frequency of urinary catheterisation in hospital patients and the associated risk of uti, it is important that patients, their relatives and healthcare workers responsible for catheter insertion and management are educated about infection prevention. all those involved must be aware of the signs and symptoms of uti and how to access expert help when difÀ culties arise. healthcare professionals must be conÀ dent and proÀ cient in associated procedures. we identiÀ ed two systematic reviews that reported evidence of the efÀ cacy of healthcare workers' education in reducing the risk of cauti within other system interventions. , most of the studies included in these reviews provided lowgrade evidence from uncontrolled before-after studies where a combination of different system interventions focusing on reducing the use of urethral catheters and risk of cauti were introduced. the À rst systematic review identiÀ ed one small controlled before-after study of an educational intervention with guideline change and posters that was associated with a reduction in use of urethral catheters [relative risk (rr) . , % ci . - . ]. another systematic review included one controlled before-after study that demonstrated a signiÀ cant (p< . ) increase in adherence to a clinical guideline on the insertion and maintenance of urethral catheters in association with an education programme. , a further study reported a reduction in cauti and an increase in adherence to protocols for hand hygiene and catheter care in association with an education programme. however, this study did not include a control group. uc healthcare workers should be trained and competent in the appropriate use, selection, insertion, maintenance and removal of short-term indwelling urethral catheters. uc ensure patients, relatives and carers are given information regarding the reason for the catheter and the plan for review and removal. if discharged with a catheter, the patient should be given written information and shown how to: • manage the catheter and drainage system; • minimise the risk of urinary tract infection; and • obtain additional supplies suitable for individual needs. a number of studies have reported the effect of quality improvement programmes on the risk of cauti. the components of these programmes include various combinations of clinical guidelines for catheter insertion and maintenance, education, audit and feedback of compliance with policy, physician/nurse reminder systems (to prompt removal if no longer necessary), automated or nurse-driven removal protocols [where the catheter is removed after a speciÀ ed period (e.g. - h) unless countermanded by the physician] and the use of bladder scanners to assess urinary retention and support appropriate catheterisation. we identiÀ ed three systematic reviews relevant to this question. , , the À rst was a review of interventions to remind physicians/nurses to remove unnecessary catheters and the outcome on cauti, short-term indwelling urethral catheter use and catheter replacement. it included studies (one rct, one nrct, three controlled before-after studies and nine uncontrolled before-after studies). interventions included prewritten or computer-generated stop orders, nurse-generated daily bedside reminders to remove catheters, and daily use of a checklist or protocol to review need for the catheter. some studies also implemented catheter placement restrictions and education. the meta-analysis suggested that the use of reminder or stop order systems reduced the rate of cauti by % (p< . ) and the mean duration of catheterisation by %, with . fewer days of catheterisation in the intervention group compared with the control group, and no difference in re-catheterisation rates. the second systematic review was a review of interventions to minimise the placement of urethral catheters in acute care patients. it included one rct, one nrct and six uncontrolled before-after studies. interventions included various combinations of clinician reminders, stop orders and indication checklists, use of bladder scanners and education. the authors concluded that the studies were too small and heterogeneous to draw a deÀ nitive conclusion about efÀ cacy in terms of reducing inappropriate catheter placement. the third systematic review included three controlled before-after studies and seven uncontrolled before-after studies measuring interventions that increased adherence to catheter care protocols or reduced unnecessary catheter use. interventions included reminders, stop orders, use of bladder scanners, education and catheterisation protocols with audit and feedback on performance. physician/nurse reminders, particularly automatic stop orders, were found to reduce the duration of catheterisation, although there were insufÀ cient data to determine their effect on cauti. many studies in this area are uncontrolled before-after designs and therefore susceptible to bias in favour of the intervention. however, these interventions constitute best practice, and this evidence supports the use of systems to minimise the insertion of catheters and promote timely removal to reduce both the duration of catheterisation and the risk of cauti. s uc use quality improvement systems to support the appropriate use and management of short-term urethral catheters and ensure their timely removal. these may include: • protocols for catheter insertion; • use of bladder ultrasound scanners to assess and manage urinary retention; • reminders to review the continuing use or prompt the removal of catheters; • audit and feedback of compliance with practice guidelines; and • continuing professional education. uc no patient should be discharged or transferred with a short-term indwelling urethral catheter without a plan documenting the: • reason for the catheter; • clinical indications for continuing catheterisation; and • date for removal or review by an appropriate clinician overseeing their care. systematic review questions . what are the clinical indications for the use of short-term urinary catheters?(*b) . what is the risk associated with short-term catheterisation in terms of bacteriuria, cauti, other morbidities and mortality? (b) . what is the effectiveness (in terms of patient acceptability and reduced risk of bacteriuria, cauti, other morbidities and mortality) and the cost-effectiveness of different types of short-term indwelling urinary catheters (material, coatings and design)? . what is the most effective catheter insertion technique in terms of patient acceptability and minimisation of urethral trauma, bacteriuria, cauti and other morbidities? . what is the most effective and cost-effective means of maintaining meatal hygiene and a closed drainage system? . what is the effectiveness of system interventions in reducing the use and duration of short-term urinary catheterisation to minimise the risk of bacteriuria, cauti, other morbidities and mortality? . what is the effectiveness of system interventions in improving healthcare workers' knowledge and behaviour relating to the insertion, maintenance and timely removal of indwelling urinary catheters to minimise the risk of bacteriuria, cauti, other morbidities and mortality? total number of articles located = abstract indicates that the article: relates to infections associated with short-term indwelling urethral catheters; is written in english; is primary research, a systematic review or a meta-analysis; and appears to inform one or more of the review questions. total number of articles retrieved from sift = full text conÀ rms that the article: relates to infections associated with short-term indwelling urethral catheters; is written in english; is primary research (randomised controlled trials, prospective cohort, interrupted time series, controlled before-after, quasiexperimental), a systematic review or a meta-analysis including the above designs; and informs one or more of the review questions. total number of studies selected for appraisal during sift = all articles that described primary research, a systematic review or a meta-analysis and met the sift criteria were independently critically appraised by two appraisers using sign and epoc criteria. consensus and grading was achieved through discussion. this guidance is based on the best critically appraised evidence currently available. the type and class of supporting evidence explicitly linked to each recommendation is described. evidence identiÀ ed in the hicpac systematic review was used to support the recommendations in these guidelines. some recommendations from the previous guidelines have been revised to improve clarity; where a new recommendation has been made, this is indicated in the text. these recommendations are not detailed procedural protocols, and need to be incorporated into local guidelines. none are regarded as optional. intravascular access devices, including peripheral, central venous and arterial catheters, are commonly used in the management of patients in acute and chronic care settings. cvcs are frequently used during clinical care and include peripherally inserted, non-tunnelled and tunnelled, and totally implantable cvcs (table ) . the use of any of these catheters can result in bloodstream infection. catheter-related bloodstream infections (cr-bsi) associated with the insertion and maintenance of cvcs are potentially among the most dangerous complications associated with health care. , , in the most recent national prevalence survey, the health protection agency reported that the prevalence of bsi was . %, accounting for . % of the hcai detected; % of bsi occurred in patients with a vascular access device. a previous point prevalence survey reported that the prevalence of bsi was . %, accounting for % of the hcai detected; of these, % were primary cr-bsi. peripheral venous catheters (pvcs) cause phlebitis in some patients, with studies indicating mean rates of - %, [ ] [ ] [ ] [ ] but evidence suggests that these devices are less frequently associated with cr-bsi. , [ ] [ ] [ ] [ ] [ ] cr-bsi involves the presence of systemic infection and evidence implicating the intravascular catheter as its source (i.e. the isolation of the same microorganism from blood cultures as that shown to be signiÀ cantly colonising the intravascular catheter). , catheter colonisation refers to the growth of microorganisms on either the endoluminal or the external catheter surface beneath the skin in the absence of systemic infection. , the microorganisms that colonise catheter hubs and the skin adjacent to the insertion site are the source of most cr-bsi. coagulase-negative staphylococci, particularly staphylococcus epidermidis, are the microorganisms most frequently implicated in cr-bsi. other microorganisms commonly involved include s. aureus, candida species and enterococci. [ ] [ ] [ ] cr-bsi is generally caused either by skin microorganisms at the insertion site, which contaminate the catheter during insertion and migrate along the cutaneous catheter track after insertion, [ ] [ ] [ ] or microorganisms from the hands of healthcare workers that contaminate and colonise the catheter hub during care interventions. less commonly, infusate contamination or seeding from a different site of infection in the body via the bloodstream is identiÀ ed as a cause of cr-bsi. , these guidelines are based upon evidence-based guidelines for preventing intravascular device (ivd)-related infections, developed at the us centers for disease control and prevention by hicpac and published in . the agree ii collaboration appraisal instrument was used by four appraisers to review the guidelines independently. the appraisal process resulted in the decision that the guideline development processes were valid and that the guidelines were evidence based, categorised to the strength of the evidence examined, reÁ ective of current concepts of best practice. the guideline development advisory group considered that they were the most authoritative reference guidelines currently available. following the agree process, we systematically searched, retrieved and appraised additional evidence published since the search period identiÀ ed in the hicpac technical report. our search period for additional evidence spanned from to . these guidelines apply to caring for all adults and children over the age of year in nhs acute care settings with a cvc or pvc that is being used for the administration of Á uids, medications, blood components and/or parenteral nutrition. they should be used in conjunction with the recommendations for standard principles for preventing hcai, previously described in these guidelines. these recommendations describe general principles of best practice that apply to all patients in hospital in whom an intravascular catheter is being used during an acute episode of treatment/care. they do not speciÀ cally address the more detailed, technical aspects of the care of infants under year of age, or those children or adults receiving haemodialysis or chemotherapy who will generally have long-term intravascular catheters managed in renal dialysis or outpatient settings. the recommendations are divided into nine distinct interventions: • education of healthcare workers and patients; • general asepsis; • selection of type of intravascular catheter; • selection of intravascular catheter insertion site; • msb precautions during insertion; • cutaneous antisepsis; • catheter and catheter site care; • replacement strategies; and • general principles for catheter management. to improve patient outcomes and reduce healthcare costs, it is essential that everyone involved in caring for patients with intravascular catheters is educated about infection prevention. healthcare workers in hospitals need to be conÀ dent and proÀ cient in infection prevention practices, and to be aware of the signs and symptoms of clinical infection. structured educational programmes that enable healthcare workers to provide, monitor and evaluate care and continually increase their competence are critical to the success of any strategy designed to reduce the risk of infection. evidence reviewed by hicpac demonstrates that the risk of infection declines following standardisation of the aseptic technique, [ ] [ ] [ ] [ ] [ ] [ ] [ ] and increases when the maintenance of intravascular catheters is undertaken by inexperienced healthcare workers. , h. p. loveday et al. / journal of hospital infection s ( ) s -s we identiÀ ed two recent systematic reviews that assessed the effectiveness of education interventions in reducing cr-bsi. , the À rst concluded that current evidence comes predominantly from uncontrolled before-after studies that do not convincingly distinguish intervention effectiveness from secular trends. clinical practices are addressed by a wide variety of educational strategies that do not draw upon pedagogic, theoretical or conceptual frameworks and consequently do not provide generalisable conclusions about the most effective approaches to education to improve practice. the second systematic review concluded À rst that educational interventions appear to have the most prolonged and profound effect when used in conjunction with audit and feedback, and when availability of clinical equipment is consistent with the content of the education provided. second, that educational interventions will have a greater impact if baseline compliance with best practice is low. third, that repeated educational sessions, fed into daily practice, using practical participation, appear to have a small, additional effect on practice change compared with education alone. healthcare workers should be aware of the manufacturers' advice relating to the compatibility of individual devices with antiseptic solutions, dwell time and connections to ensure safe use. with intravascular catheters should be trained and assessed as competent in using and consistently adhering to practices for the prevention of catheter-related bloodstream infection. ivad healthcare workers should be aware of the manufacturer's advice relating to individual catheters, connection and administration set dwell time and compatibility with antiseptics and other Á uids to ensure the safe use of devices. ivad before discharge from hospital, patients with intravascular catheters and their carers should be taught any techniques they may need to use to prevent infection and manage their device. hand decontamination and meticulous attention to the aseptic technique are essential during catheter insertion, manipulation, changing catheter site dressings and for accessing the system. hands should be decontaminated using abhr or liquid soap and water when hands are visibly soiled or potentially contaminated with organic material, such as blood and other body Á uids. , the aseptic technique should be used for the insertion and management of ivds. structured education should be provided to ensure that healthcare workers are trained and assessed as competent in performing the aseptic technique. gloves should be worn for procedures involving contact with blood or body Á uids. sterile gloves must be worn for the insertion and dressing of cvcs. ivad hands must be decontaminated, with an alcohol-based hand rub or by washing with liquid soap and water if soiled or potentially contaminated with blood or body Á uids, before and after any contact with the intravascular catheter or insertion site. ivad use the aseptic technique for the insertion and care of an intravascular access device and when administering intravenous medication. the selection of the most appropriate intravascular catheter for each individual patient can reduce the risk of subsequent catheter-related infection. intravascular catheter material may be an important determinant in the development of catheter-related infection. polytetraÁ uroethylene (teÁ on) and polyurethane catheters have been associated with fewer infections than catheters made of polyvinyl chloride or polyethylene. [ ] [ ] [ ] multi-lumen intravascular access devices may be used because they permit the concurrent administration of Á uids and medications, parenteral nutrition and haemodynamic monitoring among critically ill patients. several rcts and other studies suggest that multi-lumen catheters are associated with a higher risk of infection than single-lumen catheters. , [ ] [ ] [ ] [ ] [ ] [ ] however, other studies examined by hicpac failed to demonstrate a difference in the rates of cr-bsi. , multi-lumen catheter insertion sites may be particularly prone to infection because of increased trauma at the insertion site or because multiple ports increase the frequency of cvc manipulation. , patients with multi-lumen catheters tend to be more severely ill, although the increased risk of cr-bsi appears to be independent of underlying illness. a prospective epidemiological study in patients receiving parenteral nutrition concluded that either using a singlelumen catheter or a dedicated port in a multi-lumen catheter for parenteral nutrition would reduce the risk of cr-bsi. neither we nor hicpac identiÀ ed any additional evidence for this recommendation whilst updating our systematic review, and hicpac considered this to be a unresolved issue. in a systematic review and quantitative meta-analysis focused on determining the risk of cr-bsi and catheter colonisation in multi-lumen catheters compared with single-lumen catheters, the reviewers reported that, although cr-bsi was more common in patients with multi-lumen catheters, when conÀ ned to highquality studies that control for patient differences, there is no signiÀ cant difference in rates of cr-bsi for the two types of catheter. this analysis suggests that multi-lumen catheters are not a signiÀ cant risk factor for increased cr-bsi or local catheter colonisation compared with single-lumen cvcs. a later systematic review and quantitative meta-analysis tested whether single-vs multi-lumen cvcs had an impact on catheter colonisation and cr-bsi. the study authors concluded that there is some evidence from À ve rcts with data on cvcs that for every single-lumen catheters inserted, one cr-bsi (which would have occurred had multi-lumen catheters been used) would be avoided. neither we nor hicpac identiÀ ed any additional evidence of acceptable quality whilst updating our systematic reviews. ivad use a catheter with the minimum number of ports or lumens essential for management of the patient. ivad preferably use a designated singlelumen catheter to administer lipidcontaining parenteral nutrition or other lipid-based solutions. surgically implanted (tunnelled) devices (e.g. hickman ® catheters) are commonly used to provide vascular access to patients requiring long-term intravenous therapy. alternatively, totally implantable intravascular access devices (e.g. port-a-cath ® ) are also tunnelled under the skin, but have a subcutaneous port or reservoir with a self-sealing septum that is accessible by needle puncture through intact skin. multiple studies comparing the incidence of infection associated with long-term tunnelled cvcs and/or totally implantable ivds with that from percutaneously (non-tunnelled) inserted catheters have been assessed by hicpac. although most studies reported a lower rate of infection in patients with tunnelled cvcs, [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] some studies found no signiÀ cant difference in the rate of infection between tunnelled and nontunnelled catheters. , additionally, most studies concluded that totally implantable devices had the lowest reported rates of cr-bsi compared with either tunnelled or non-tunnelled cvcs. [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] however, although these devices are less disruptive for patients in terms of daily living, they have a number of disadvantages including the need for needle insertion resulting in increased discomfort. additional evidence was obtained from studies of efÀ cacy of tunnelling to reduce catheter-related infections in patients with short-term cvcs. one rct demonstrated that subcutaneous tunnelling of short-term cvcs inserted into the internal jugular vein reduced the risk for cr-bsi. in a later rct, the same investigators failed to show a statistically signiÀ cant difference in the risk for cr-bsi for subcutaneously tunnelled femoral vein catheters. an additional meta-analysis of rcts was focused on the efÀ cacy of tunnelling short-term cvcs to prevent catheterrelated infections. data synthesis demonstrated that tunnelling decreased catheter colonisation by % and decreased cr-bsi by % in comparison with non-tunnelled placement. the majority of the beneÀ t in the decreased rate of catheter sepsis came from one trial of cvcs inserted at the internal jugular site. the reduction in risk was not signiÀ cant when pooled with data from À ve subclavian catheter trials. tunnelling was not associated with increased risk of mechanical complications from placement or technical difÀ culties during placement. this meta-analysis concluded that tunnelling decreased catheterrelated infections; however, a synthesis of the evidence in this meta-analysis does not support routine subcutaneous tunnelling of short-term subclavian venous catheters, and this cannot be recommended unless efÀ cacy is evaluated at different placement sites and relative to other interventions. peripherally inserted central catheters (piccs) are increasingly used for medium term ( weeks to months) intravascular access, particularly in adults and children requiring antimicrobial treatment, chemotherapy and parenteral nutrition. evidence examined by hicpac suggested that piccs are associated with a lower rate of infection than that associated with other non-tunnelled cvcs. , retrospective studies in outpatient settings indicate that rates of picc-related bloodstream infection range from . to . per catheter-days. [ ] [ ] [ ] [ ] [ ] [ ] however, there is little recent robust evidence regarding comparison of rates of cr-bsi in piccs vs other long-term central venous access devices. a prospective study that compared the use of inpatient piccs indicated a similar rate of cr-bsi to non-tunnelled catheters placed in the internal jugular or subclavian veins and a higher rate than cuffed and tunnelled (ct) catheters (picc . cr-bsi per catheter-days vs nontunnelled . cr-bsi per catheter-days vs cuffed and tunnelled . cr-bsi per catheter-days). a systematic review of studies indicated that when used in inpatients, piccs pose a slightly lower risk of cr-bsi than standard noncuffed and non-medicated cvcs placed in the subclavian or internal jugular vein ( . cr-bsi per catheter-days vs . cr-bsi per catheter-days). neither we nor hicpac identiÀ ed any additional evidence of acceptable quality whilst updating our systematic review. ivad use a tunnelled or implanted central venous access device with a subcutaneous port for patients in whom long-term vascular access is required. ivad use a peripherally inserted central catheter for patients in whom mediumterm intermittent access is required. some catheters and cuffs are marketed as anti-infective and are coated or impregnated with antimicrobial or antiseptic agents, e.g. chlorhexidine/silver sulfadiazine, minocycline/ rifampicin, platinum/silver, and ionic silver in subcutaneous collagen cuffs attached to cvc. evidence reviewed by hicpac [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] indicated that the use of antimicrobial or antisepticimpregnated cvc in adults whose catheter is expected to remain in place for more than À ve days could decrease the risk for cr-bsi. this may be cost-effective in high-risk patients (intensive care, burn and neutropenic patients) and in other patient populations in whom the rate of cr-bsi exceeds . per , catheter days even when there is a comprehensive strategy to reduce rates of cr-bsi. a meta-analysis of rcts published between - included data on , catheters ( , anti-infective and , control). eleven of the trials in this meta-analysis were conducted in intensive care unit (icu) settings; four among oncology patients, two among surgical patients; two among patients receiving total parenteral nutrition (tpn) and four among other patient populations. study authors concluded that antibiotic and chlorhexidine-silver sulfadiazine coatings are anti-infective for short (approximately one week) insertion time. for longer insertion times, there was no data on antibiotic coating, and there is evidence of lack of effect for À rst generation chlorhexidine-silver sulfadiazine coating. for silver-impregnated collagen cuffs, there is evidence of lack of effect for both short-and long-term insertion. second generation chlorhexidine/silver sulfadiazine catheters with chlorhexidine coating on both the internal and external luminal surfaces are now available. the external surface of these catheters have three times the amount of chlorhexidine and extended release of the surface bound antiseptics than that in the À rst generation catheters (which are coated with chlorhexidine/silver sulfadiazine only on the external luminal surface). early studies indicated that the prolonged anti-infective activity associated with the second generation catheters improved efÀ cacy in preventing infections. a systematic review and economic evaluation in concluded that rates of cr-bsi were statistically signiÀ cantly reduced when an antimicrobial cvc was used. studies in this review report the best effect when catheters were treated with minocycline/rifampin, or internally and externally treated with silver or chlorhexidine/silver sulfadiazine. a trend to statistical signiÀ cance was seen in catheters only extraluminally coated. investigation of other antibiotic treated catheters is limited to single studies with non-signiÀ cant results. we identiÀ ed two additional systematic reviews and one rct in our updated search. a recent cochrane review of studies using impregnation, coating or bonding for reducing central venous catheter-related infections in adults included , predominantly unblinded studies, with low or unclear risk of bias. patients with impregnated catheters had lower rates of cr-bsi (actual risk reduction of % ( % ci, % to %)), and catheter colonisation (actual risk reduction % ( % ci, % to %)). in terms of catheter colonisation sub-group analysis showed that impregnated catheters were more beneÀ cial in studies conducted in intensive care units (rr . ( % ci, . to . )) than in studies conducted in haemo-oncology (rr . ( % ci, . to . )) or in patients requiring long-term parenteral nutrition rr . ( % ci, . to . )). however, sub-group analysis did not identify the same beneÀ t in terms of cr-bsi. there were no statistically signiÀ cant differences in the overall rates of bloodstream infections or mortality, although these outcomes were less often assessed than cr-bsi and catheter colonisation. a collaborative network metaanalysis of cvc use in adults indicated that rifampicin-based impregnated cvc was the only type of impregnated/coated cvc that reduced catheter colonisation and cr-bsi compared with standard cvc. in a single blind non-inferiority trial, authors concluded that cvc coated with -Á uorouracil were non-inferior to chlorhexidine and silver sulfadiazine coated cvcs with respect to the incidence of catheter colonisation ( . % vs. . %, respectively). chlorhexidine is a potential allergenic antiseptic that is present in many products and is widely used in health care for skin antisepsis, insertion of urinary catheters or coating cvcs. in susceptible individuals, initial contact will cause a minor hypersensitivity reaction that, although not severe, should not go undocumented as subsequent exposures to chlorhexidine may lead to anaphylaxis. , the medicines and healthcare products regulatory agency has alerted all healthcare providers in the uk to the risk of chlorhexidine allergy and requires them to have systems in place that ensure: • awareness of the potential for an anaphylactic reaction to chlorhexidine; • known allergies are recorded in patient notes; • labels and instructions for use are checked to establish if products contain chlorhexidine prior to use on patients with a known allergy; • if a patient experiences an unexplained reaction, checks are carried out to identify whether chlorhexidine was used or was impregnated in a medical device that was used; and • reporting of allergic reactions to products containing chlorhexidine to the medicines and healthcare products regulatory agency. ivad use an antimicrobial-impregnated central venous access device for adult patients whose central venous catheter is expected to remain in place for > days if catheter-related bloodstream infection rates remain above the locally agreed benchmark, despite the implementation of a comprehensive strategy to reduce catheter-related bloodstream infection. the site at which a vascular access catheter is placed can inÁ uence the subsequent risk of cr-bsi because of variation in both the density of local skin Á ora and the risk of thrombophlebitis. cvcs are generally inserted in the subclavian, jugular or femoral veins, or peripherally inserted into the superior vena cava by way of the major veins of the upper arm (i.e. the cephalic and basilar veins of the antecubital space). pvcs are normally inserted in the upper extremity, although alternatives, such as the foot and scalp, may be used in children and babies. hicpac examined a number of studies that compared insertion sites and concluded that cvcs inserted into subclavian veins had a lower risk for catheter-related infection than those inserted into either jugular or femoral veins. , , [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] guideline developers suggested that internal jugular insertion sites may pose a greater risk for infection because of their proximity to oropharyngeal secretions and because cvcs at this site are difÀ cult to immobilise. however, mechanical complications associated with catheterisation might be less common with internal jugular than with subclavian vein insertion. femoral catheters have been demonstrated to have relatively high colonisation rates compared with subclavian and internal jugular sites when used in adults, and current guidelines suggest that the femoral site should be avoided because it is associated with both a higher risk of deep vein thrombosis and catheter-related infection than internal jugular or subclavian catheters. , [ ] [ ] [ ] [ ] [ ] [ ] one study also found that the risk of infection associated with catheters placed in the femoral vein is accentuated in obese patients. thus, in adult patients, a subclavian site is preferred for preventing infection, although other factors (e.g. the potential for mechanical complications, risk for subclavian vein stenosis and catheter-operator skill) should be considered when deciding where to place the catheter. we identiÀ ed a systematic review and meta-analysis in which investigators reviewed two rcts, eight cohort studies and data from a national hcai programme. these provided evidence that the selection of device insertion site is not a signiÀ cant factor for the prevention of cr-bsi. the metaanalysis demonstrated no difference in the risk of cr-bsi between the femoral, subclavian and internal jugular sites, s having removed two studies that were statistical outliers. the authors concluded that a pragmatic approach to site selection for central venous access, taking into account underlying disease (e.g. renal disease), the expertise and skill of the operator and the risks associated with placement, should be used. two meta-analyses , indicate that the use of real-time two-dimensional ultrasound for the placement of cvcs substantially reduced mechanical complications compared with the standard landmark placement technique. consequently, the use of ultrasound may indirectly reduce the risk of infection by facilitating mechanically uncomplicated subclavian placement. in the uk, nice guidelines provide recommendations for two-dimensional ultrasound placement of cvcs. piccs may be used as an alternative to subclavian or jugular vein catheterisation. these are inserted into the superior vena cava via the major veins of the upper arm above the antecubital fossa. hicpac indicated that they are less expensive, associated with fewer mechanical complications (e.g. haemothorax, inÀ ltration and phlebitis) and easier to maintain than short peripheral venous catheters. in a prospective cohort study using data from two randomised trials and a systematic review to estimate rates of picc-related bloodstream infection in hospitalised patients, the author concluded that piccs used in high-risk hospitalised patients are associated with a rate of cr-bsi similar to conventional cvcs placed in the internal jugular or subclavian veins (two to À ve per catheter-days). to reduce the risk of cr-bsi and phlebitis, it is preferable to use an upper extremity site for inserting a pvc in adults and to replace a device inserted in a lower extremity to a site in the upper extremity as soon as possible. in paediatric patients, the upper or lower extremity and the scalp (in young infants) can be used for siting a pvc. , ivad in selecting an appropriate intravascular insertion site, assess the risks for infection against the risks of mechanical complications and patient comfort. ivad use the upper extremity for nontunnelled catheter placement unless medically contraindicated. the importance of strict adherence to hand decontamination and the aseptic technique as the cornerstone for preventing catheter-related infection is widely accepted. although this is considered adequate for preventing infections associated with the insertion of short peripheral venous catheters, it is recognised that central venous catheterisation carries a signiÀ cantly greater risk of infection. studies examined by hicpac concluded that if msb precautions were used consistently during cvc insertion, catheter contamination and subsequent catheter-related infections could be reduced signiÀ cantly. , , , a prospective randomised trial that tested the efÀ cacy of msb precautions to reduce infections associated with long-term, non-tunnelled subclavian silicone catheters, compared with routine procedures, found that they decreased the risk of cr-bsi signiÀ cantly. msb precautions involve wearing sterile gloves and gown, cap and mask, and using a full-body sterile drape during insertion of the catheter. it has been generally assumed that cvcs inserted in the operating theatre pose a lower risk of infection than those inserted on inpatient wards or other patient care areas. however, data examined by hicpac from two prospective studies suggest that the difference in risk of infection depended largely on the magnitude of barrier protection used during catheter insertion, rather than the surrounding environment (i.e. ward vs operating theatre). , a systematic review of the value of msb precautions to prevent cr-bsi deÀ ned the components as: the person inserting the catheter should wear a head cap, face mask, sterile body gown and sterile gloves, and use a full-size sterile drape. their search identiÀ ed papers discussing the prevention of cr-bsi. the majority of these were narrative reviews or consensus statements. three primary research studies, differing in design, patient population and clinical settings, that compared infection outcomes using msb precautions with less stringent barrier techniques, concluded that the use of msb precautions resulted in a reduction in catheter-related infections. the authors concluded that using msb precautions appears to decrease transmission of microorganisms, delay colonisation and reduce the rate of hcai. they also suggested that biological plausibility and the available evidence support using msb precautions during routine insertion of a cvc to minimise the risk of infection. they recommended that, given the lack of adverse patient reactions, the relatively low cost of msb precautions and the high cost of cr-bsi, it is probable that msb precautions will prove to be a cost-effective, or even a cost-saving, intervention. neither we nor hicpac identiÀ ed any additional evidence of acceptable quality whilst updating our systematic review. ivad use maximal sterile barrier precautions for the insertion of central venous access devices. microorganisms that colonise catheter hubs and the skin surrounding the vascular catheter insertion site are the cause of most cr-bsi. , as the risk of infection increases with the density of microorganisms around the insertion site, skin cleansing/antisepsis of the insertion site is one of the most important measures for preventing catheter-related infections. since the early s, research has focused on identifying the most effective antiseptic agent for skin preparation prior to the insertion of ivds in order to prevent catheter-related infections, especially cr-bsi. in the uk, clinicians principally use alcohol, or either povidone iodine (pvi) or chg, in various strengths, and the latter two as either aqueous or alcohol-based solutions. a prospective randomised trial of agents used for cutaneous antisepsis demonstrated that % aqueous chg was superior to either % pvi or % alcohol for the prevention of central venous and arterial catheter-related infections. a further prospective, randomised trial demonstrated that a % alcoholbased solution of . % chg and . % benzalkonium chloride was more effective for the prevention of central venous or arterial catheter colonisation and infection than % pvi. the use of % pvi solution in % ethanol has been shown to be associated with a substantial reduction in catheter-related colonisation and infection compared with % aqueous pvi. clinicians may À nd this useful for those patients for whom alcoholic chg is contraindicated. a meta-analysis of studies that compared the risk for cr-bsi following insertion-site skin care with any type of chg solution vs pvi solution indicated that the use of chg rather than pvi can reduce the risk for cr-bsi by approximately % (rr . , % ci . - . ) in hospitalised patients who require short-term catheterisation (i.e. for every catheter sites disinfected with chg rather than pvi, episodes of catheter colonisation and episodes of cr-bsi would be prevented). in this analysis, several types of chg solution were used in the individual trials, including . % or % chg alcohol solution and . % or % chg aqueous solution. all of these solutions provided a concentration of chg that is higher than the minimal inhibitory concentration (mic) for most nosocomial bacteria and yeasts. subset analysis of aqueous and non-aqueous solutions showed similar effect sizes, but only the subset analysis of the À ve studies that used alcoholic chg solution produced a signiÀ cant reduction in cr-bsi. as few studies used chg aqueous solution, the lack of a signiÀ cant difference seen for this solution compared with pvi solution may be a result of inadequate statistical power. additionally, an economic decision analysis based on available evidence from the same authors suggested that the use of chg, rather than pvi, for skin care would result in a . % decrease in the incidence of cr-bsi, a . % decrease in mortality, and À nancial savings per catheter used. several studies were examined that focused on the application of antimicrobial ointments to the catheter site at the time of catheter insertion, or during routine dressing changes, to reduce microbial contamination of catheter insertion sites. reported efÀ cacy of this practice for the prevention of catheter-related infections yielded contradictory À ndings. [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] there was also concern that the use of polyantibiotic ointments that were not fungicidal could signiÀ cantly increase the rate of colonisation of the catheter by candida species. , nice identiÀ ed three rcts that compared the effectiveness of different antiseptic solutions for the insertion of pvcs in hospitalised patients. the evidence from these studies was considered to be of very low quality, and no conclusion could be drawn about the beneÀ ts of one particular antiseptic solution over another. however, while there is no evidence comparing different concentrations of chg, the reviewers indicated that the trend in the evidence suggests that chg in alcohol may be more effective than pvi in alcohol. we identiÀ ed one recent systematic review of the clinical efÀ cacy and perceived role of chg in skin antisepsis that included studies about intravascular access. the authors suggested a potential source of bias, as many studies have overlooked the importance of alcohol when assessing the efÀ cacy of chg. the authors assessed the attribution of chg in each study as correct, incorrect or intermediate. studies were scored and analysis was performed separately to assess chg efÀ ciency. the authors concluded that chg is more efÀ cient than pvi or any other technique alone, but that the presence of alcohol provides additional beneÀ t. the authors suggested that vascular catheters require the immediate antiseptic activity provided by alcohol prior to insertion. they also require a long-lasting antiseptic, as they stay in place for prolonged periods of time. ivad decontaminate the skin at the insertion site with a single-use application of % chlorhexidine gluconate in % isopropyl alcohol (or povidone iodine in alcohol for patients with sensitivity to chlorhexidine) and allow to dry prior to the insertion of a central venous access device. ivad decontaminate the skin at the insertion site with a single-use application of % chlorhexidine gluconate in % isopropyl alcohol (or povidone iodine in alcohol for patients with sensitivity to chlorhexidine) and allow to dry before inserting a peripheral vascular access device. ivad do not apply antimicrobial ointment routinely to the catheter placement site prior to insertion to prevent catheter-related bloodstream infection. the safe maintenance of an intravascular catheter and appropriate care of the insertion site are essential components of a comprehensive strategy for preventing catheter-related infections. this includes good practice in caring for the patient's catheter hub and connection port, the use of an appropriate intravascular catheter site dressing regimen, and using Á ush solutions to maintain the patency of the catheter. following placement of a pvc or cvc, a dressing is used to protect the insertion site. as occlusive dressings trap moisture on the skin and provide an ideal environment for the rapid growth of local microÁ ora, dressings for insertion sites must be permeable to water vapour. the two most common types of dressings used for insertion sites are sterile, transparent, semi-permeable polyurethane dressings coated with a layer of an acrylic adhesive ('transparent dressings') and gauze and tape dressings. transparent dressings are permeable to water vapour and oxygen, and impermeable to microorganisms. hicpac reviewed the evidence related to which type of dressing provided the greatest protection against infection, including the largest controlled trial of dressing regimens on pvcs, a meta-analysis comparing the risk of cr-bsi using transparent vs gauze dressings and a cochrane review. all concluded that the choice of dressing can be a matter of preference, but if blood is leaking from the catheter insertion site, a gauze dressing might be preferred to absorb the Á uid. we identiÀ ed an updated cochrane review which concluded that bloodstream infection was higher in the transparent polyurethane group compared with the gauze and tape group. the included trials were graded low quality due to the small sample size and risk of bias. there was additional low-quality evidence that demonstrated no difference between highly permeable polyurethane dressings and other polyurethane dressings in the prevention of cr-bsi. hicpac reviewed the evidence related to impregnated sponge dressings compared with standard dressings and found two rcts in adults which demonstrated that chlorhexidineimpregnated sponge dressings were associated with a signiÀ cant reduction in cr-bsi. however, a meta-analysis that included eight rcts found a reduction in exit site colonisation but no signiÀ cant reduction in cr-bsi. in paediatric patients, two small rcts found a reduction in catheter colonisation but not cr-bsi, and evidence of localised contact dermatitis when used for infants of very low birth weight. we identiÀ ed one systematic review and meta-analysis, undertaken as part of a quality improvement collaborative, that synthesised the effects of the routine use of chgimpregnated sponge dressings in reducing centrally inserted cr-bsi. five studies were included in the analysis; two of the À ve studies were in patients in haemo/oncological icus, and the remaining three studies were in surgical and medical icus. four of the À ve studies were sponsored by the manufacturer of the product. the reviewers concluded that chg-impregnated sponge dressings are effective for the prevention of cr-bsi (or . , % ci . - . ) and catheter colonisation (or . , % ci . - . ). we identiÀ ed an economic evaluation of the use of chg sponge dressings and the non-inferiority of dressing changes at and days. the authors concluded that the major cost avoided by the use of chg sponge dressings and -day dressing changes rather than -day dressing changes was the increased length of stay of days associated with cr-bsi. chlorhexidineimpregnated sponge dressings remained cost saving for any value where the cost per cr-bsi was >$ and the baseline rate of cr-bsi was > . %. we identiÀ ed a further rct of chg dressings compared with highly adhesive semi-permeable dressings or standard semi-permeable dressings for the prevention of cr-bsi in patients. in the chg group, the major catheterrelated infection rate was % lower ( . vs . per catheter-days, hr . , % ci . - . , p= . ) and the cr-bsi rate was % lower ( . vs . per catheterdays, hr . , % cl . - . , p= . ) than with nonchlorhexidine dressings. decreases were also noted in catheter colonisation and skin colonisation rates at catheter removal. highly adhesive dressings decreased the detachment rate to . % vs . % (p< . ) and the number of dressings per catheter to two (one to four) vs three (one to À ve) (p< . ), but increased skin colonisation (p< . ) and catheter colonisation (hr . , % cl . - . , p= . ) without inÁ uencing cr-bsi rates. hicpac identiÀ ed three studies that investigated the efÀ cacy of a % chg-impregnated washcloth in reducing the risk of cr-bsi. these studies were included in a subsequent systematic review and meta-analysis on the efÀ cacy of either % chg-impregnated cloths or % chg solution for daily skin cleansing in adult acute care settings, mostly icus. twelve studies were included: one rct, one cluster nrct and controlled interrupted time series. five studies that reported the insertion technique included the use of chg. there was a high level of clinical heterogeneity and moderate statistical heterogeneity, which remained following a subgroup analysis by type of chg formulation. the authors concluded that among icu patients, daily chg bathing with chg liquid (or . , % ci . - . ) or cloths (or . , % ci . - . ) reduces the risk of cr-bsi. similar beneÀ t is obtained regardless of whether chg cloths or liquid preparation is used (or . , % ci . - . ). this review was not generalisable to paediatric care. whenever chg is used for insertion site dressings or skin cleansing, systems should be in place to ensure that it is not used for patients with a history of chlorhexidine sensitivity. a single rct compared the efÀ cacy of two commercially available alcohol-based antiseptic solutions for preparation and care of cvc insertion sites, with and without octenidine dihydrochloride. data were collected from to and published in . the authors concluded that octenidine in alcoholic solution is a better option than alcohol alone for the prevention of cvc-associated infections, and may be as effective as chg in practice but a comparative trial is needed. ivad use a sterile, transparent, semipermeable polyurethane dressing to cover the intravascular insertion site. ivad transparent, semi-permeable polyurethane dressings should be changed every days, or sooner, if they are no longer intact or if moisture collects under the dressing. ivad use a sterile gauze dressing if a patient has profuse perspiration or if the insertion site is bleeding or leaking, and change when inspection of the insertion site is necessary or when the dressing becomes damp, loosened or soiled. replace with a transparent semi-permeable dressing as soon as possible. ivad consider the use of a chlorhexidineimpregnated sponge dressing in adult patients with a central venous catheter as a strategy to reduce catheterrelated bloodstream infection. ivad consider the use of daily cleansing with chlorhexidine daily in adult patients with a central venous catheter as a strategy to reduce catheter-related bloodstream infection. ivad dressings used on tunnelled or implanted catheter insertion sites should be replaced every days until the insertion site has healed unless there is an indication to change them sooner. a dressing may no longer be required once the insertion site is healed. research previously described in these guidelines has described the superior effectiveness of chg to minimise the density of microorganisms around vascular catheter insertion sites. , , consequently, alcoholic chg is now widely used in the uk for disinfecting the insertion site during dressing changes. studies focused on the use of antimicrobial ointment applied under the dressing to the catheter insertion site to prevent catheter-related infection do not clearly demonstrate efÀ cacy. , most modern intravascular catheters and other catheter materials are not damaged by contact with alcohol. however, alcohol, and other organic solvents and oil-based ointments and creams, may damage some types of polyurethane and silicon catheter tubing (e.g. some catheters used in haemodialysis). the manufacturer's recommendations to only use disinfectants that are compatible with speciÀ c catheter materials must therefore be followed. ivad use a single-use application of % chlorhexidine gluconate in % isopropyl alcohol (or povidone iodine in alcohol for patients with sensitivity to chlorhexidine) to clean the central catheter insertion site during dressing changes, and allow to air dry. ivad use a single-use application of % chlorhexidine gluconate in % isopropyl alcohol (or povidone iodine in alcohol for patients with sensitivity to chlorhexidine) to clean the peripheral venous catheter insertion site during dressing changes, and allow to air dry. ivad do not apply antimicrobial ointment to catheter insertion sites as part of routine catheter site care. evidence indicates that the routine replacement of cvcs at scheduled time intervals does not reduce rates of cr-bsi. three randomised trials investigated strategies for replacing cvcs routinely at either days , or days compared with changing catheters when clinically indicated. two studies were conducted in adult icus , and a third study was undertaken in a renal dialysis unit. no difference in cr-bsi was observed in patients in the scheduled replacement groups compared with those replaced when clinically indicated. another suggested strategy for the prevention of cr-bsi is the routine scheduling of guidewire exchange of cvcs. a systematic review and meta-analysis of rcts concluded that when compared with insertion at a new site, guidewire exchange was associated with a trend towards increased rates of catheter colonisation (rr . , % ci . - . ), regardless of suspected cr-bsi at the time of replacement. guidewire exchange was also associated with a trend towards increased rates of catheter exitsite infection (rr . , % ci . - . ) and cr-bsi (rr . , % ci . - . ), but also associated with fewer mechanical complications relative to insertion at a new site. neither we nor hicpac identiÀ ed any additional evidence for these recommendations whilst updating our systematic review. we identiÀ ed one rct that compared a routine -day re-siting of pvcs compared with a clinically indicated resiting. ivd-related complication rates were per ivddays (clinically indicated) and per ivd-days (routine replacement) (p= . , hazard ratio . , % ci . - . ). re-siting a device on clinical indication would allow one in two patients to have a single cannula per course of intravenous treatment, as opposed to one in À ve patients managed with routine re-siting; overall complication rates appear similar. clinically indicated re-siting would achieve savings in equipment, staff time and patient discomfort. a recent update of a cochrane review found no evidence to support changing catheters every - h. evidence demonstrating that contamination of the catheter hub contributes to intraluminal microbial colonisation of catheters, particularly long-term catheters, was considered by hicpac. , [ ] [ ] [ ] [ ] [ ] [ ] catheter hubs are accessed more frequently when catheterisation is prolonged, and this increases the risk of cr-bsi originating from a colonised catheter hub rather than the insertion site. evidence from a prospective cohort study suggested that frequent catheter hub manipulation increases the risk for microbial contamination. additional studies concurred and recommended that hubs and sampling ports should be disinfected using either povidone iodine or chlorhexidine before they are accessed. , , a randomised prospective clinical trial investigated the use of needleless connectors or standard caps attached to cvc luer connections. results suggested that the use of needleless connectors may reduce the microbial contamination rate of cvc luers compared with standard caps. furthermore, disinfection of needleless connectors with either chlorhexidine/alcohol or pvi signiÀ cantly reduced external microbial contamination. both these strategies may reduce the risk of catheter-related infections acquired via the intraluminal route. we found no rct evidence comparing the efÀ cacy of different methods for the decontamination of ports and hubs prior to access. expert opinion, based on consensus and evidence extrapolated from experimental studies of hub decontamination, , , and studies of skin decontamination prior to insertion and during dressing changes, suggests that injection ports or catheter hubs should be decontaminated for a minimum of s using chg in % alcohol before and after accessing the system. although most intravascular catheters and catheter hub materials are now chemically compatible with alcohol or iodine, some may be incompatible and therefore the manufacturer's recommendations should be followed. ivad a single-use application of % chlorhexidine gluconate in % isopropyl alcohol (or povidone iodine in alcohol for patients with sensitivity to chlorhexidine) should be used to decontaminate the access port or catheter hub. the hub should be cleaned for a minimum of s and allowed to dry before accessing the system. the procedure of Á ushing and then leaving the lumen of a cvc À lled with an antibiotic solution is termed 'antibiotic lock prophylaxis' and has been described as a measure to prevent cr-bsi in haemodialysis or a patient who has a history of multiple cr-bsi despite optimal maximal adherence to the aseptic technique. evidence reviewed by hicpac demonstrated the effectiveness of this type of prophylaxis. however, the majority of the studies were conducted in haemodialysis patients and therefore may not be generalisable. we identiÀ ed a systematic review of rcts which concluded that the scientiÀ c evidence for the effectiveness of the routine use of antibiotic-based lock solutions is weak, thus supporting the hicpac evidence. in addition, there is concern that the use of such solutions could lead to an increase in antimicrobialresistant microorganisms. an additional placebo-rct of daily ethanol locks to prevent cr-bsi in patients with tunnelled catheters found that the reduction in the incidence of endoluminal cr-bsi using preventive ethanol locks was non-signiÀ cant, although the low incidence of endoluminal cr-bsi precludes deÀ nite conclusions, and the low incidence of cr-bsi in the placebo arm meant the study was underpowered in retrospect. signiÀ cantly more patients treated with ethanol locks discontinued their prophylactic treatment due to non-severe, ethanol-related adverse effects. ivad antimicrobial lock solutions should not be used routinely to prevent catheterrelated bloodstream infections. hicpac identiÀ ed no studies which demonstrated that oral or parenteral antibacterial or antifungal drugs reduced the incidence of cr-bsi among adults. however, among lowbirthweight infants, two studies on vancomycin prophylaxis demonstrated a reduction in cr-bsi but no reduction in mortality. as the prophylactic use of vancomycin is an independent risk factor for the acquisition of vre, it is likely that the risk of acquiring vre outweighs the beneÀ t of using prophylactic vancomycin. , topical mupirocin is used to suppress s. aureus in nasal carriers. some studies have shown that mupirocin applied nasally (or locally to the insertion site) results in reduced risk of cr-bsi. however, rates of mupriocin resistance of % have been reported in the uk, and its incompatibility with polyurethane catheters means that it should not be used routinely. long-term tunnelled cvcs are frequently used for patients with cancer who require intravenous treatments. a cochrane review published in concluded that prophylactic antibiotics or catheter Á ushing with vancomycin and heparin may be of beneÀ t in reducing the risk of catheter-related infections in these high-risk cancer patients. however, this practice should not be used routinely in order to minimise the development of antimicrobial resistance. ivad do not routinely administer intranasal or systemic antimicrobials before insertion or during the use of an intravascular device to prevent catheter colonisation or bloodstream infection. the placement of any cvc or pulmonary artery catheter leads to thrombus formation shortly after insertion, providing a focus for bacterial growth. catheters manufactured from silicone or polyethylene and placed in the subclavian vein are less frequently associated with thrombus formation. between % and % of patients with long-term cvcs and piccs develop a thrombosis of the large vessels, and patients are treated with prophylactic heparin to prevent the formation of both deep vein thrombosis and catheter thrombus. , [ ] [ ] [ ] [ ] [ ] [ ] the use of anticoagulants heparin may be administered through several different routes. an early meta-analysis of rcts compared the effectiveness of heparin administration via an infusion, subcutaneously or intermittent Á ush for the prevention of thrombus formation and cr-bsi in patients with short-term cvcs. prophylactic heparin infusion was associated with a decrease in catheter thrombus formation, deep vein thrombosis, catheter colonisation and a trend towards reductions in cr-bsi, but this was not statistically h. p. loveday et al. / journal of hospital infection s ( ) s -s s signiÀ cant. hicpac identiÀ ed an additional prospective randomised trial that demonstrated a signiÀ cant decrease in the rate of cr-bsi in patients with non-tunnelled cvcs who received continuous heparin infusion. heparin-bonded (hb) catheters have also been shown to reduce the risk of both thrombus formation and cr-bsi. [ ] [ ] [ ] [ ] we identiÀ ed one systematic review of hb cvcs in children. the reviewers identiÀ ed two rcts of children aged day to years who received either an hb catheter or a standard catheter. there was no signiÀ cant difference in the median duration of catheter patency in the two groups: days in the hb catheter group and days in the standard catheter group. the authors also reported a trend towards a reduction in the risk of catheter-related thrombosis and catheter occlusion in the hb group. the risks of catheter colonisation and catheterrelated infection were signiÀ cantly reduced in the treatment group, with a delay to infection in the hb catheter group. however, the reviewers considered the need for further studies to conÀ rm the efÀ cacy of hb catheters. the use of warfarin has also been shown to reduce the risk of catheter-related thrombosis in some patient groups but not in others, and is generally not associated with a reduction in infection-related complications. , - systemic heparin, as either an infusion or Á ush, has a number of side effects that contraindicate its routine use for maintaining the patency of cvcs and preventing thrombus formation; these include thrombocytopenia, allergic reactions and bleeding. normal saline is an alternative to the use of heparin Á ush. hicpac refer to three systematic reviews, and meta-analysis of rcts evaluating the effect of heparin on the duration of catheter patency and on the prevention of complications associated with the use of peripheral venous and arterial catheters concluded that heparin at doses of u/ml for intermittent Á ushing is no more beneÀ cial than Á ushing with normal saline alone. [ ] [ ] [ ] [ ] however, manufacturers of implanted ports or opened-ended catheter lumens may recommend heparin Á ushes for maintaining cvcs that are accessed infrequently. we identiÀ ed one systematic review and two rcts that compared heparin with normal saline to maintain the patency of cvcs and pvcs, respectively. - a systematic review of heparin Á ushing and other interventions to maintain the patency of cvcs concluded that the evidence base for heparin Á ushing and other interventions to prevent catheter occlusion is limited and published studies are of low quality. the reviewers concluded that there is no direct evidence of the effectiveness of heparin Á ushes to prevent cr-bsi or other central line complications. in a single-centre rct of newly placed multi-lumen cvcs in patients in medical icus and surgical/burn/trauma icus, normal saline and heparin Á ush solutions were found to have similar rates of lumen non-patency. given potential safety concerns with the use of heparin, normal saline may be the preferred Á ushing solution for short-term use for cvc maintenance. secondary outcomes for cr-bsi were non-signiÀ cant between groups. a single-centre cluster rct of medical patients found that twice-daily heparin ( u/ml) Á ushes for maintenance of pvcs was more effective than normal saline solution. the number of catheter-related phlebitis/occlusions and the number of catheters per patient was reduced; however, infection outcomes were not measured. ivad do not use systemic anticoagulants routinely to prevent catheter-related bloodstream infection. ivad use sterile normal saline for injection to Á ush and lock catheter lumens that are accessed frequently. needle-free infusion systems and connection devices have been widely introduced to reduce the incidence of sharps injuries and minimise the risk of transmission of bloodborne pathogens to healthcare workers. there is limited evidence that needleless devices or valves reduce the risk of catheter colonisation compared with standard devices. in addition, the design features of some of these devices pose a potential risk for contamination, and have been associated with reports of an increase in bloodstream infection rates. [ ] [ ] [ ] [ ] ivad the introduction of new intravascular devices or components should be monitored for an increase in the occurrence of device-associated infection. if an increase in infection rates is suspected, this should be reported to the medicines and healthcare products regulatory agency in the uk. ivad when safer sharps devices are used, healthcare workers should ensure that all components of the system are compatible and secured to minimise leaks and breaks in the system. hicpac reviewed three well-controlled studies on the optimal interval for the routine replacement of intravenous solution administration sets. a cochrane review of rcts with patients concluded that there is no evidence that changing intravenous administration sets more often than every h reduces the incidence of bloodstream infection. the reviewers were unable to conclude if changing administration sets less often than every h affects the incidence of infection from the studies. there were no differences between participants with central vs peripheral catheters, nor between participants who did and did not receive parenteral nutrition, or between children and adults. administration sets that do not contain lipids, blood or blood products may be left in place for intervals of up to h without increasing the incidence of infection. there is no evidence to suggest that administration sets which contain lipids should not be changed every h as currently recommended. ivad administration sets in continuous use do not need to be replaced more frequently than every h, unless device-speciÀ c recommendations from the manufacturer indicate otherwise, they become disconnected or the intravascular access device is replaced. class a ivad administration sets for blood and blood components should be changed when the transfusion episode is complete or every h (whichever is sooner). ivad administration sets used for lipidcontaining parenteral nutrition should be changed every h. ensuring that patients receive care that is evidence based is an essential element of delivering high-quality health care. in , the department of health issued a series of highimpact interventions that were derived from national and international evidence-based guidelines for the prevention of healthcare-associated infection and based on experience from the institute of healthcare improvement , lives campaign focused on reducing patient harm. the high-impact interventions focused on increasing the reliability of care and ensuring that recommendations were implemented every time for every patient. the intervention for the prevention of infection associated with the use of ivds included six key interventions often referred to as a 'care bundle', together with audit tools to measure adherence. these six practices included: • aseptic insertion of an appropriate device; • correct siting of the device; • effective cutaneous antisepsis; and for continuing care of the device: • hand decontamination and asepsis for any contact with the device; • daily observation of the insertion site; and • clean, intact dressing. a small number of well-designed studies , have described the use of 'bundled' approaches to reducing cr-bsi, and have stimulated individual observational and quality improvement reports of the results of using key evidence-based practices for the prevention of cr-bsi. the most prominent of these was a study conducted in the icu setting of hospitals in the usa, which was then adopted by other countries including the uk. , the authors reported the success of À ve evidence-based practices combined with system and organisational support, which resulted in a % decrease in cr-bsi months after the inception of the programme (incidence rate ratio . , % ci . - . to incidence rate ratio . , % ci . - . ) and sustained reductions thereafter. the intervention comprised: hand hygiene using abhr; msb precautions for insertion; cutaneous antisepsis of the insertion site with % chg; avoiding the femoral site; and removing cvcs as soon as they are no longer clinically indicated. in addition, system changes that prompted the clinician to 'do the right thing' included placing all the equipment needed in a cart for ease of access; the use of a checklist; authorising staff to halt procedures if best practice was not being followed; daily rounds to ensure the timely removal of cvcs; feedback of cr-bsi cases to clinical staff; and organisational support to purchase essential equipment and solutions prior to the start of the study. audit and feedback are an essential component of any quality improvement intervention as this promotes a continuous 'hawthorne effect' and enables staff to maintain vigilance and sustain improvement. the use of dashboards and statistical process control charts alerts clinicians to variability outside control limits, and prompts scrutiny of practice and organisational systems, and remedial action to be taken. we identiÀ ed three additional studies that reported 'bundled interventions' to reduce cr-bsi. [ ] [ ] [ ] none were included in the systematic review as they failed to meet study quality criteria. the features of any quality improvement initiative need to be tailored to the local conditions and may include some or all of the following: • hand hygiene, aseptic insertion using msb precautions (cvc), aseptic technique (pvc), cutaneous antisepsis using % chg in alcohol unless contraindicated, appropriate siting of the cvc or pvc, and prompt removal when no longer indicated; • audit and feedback; • education and training; and • accessibility of equipment and appropriate system changes developed with clinical staff to make best practice the norm. in one cost-effectiveness study, a markov decision model was used to evaluate the cost-effectiveness of a care bundle to prevent cr-bsi. the care bundle included in the model was based on the bundle advocated by the institute for health improvement , lives campaign, comprising optimal hand hygiene, chlorhexidine skin antisepsis, msb precautions for catheter insertion and insertion equipment kit, optimal insertion site and prompt catheter removal. costs included monitoring, education and clinical leadership activities. the authors estimated that the bundle would be cost-effective if the costs of implementation were less than aus$ , (£ , ) per icu. to support the appropriate use and management of intravascular access devices (central and peripheral venous catheters) and ensure their timely removal. these may include: • protocols for device insertion and maintenance; • reminders to review the continuing use or prompt the removal of intravascular devices; • audit and feedback of compliance with practice guidelines; and • continuing professional education. systematic review questions . what types of cvcs (material, coating, antibiotic impregnation, cuffed, tunnelled, midline, picc) and pvcs (material, coating, antibiotic impregnation) are most effective in reducing the risk of cr-bsi and related complications/adverse events including phlebitis, related mortality, catheter tip colonisation and premature line removal? . which cvc/pvc insertion site is associated with the lowest risk of cr-bsi and related complications including phlebitis, related mortality, catheter tip colonisation and premature line removal? . what is the evidence that additional ports or lumens increase the risk of cr-bsi and related complications/adverse events including phlebitis, mortality, catheter tip colonisation and premature line removal? . which infection prevention precautions used for inserting intravascular catheters are most effective in reducing the risk of cr-bsi and related complications/adverse events including phlebitis, catheter tip colonisation, premature line removal and mortality? . what levels of barrier precautions are most effective in reducing the risk of cr-bsi and related complications/adverse events including phlebitis, catheter tip colonisation, premature line removal and mortality? . what is the most effective skin antisepsis solution/antiseptic-impregnated product for decontamination of the skin prior to insertion of cvcs and pvcs to reduce the risk of cr-bsi and related complications including phlebitis, catheter tip colonisation, premature line removal and mortality? . what is the effectiveness of antiseptics vs antiseptic-impregnated products (sponges or cloths) for decontaminating skin at the insertion site or surrounding area whilst a cvc or pvc is in situ in reducing the risk of cr-bsi and related complications including phlebitis, catheter tip colonisation, premature line removal and mortality? . what is the evidence for the effectiveness of using antibiotics or antiseptics to lock, Á ush or clean the catheter hub or entry ports of cvcs and pvcs in reducing the risk of cr-bsi and related complications including phlebitis, catheter tip colonisation, premature line removal and mortality? . what is the effectiveness of low-dose systemic anticoagulation to reduce the risk of cr-bsi and related complications including phlebitis, catheter tip colonisation, premature line removal and mortality? . which dressing type is the most clinically effective in reducing the risk of cr-bsi and related complications including phlebitis, catheter tip colonisation, premature line removal and mortality, and how frequently should dressings be changed? . what is the optimal frequency to change or re-site pvcs or midline catheters to reduce the risk of cr-bsi and related complications including phlebitis, catheter tip colonisation, premature line removal and mortality? . what is the evidence for the effectiveness of replacing administration sets to reduce the risk of cr-bsi and related complications including phlebitis, catheter tip colonisation, premature line removal and mortality? . what is the effectiveness of the prophylactic administration of systemic antimicrobials in reducing the incidence of cr-bsi and related complications including phlebitis, catheter tip colonisation, premature line removal and mortality? . what is the evidence that the needle-safe devices are associated with increased risk of cr-bsi and related complications including phlebitis, catheter tip colonisation, premature line removal and mortality? . what is the effectiveness of system interventions in reducing the risk of cr-bsi and related complications including phlebitis, catheter tip colonisation, premature line removal and mortality, and improving healthcare workers' knowledge and behaviour relating to the use of central venous access device (cvad) and peripheral vascular device (pvd)? total number of articles located = abstract indicates that the article: relates to infections associated with intravascular access devices; is written in english; is primary research, a systematic review or a meta-analysis; and appears to inform one or more of the review questions. total number of articles retrieved from sift = full text conÀ rms that the article: relates to infections associated with intravascular access devices; is written in english; is primary research (randomised controlled trials, prospective cohort, interrupted time series, controlled before-after, quasi-experimental), a systematic review or a metaanalysis including the above designs; and informs one or more of the review questions. total number of studies selected for appraisal during sift = all articles that described primary research, a systematic review or a meta-analysis and met the sift criteria were independently critically appraised by two appraisers using sign and epoc criteria. consensus and grading was achieved through discussion. total number of studies accepted after critical appraisal = total number of studies rejected after critical appraisal = the epic project: developing national evidence-based guidelines for preventing healthcare associated infections. phase i: guidelines for preventing hospital-acquired infections national evidencebased guidelines for preventing 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school students in southern taiwan department of health. an organisation with a memory. london: stationery ofÀ ce the management of health safety and welfare: issues for nhs staff. london: stationery ofÀ ce sharps safety and needlestick prevention efÀ cacy of catheter needles with safeguard mechanisms effect of implementing safety-engineered devices on percutaneous injury epidemiology a comprehensive approach to percutaneous injury prevention during phlebotomy: results of a multicenter study impact of safety devices for preventing percutaneous injuries related to phlebotomy procedures in health care workers evaluation of a safety resheathable winged steel needle for prevention of percutaneous injuries associated with intravascular-access procedures among healthcare workers a comparative user evaluation of three needle-protective devices potential for reported needlestick injury prevention among healthcare workers through safety device usage and improvement of guideline adherence: expert panel assessment evaluation of safety devices for preventing percutaneous injuries among health care workers during phlebotomy procedures blunt s needles for the reduction of needlestick injuries during cesarean delivery: a randomized controlled trial a retractable winged steel (butterÁ y) needle performance improvement project role of safetyengineered devices in preventing needlestick injuries in french hospitals effect of the introduction of an engineered sharps injury prevention device on the percutaneous injury rate in healthcare workers safety-engineered device implementation: does it introduce bias in percutaneous injury reporting? guarded À stula needle reduces needlestick injuries in hemodialysis evaluation of interventions to prevent needlestick injuries in health care occupations assessing the effect of long-term availability of engineering controls on needlestick injuries among health care workers: a -year preimplementation and postimplementation comparison a prospective randomized trial of two safety peripheral intravenous catheters use of needle safety devices by clinical laboratories in north carolina hospitals the usability and acceptability of a needleless connector system organizational climate, stafÀ ng, and safety equipment as predictors of needlestick injuries and near-misses in hospital nurses national institute for occupational safety and health. preventing needlestick injuries in health care settings. cincinnati: department of health and human services infection control in clinical practices what features of educational interventions lead to competence in aseptic insertion and maintenance of cv catheters in acute care? beme guide no. antt v : an updated practice framework for aseptic technique guideline for prevention of catheter-associated urinary tract infections english national point prevalence survey on healthcare associated infections and antimicrobial use, : preliminary data four country healthcare associated infection prevalence survey : overview of the results urinary catheter care. essential steps to safe, clean care: reducing healthcare associated infections. london: department of health preventing catheter-associated urinary tract infections in the intensive care unit systematic review: antimicrobial urinary catheters to prevent catheter-associated urinary tract infection in hospitalized patients a prospective microbiologic study of bacteriuria in patients with chronic indwelling urethral catheters catheter-associated urinary tract infections are physicians aware of which of their patients have indwelling urinary catheters? appropriateness of use of indwelling urinary catheters in patients admitted to the medical service overuse of the indwelling urinary tract catheter in hospitalized medical patients trends in catheter-associated urinary tract infections in adult intensive care units -united states clinical and economic consequences of nosocomial catheter-related bacteriuria recognition and prevention of healthcare-associated urinary tract infections in the intensive care unit epidemiology of hospital-acquired urinary tract-related bloodstream infection at a university hospital silver alloy vs. uncoated urinary catheters: a systematic review of the literature catheter-associated urinary tract infections: new aspects of novel urinary catheters a review of strategies to decrease the duration of indwelling urethral catheters and potentially reduce the incidence of catheter-associated urinary tract infections enhancing the safety of critically ill patients by reducing urinary and central venous catheterrelated infections comparison of urethral reaction to full silicone, hydrogen-coated and siliconised latex catheters effect of catheter material on the incidence of urethral strictures randomised study of the effect of midnight versus removal of urinary catheters the association between indwelling urinary catheter use in the elderly and urinary tract infection in acute care aiming to reduce catheter associated urinary tract infections (cauti) by adopting a checklist and bundle to achieve sustained system improvements evidence for the use of silver-alloycoated urethral catheters the high impact actions for nursing and midwifery : protection from infection preventing catheter-related bacteriuria: should we? can we? how? epidemiology of urinary tract infections: incidence, morbidity, and economic costs guideline for prevention of catheter-associated urinary tract infections computerbased order entry decreases duration of indwelling urinary catheterization in hospitalized patients effect of nurse-led multidisciplinary rounds on reducing the unnecessary use of urinary catheterization in hospitalized patients systematic review and s meta-analysis: reminder systems to reduce catheter-associated urinary tract infections and urinary catheter use in hospitalized patients stop orders to reduce inappropriate urinary catheterization in hospitalized patients: a randomized controlled trial reduction of urinary tract infection and antibiotic use after surgery: a controlled, prospective, before-after intervention study interventions to minimise the initial use of indwelling urinary catheters in acute care: a systematic review non-invasive measurement of bladder volume as an indication for bladder catheterization after orthopaedic surgery and its effect on urinary tract infections a collaborative, nurse-driven initiative to reduce hospital-acquired urinary tract infections prevention of nosocomial catheter-associated urinary tract infections through computerized feedback to physicians and a nurse-directed protocol continence clinic. catheters: design, selection and management urinary tract infections: detection, prevention and management. th ed. baltimore: williams and wilkins prevention of catheter-associated urinary tract infections study of patients with indwelling catheters rapid response report: female urinary catheters causing trauma to adult males. nspca effect of a siliconized latex urinary catheter on bacterial adherence and human neutrophil activity incidence and importance of bacteriuria in postoperative, short-term urinary catheterization types of urethral catheters for management of short-term voiding problems in hospitalized adults: a short version cochrane review a controlled trial of a new material for coating urinary catheters comparison of hydrophilic polymer-coated latex, uncoated latex and pvc indwelling balloon catheters in the prevention of urinary infection the epic project: updating the evidence base for national evidence-based guidelines for preventing healthcareassociated infections in nhs hospitals in england. a report with recommendations types of urethral catheters for management of short-term voiding problems in hospitalised adults the efÀ cacy of silver alloy-coated urinary catheters in preventing urinary tract infection: a meta-analysis management of short term indwelling urethral catheters to prevent urinary tract infections. a systematic review is there evidence for recommending silver-coated urinary catheters in guidelines? clinical application of the bardex ic foley catheter a randomized crossover study of silver-coated urinary catheters in hospitalized patients the potential clinical and economic beneÀ ts of silver alloy urinary catheters in preventing urinary tract infection a comparison of the effect of early insertion of standard latex and silver-impregnated latex foley catheters on urinary tract infections in burn patients using silver to reduce catheter-associated urinary tract infections the impact of using silver alloy urinary catheters in reducing the incidence of urinary tract infections in the critical care setting effect of silver-coated urinary catheters: efÀ cacy, cost-effectiveness, and antimicrobial resistance a rapid method of impregnating endotracheal tubes and urinary catheters with gendine: a novel antiseptic agent gentamicin-releasing urethral catheter for short-term catheterization randomized multicentre trial of the effects of a catheter coated with hydrogel and silver salts on the incidence of hospital-acquired urinary tract infections use of silver-hydrogel urinary catheters on the incidence of catheter-associated urinary tract infections in hospitalized patients evaluation of the antimicrobial efÀ cacy of urinary catheters impregnated with antiseptics in an in vitro urinary tract model efÀ cacy of antimicrobialimpregnated bladder catheters in reducing catheter-associated bacteriuria: a prospective, randomized, multicenter clinical trial assessment of nosocomial urinary tract infections in orthopaedic patients: a prospective and comparative study using two different catheters a large randomized clinical trial of a silver-impregnated urinary catheter: lack of efÀ cacy and staphylococcal superinfection prevention of catheter-associated urinary tract infection with a silver oxide-coated urinary catheter: clinical and microbiologic correlates reÀ nements in the coating of urethral catheters reduces the incidence of catheter-associated bacteriuria. an experimental and clinical study silver alloy coated catheters reduce catheter-associated bacteriuria antimicrobial catheters for reduction of symptomatic urinary tract infection in adults requiring short-term catheterisation in hospital: a multicentre randomised controlled trial preventing hospital-acquired infection: clinical guidelines. london: public health laboratory service philadelphia: lippincott-raven entry of bacteria into the urinary tracts of patients with inlying catheters technical advances in the prevention of urinary tract infection prevention of catheter-induced urinary-tract infections by sterile closed drainage factors predisposing to bacteriuria during indwelling urethral catheterization bacteriuria during indwelling catheter drainage: ii. effect of a closed sterile draining system does the addition of disinfectant to urine drainage bags prevent infection in catheterised patients? prevention of urinary tract infection in gynaecology reduction of mortality associated with nosocomial urinary tract infection incidence of urinary tract infections in patients with short-term indwelling urethral catheters: a comparison between a -day urinary drainage bag change and no change regimens decreased incidence of bacteriuria associated with periodic instillations of hydrogen peroxide into the urethral catheter drainage bag evaluation of h o prophylaxis of bacteriuria in patients with long-term indwelling foley catheters: a randomized controlled study catheter-associated bacteriuria. failure to reduce attack rates using periodic instillations of a disinfectant into urinary drainage systems prevention of bacteriuria in female patients with indwelling catheters prevention of catheter-associated urinary tract infections. efÀ cacy of daily meatal care regimens evaluation of daily meatal care with poly-antibiotic ointment in prevention of urinary catheter-associated bacteriuria prevention of catheter-associated bacteriuria: clinical trial of methods to block three known pathways of infection daily meatal care for prevention of catheter-associated bacteriuria: results using frequent applications of polyantibiotic cream randomized trial of meatal care with silver sulfadiazine cream for the prevention of catheter-associated bacteriuria water or antiseptic for periurethral cleaning before urinary catheterization: a randomized controlled trial does instillation of chlorhexidine into the bladder of catheterized geriatric patients help reduce bacteriuria? bladder irrigation with chlorhexidine for the prevention of urinary infection after transurethral operations: a prospective controlled study controlled trial of intravesical noxythiolin in the prevention of infection following outÁ ow tract surgery a randomized study on the effect of bladder irrigation with povidone-iodine before removal of an indwelling catheter antibiotic irrigation and catheter-associated urinary-tract infections once-daily irrigation of long-term urethral catheters with normal saline. lack of beneÀ t assessment of the use of bladder washouts/instillations in patients with long-term indwelling catheters neomycin-polymyxin prophylaxis of urinary-tract infection associated with indwelling catheters the use of bladder wash-outs to reduce urinary catheter encrustation closing the quality gap: a critical analysis of quality improvement strategies evaluating the efÀ cacy of the infection control liaison nurse in the hospital guidelines for the prevention of intravascular catheter-related infections nosocomial bloodstream infection in critically ill patients. excess length of stay, extra costs, and attributable mortality is routine replacement of peripheral intravenous catheters necessary? peripheral teÁ on catheters: factors determining incidence of phlebitis and duration of cannulation phlebitis rate and time kinetics of short peripheral iv catheters routine versus clinically indicated replacement of peripheral intravenous catheters: a randomised controlled equivalence trial the risk of bloodstream infection in adults with different intravascular devices: a systematic review of published prospective studies nosocomial bloodstream infections in us hospitals: analysis of , cases from a prospective nationwide surveillance study national nosocomial infections surveillance system. overview of nosocomial infections caused by gram-negative bacilli the pathogenesis of catheter-related bloodstream infection with noncuffed short-term central venous catheters saraÀ n hw. a semiquantitative culture method for identifying intravenous-catheter-related infection the pathogenesis and epidemiology of catheter-related infection with pulmonary artery swan-ganz catheters: a prospective study utilizing molecular subtyping ultrastructural analysis of indwelling vascular catheters: a quantitative relationship between luminal colonization and duration of placement dna À ngerprinting analysis of coagulase negative staphylococci implicated in catheter related bloodstream infections colonization and infrequent hematogenous seeding in catheterrelated infections optimal frequency of changing intravenous administration sets: is it safe to prolong use beyond hours? effectiveness of surveillance of central catheter-related bloodstream infection in an icu in korea effect of an education program on decreasing catheter-related bloodstream infections in the surgical intensive care unit education of physiciansin-training can decrease the risk for vascular catheter infection impact of a prevention strategy targeted at vascularaccess care on incidence of infections acquired in intensive care septic complications of total parenteral nutrition. a À ve year experience catheter complications in total parenteral nutrition. a prospective study of consecutive patients central venous catheter care in parenteral nutrition: a review prospective study of catheter replacement and other risk factors for infection of hyperalimentation catheters educational interventions for preventing vascular catheter bloodstream infections in critical care: evidence map, systematic review and economic evaluation total parenteral nutrition-related infections: prospective epidemiologic study using semiquantitative methods colonization of bacteria on polyvinyl chloride and teÁ on intravascular catheters in hospitalized patients evaluation of dressing regimens for prevention of infection with peripheral intravenous catheters. gauze, a transparent polyurethane dressing, and an iodophortransparent dressing sepsis from triplevs single-lumen catheters during total parenteral nutrition in surgical or critically ill patients prospective evaluation of single and triple lumen catheters in total parenteral nutrition central catheter infections: single-versus triple-lumen catheters. inÁ uence of guide wires on infection rates when used for replacement of catheters infection rate for single lumen v triple lumen subclavian catheters use of triple-lumen subclavian catheters for administration of total parenteral nutrition increased infection rate in double-lumen versus single-lumen hickman catheters in cancer patients single-versus triple-lumen central catheter-related sepsis: a prospective randomized study in a critically ill population triple-vs single-lumen central venous catheters. a prospective study in a critically ill population rates of infection for single-lumen versus multilumen central venous catheters: a meta-analysis colonization and bloodstream infection with single-versus multi-lumen central venous catheters: a quantitative systematic review guideline for prevention of intravascular devicerelated infections. hospital infection control practices advisory committee a prospective study of prolonged central venous access in leukemia broviac catheter-related bacteremia in oncology patients hickman catheter infections in patients with malignancies problems associated with indwelling central venous catheters complications of hickman-broviac catheters management of hickman catheter sepsis catheter-related septicemia in patients receiving home parenteral nutrition single-vs double-lumen central venous catheters in pediatric oncology patients bacteraemia related to indwelling central venous catheters: prevention, diagnosis and treatment low infection rate and long durability of nontunneled silastic catheters. a safe and costeffective alternative for long-term venous access lack of clinical beneÀ t from subcutaneous tunnel insertion of central venous catheters in immunocompromised patients a totally implanted injection port system for blood sampling and chemotherapy administration complications and management of implanted venous access catheters a totally implanted venous access system for the delivery of chemotherapy implantable subcutaneous venous catheters fifty-À ve patient years' experience with a totally implanted system for intravenous chemotherapy infection rates of broviac-hickman catheters and implantable venous devices complications from long-term indwelling central venous catheters in hematologic patients with special reference to infection classical external indwelling central venous catheter versus totally implanted venous access systems for chemotherapy administration: a randomized trial in patients with solid tumors comparison of infections in hickman and implanted port catheters in adult solid tumor patients experience with a totally implantable venous access device (port-a-cath) in patients with aids infectious morbidity associated with long-term use of venous access devices in patients with cancer long-term central venous access effect of subcutaneous tunneling on internal jugular catheter-related sepsis in critically ill patients: a prospective randomized multicenter study use of tunneled femoral catheters to prevent catheter-related infection. a randomized, controlled trial tunneling short-term central venous catheters to prevent catheter-related infection: a meta-analysis of randomized, controlled trials peripheral access options long-term intravenous therapy with peripherally inserted silicone elastomer central venous catheters in patients with malignant diseases infectious complications among patients receiving home intravenous therapy with peripheral, central, or peripherally placed central venous catheters peripherally inserted central venous catheters. low-risk alternatives for ongoing venous access survey of the use of peripherally inserted central venous catheters in children peripherally inserted central catheters in patients with aids are associated with a low infection rate risk of catheter-related bloodstream infection with peripherally inserted central venous catheters used in hospitalized patients prevention of central venous catheter-related bloodstream infection by use of an antiseptic-impregnated catheter. a randomized, controlled trial evaluation of chlorhexidine and silver-sulfadiazine impregnated central venous catheters for the prevention of bloodstream infection in leukaemic patients: a randomized controlled trial inÁ uence of triple-lumen central venous catheters coated with chlorhexidine and silver sulfadiazine on the incidence of catheter-related bacteremia a meta-analysis dealing with the effectiveness of chlorhexidine and silver-sufhadiazine impregnated central venous catheters anaphylactic shock induced by an antiseptic-coated central venous [correction of nervous] catheter cost-effectiveness of antiseptic-impregnated central venous catheters for the prevention of catheter-related bloodstream infection central venous catheters coated with minocycline and rifampin for the prevention of catheter-related colonization and bloodstream infections. a randomized, double-blind trial. the texas medical center catheter study group decreasing catheter colonization through the use of an antiseptic-impregnated catheter: a continuous quality improvement project a comparison of two antimicrobial-impregnated central venous catheters efÀ cacy of antiseptic-impregnated central venous catheters in preventing catheter-related bloodstream infection: a meta-analysis prevention of intravascular catheter-related infections prevention of bloodstream infections with central venous catheters treated with antiinfective agents depends on catheter type and insertion time: evidence from a meta-analysis prolonged antimicrobial activity of a catheter containing chlorhexidine-silver sulfadiazine extends protection against catheter infections in vivo the clinical effectiveness and cost-effectiveness of central venous catheters treated with anti-infective agents in preventing bloodstream infections: a systematic review and economic evaluation catheter impregnation, coating or bonding for reducing central venous catheter-related infections in adults effectiveness of different central venous catheters for catheterrelated infections: a network meta-analysis anti-infective external coating of central venous catheters: a randomized, noninferiority trial comparing -Á uorouracil with chlorhexidine/silver sulfadiazine in preventing catheter colonization immediate hypersensitivity to chlorhexidine is increasingly recognised in the united kingdom anaphylaxis to chlorhexidine-coated central venous catheters: a case series and review of the literature medical device alert: all medical devices and medicinal products containing chlorhexidine. mda/ / . london: medicines and healthcare products regulatory agency femoral vs jugular venous catheterization and risk of nosocomial events in adults requiring acute renal replacement therapy: a randomized controlled trial impact of central venous catheter type and methods on catheter-related colonization and bacteraemia to reduce catheterrelated bloodstream infections: is the subclavian route better than the jugular route for central venous catheterization? complications of central venous catheters: internal jugular versus subclavian access -a systematic review comparison between the jugular and subclavian vein as insertion site for central venous catheters: microbiological aspects and risk factors for colonization and infection prospective multicenter study of vascular-catheter-related complications and risk factors for positive central-catheter cultures in intensive care unit patients a review of risk factors for catheter-related bloodstream infection caused by percutaneously inserted, noncuffed central venous catheters: implications for preventive strategies the micro-organism responsible for central venous catheter s s -s related bloodstream infection depends on catheter site prospective study of arterial and central venous catheter colonization and of arterial-and central venous catheter-related bacteremia in intensive care units complications of femoral and subclavian venous catheterization in critically ill patients: a randomized controlled trial risk of infection due to central venous catheters: effect of site of placement and catheter type the incidence of infectious complications of central venous catheters at the subclavian, internal jugular, and femoral sites in an intensive care unit population the risk of catheter-related bloodstream infection with femoral venous catheters as compared to subclavian and internal jugular venous catheters: a systematic review of the literature and meta-analysis ultrasound guidance for placement of central venous catheters: a metaanalysis of the literature ultrasonic locating devices for central venous cannulation: meta-analysis guidance on the use of ultrasound locating devices for placing central venous catheters infection control in intravenous therapy prevention of central venous catheter-related infections by using maximal sterile barrier precautions during insertion effect of different sterile barrier precautions and central venous catheter dressing on the skin colonization around the insertion site using maximal sterile barriers to prevent central venous catheter-related infection: a systematic evidence-based review catheter-related sepsis: an overview -part prospective randomised trial of povidone-iodine, alcohol, and chlorhexidine for prevention of infection associated with central venous and arterial catheters prospective, randomized trial of two antiseptic solutions for prevention of central venous or arterial catheter colonization and infection in intensive care unit patients alcoholic povidone-iodine to prevent central venous catheter colonization: a randomized unit-crossover study chlorhexidine compared with povidone-iodine solution for vascular cathetersite care: a meta-analysis vascular catheter site care: the clinical and economic beneÀ ts of chlorhexidine gluconate compared with povidone iodine guideline for use of topical antimicrobial agents catheter-related sepsis in long-term parenteral nutrition with broviac catheters. an evaluation of different disinfectants colonization of central venous catheters a clinical and bacteriologic study of infections associated with venous cutdowns application of antibiotic ointment to the site of venous catheterization -a controlled trial risk of infection with intravenous indwelling catheters: effect of application of antibiotic ointment the effects of antibiotic ointments and antiseptics on the skin Á ora beneath subclavian catheter dressings during intravenous hyperalimentation a comparative study of polyantibiotic and iodophor ointments in prevention of vascular catheter-related infection the forgotten role of alcohol: a systematic review and meta-analysis of the clinical efÀ cacy and perceived role of chlorhexidine in skin antisepsis transparent polyurethane À lm as an intravenous catheter dressing. a metaanalysis of the infection risks gauze and tape and transparent polyurethane dressings for central venous catheters gauze and tape and transparent polyurethane dressings for central venous catheters using the collaborative evidence based practice model: a systematic review and uptake of chlorhexidine-impregnated sponge dressings on central venous access devices in a tertiary cancer centre economic evaluation of chlorhexidine-impregnated sponges for preventing catheterrelated infections in critically ill adults in the dressing study randomized controlled trial of chlorhexidine dressing and highly adhesive dressing for preventing catheter-related infections in critically ill adults the efÀ cacy of daily bathing with chlorhexidine for reducing healthcareassociated bloodstream infections: a meta-analysis skin disinfection with octenidine dihydrochloride for central venous catheter site care: a double-blind, randomized, controlled trial catheterrelated sepsis: prospective, randomized study of three methods of long-term catheter maintenance changing subclavian haemodialysis cannulas to reduce infection a controlled trial of scheduled replacement of central venous and pulmonary-artery catheters central venous catheter replacement strategies: a systematic review of the literature routine resite of peripheral intravenous devices every days did not reduce complications compared with clinically indicated resite: a randomised controlled trial clinically-indicated replacement versus routine replacement of peripheral venous catheters source and route of microbial colonisation of parenteral nutrition catheters catheter sepsis due to coagulase-negative staphylococci in patients on total parenteral nutrition a prospective study of the catheter hub as the portal of entry for microorganisms causing catheter-related sepsis in neonates adherence and growth of coagulase-negative staphylococci on surfaces of intravenous catheters pathogenesis of catheter sepsis: a prospective study with quantitative and semiquantitative cultures of catheter hub and segments a randomized trial on the effect of tubing changes on hub contamination and catheter sepsis during parenteral nutrition contamination of stopcocks mounted in administration sets for central venous catheters with replacement at hrs versus hrs: a prospective cohort study use of disinfectants to reduce microbial contamination of hubs of vascular catheters effectiveness of disinfectant techniques on intravenous tubing latex injection ports a randomized, prospective clinical trial to assess the potential infection risk associated with the posiflow ® needleless connector scrub the hub': cleaning duration and reduction in bacterial load on central venous catheters successful disinfection of needleless access ports: a matter of time and friction antibiotic-based catheter lock solutions for prevention of catheter-related bloodstream infection: a systematic review of randomised controlled trials prevention of catheter-related bacteremia with a daily ethanol lock in patients with tunnelled catheters: a randomized, placebo-controlled trial guidelines for the prevention of intravascular-catheter-related infections can high-level mupirocin resistance reporting be relied upon to ensure patients are prescribed appropriate treatment? prophylactic antibiotics for preventing early central venous catheter gram positive infections in oncology patients heparin bonding reduces thrombogenicity of pulmonaryartery catheters central venous access sites for the prevention of venous thrombosis, stenosis and infection the relationship between the thrombotic and infectious complications of central venous catheters thrombosis as a complication of pulmonary-artery catheterization via the internal jugular vein: prospective evaluation by phlebography central vein thrombosis associated with intravenous feeding -a prospective study a cross-sectional study of catheter-related thrombosis in children receiving total parenteral nutrition at home catheter-related thrombosis in critically ill children: comparison of catheters with and without heparin bonding a prospective study of femoral catheter-related thrombosis in children beneÀ t of heparin in central venous and pulmonary artery catheters: a meta-analysis of randomized controlled trials very low doses of warfarin can prevent thrombosis in central venous catheters. a randomized prospective trial randomized trial of prevention of catheter-related bloodstream infection by continuous infusion of low-dose unfractionated heparin in patients with hematologic and oncologic disease heparin-bonded central venous lines reduce thrombotic and infective complications in critically ill children surface heparinization of central venous catheters reduces microbial colonization in vitro and in vivo: results from a prospective, randomized trial use of heparincoated central venous lines to prevent catheter-related bloodstream infection heparin-bonded catheters for prolonging the patency of central venous catheters in children prevention of central venous catheter associated thrombosis using minidose warfarin in patients with haematological malignancies anticoagulation for thrombosis prophylaxis in cancer patients with central venous catheters anticoagulation in patients with cancer: an overview of reviews thrombosis prophylaxis in patient populations with a central venous catheter: a systematic review the heparin Á ush syndrome: a cause of iatrogenic hemorrhage beneÀ t of heparin in peripheral venous and arterial catheters: systematic review and meta-analysis of randomised controlled trials a meta-analysis of effects of heparin Á ush and saline Á ush: quality and cost implications analysis of the research about heparinized versus nonheparinized intravascular lines heparin Á ushing and other interventions to maintain patency of central venous catheters: a systematic review heparin or . % sodium chloride to maintain central venous catheter patency: a randomized trial intermittent Á ushing with heparin versus saline for maintenance of peripheral intravenous catheters in a medical department: a pragmatic clusterrandomized controlled study outbreak of bloodstream infection temporally associated with the use of an intravascular needleless valve increased rate of catheter-related bloodstream infection associated with use of a needleless mechanical valve device at a long-term acute care hospital increased catheterrelated bloodstream infection rates after the introduction of a new mechanical valve intravenous access port incidence of catheterrelated bloodstream infection among patients with a needleless, mechanical valve-based intravenous connector in an australian hematology-oncology unit optimal timing for intravenous administration set replacement saving lives: a delivery programme to reduce healthcare associated infection including mrsa. london: department of health eliminating catheter-related bloodstream infections in the intensive care unit an intervention to decrease catheter-related bloodstream infections in the icu sustaining reductions in catheter related bloodstream infections in michigan intensive care units: observational study results of a multicentre randomised controlled trial of statistical process control charts and structured diagnostic tools to reduce ward-acquired meticillin-resistant staphylococcus aureus: the chart project a multifaceted intervention for quality improvement in a network of intensive care units: a cluster randomized trial effectiveness of stepwise interventions targeted to decrease central catheterassociated bloodstream infections matching michigan': a -year stepped interventional programme to minimise central venous catheter-blood stream infections in intensive care units in england costeffectiveness of a central venous catheter care bundle the , lives campaign: setting a goal and deadline for improving healthcare quality an initial search was made for national and international guidelines and systematic reviews of randomised controlled trials. search questions were based on the scope of the original review and advice from the guideline development group. databases to be searched were identiÀ ed together with search strategy [i.e. relevant medical subject headings (mesh), free-text and thesaurus terms]. abstracts of all articles retrieved from the search were reviewed against pre-determined inclusion criteria (e.g. relevant to a review question, primary research/systematic review/meta-analysis, written in english). full text of all articles that met the inclusion criteria was reviewed against pre-determined criteria to identify primary research which answers review questions. all articles that described primary research, a systematic review or a meta-analysis were critically appraised by two experienced appraisers. consensus and grading was achieved through discussion in the context of pre-determined grading criteria. the following organisations were approached for comment: a chemical compound that contains 'energy-rich bonds' and is used by cells to store and deliver energy an organism that requires free oxygen for life and growth a hand decontamination preparation based on alcohol that, for the purposes of these guidelines, encompasses solutions, gels or wipes antimicrobial a substance that kills or inhibits the growth of microorganisms the absence of pathogenic microorganisms antiseptic a substance that destroys or inhibits the growth of microorganisms and is sufÀ ciently non-toxic to be applied to skin or mucous membranes a framework for the aseptic technique based on the concept of deÀ ning key parts and key sites to be protected from contamination. a carefully controlled procedure that aims to prevent contamination by microorganisms the presence of microorganisms in the bloodstream the presence of microorganisms in the urine. if there are no symptoms of infection, this is called 'asymptomatic bacteriuria' a complex structure comprising microorganisms and extracellular polymers that forms over surfaces, such as those in contact with water or tissues continuous Á ow of a solution through the bladder to remove clots or debris a viral infection transmitted by exposure to blood and sometimes other bodily Á uids. bloodborne viruses include hepatitis b and c as well as human immunodeÀ ciency virus the presence of microbes in the blood with symptoms of infection an analytical observational study that compares people with the disease of interest with a group of similar 'control' people who do not in order to determine potential causes or risk factors a scientiÀ c article that describes an individual case in detail a report describing a series of several similar events the presence of symptoms or signs attributable to microorganisms that have infection (cauti)invaded the urinary tract, where the patient has, or has recently had, a urinary catheter microorganisms present on a surface of a catheter that could potentially lead to infection an infection of the bloodstream where microorganisms are found in the blood infection (cr-bsi) of a patient with a central venous access device, the patient has clinical signs of infection (e.g. fever, chills and hypotension) and there is no other apparent source for the infection. for surveillance purposes, this often refers to bloodstream infections that occur in patients with a central venous access device and where other possible sources of infection have been excluded. a more rigorous deÀ nition is where the same microorganism is cultured from the tip of the catheter as grown from the blood; simultaneous quantitative blood cultures with at least a : ratio of microorganisms cultured from the central venous access device vs peripheral; differential time to positivity of at least h for blood cultures cultured peripherally vs from central venous access device waste material that consists wholly or partly of human or animal tissue, blood or body Á uids, excretions, drugs or other pharmaceutical products, swabs/ dressings, syringes, needles or other sharp instruments closed urinary drainage system a system where a urinary catheter is connected via tubing to a collecting bag.the system relies on gravity to drain the urine a prospective or retrospective follow-up study where groups to be followed-up are deÀ ned on the basis of presence or absence of exposure to a risk factor or intervention microorganisms that establish themselves in a particular environment, such as a body surface, without producing disease an estimate of the number of viable bacterial cells made by counting visible colonies derived from the replication of a single microbial cell transmission of a pathogenic organism from one person to another a comparison of the outcome between two or more groups of patients that are exposed to different regimens of treatment/intervention where the groups exchange treatment/intervention after a pre-arranged period a process that removes hazardous substances, including chemicals or microorganisms a cleansing agent that removes dirt from a surface by bonding with lipids and other particles a process that reduces the number of pathogenic microorganisms to a level at which they are not able to cause harm, but which does not usually destroy spores particles - õm in diameter comprising the dried residue formed by evaporation of droplets coughed or sneezed from the respiratory tract difÀ cult or painful urination urinary proteins, salts and crystals that adhere to the internal and external surface of a urinary catheter the use of equipment designed to prevent injury to the operator administration of nutrients into stomach or other part of the gastrointestinal tract using tubes infections caused by microorganisms acquired from another person, animal or the environment opinion derived from seminal works and appraised national and international guidelines the type of bacteria as identiÀ ed by gram's staining method. gram-positive bacteria appear dark blue or purple under a microscope. such bacteria have a thick layer of peptidoglycan on their cell walls. gram-negative bacteria appear red under a microscope and have an outer layer of lipoprotein and a thin layer of peptidoglycan a wire used to facilitate insertion of the intravascular catheter into the body blood in the pleural cavity, usually due to injury. if the blood is not drained, it may impair the movement of the lungs or become infected the use of soap and water or an antiseptic solution to reduce the number of microorganisms on the hands a phenomenon in which the participants change their behaviour or performance in response to being studied infection acquired as a result of the delivery of health care either in an acute (hospital) or non-acute setting any person employed by a health service, social service, local authority or agency to provide care for sick, disabled or elderly people a central venous access device that is tunnelled under the skin with a subcutaneous port or reservoir with a self-sealing septum that is accessible by needle puncture through intact skin the number of new events (e.g. cases of disease) occurring in a population over a deÀ ned period of time a catheter inserted into the bladder via the urethra and left in place for a period of time microorganisms that have entered the body and are multiplying in the tissues, typically causing speciÀ c symptoms an analysis in which the results of the study are based on initial treatment assignment and not on a treatment actually received a study in which measurements from the group under investigation are taken repeatedly before and after the intervention a device inserted into a vascular system in order to administer Á uids, medicines and nutrients or to obtain blood samples. these include devices inserted peripherally, as well as those inserted into larger veins any device that requires insertion through skin or other normal body defences a system of attaching catheters, syringes, tubes and any other components of ivad to each other external opening of the urethra the combination of data from several studies to produce a single estimate of an effect of a particular intervention strains of s. aureus that are resistant to many of the antibiotics commonly staphylococcus aureus (mrsa) used to treat infections. epidemic strains also have a capacity to spread easily from person to person a long peripheral venous catheter inserted in the antecubital vein and advanced to a vein in the upper arm. designed for short-term (up to weeks) intravenous access a membrane lining many tubular structures and cavities such as respiratory tractneedle-free devices (also needleless intravascular connector systems developed to help reduce the incidence of intravascular catheter connectors) needlestick injury while facilitating medication delivery through intravascular catheters. there are three types of needle-free connectors: blunt cannula (two-piece) systems, one-piece needle-free systems, and one-piece needlefree systems with positive pressure needle safety device (also needle any device designed to reduce the risk of injury associated with a protection/prevention device) contaminated needle. this may include needle-free devices or mechanisms on a needle, such as an automated resheathing device, that cover the needle immediately after use the puncture of skin by a contaminated needle or other sharp medical device abnormal decrease in the number of neutrophils in peripheral blood, which results in increased susceptibility to infections nitrile a synthetic rubber made from organic compounds and cyanide a retrospective or prospective study in which the investigator observes participants, with or without control groups any derivative of a living or once-living organism two or more cases of the same disease where there is evidence of an epidemiological link between them administration of nutrients by an infusion into a vein h. p. loveday et al. / journal of hospital infection s ( ) s -s particulate À lter masks (or respirator masks) face masks designed to protect the wearer from inhaling airborne particles including microorganisms. they are made to deÀ ned performance standards that include À ltration efÀ ciency. to be effective, they must be À tted close to the face to minimise leakage pathogen a microorganism that causes disease an independent assessment or evaluation of the research by a professional with knowledge of the À eld an injury that results in a sharp instrument/object (e.g. needle, scalpel) puncturing the skin a vascular catheter inserted into the superior vena cava from the basilic or catheter (picc) cephalic vein specialised clothing or equipment worn to protect against substances or situations that present a hazard to health or safety post-exposure prophylaxis drug treatment regimen administered as soon as possible after an occupational exposure to reduce the risk of acquisition of a bloodborne virus a topical preparation used for antisepsis of the skin in a form of solution or ointment the number of events (e.g. cases of disease) present in a deÀ ned population at one point in time study in which people are entered into the research and then followed-up over a period of time with events recorded as they happen a small, Á exible tube placed into a peripheral vein for the safe infusion of medications, hydration Á uids, blood products and nutritional supplements quasi-experimental research designs speciÀ cally lack the element of random assignment of participants (individuals or clinical settings/units) to the treatment or the control group. randomisation minimises the risk that patients entered into the control and treatment groups will be different an rct is a clinical trial where at least two treatment groups are compared, non-randomised controlled trial (nrct) one of them serving as the control group. allocation to the group uses a random, unbiased method. an nrct compares a control and treatment group but allocation to each group is not random. bias is more likely to occur in an nrct microorganisms that live in the deeper crevices of skin and hair follicles. these form part of the normal Á ora of the body and are not readily transferred to other people or objects, or removed by the mechanical action of soap and water. they can be reduced in number with the use of antiseptic soap a mask that covers the mouth and nose to prevent droplets from the wearer being expelled into the environment. as they are also Á uid repellent, they provide some protection for the wearer against exposure of mucous membranes to splashes of blood/body Á uid research that summarises the evidence on a clear question according to a deÀ ned protocol using explicit and systematic methods to identify, select and appraise relevant studies and extract, collate and report their À ndings an infection where the pathogen is distributed throughout the body, rather than being concentrated in one area the decontamination of a room or patient area after a patient has been transferred or discharged in order to ensure that any dirt, dust or contamination by potentially pathogenic microorganisms is removed before use by another patient a reduction in the number of platelets (thrombocytes) in the blood. this may result in bleeding into the skin, spontaneous bruising or prolonged bleeding after injury a clot in a blood vessel caused by coagulation of blood phlebitis (vein inÁ ammation) related to a thrombus (blood clot) microorganisms acquired on the skin through contact with surfaces. the hostile environment of skin means that they can usually only survive for a short time, but they are readily transferred to other surfaces touched. can be removed by washing with soap and water, and most are destroyed by alcohol-based hand rubs the invasion of the tissues of the bladder by microorganisms causing symptoms or signs of infection such as dysuria, loin pain, suprapubic tenderness, fever, pyuria and confusion key: cord- - mtwbwkk authors: olesen, bente; gyrup, helene bjergegaard; troelstrup, martin winther; marloth, tina; mølmer, michael title: infection prevention partners up with psychology in a danish hospital successfully addressing staffs fear during the covid- pandemic date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: mtwbwkk nan in relation a recent paper "risk of nosocomial transmission of coronavirus disease : an experience in a general ward setting in hong kong" [ ] we would like to share an interesting experience from denmark. nordsjaellands hospital (noh) is a -bed hospital situated north of copenhagen, denmark. the first danish covid- patient was diagnosed february th , (https://www.ssi.dk). a (first?) peak of the danish outbreak was reached around april , and is and presently, in mid-april , on the way down (https://politi.dk/coronavirus-i-danmark/in-english). noh follows national infection control guidelines for covid- from national board of health (www.sst.dk). we have worked hard at noh hard to prepare for the pandemic building covid- cohort isolation wards using existing wards, creating new workflows, tripling the available number of intensive care beds, and initiating intensive education of literally all groups of staff. we pride ourselves to be used to a high standard regarding hand hygiene [ ] , we are well familiar with the occasional seasonal occurrence of influenza, norovirus, cdiff and vre [ ] ; however, covid is a new virus and reports of deaths among healthcare staff from italy, china and spain are scary reading, especially for front line healthcare personal. recently the mental health care for medical staff in china during the covid- outbreak including various remedial actions was reported [ , ] . the frontline staff at noh predominately expressed fear of not being sufficiently protected from infection when using personal protection equipment (ppe). this problem was hospital wide but particularly pronounced at the covid cohort wards since the workflow was new and unfamiliar and the exposure intense. accordingly, a new and unusual collaboration between an infection prevention and control nurse and a psychologist was initiated. an inductive change strategy (bottom-up) addressing staffs fear and anxiety was used in the attempt to release defense mechanisms blocking rational thinking and change of behavior. the intervention was based on edgar h. schein's process consultation and how to help people change [ , ] . the psychologist acted as a process facilitator and the infection prevention and control nurse acted as a teacher during the process. facilitation was combined with psychoeducation in coping strategies towards fear and high level of stress, and the education focused primarily on recalling staffs existing knowledge of infection prevention and secondly on how to use ppe correctly. so far, this new approach has been used in five sessions comprising nurses and physicians. the response from staff has been overwhelmingly positive. most were relieved that their worries were acknowledged and became eager to discuss different scenarios of virus transmission. many were reassured of their professional ability to risk assess behavior when close to patients with covid- and began trusting their knowledge of infection prevention and correct use of ppe. combining the professional angles of psychology and infection prevention proved fruitful. addressing and acknowledging fear of health care staff might lead to reappearance of rational thinking and a professional attitude in the fearful time of a pandemic. risk of nosocomial transmission of coronavirus disease : an experience in a general ward in hong kong hand hygiene excellence award winner a new successful approach to combating vancomycin-resistant enterococcus mental health care for medical staff in china during the covid- outbreak online mental health services in china during the covid- outbreak helping: how to offer, give, and receive help process consultation key: cord- -gzntdlp authors: paul, s.p.; mukherjee, a.; mcallister, t.; harvey, m.j.; clayton, b.a.; turner, p.c. title: respiratory-syncytial-virus- and rhinovirus-related bronchiolitis in children aged < years in an english district general hospital date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: gzntdlp background: bronchiolitis is the most common reason for hospitalization in young children. in addition to respiratory syncytial virus (rsv), other viruses have been increasingly implicated. guidance on testing has also changed. aims: to compare clinicopathological outcomes in young children admitted with bronchiolitis due to rsv in comparison with rhinovirus (rv), and identify associated risk/epidemiological factors. methods: children aged less than two years admitted to hospital with a clinical diagnosis of bronchiolitis with positive results for either rsv or rv were included in this study. polymerase-chain-reaction-negative cases using an extended respiratory virus panel served as a control group. retrospective data were collected on sex, risk factors, respiratory support, intravenous fluids and antibiotics. outcomes such as length of stay (los) and need for transfer to the high-dependency unit/paediatric intensive care unit were included. findings: two hundred and twenty-seven out of nasopharyngeal aspirate samples were positive for either rsv (n = ) or rv (n = ). the median age of cases was three months and % had at least one risk factor. risk factors were higher in the rv group (p = . ). rv accounted for the majority of cases outside the rsv season (p < . ). rv-associated bronchiolitis had a longer los (more than seven days) (p < . ) and increased need for chest x-rays and/or antibiotics (p < . ). use of intravenous fluids and respiratory support were higher in the rv group, but the difference was not significant. conclusions: rv is the second most common pathogen associated with bronchiolitis and is isolated all year round. this may be important in those with risk factors resulting in prolonged los. further research is necessary to establish the exact role of rv in this common condition, particularly outside the traditional rsv season. acute viral bronchiolitis is common in children aged less than two years. it is a major reason for admission to hospital, and secondary spread can lead to hospital-associated infections and outbreaks. it usually presents with cough and increased work of breathing, and often affects a child's ability to feed [ ] . respiratory syncytial virus (rsv) is the most common pathogen detected in hospitalized children, particularly during the winter months in temperate climates. a nasopharyngeal aspirate (npa) has traditionally been used to inform cohorting of infectious patients (i.e. to minimize secondary spread) and to aid clinical decision making (e.g. avoiding unnecessary antibiotics). however, bronchiolitis remains primarily a clinical diagnosis, and recent studies have highlighted a large number of other viral pathogens such as adenovirus, influenza virus, parechovirus, bocavirus, human metapneumovirus and rhinovirus (rv) as pathogens associated with this clinical condition [ ] . neither the american academy of pediatrics (aap, ) nor the national institute for health and care excellence (nice, ) guidelines recommend routine use of npa testing for rsv in the diagnosis of infants with bronchiolitis [ , ] . extended polymerase chain reaction (pcr) testing for viral respiratory tract pathogens, including those associated with bronchiolitis, is now available for routine use in most diagnostic microbiology laboratories. as part of a review of the use of this technology, the role of rv as a cause of non-rsv-associated cases, particularly those occurring outside the traditional rsv season (octoberefebruary in the northern hemisphere), was examined. as rv is a common virus in both children and adults, there is also a risk of nosocomial spread involving healthcare workers and visitors, adding to the challenge of controlling these infections in hospitals. the aim of this study was to determine the clinicopathological outcomes in a cohort of infants and young children aged less than two years admitted with bronchiolitis, where the presence of either rsv or rv as a single pathogen was detected on analysis of npa samples. npa samples that were negative on pcr using an extended panel of respiratory viruses served as a control group. an extended panel of respiratory viruses has been available for a number of years from the microbiology laboratory at the study hospital. rv figure ). this was in accordance with the hospital policy at the time to support diagnosis while limiting unnecessary tests. children aged less than two years admitted to hospital with a clinical diagnosis of bronchiolitis with a positive npa for rsv or rv were identified from a search of the microbiology department's electronic database. data were collected over a period of three years and nine months (april edecember ). infants who only had a single pathogen (either rsv or rv) were included in the study. npa samples that identified more than one pathogen were excluded. respiratory pathogens detected from babies in the neonatal unit (n ¼ ) were also excluded as bronchiolitis is more difficult to diagnose in this group, and they were more likely to have acquired infection nosocomially. npa samples that were negative on pcr using an extended panel of respiratory viruses served as a control group. the study was a service evaluation project, and patient consent was not required. data were collected on median age at presentation, sex, associated risk factors (chronic lung disease, prematurity, congenital heart disease, genetic conditions), therapeutic interventions (intravenous fluids, intravenous antibiotics, chest x-ray), need for respiratory support (high flow oxygen, continuous positive airway pressure, ventilation), management in high-dependency unit (hdu)/paediatric intensive care unit (picu) and outcome [length of stay (los) and any deaths]. los of seven days or less was defined as short, and los of eight to days was defined as prolonged. statistical analysis was performed using standard chi-squared analysis, and p < . was considered to indicate significance. in total, npa samples were tested for children aged less than two years. one hundred and eighteen children were excluded from the study, either because they had a single respiratory pathogen other than rsv or rv (n ¼ ) or they had co-infection with two or more viruses (n ¼ ). of the children who had a single virus detected on extended pcr panel, the three most common viruses were: parainfluenza virus (n ¼ ), human metapneumovirus (n ¼ ) and coronavirus (n ¼ ). there was no single third predominant viral pathogen identified. the three most common viruses in the coinfection group (n ¼ ) were: rhinovirus (n ¼ ), rsv (n ¼ ) and human metapneumovirus (n ¼ ). sixty-three patients had two pathogens, patients had three pathogens, and one patient was co-infected with four pathogens. the remaining children were included in the study: had rsv ( antigen positive; pcr positive), had rv and served as negative controls. the male:female ratio was . : for rsv and . : for rv. in the pcr-negative control group, the ratio was . : . the median age at presentation was days (range e days) for the rsv group, days (range nine to days) for the rv group and days (range e days) for the pcr-negative control group. as expected, the occurrence of rsv infections was seasonal, with only / ( . %) cases diagnosed between february and october ( figure ) . rv was much more evenly distributed all year round, with a peak in december [ / ( %)]. fortyeight percent of cases (n ¼ ) of rv-associated bronchiolitis occurred outside the non-rsv season (februaryeoctober). this difference was significant when comparing the rv group with the rsv group (p < . ). figure highlights the distribution of risk factors amongst the three different groups. children with rsv had significantly fewer risk factors ( / ; %) compared with the rv group ( / ; %) (p ¼ . ). table i summarizes the elements of supportive management (intravenous fluids, intravenous antibiotics, chest x-ray, need for respiratory support) given to patients. few children in any of the three groups needed hdu and picu care for advanced respiratory management. few significant differences between the groups were found, but this may reflect the relatively small number of cases and controls. infants with bronchiolitis will often have changes noted in their chest x-rays. figure compares the three groups when ordering a chest x-ray (if requested) and use of intravenous antibiotics. the study data did not show an increase in the use of antibiotics after a chest x-ray (n ¼ / ; %) in the rsv or rv group when compared with cases in the rsv or rv group who were treated with antibiotics but did not have a chest x-ray (n ¼ / ; %). however, patients with rv were more likely to have interventions (chest x-rays and/or antibiotics) than patients with rsv (p ¼ . ). there were no deaths amongst any of the patients. the mean los in the study group was: rsv group, . days (range e days), rv group, . days (range e days); and figure . pathway for nasopharyngeal aspirate sample testing and study inclusion/exclusion algorithm. npa, nasopharyngeal aspirate; rsv, respiratory syncytial virus; rv, rhinovirus; pcr, polymerase chain reaction. control group, . days (range e days). the greater los in the rv group compared with the rsv group was significant (p ¼ . ). children who had a chest x-ray and/or antibiotics had a longer los compared with children who did not need such interventions. for the rsv group, the mean los for those who needed interventions was . days, compared with . days for those who did not need interventions. in the rv group, the comparable figures were . and . days. rv is often considered to be a trivial infection as it is the most common viral pathogen causing common colds in adults and older children. this study has highlighted that rv is also an important cause of bronchiolitis in infancy and early childhood throughout the year. until relatively recently, the role of rv may have been under-recognized in hospital settings due to the limited availability of routine rv diagnostic testing. this study showed that rv is a year-round virus, and as such is the main cause of viral bronchiolitis outside the rsv season (p < . ). this study is a good example of pathway management in that only npas that were rsv antigen negative went on to have rv pcr testing as part of the extended pcr respiratory virus panel. this approach runs the risk of missing rsv-positive patients co-infected with rv or other pathogens. however, it is reassuring that only % of the children who had rsv detected by pcr also had rv detected. in a multi-centre us study with children with bronchiolitis, % had rsv and . % had rv (ratio . : ) [ ] . a greek study showed rsv in . % of cases, compared with rv in % of cases (ratio . : ) [ ] . this was similar to the results of the present study (rsv:rv ratio of . : ). in a multi-centre us study of children with bronchiolitis, the median age at diagnosis was four months and % were males [ ] . the present study also had a male predominance ( %), with a median age at diagnosis of three months. the us study reported that % of patients had sole rsv infection, % had sole rv infection, and % had rsv/rv co-infection [ ] . in contrast, the present study showed that rsv/rv co-infection was far less frequent in those tested by pcr, with only cases identified. in a turkish study of infants, rsv (n ¼ ) was identified as the major viral pathogen, although more than % of cases were associated with other respiratory viruses; the two most common were rv (n ¼ ) and human metapneumovirus (n ¼ ) [ ] . another us study showed that bronchiolitis-related hospitalizations in children aged less than two years (n ¼ ) increased significantly from ( . %) in to ( . %) in , and that rsv-positive cases had a lower percentage of underlying medical conditions than children hospitalized with non-rsv bronchiolitis ( % vs . %; p < . ) [ ] . the present study also found that comorbidities were more common in the rv-associated bronchiolitis group (p ¼ . ). following analysis by a logistic regression model controlling for age, sex, birth weight, presence of fever, and day of disease on admission, a greek study found that the presence of rv was associated with more severe disease, and that this risk was approximately fivefold greater [ ] . the present study found a higher morbidity rate for rv infection compared with rsv, especially for prolonged los (p < . ), as well as the need for chest x-rays and/ or antibiotics (p < . ). this trend was noted for other parameters such as need for intravenous fluids and respiratory support, although these differences did not reach statistical significance. it is hypothesized that younger children with rvrelated bronchiolitis behave differently to those with rsvrelated bronchiolitis, and may need longer to recover due to a longer period of oxygen dependency and the requirement for feeding support. interestingly, use of chest x-rays, antibiotics and intravenous fluids (table i) was lower in the rsv and rv groups than in the pcr-negative group which served as a control. this may reflect the possibility of primary or secondary bacterial infection in the control group. neither the aap ( ) nor the nice ( ) guidelines recommend routine npa testing in bronchiolitis, as it primarily remains a clinical diagnosis and tends to be self-limiting, requiring symptomatic management [ , ] . however, it may still be a useful adjunct in infants and young children with additional risk factors, as this and other studies have suggested an association with prolonged los where children are less likely to need antibiotic intervention. also, lower respiratory tract infections caused by viral pathogens including rsv have been implicated in numerous nosocomial outbreaks, which could be missed easily, particularly if routine testing is no longer recommended and diagnosis is based on clinical presentation alone. therefore, it remains essential that there is rapid access to screening, followed by extended pcr testing including rv should secondary cases occur in a hospital setting. as children are expected to recover from an acute episode of respiratory illness within three weeks, those (n ¼ ) whose los extended beyond three weeks were not included in the data analysis. cross-infection may be more likely to occur in neonates who are already inpatients in the neonatal units [ ] . of note, three of neonates were already being managed as inpatients in the neonatal unit when they developed bronchiolitis, and required an extended los because of their prematurity. the remaining five children who had los exceeding three weeks had ongoing health issues, including four children who developed a bronchiolitis-like illness during their inpatient stay. this suggests that cross-infection may occur readily in the hospital setting [ ] . only one case could be correlated directly with significant complications from his original bronchiolitis infection on admission. following this study, and taking into account the aap and nice guidelines, the authors now follow a revised policy in their centre by only performing targeted extended respiratory pcr testing of npa samples in children needing hdu care or in children with two or more risk factors (e.g. prematurity, chronic lung disease on supplemental home oxygen, congenital heart disease). children are also tested if there is any suspicion of secondary spread or outbreak occurring in an inpatient setting, or if cohorting is being considered due to lack of suitable isolation facilities. these approaches help to avoid unnecessary investigations or antibiotic treatment in this group, while minimizing the risk of further spread. however, for infants and children where npas are negative by the extended respiratory panel pcr, serious consideration of other primary causes of infection, including bacteria, needs to be sought and treated appropriately in keeping with managing sepsis while supporting antimicrobial stewardship. in conclusion, this single-centre study of cases of bronchiolitis showed that rsv and rv are the two main viral pathogens associated with bronchiolitis in children. the study highlights the importance of considering rv as an important respiratory pathogen in infants and young children who present with bronchiolitis, particularly during the non-rsv season, which can necessitate hospitalization and therapeutic interventions, and lead to prolonged los. rv was found to be more common in children with pre-existing risk factors, and targeted npa testing may be useful in selective settings. the study data further support the limited existing literature that rv may be an important causative viral pathogen in bronchiolitis. larger multi-centre studies are required to further categorize clinicopathological outcomes in bronchiolitis caused by rsv and rv, as well as other viral pathogens. bronchiolitis: diagnosis and management of bronchiolitis in children. clinical guideline ng . london: national institute for health and clinical excellence prospective multicenter study of viral etiology and hospital length of stay in children with severe bronchiolitis clinical practice guideline: the diagnosis, management, and prevention of bronchiolitis association of rhinovirus infection with increased disease severity in acute bronchiolitis multicenter study of viral etiology and relapse in hospitalized children with bronchiolitis viral etiology in infants hospitalized for acute bronchiolitis risk factors in children hospitalized with rsv bronchiolitis versus non-rsv bronchiolitis respiratory syncytial virus outbreak defined by rapid screening in a neonatal intensive care unit rsv outbreak in a paediatric intensive care unit the authors wish to thank neil hurd and cheryl bailiss for help with testing and database searches. none declared. none. key: cord- -xfq s authors: cheng, v.c.c.; tai, j.w.m.; wong, l.m.w.; chan, j.f.w.; li, i.w.s.; to, k.k.w.; hung, i.f.n.; chan, k.h.; ho, p.l.; yuen, k.y. title: prevention of nosocomial transmission of swine-origin pandemic influenza virus a/h n by infection control bundle date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: xfq s after the outbreak of severe acute respiratory syndrome in hong kong, the importance of preventing nosocomial transmission of respiratory viruses has become a top priority in infection control. during the containment and early mitigation phases of the swine-origin influenza virus (s-oiv) a h n pandemic, an infection control bundle consisting of multiple coherent measures was organised by our infection control team to minimise nosocomial transmission. this included repeated open staff forum achieving high attendance; early recognition of index cases among inpatients by liberal testing; early relief of sick staff from work; directly observed hand hygiene practice during outbreaks; and monitoring of compliance with infection control practice. during the first days (from may to august ) when the first laboratory-confirmed patients with s-oiv and infected healthcare workers (hcws) were identified, a total of asymptomatic exposed persons ( patients and hcws) were required to undergo a seven-day medical surveillance. the infection control nurses monitored them for the onset of symptoms. four ( . %) exposed persons (one house officer, two non-clinical staff, and one patient) were virologically confirmed with s-oiv. not wearing a surgical mask either by the exposed persons during contact with the index cases ( / vs / , p = . ) or vice versa ( / vs / , p = . , fisher's exact test) were found to be significant risk factors for nosocomial acquisition of s-oiv. summary after the outbreak of severe acute respiratory syndrome in hong kong, the importance of preventing nosocomial transmission of respiratory viruses has become a top priority in infection control. during the containment and early mitigation phases of the swine-origin influenza virus (s-oiv) a h n pandemic, an infection control bundle consisting of multiple coherent measures was organised by our infection control team to minimise nosocomial transmission. this included repeated open staff forum achieving high attendance; early recognition of index cases among inpatients by liberal testing; early relief of sick staff from work; directly observed hand hygiene practice during outbreaks; and monitoring of compliance with infection control practice. during the first days (from may to august ) when the first laboratory-confirmed patients with s-oiv and infected healthcare workers (hcws) were identified, a total of asymptomatic exposed persons ( patients and hcws) were required to undergo a seven-day medical surveillance. the infection control nurses monitored them for the onset of symptoms. four ( . %) exposed persons (one house officer, two non-clinical staff, and one since the outbreak of severe acute respiratory syndrome (sars) spreading from hospitals to the community in , nosocomial infection by respiratory viruses has received the highest level of attention by the government and the public in hong kong. the hospital infection control team has been promoting infection control training for healthcare workers (hcws), and implementing standard and transmission-based precautions with special reference to directly observed hand hygiene practice during outbreaks. when the outbreak of swineorigin influenza virus (s-oiv) a h n infection occurred in mexico and north america in early , our infection control team immediately designed a series of strategic measures promulgated as an infection control bundle to enhance our colleagues' awareness and compliance to these measures. in hong kong, the first confirmed case of s-oiv was diagnosed in a traveller from mexico on may . as of august , there were laboratory-confirmed cases with four deaths. here, we report the effect of such measures on the occurrence of nosocomial s-oiv in our hospital. in collaboration with the stakeholders including hospital administration, clinicians, and nursing colleagues, a strategic infection control bundle was established (box i). open staff forum and special education sessions were arranged by the hospital administration and infection control team. nasopharygneal aspirates or nasopharyngeal flocked swabs were collected from cases, either patients or hcws, who had upper respiratory tract infection (urti) symptoms. direct immunofluorescent antigen test for influenza a and other respiratory viruses (influenza b virus, respiratory syncytial virus, parainfluenza virus types , and , and adenovirus) and reverse transcriptionepolymerase chain reaction (rt-pcr) for s-oiv h gene were performed, as previously described. , the infection control team checked with the microbiology laboratory on a daily basis for positive results. cases were reviewed to determine the route of acquisition. for patients, they were considered as having community-acquired infection if they presented with urti symptoms within h of admission, without history of contact with any confirmed case in the hospital. for hcws, they were considered as having community-acquired infection if they had confirmed cases in their household with no history of unprotected exposure to any confirmed case in the hospital. otherwise, the case was classified as nosocomial infection. unprotected exposure was defined as the contact within m between a confirmed case and the exposed with both of them not having worn a surgical mask, whereas protected exposure meant that either one had worn a surgical mask during their contact. the incidence of nosocomial infection by influenza a virus and the other respiratory viruses expressed as number per patient-days between and the first six months of were reviewed. the total patient-days of the hospital were obtained from the record office. hand hygiene was promoted in and fully implemented in our hospital in . compliance of hand hygiene has been regularly audited by the infection control team according to a predetermined protocol. the consumption data of alcohol-based hand rub in terms of volume used per admissions was retrieved from hospital administration. this study was performed in queen mary hospital, a -bed tertiary referral university-affiliated hospital with three adult isolation wards and one paediatric isolation ward in hong kong. the local hospital admission policies were modified during the various phases of s-oiv outbreak. in phase , the containment phase (from may to june ), all patients with influenza-like illness (ili), defined as fever with a temperature of c with sore throat or cough, and returned from countries with confirmed cases of s-oiv in the preceding seven days, were admitted for single room isolation. close contacts of the confirmed cases were quarantined. close contacts were defined as individuals from the same household and flight passengers seated three rows in front or behind the confirmed cases. in phase , the early mitigation phase (from june to june ), all patients with laboratory-confirmed s-oiv were hospitalised for cohort nursing and consideration of antiviral therapy. during phase , the late mitigation phase (from june onwards), only high risk patients (children aged years or pregnant women) with s-oiv, and patients with clinical evidence of complicated influenza were admitted for further management. hcws were monitored for urti symptoms during and seven days after rotating out from the isolation facilities. for those patients diagnosed in the general wards, patients staying in the same cubicle and hcws working in the same wards were subjected to contact tracing and underwent a sevenday medical surveillance which included daily monitoring of body temperature and urti symptoms by the ward-in-charge and infection control team. if the patients or hcws had unprotected exposure, oseltamivir ( mg daily for days) would be offered as post-exposure prophylaxis. for those with protected exposure, no oseltamivir was given. when s-oiv was confirmed in hcws, a seven-day sick leave would be issued. the infection control team would follow up on the clinical progress of the staff, investigate the source of infection and classify it as community-or hospital-acquired infection. contact tracing of the exposed inpatients and co-workers was followed by a seven-day medical surveillance. if the infected hcw had worn a surgical mask and practice hand hygiene during patient care, antiviral agent would not be prescribed to the exposed patients. however, oseltamivir ( mg daily for days) would be recommended to the co-workers as postexposure prophylaxis if they had not worn a surgical mask during tea break, lunch, and dinner with the infected staff. the infected hcws were interviewed by the infection control team for compliance with infection control practice according to a standard questionnaire. risk factors for nosocomial infection by s-oiv in both patients and hcws were investigated. persons exposed to the same environment who were asymptomatic for urti after seven days of medical surveillance were chosen as control. fisher's exact test was used to compare independent categorical variables between groups. all reported p-values were two-sided. p < . was considered statistically significant. computation was performed using the spss version . for windows. infection control preparedness for s-oiv during the first days ( may to august ) after the first case of s-oiv had occurred in hong kong, a total of inpatients in queen mary hospital were tested for s-oiv by rt-pcr. a total of patients were admitted in phase , in phase , and in phase . there were males and females, including five pregnancies. the median age was years (range: e ). they were admitted because of ili after returning from countries with s-oiv (n ¼ ), asymptomatic close contact to confirmed cases (n ¼ ), local residents with confirmed s-oiv with or without risk factors for complications (n ¼ ), local residents with suspected s-oiv (n ¼ ), and symptomatic hcws with history of contact with the confirmed patients (n ¼ ). one hundred ( %) of patients were positive for s-oiv by rt-pcr, with a male to female ratio of : . the median age was years (range: months to years). the confirmed cases were aged e years ( cases, %), e years ( cases, %), e years ( cases, %), and years ( cases, %). eight cases ( %) were aged e years, and four cases were aged years. fifty-four of cases with ili and four with mild pneumonia responded to oseltamivir. they were discharged at a median length of stay of four days (range: e ). sixty-six patients were ethnic chinese. twenty-five patients were considered as imported cases and patients as locally acquired, of the latter due to local school outbreaks. twelve patients were diagnosed with s-oiv outside the isolation facilities in seven general wards from medical, paediatric, surgical, and orthopaedic specialties for a total of patient-days, resulting in exposure of inpatients in the same cubicle, and hcws serving in these wards ( figure a ). one infected house officer admitted lapses in infection control practice by not wearing a surgical mask and not using alcohol-based hand rub when setting up a peripheral venous catheter for a presymptomatic infected patient during the night call. the same index patient transmitted the infection to another patient staying in the same cubicle. overall, nosocomial acquisition of s-oiv from hospitalised patients was two ( . %) out of exposed persons. in addition to the house officer who acquired s-oiv at work, another hcws had communityacquired s-oiv infection in eight different units, including surgery, paediatric, orthopaedic surgery, obstetric and gynaecology, oncology, psychiatry, endoscopy room, and general office ( figure b ). since all of these hcws wore a surgical mask and practised hand hygiene with alcohol-based hand rub during patient care, none of the exposed patients required post-exposure prophylactic oseltamivir or developed urti symptoms in the seven-day medical surveillance period. thirty-three ( . %) out of exposed co-workers received post-exposure prophylactic oseltamivir for unprotected exposure during tea break, lunch and dinner with the index cases. two hcws (one dispenser and one workman in pharmacy) acquired s-oiv from another dispenser during the pre-symptomatic shedding period because surgical mask was not mandatory in non-clinical areas. the nosocomial infection of s-oiv among hospital staff was two ( . %) out of exposed hcws. a total of four ( . %) out of exposed persons acquired s-oiv in the hospital environment during the study period. not wearing surgical mask by the exposed persons during contact with the index cases ( / vs / , p ¼ . ) or vice versa ( / vs / , p ¼ . , fisher's exact test) was found to be a significant risk factor for nosocomial infection of s-oiv (table i) . infection control is the most important strategy in the control of s-oiv in the hospital before the availability of influenza vaccination. the implementation of infection control bundle in the first days after the arrival of s-oiv in hong kong appeared to have minimised the nosocomial transmission of s-oiv among both patients and hcws resulting in a secondary attack rate of . %. it was much lower than a rate of e % as reported in a recent review of published data on hospitalacquired influenza. enhancement of staff awareness of infection control practice in both the hospital and community is essential for the programme's success and avoidance of misunderstanding. our infection control teaching session has provided coverage for more than % of hospital staff. whenever patients or hcws were in particular, when the hcws were undergoing medical surveillance, they were strongly advised not to have tea, lunch, and dinner with other co-workers because the shedding of influenza virus could occur one day before onset of symptoms. this measure is important for stopping the chain of transmission among hcws. therefore, hcws were released from clinical duty and required to seek medical consultation for appropriate testing. such measures radically changed the past practice of not collecting nasopharyngeal specimens in our staff clinic. one hcw acquired s-oiv infection at the clinical area when he forgot to wear a surgical mask at night call. this shows that the routine use of surgical masks in all clinical areas is important in reducing the risk of nosocomial infection of s-oiv. according to our analysis, use of surgical masks by the exposed persons was associated with a lower risk of nosocomial acquisition of s-oiv, which was consistent with previous studies suggesting that wearing a surgical mask might decrease the risk of sars infection. this measure discouraged the use of fingers to touch the mucous membranes of the nostrils and mouth since such spontaneous behaviour was not infrequently observed. wearing surgical masks by the index persons as a form of source control also reduced the risk of transmission. as the use of surgical mask was mandatory for hcws while in clinical areas, none of the patients exposed to the clinical staff diagnosed with s-oiv during work acquired the infection despite not wearing masks themselves. self-reporting of compliance to hand hygiene by exposed persons was up to %, which was higher than the rate of e % by unobtrusive hand hygiene observation during the study period. it may be related to recall bias by the exposed person. unexpectedly the practice of hand hygiene after contact with the index cases did not reach statistical significance in reducing nosocomial infection of s-oiv in our study. this could be due to the small sample size in the group of infected persons. in fact, hand hygiene practice by using alcohol-based hand rub has been consistently promoted in our hospital since and directly observed hand hygiene (dohh) has been strategically implemented during outbreaks. dohh has been shown to be effective in reducing the frequency and the number of persons involved in the nosocomial outbreaks in our previous studies. , there are several limitations to this study. first, it was a quasi-experimental design to assess the nosocomial transmission of s-oiv, based on the epidemiological analysis of clinical symptoms of the exposed persons without serological confirmation. this might have underestimated the true incidence of nosocomial transmission. second, the gradual decrease in the incidence of nosocomial influenza a and other respiratory virus infections may also be attributable to our ongoing promotion of infection control practice, which has been intensified at the time of the s-oiv pandemic. third, the sustainability of this programme remains questionable since the workload of laboratory staff, infection control team, and the frontline hcws has greatly increased during the current pandemic. the recent finding of viral pneumonitis in animal models and mortality in immunocompetent young adults due to s-oiv have reminded us that this novel virus may be more pathogenic than seasonal influenza virus. as the first wave in the summer may be mild, this infection control bundle may play an even more impartant role during the second wave of this pandemic in the winter time. clinical progression and viral load in a community outbreak of coronavirus-associated sars pneumonia: a prospective study outbreak of human metapneumovirus infection in psychiatric inpatients: implications for directly observed use of alcohol hand rub in prevention of nosocomial outbreaks confirmation of the first hong kong case of human infection by novel swine origin influenza a (h n ) virus diagnosed using ultrarapid, real-time reverse transcriptase pcr evaluation of the directigen flua þ b test for rapid diagnosis of influenza virus type a and b infections the world health organization guidelines on hand hygiene in health care and their consensus recommendations hospitalacquired influenza: a synthesis using the outbreak reports and intervention studies of nosocomial infection (orion) statement risk factors for sars among persons without known contact with sars patients transmission of rhinovirus colds by self-inoculation successful control of norovirus outbreak in an infirmary with the use of alcoholbased hand rub in vitro and in vivo characterization of new swine-origin h n influenza viruses none declared. this work was partly funded by research fund for the control of infectious diseases. key: cord- - swwc kr authors: secker, thomas.j.; leighton, timothy.g.; offin, douglas.g.; birkin, peter.r.; hervé, rodolphe.c.; keevil, charles.w. title: journal of hospital infection a cold water, ultrasonic activated stream efficiently removes proteins and prion-associated amyloid from surgical stainless steel date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: swwc kr background: sterile service department decontamination procedures for surgical instruments struggle to demonstrate efficient removal of the hardiest infectious contaminants, such as prion proteins. a recently designed novel system, which utilises a low pressure ultrasonic activated, cold water stream, has previously demonstrated efficient hard surface cleaning of several biological contaminants. aim: to test the efficacy of an ultrasonically activated stream for the removal of tissue proteins, including prion-associated amyloid, from surgical stainless steel (ss) surfaces. methods: test surfaces were contaminated with l, me or k prion infected brain homogenates. the surfaces were treated with the ultrasonically activated water stream for contact times of and seconds. residual proteinaceous and amyloid contamination were quantified using sensitive microscopic analysis, and immunoblotting was used to characterize the eluted prion residues before and after treatment with the ultrasonically activated stream. findings: efficient removal of the different prion strains from the surgical ss surfaces was observed, and reduced levels of protease sensitive and resistant prion protein was detected in recovered supernatant. conclusions: this study demonstrated that an ultrasonically activated stream has the potential to be a cost-effective solution to improve current decontamination practices and has the potential to reduce hospital acquired infections. instruments struggle to demonstrate efficient removal of the hardiest infectious contaminants, such as prion proteins. a recently designed novel system, which utilises a low pressure ultrasonic activated, cold water stream, has previously demonstrated efficient hard surface cleaning of several biological contaminants. aim: to test the efficacy of an ultrasonically activated stream for the removal of tissue proteins, including prion-associated amyloid, from surgical stainless steel (ss) surfaces. methods: test surfaces were contaminated with l, me or k prion infected brain homogenates. the surfaces were treated with the ultrasonically activated water stream for contact times of and seconds. residual proteinaceous and amyloid contamination were quantified using sensitive microscopic analysis, and immunoblotting was used to characterize the eluted prion residues before and after treatment with the ultrasonically activated stream. at present, the reprocessing of surgical instruments utilises; a pre-wash, washer/disinfector cycle (run at elevated temperature with detergents) and sterilisation in high heat/pressure autoclaves . decontamination protocols for reusable surgical instruments are very efficient against microbiological contaminants. however, highly hydrophobic proteins such as prions, responsible for the transmission of variant creutzfeldt-jakob disease (vcjd), are readily adsorbed to surgical stainless-steel surfaces and poorly removed or inactivated by current decontamination methods. this results in an impending risk of iatrogenic transmission of vcjd - . a risk that has been experimentally demonstrated in both animal and cell-based bioassays [ ] [ ] [ ] [ ] . the latest estimated prevalence of asymptomatic carriers of the causative protein of vcjd (prp sc ) in the uk is approximately / . while the full impact of the genetic susceptibility of the host remains unclear, the ostensibly long incubation periods and the potential for disease transmission via infected blood [ ] [ ] [ ] , imply that all surgical procedures pose a risk of vcjd transmission. improvements in the methodologies used for reprocessing surgical instruments, potentially contaminated with prions, are required to diminish the risk of iatrogenic vcjd transmission. novel, specialised prion decontamination protocols have been developed and in some cases marketed for sterile service departments (ssds) , - . however, some of these protocols are very aggressive and can be damaging to instrument surfaces and/or the washer/disinfectors themselves . simple methods to adopt into ssd's have been researched and demonstrated improved efficiency over current practices, such as preventing instruments from drying once contaminated, i.e. keeping them in a moist environment prior to cleaning - . j o u r n a l p r e -p r o o f bjerknes forces aid the scrubbing bubbles in efficiently removing contaminants from microscopic crevices, such as those found on worn surgical instruments , that are traditionally difficult to clean by brushes, wiping, or by chemical means that rely on passive diffusion for reagents to penetrate deep into the crevice . the efficient removal of contamination from crevices using a uas system has been demonstrated previously . furthermore, the microstreaming that radiates from the resonating bubbles can penetrate into crevices present on the surfaces of the contaminant as shown in the insert in figure . the fact that such results can be obtained in cold water without chemical additives warrants investigation of uas for the removal of infectious prion proteins from surgical surfaces. high temperature decontamination using aggressive enzymatic or alkaline solutions, that are currently adopted to clean expensive surgical items (such as intricate neurosurgical tools) are ineffective at protein and prion removal, and can shorten the surgical item lifetime . it is not the purpose of this study to explore the replacement of such standard cleaning practices. however, given the above properties of uas, it is important to explore the possible benefits of including an innovative cold-water uas pre-wash (at the stage where ssds conduct hand brushing of instruments under a stream of water) that can be introduced with minimal operator training. this would be particularly beneficial if it could be conducted immediately after instrument use (e.g. before contaminated tissue dries on the instrument and becomes harder to remove), although in this trial the contaminant is tested in a dried-on state. the question is whether such a uas pre-wash could remove a substantial proportion of the contaminant, especially from microscopic crevices of the type associated with worn surgical instrument surfaces, and break up aggregates in which the inner portion of biological contaminant is partially protected from subsequent enzymatic cleaning chemistries. a previous study demonstrated efficient tissue protein removal from surgical stainless steel using the uas . however, due to the globular nature of the predominantly β-sheet structured infectious prion protein, it adheres to surgical stainless steel far more rigorously than do normal brain tissue proteins, and therefore the ability of uas to remove brain tissue protein cannot be taken as an indicator of any efficacy in reducing the iatrogenic transmission risk of vcjd. therefore, this study involved the contamination of surgical stainless-steel surfaces with several amyloid-rich brain homogenates from prion infected rodents. normal tissue proteins and more hazardous prion-associated amyloid were differentially stained and analysed using sensitive in situ microscopy, to compare the ability of uas to remove both during the same cleaning operation. inoculating, tokens were decontaminated and analysed to be deemed free of any contamination following a previously described protocol . murine scrapie me -infected brain homogenate produced from c bl mice (tse resource centre, roslin institute, university of edinburgh, scotland, uk); murine scrapie l- infected brain homogenate produced from c bl/ j mice (kindly donated from the neuroscience department, school of biological sciences, university of southampton) and syrian hamster scrapie k-infected brain homogenates (tse resource centre, roslin institute, university of edinburgh, scotland, uk) were standardized to mg/ml (bsa equivalent) in phosphate buffered saline (pbs, gibco) with . % (v/v) tween (sigma- aldrich) as previously described . pristine tokens were spiked with µl ( µg bsa equivalent) drops of l, me or k infected brain homogenate, and dried at o c for hours or room temperature for hours. tokens were subjected to decontamination using a prototype recirculating uas device (the mark i starstream ® system (f )) using fresh dh o for each sample, running at . ± . l/min at room temperature with the ultrasound on for and s contact times, with the sample being mm from the nozzle ( figure ). once processed the tokens were dried at o c for hour prior to staining and analysis. residual tissue protein and prion-associated amyloid on the control and processed surfaces was quantified, in situ, using the total protein blot stain sypro ruby (sr; invitrogen, uk) and the amyloid specific stain thioflavin t (tht [ . % (w/v) in . m hcl]; sigma- aldrich), as described elsewhere , . fluorescent signal was visualised using episcopic differential interference contrast (edic) microscopy coupled with epifluorescence (ef - best scientific, wroughton, uk) , . full x/y scans of the contaminated areas were acquired at x magnification showing the sypro ruby (excitation: nm; emission: nm) and tht ( . % (w/v) in . m hcl sigma-aldrich) signals. the captured images were analysed using imagej software (national institutes of health). to analyse the effects of the uas treatment on infectious prion proteins, immunoblot analysis was used to determine the presence of prp c and proteinase k (pk) resistant prp sc in both l-spiked distilled water, as an untreated control, and the effluent taken from the uas system post cleaning of l-spiked stainless-steel tokens. controls were prepared by spiking l of sterile distilled water with µg of l-infected brain homogenate. uas positive samples were prepared from capturing the l uas effluent post cleaning of surgical stainless-steel tokens contaminated with µg l-infected brain homogenates each (dried for hours at room temperature) as described above. the control and effluent solutions were filtered through nitrocellulose membranes to capture the suspended protein aggregates. after h drying at room temperature the l brain homogenate, again demonstrated the highest affinity for the stainless steel with the highest attachment of protein and prion- associated amyloid observed. when compared with hours drying, the k-contaminated homogenate resulted in higher protein attachment after h drying and the me infected brain homogenates demonstrated similar protein attachment but higher prion-associated amyloid attachment (figure ). the removal of l and me tissues was slightly more difficult using a s uas treatment with and % protein and and % amyloid removal, respectively (figure ). after s uas treatment the removal was improved with and % protein and - % amyloid removal, respectively. the k was harder to remove after hours drying with only % protein and % amyloid removal after the s uas treatment, however, after the s uas treatment the cleaning was improved with % protein and % amyloid removal (figure ). the percentage of amyloid within the total residual contamination was again very low with - % amyloid remaining for all the samples after s uas contact time (figure ) . the effluent from the uas system after decontaminating the l spiked surfaces was filtered and labelled for residual prion protein (both non-resistant and pk-resistant) and compared to control samples of distilled water spiked with the equivalent amount of l brain homogenate. a clear reduction of both the pk-sensitive and pk-resistant prion protein from the tokens was observed (as demonstrated by the protein capture on nitrocellulose membranes following the previously demonstrated - % protein and - % amyloid removal, described above) after s uas treatment (figure ) . the reduction in immuno-labelled prion proteins post uas treatment could be demonstrating that the uas treatment is destructive to the antibody specific epitopes of the prion protein, therefore reducing the immunochemical detection post uas treatment. furthermore, small protein aggregates could be observed in the control samples but not in the samples post uas treatment, suggesting that the uas may degrade and/or solubilize these aggregates. current practices for the decontamination and sterilisation of surgical instruments within ssds are not entirely efficient at removing all potentially infectious material, especially, hardy prion proteins. therefore, surgical instruments which may have come in contact with cjd-infected tissues cannot be deemed safe post cleaning , , , and are subsequently quarantined. simple, cost effective methods to prevent the initial attachment of bioburden to surgical surfaces have been demonstrated [ ] [ ] [ ] . ultrasonic baths provide efficient cleaning using water alone, however; the limitations associated with water baths was described earlier in this manuscript. this study has tested the efficacy of uas technology for the removal of total protein and prion-amyloid from stainless steel, which is considered the most difficult contaminant to decontaminate in the surgical field. the uas technology demonstrated significant removal of the three prion strains tested after differing drying and uas treatment times; however, increased uas treatment times are required to further improve the efficacy of the uas treatment. the efficient removal of me and l, both murine adapted scrapie strains, was very similar following both drying and uas treatment times. however, k, a hamster adapted scrapie strain, was harder to remove and would require a longer uas treatment to reduce to the levels observed with the two murine strains. this observation suggests that the hamster brain constituents and prp sc conformation is different to the mouse brains and showed increased affinity to stainless steel. this highlights the importance of studying different prion strains, from different hosts when determining the efficacy of hospital decontamination tools. for comparison of the efficacy of the uas system to that of cleaning chemistries used in ssds, the removal of me -infected brain homogenate from stainless steel tokens using the same methodology as this study have been previously published , . hervé et al ( ) , tested four different cleaning chemistries marketed for proteinaceous decontamination which demonstrated total protein removals of %, . %, . % and . %, respectively . secker et al ( ) , tested two cleaning chemistries, also marketed for proteinaceous decontamination, which demonstrated total protein removal of % and . %, respectively . all the cleaning chemistries tested in these studies required heating of the cleaning solution, whereas the uas system tested here removed % total protein with cold water and only a s contact time. a recent nihr health technology assessment (hta) has extensively compared studies quantifying the efficacy of interventions to reduce the surgical transmission of vcjd . the other important observation was that the uas system favourably removed the prion-associated amyloid (infectious prion proteins in the aggregated form) from the surfaces. demonstrated by the low percentages of the total residual proteinaceous contamination being tht positive amyloid, compared to the comparative treatment using commercially available cleaning chemistries , . immunoblot analysis of both pk-sensitive and -resistant residues of prp was carried out to determine the presence and state of prion aggregates post uas decontamination. following the predetermined - % protein and - % prion-amyloid removal, described above, the supernatant from the uas treatment was filtered and the prion proteins were labelled. the pk resistant and sensitive aggregates observed in the control immunoblots were not present in the uas treated samples; suggesting that the uas mechanism of action is causing the breakdown of the prp aggregates, reducing the available epitopes for antibody binding, and therefore a reduction in antibody positive prp residues. furthermore, this would explain why an increase in the removal of prion-amyloid using the uas system was observed, as described earlier. further work is required to confirm and determine if the breakdown of prp caused by the action of uas correlates with a reduction in prion the results from this study demonstrated efficient removal of tissue proteins, and more importantly prion-associated amyloid from surgical stainless-steel harnessing the power of water at ambient temperature. while the cleaning efficacy demonstrated by this system is improved compared to that of the best currently available cleaning chemistries tested on the same contaminants, interestingly the uas appeared more effective at removing prion- amyloid as well as the total proteinaceous contamination. this study has demonstrated the efficacious ability of the uas to clean with just cold water. however, the uas system could work also with chemical cleaners, so that you can get a synergistic effect of mechanical (acoustically activated bubbles) and chemical cleaning. furthermore, previous studies have demonstrated that the uas efficiently removes microbial contamination from rough, etched surfaces . thus demonstrating that a uas has the ability to clean items, such as surgical instruments, that contain dynamic differences in surface topography . in its current form, the uas system is designed as a hand-held device, and the plan is to include this in a pilot to test as a pre-clean before the surgical instruments proceed on to washer-disinfectors (i.e. at the stage where currently ssds conduct washing by hand, brushing and pre-cleaning of surgical instruments). the mechanical removal by uas of prion-associated amyloid embedded in dried-on brain homogenate, demonstrates an interesting parallel with the problem of removing the sars-cov- virus responsible for the current covid- from touch-surfaces. lacking an appropriate attachment mechanism, the virus relies on the stickiness of respiratory secretions in which it resides (that are composed mainly of mucin glycoproteins, surfactant and intercellular fluid) to attach to abiotic surfaces. therefore, the efficient ability of the uas system for removing prion-associated amyloid by cleaning away the biological material, in the case of this study brain homogenate, as well as bacteria and lubricant contamination, previously published , , highlights the importance of testing this system against viruses. if viruses can also be removed by uas, then incorporation of uas in society to clean these surfaces with just water could aid infection prevention, the datasets generated and analysed during this study will be openly available from the university of southampton repository at http://dx.doi.org/ . /soton/[ note to editors: the policy of the university of southampton is that they will grant a link for insertion once the paper is accepted to avoid their repository referring to papers that were not published]. ts carried out laboratory experimentation, data analysis interpretation, participated in the design of the study and drafted the manuscript; tl conceived the study, coordinated across disciplines, and helped draft the manuscript; do and pb helped conceive the study and provided support for the set-up and running of the uas; rh helped with experimental design and drafting the manuscript; ck oversaw the microbiological components and helped draft the manuscript. all authors gave final approval for publication. one of the authors (t.g.l.) is director and inventor-in-chief of the company (sloan water technology, ltd.) that holds the patent to this technology but has drawn no salary from this. j o u r n a l p r e -p r o o f tissue protein (dark grey bars) and prion-associated amyloid (light grey bars) attachment from different prion-infected brain homogenates ( l, me and k) to surgical stainless steel pre and post treatment with an ultrasonically activated stream (uas) (graph a). brain homogenate was initially dried for h at o c prior to cleaning (pos). the orange dashes represent percentage protein removal and the blue dashes represent percentage prion- associated amyloid removal (graph a). graph b has an expanded y-axis scale to distinguish the lower levels of contamination. data shows mean ± sem (n= ), however, in decontamination and other research areas , outliers are also important to assessing outcomes, whether it be risk of infection, or the response of the most sensitive individuals to some stimulus; ***: p=≤ . for total proteins; † †: p=≤ . for amyloid, when compared to the corresponding positive controls, respectively. tissue protein (dark grey bars) and prion-associated amyloid (light grey bars) attachment from different prion-infected brain homogenates ( l, me and k) to surgical stainless steel pre and post treatment ( and s contact times) with an ultrasonically activated stream (uas) (graph a). brain homogenate was initially dried for h at room temperature prior to cleaning (pos). the orange dashes represent percentage protein removal and the blue dashes represent percentage prion-associated amyloid removal (graph a). graph b has an expanded y-axis scale to highlight the lower levels of contamination. data shows mean ± sem (n= ); however, in decontamination and other research areas , outliers are also important to assessing outcomes, whether it be risk of infection, or the response of the most sensitive individuals to some stimulus; *: p=≤ . and ***: p=≤ . for total proteins; † †: p=≤ . and † † †: p=≤ . for amyloid, when compared to the corresponding positive controls, respectively. immunoblot films showing captured proteins from l of l-spiked solution containing µg of l homogenate in distilled water (a and b) and from the uas system effluent after treating surfaces contaminated with the equivalent amount of l homogenate (c and 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processes wong r interventions to reduce the risk of surgically transmitted creutzfeldt-jakob disease: a cost-effective modelling review analogies in contextualizing human response to airborne ultrasound and fish response to acoustic noise and deterrents key: cord- -kftdqzg authors: au, s.s.w.; gomersall, c.d.; leung, p.; li, p.t.y. title: a randomised controlled pilot study to compare filtration factor of a novel non-fit-tested high-efficiency particulate air (hepa) filtering facemask with a fit-tested n mask date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: kftdqzg use of a fit-tested n or ffp mask is recommended to protect against transmission of airborne pathogens. this poses considerable logistic problems when preparing for, or dealing with, an epidemic. some of these problems might be overcome by use of a compact reusable high-efficiency particulate air filtering mask that can be cut to size. we carried out a randomised controlled cross-over study to compare the efficacy of such a mask (totobobo, dream lab one pte ltd, singapore) with fit-tested n masks ( or s or ; m, st paul, mn, usa) in healthy volunteers. the median (interquartile range) reduction in airborne particle counts was significantly higher [ -fold ( – )] for n masks than for totobobo masks [ -fold ( – )] (p < . ). there was no statistically significant difference between the proportion of subjects achieving a reduction of ≥ -fold between n ( / ) and totobobo ( / ) masks. we conclude that use of the totobobo mask without fit testing cannot be recommended, but its performance is sufficiently promising to warrant further investigation. a fit-tested, disposable, negative pressure respirator of n (ffp ) standard or higher is considered a standard part of protective equipment for staff caring for patients with diseases spread by airborne particles. , fit-testing of n masks is recommended, as the benefit of their high level of filtration is negated if the wearer inspires unfiltered gas around the edges of the mask. , the masks most likely to fit a population of staff will depend on the facial characteristics of that population. it may be possible to identify a small number of masks most likely to fit the population of at-risk staff by testing a larger range of masks on a sample of about staff members. nevertheless, not all staff will successfully fit the initial mask tested, and fit-testing takes min per person on average. repeat testing is recommended following a bodyweight change of more than % and annually. as a result, fit-testing requires considerable resources and considerable preparation in case of an epidemic. further problems related to the use of disposable n masks include the logistic problems of keeping large stocks of masks available and the need to stock multiple brands/models. recently, a compact reusable mask (totobobo; dream lab one pte ltd, singapore) has been produced. it is made of a plastic material which is trimmed to fit the user's face. inspired air is filtered by disposable high-efficiency particulate air (hepa) filters ( figure ). if effective, this mask may address many of the problems related to use of disposable n masks. in particular, as the mask is trimmed to fit the user's face it may not be necessary to carry out fit-testing, and the fact that it is reusable may obviate the need to stock large quantities of masks. in view of the potential benefits of this new mask, we carried out a controlled cross-over pilot study to compare the in-vivo filtration capacity of trimmed but non-fittested totobobo masks with a fit-tested n mask ( or s or ; m, st paul, mn, usa). this was a prospective unblinded study of healthy chinese volunteers using two different protective devices: a totobobo mask (dream lab one pte. ltd, singapore) and a fitted n filtering facepiece respirator ( or s or , m, st paul, mn, usa). approval was obtained from the joint chinese university of hong kong/new territories east cluster clinical research ethics committee. written informed consent was obtained from all participants and the study was carried out in accordance with international conference on harmonisation-good clinical practice standards and the declaration of helsinki. twenty-two healthy volunteers who had previously passed a fit test with an , s or n filtering facepiece respirator were recruited. new masks were used for each subject. prior to testing the n mask, the subject adjusted the mask and performed a user seal test. prior to testing the totobobo mask the investigator trimmed the mask according to the manufacturer's instructions and following training by the inventor. the investigator also visually checked the fit of both types of mask. volunteers underwent a standard mask-fitting protocol. in brief, the tests consisted of comparisons of particle counts inside and outside the protective device during a series of activities: normal breathing, deep breathing, turning the head from side to side, flexing and extending the head, talking loudly and bending over followed by normal breathing again. the sampling probe (tsi incorporated, st paul, mn, usa) for sampling the mask particle count was inserted through the fabric or plastic of the protective device. air samples for measuring the ambient particle count were taken from just outside the mask about cm from the sampling probe. a portacount plus (tsi incorporated) connected to a computer running fitplus for windows software (tsi incorporated) was used to count particles and calculate the ratio of ambient:device particle counts. this device counts all particles sized between . and mm diameter. it calculates a fit factor, which is the average ratio of atmospheric:device particle concentrations. to ensure an adequate ambient particle count throughout the testing, the particle generator (tsi incorporated) was used to generate saline particles throughout the testing procedures. all subjects were asked which mask they found more comfortable after completion of testing. the primary end-point was the median ratio of ambient:mask particle counts. these ratios were compared using the wilcoxon signed ranks test. p < . was considered significant. the sample size was calculated to achieve a power of % based on an effect size of a probability of . that the filtration factor using one mask is less than the filtration factor using the other mask and an a-value of . (two-tailed). the secondary end-point was the proportion of patients achieving a ratio of : . this proportion was compared using fisher's exact test. the median (interquartile range) filtration factor was significantly higher [ ( - ) ] for n masks compared to totobobo masks [ ( - )] (p < . ). however, there was no statistically significant difference between the proportion of subjects achieving a ratio of between n ( / ) and totobobo ( / ) masks. of the subjects who gave an opinion on comfort, [ %, confidence interval (ci): - %] found the totobobo mask more comfortable. our results indicate that the performance of a totobobo mask cut to fit the subject's face, but not fit-tested, is inferior to the performance of a fit-tested n mask. furthermore the filtration factor was > in only of subjects when wearing the totobobo mask. these data suggest that the use of totobobo masks, even when cut to fit the subject's face, does not obviate the need for a mask-fitting programme. our failure to demonstrate a significant difference in the proportion of subjects achieving a filtration factor may be due to the relatively small number of subjects in our study, which was not powered to show a difference in a binary outcome. however, our finding does not mean that the totobobo mask is not worthy of further evaluation, only that it should not be used without fit-testing. data on the performance of different n masks in a population that has not previously been assessed for mask-fit demonstrate that the proportion of subjects achieving an adequate fit (filtration factor ) with an individual mask varies from to %, with the majority of masks fitting < % of the test population. , [ ] [ ] [ ] in this context the performance of the totobobo mask ( % of subjects achieved filtration factor ) is good. if this finding is replicated, particularly in a population with different facial characteristics, then using the totobobo mask in the panel of masks to be tested may reduce the number of masks that need to be tested before an adequate fit is found. this potential advantage, however, will need to be balanced against the time taken to trim the totobobo mask to size. furthermore, in situations where there is insufficient time to carry out fit-testing, use of the totobobo mask may be a useful interim measure. in addition to this, the fact that the totobobo mask is designed to be reusable may provide significant advantage. this would minimise the problems associated with the need to stockpile disposable masks and the difficulty of obtaining supplies in an epidemic. prior to concluding that the mask is reusable, it is necessary to test the effect of sterilisation processes on the mask. it is conceivable that such processes may make the mask less pliable and the fit less good. moreover, it is important to ensure that the process of changing the hepa filters does not contaminate the user with infectious particles. in terms of comfort, % (ci: - %) of subjects preferred the totobobo mask to the n mask ( , s; m). although the ci straddles %, this may be due to our small sample size. comfort is an important issue when masks need to be worn for long periods of time. greater comfort may translate into greater compliance with proper use of the mask and hence greater protection in clinical use. the experience of our intensive care unit during the severe acute respiratory syndrome epidemic suggests that compliance is an important factor in determining the risk of occupational infection. in theory, all subjects should have achieved a filtration factor with the n mask, as they had previously passed a fit test with the same model of n mask. the lower than expected pass rate may reflect the fact that subjects did not undergo a regular fittesting programme. the us occupational safety and health administration, centers for disease control and protection recommends that workers using n respirators should have repeated fit-testing on a regular basis. although this imposes a considerable logistic and financial burden and is controversial, our data suggest that a significant proportion of subjects may not be adequately protected without regular testing. the results of a recent randomised controlled trial conducted in emergency departments and medical and paediatric wards suggest that surgical masks provide a similar level of protection to n masks against transmission of seasonal influenza. however, we would be cautious concerning extrapolation of these data to all healthcare environments and to patients with influenza a h n ( ) infection. the risk of healthcare worker infection relates to a number of factors including number of infectious particles produced by patients and the number of organisms that constitutes an infectious dose. if the infectious dose is very small or the number of infectious particles produced is very high, then the benefit of the much higher filtration efficacy of n respirators should be greater. these values vary with the organism and are currently unknown for influenza a h n . furthermore, in certain areas, such as intensive care units, the frequent use of aerosolgenerating procedures will increase the number of infectious particles produced and therefore the likely benefit of n respirators. there are a number of weaknesses in our study. first, the investigator responsible for cutting the masks received direct training from the inventor of the mask. it is possible that the performance of the mask might not be as good if this training were conducted by an individual with less insight into the functioning of the mask. second, our study was conducted in an exclusively chinese group of subjects. facial characteristics may vary between racial groups and it is possible that our results will not be replicated in other racial groups. third, the sample size was too small to adequately assess the effect of type of mask on the proportion of subjects with an adequate fit or comfort. fourth, the comfort of the masks was only superficially tested. however, our study was a pilot study designed to determine if the mask was worthy of more extensive investigation, and in this respect we believe it has generated useful data. based on our findings we feel that a larger multi-racial study that assesses comfort as well as fit is warranted. cost analysis was not part of our study although it would be an important consideration if our results are confirmed in a larger multi-racial study. the approximate retail prices (without bulk discount or delivery) of the masks are us$ for the reusable totobobo mask, with replacement filters costing us$ . , and us $ . for single-use m respirators. other factors that would need to be considered in a costing exercise are the costs of storage of masks, cleaning of totobobo masks and fit-testing as well as bulk purchase discounts, and the number of times that a totobobo mask can be reused. in conclusion, despite being cut to size, the totobobo mask (nonfit-tested) does not perform as well as a fit-tested n mask. its performance and design features are sufficiently promising to warrant further investigation of its use. none declared. this study was supported by a direct grant for research from the chinese university of hong kong. totobobo masks were supplied free by the manufacturer. expanding icu facilities in an epidemic: recommendations based on experience from the sars epidemic in hong kong and singapore pandemic preparedness performance of n respirators: filtration efficiency for airborne microbial and inert particles laboratory performance evaluation of n filtering facepiece respirators the effect of subject characteristics and respirator features on respirator fit respiratory protection against mycobacterium tuberculosis: quantitative fit test outcomes for five type n filtering-facepiece respirators implementing fit testing for n filtering facepiece respirators: practical information from a large cohort of hospital workers fitting characteristics of eighteen n filtering-facepiece respirators respirator tolerance in health care workers transmission of sars to healthcare workers. the experience of a hong kong icu the costs of healthcare worker respiratory protection and fit-testing programs surgical mask vs n respirator for preventing influenza among health care workers: a randomized trial the relative efficacy of respirators and room ventilation in preventing occupational tuberculosis protecting healthcare staff from severe acute respiratory syndrome. a study of the filtration capacity of multiple surgical masks key: cord- -rirmvf l authors: gray, s.; clough, t.; mcgee, y.; murphy, t.; poulikakos, d. title: increased risk of covid- in haemodialysis healthcare workers in a tertiary centre in the north west of england date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: rirmvf l nan we have read with interest the manuscript by montesinos et al. [ ] assessing sars-cov- positivity and seroprevalence in healthcare workers (hcws) working in a tertiary reference hospital for infectious diseases in belgium. their study showed that hcws in direct contact with covid- -infected patients did not have increased risk of covid- compared with other hcws. similarly, in a recent study in hcws from a large hospital in spain, direct contact with covid- cases was not associated with increased risk of covid- [ ] . both studies offer reassurance that personal protective equipment (ppe) measures in accordance with european centre for disease prevention and control ecdc [ ] provide the appropriate level of protection from covid- . conversely, in an audit of occupational exposure in our haemodialysis (hd) services at a tertiary centre in the north west of england, we noticed increased risk of covid- in hcws in direct contact with covid- -infected patients. this observation highlights the need to evaluate the existing public health england ppe guidance [ ] in hd units that recommends fluid repellent surgical masks and plastic aprons in conjunction with bare below the elbows policy in hcws treating covid- -suspected or -confirmed patients not involved in aerosol-generating procedures [ ] instead of ecdc [ ] and cdc [ ] recommended ffp / masks and long-sleeved gowns in similar clinical settings. our regional renal service covers a population of . million people and provides in-centre hd for patients in one main and four satellite hd units. at the beginning of the covid- pandemic in the north west of england initially one shift ( th march ) and subsequently the whole main hospital hd unit ( th april ) was designated for treatment of suspected or confirmed covid- patients receiving hd. hd patients were screened prior to attendance for hd treatment to the satellite units and those with symptoms or with previous contact with covid- cases were transferred immediately to the main unit for covid- nasopharyngeal swab testing, medical assessment and hd treatment. symptom-free hd patients received hd treatment at covid- -negative satellite units. a nursing team of hcws was assigned to cover the main covid- unit and hcws were assigned to cover the two of the four satellite units. for the remaining two satellite hd units, nursing workforce is provided and managed by our industry partner and we do not have access to occupational exposure data. the nursing staff was not allowed to move between covid- positive and -negative units from th march until th june when our hd programme was reconfigured at the recovery phase of the pandemic. during this period, covid- patients were dialysed at the main unit (including patients on maintenance hd and with acute kidney injury) and patients were dialysed in the two satellite units staffed by nursing hcws from our department. public health england ppe guidance [ ] was followed for staff caring for suspected and confirmed covid- patients including surgical masks, plastic aprons, protective eyewear and gloves and there were no issues with ppe supplies. since april , following uk renal association recommendations [ ] , this level of ppe was extended to all staff caring for hd patients (irrespective of covid- status of patients) and all hd patients were advised to wear surgical masks. nasopharyngeal testing for symptomatic (new continuous cough, high temperature) hcws was introduced on march . prior to this date testing was prioritized for patients presenting to the healthcare system with symptoms compatible with covid- infection and symptomatic hcws were advised to stay at home for days. amongst the hcws assigned to work at covid- hd unit, ( . %) became symptomatic, six ( %) were diagnosed with covid- on nasopharyngeal swabs (two of whom required hospitalization), three had negative nasopharyngeal swabs and six were not tested with nasopharyngeal swabs because hcw testing was not yet recommended at that period. the dates of symptom onset of the covid- hcws were th march (two hcws), th april (one hcw), th april (one hcw), th april (one hcw) and th june (one hcw). amongst the hcws j o u r n a l p r e -p r o o f covering the two satellite units, ( . %) became symptomatic, none had positive nasopharyngeal swabs, four had negative nasopharyngeal swabs and the remaining symptomatic hcws were not tested because hcw testing was not yet recommended during that period. our observations suggest that hcws caring for suspected or confirmed covid- hd patients are at high risk of covid- with the existing level of ppe. a precautionary approach with enhanced levels of ppe in line with european recommendations [ , ] should be considered in hcws caring for hd patients with suspected or confirmed covid- before the emergence of a second wave of the pandemic. dynamic of sars-cov- rt-pcr positivity and seroprevalence among high-risk health care workers and hospital staff seroprevalence of antibodies against sars-cov- among health care workers in a large spanish reference hospital european centre for disease prevention and control. infection prevention and control and preparedness for covid- in healthcare settings -third update guidance covid- personal protective equipment (ppe) updated summary of ppe recommendations for health and social care workers recommended infection prevention and control (ipc) practices when caring for a patient with suspected or confirmed sars-cov- infection ppe and use of masks by dialysis patients. the renal association website recommendations for the prevention, mitigation and containment of the emerging sars-cov- (covid- ) pandemic in haemodialysis centres the authors have no conflicts of interest to declare. none. key: cord- -z arb k authors: goel, s.; gupta, a.k.; singh, a.; lenka, s.r. title: preparations and limitations for prevention of severe acute respiratory syndrome in a tertiary care centre of india date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: z arb k this short-term observational study of infection control practice was performed in the medical emergency outpatient department (emopd) of a tertiary-care hospital in india when threatened by an outbreak of severe acute respiratory syndrome (sars). an investigator attended the lobby daily to screen patients with symptoms for sars. patient/attendant load, patient flow, medical staff working practices and position in the emopd were observed. infection control measures such as fumigation and cleaning were noted, as was the emopd laboratory function, use of personnel protection and display of information on infectious diseases. a total of ( . %) of the patients surveyed had respiratory symptoms but no cases of sars were found. the flow of patients and their attendants was not systematic. no laboratory tests for sars were available, and no educational material on sars was displayed. the emopds in key hospitals need be able to screen for infectious diseases, especially in view of the threats from sars and avian influenza. the post graduate institute of medical education and research (pgimer), chandigarrh was conceived in as a centre of excellence for medical care in north india, and includes the nehru hospital, a centre of national importance with beds (table i) . it caters for . million outpatients, inpatients and emergencies per year. infectious diseases are a common reason for medical consultations, and the threats posed by them have been receiving considerable attention at national levels. in february a few cases of a mysterious plague-like disease were admitted to pgimer. the diagnosis was initially missed, and the patients were not isolated until a formal diagnosis was made. by that time, infection had been transmitted to a visitor to another patient in the ward; a -year-old man, who later died. the need to screen all patients with suspected infectious disease in the medical emergency outpatient department (emopd), and for control and prevention of infection, was recognized. two community physicians were deputed to assess the situation, and an outbreak control committee was formed. this arrangement lapsed when the plague situation was controlled. shortly afterwards, cases of suspected severe acute respiratory syndrome (sars) were reported in india. twenty persons were found to be serologically positive, although none fell within the world health organization (who) definition of sars. a national alert was sounded and patient screening in the emopd was recommenced. a 'control room' was established near the reception to screen all patients with respiratory symptoms for sars. this study was performed to analyse infection control in the emopd and to examine the patient flow system. this was a short-term study (aprilemay ). consent was obtained from the senior medial officer, the patients and their attendants. the physical space, entry and exit system, location, registration area, lobby/corridor, waiting area, triage area, examination rooms, observational beds, emergency x-ray room and laboratory, treatment rooms, nurse's station, staff rest rooms, stores, police post and public relations office were observed. in addition, the patient/attendant load, patient flow, and medical staff practice were observed, and information displayed on sars or other infectious diseases was noted. the emopd has four entrances manned by security guards. these open into a spacious, welllit lobby. there are separate emergency wards for medicine and surgery (total beds), and observational beds. on average, e patients are admitted daily and almost twice that number of attendants accompany them. a computed tomography (ct) scan/radiology department, seven operating theatres, a blood bank, an attendant waiting room, laboratory, and a public relation officer's room are attached to the emopd. no isolation facility is available. at any one time, there is a consultant, two senior residents, three junior residents, four nursing staff and a sanitary staff member present. the principal investigator was a senior resident (md) in community medicine with six years' experience. he sat with a public health nurse in a lobby near an emopd entrance from : to : and was on call for the rest of the day. the security guards directed patients with respiratory symptoms to the principal investigator, who asked them and their relatives the sars screening questions specified in the who protocol, i.e. do you have a fever? do you have one or more of the following symptoms: cough, shortness of breath, difficult breathing? have you been in contact with a person with respiratory symptoms in the last days? they were also asked to provide their travel history over the past days. there was no objective assessment of temperature. patients with at least two of the three symptoms had chest radiographs. the who protocol was used to classify the patients as having suspected or probable sars. on april , emopd began screening all febrile patients with respiratory complaints for sars. a -year-old male suspect case of sars was admitted on may with fever ( c), chills and breathlessness. he developed respiratory failure and was transferred to the respiratory intensive care unit on may. one day later he was put into the isolation ward as a suspected sars case along with six contacts. a senior resident in pulmonary medicine and the principal investigator examined any contacts in the ward. after five days of isolation, he was moved into a general ward. facemasks were provided for him and his family but standard procedures for handling samples from sars cases were not followed. a blood sample taken on admission was sent to the national institute of communicable diseases, delhi and proved to be negative for sars. no convalescent sample was sent, nor were any other respiratory samples examined. the case and the contacts were then discharged. they were asked to report immediately if any sign/symptom appeared in next fortnight. a total of patients were screened in days, ( . %) of whom had a history of respiratory complaints. an average of six or seven patients with respiratory complaints were screened for sars daily. no confirmed case of sars was found. the flow of patients and their attendants was not systematic and their movement was uncontrolled. two or three or even more attendants usually accompanied one patient. at the entrance, there was no sign showing the direction to the patient reception area. the corridor was overcrowded, leaving little space for movement of patients, nurses and doctors. there is a central airconditioning system with different airflow control units, but no negative-pressure isolation room or other isolation facility. the floors were wet mopped two or three times per day and once a day with cresol. the emergency operation theatres were fumigated monthly. initially the principal investigator was only provided with standard facemasks. he wore two at a time for protection. an n- mask was made available for the final days. the suspected sars case and his contacts were also given standard facemasks. laboratory investigations for sars were not available in the emopd. attendants crowded around the place of collection for laboratory reports, which they searched for themselves. no information on sars was displayed, and the staff told the patients/attendants about the symptoms of sars only when asked. most of the attendants/patients targeted the principal investigator for information. in the emopd there was no online access to information on recent outbreaks of communicable diseases. journals such as cd alert are not taken by the emopd and none of the resident doctors had heard of cd alert or the who weekly epidemiological report. they were unaware of the notifiable diseases or sars management protocols. there were no confirmed cases of sars in india despite initial concern but the recent threats of avian influenza and sars have reinforced the need for a screening system for such infections in emopd. infected patients can transmit their infection to others in emopd as happened in the plague outbreak. the role of hospitals in the spread of infectious diseases was emphasized by experiences with sars, for example in taiwan, where cases occurred after exposure to the index case in the emopd itself. therefore, the promptness and quality of emergency medical care may be crucial in preventing the spread of infection. surveillance is an essential part of hospital control of infectious diseases. many countries have tried to incorporate surveillance in their emergency medical services, and the role of national government in strengthening infectious disease control in an emergency has been debated. in india an integrated disease surveillance project (idsp) has been implemented in many states to focus on early detection and control of spread of infectious diseases. a draft contingency plan for avian influenza has been included in the idsp training of medical officers, but the idsp lacks the necessary focus for the emopd. in our study, the who protocol was used to classify the cases as having suspected or probable sars. suspect patients were straightaway shifted to the isolation room (in a different block, m from the emopd). however, the chances of infection spreading to patients/attendants during transfer of the patient remained. grouping infectious patients in a centralized location in an early stage of infection may reduce the extent of an epidemic. lingappa et al. also suggested that the hospital setting was the primary amplifier of sars transmission. table ii shows the sars control measures that ought to have been taken and what was actually done during the survey period. the standard management protocol was not followed. the casual approach was evident by the fact that collection of a single blood sample was done on day of onset of symptoms in a suspected sars case e a procedure with no diagnostic value. the resident doctors of medicine and surgery should be aware of the locally endemic diseases and impending outbreaks. accordingly they should watch for the suggestive symptoms in every case. this should be included in their training/teaching. a set of standard protocols for screening and management of infectious disease patients should be framed and displayed prominently. these guidelines should be regularly updated whenever any new emerging or re-emerging disease is reported. the latest updates from cd alert and global infectious disease alert should also be prominently displayed in the emopd. the layout of an emergency department affects the chances of spread of infection. open wards with many beds separated by curtains and no controlled ventilation have been regarded as contributory factors to the spread of the virus. in singapore changed triage and infection control practices stopped nosocomial transmission of the virus. in our study, patient flow was not systematic and there was no regulation of numbers. others have reported similar scenarios. the number of air exchanges, air filters and flow of air in the emopd were as per accredited international norms, but there was no negative-pressure isolation room. pgimer emopd has a core type of design. two kinds of change are possible: (a) structure. the emopd initially contained e beds, but now has , leaving little scope for further expansion. to prevent spread of infection, a permanent 'triage/control room' should be established near reception for screening patients. this should include a cubicle for examination of critically ill infectious disease patients. if a doctor/nurse suspects that s/he is dealing with a highly infectious disease, s/he should have an option to isolate the suspected cases in an isolation room/ward located nearby. (b) function. this could be changed without undue disturbance and cost, provided that the building has sufficient flexibility. , the flow of patients and visitors can be easily regulated. a sign should be placed at the entry of emopd instructing people where to report first. proper directions to patients/attendants should be displayed inside the hall. a systematic patient flow control mechanism should be installed and a screening system for patients' attendants should also be initiated. only one attendant (at the most two, in case of serious emergency) should be allowed into the emopd. a public health nurse (phn) along with an emergency medical officer e surveillance and screening (emo-s&s) should be posted permanently in the emopd. the phn should conduct a daily census of infectious and notifiable diseases. patients arriving in emopd should first be examined thoroughly to rule out the chance of patients with acute infectious disease from mixing with the opd crowd. only the patients screened by the emo-s&s should be allowed to enter along with one attendant. restriction of patient movement is crucial for ensuring infection control. until a larger emopd is constructed, overcrowding and lack of scope of flexibility for functional changes will continue to compromise infection control measures (figure ). medical personnel are also a recognized source of transmission of infectious diseases in hospitals. , emergency department workers in large hospitals are generally more severely affected by an epidemic. personal protection equipment (ppe), namely gloves, gowns and surgical masks, is important in preventing transmission of sars. failure to implement a policy of universal ppe use early in an outbreak enables the spread of infectious diseases. use of fitness-tested personal protective equipment in all patient-care areas has been shown to prevent nosocomial spread of sars. in our study, provision of the recommended n- masks was delayed due to late procurement. such personal protective equipment should be permanently available in an emopd. availability of quick and reliable laboratory investigation facilities is vital for the early diagnosis of acute infectious diseases and allows initiation of prompt treatment and control measures. standard protocols for specimen collection for infectious diseases should be used. in the present study, the standard protocol for specimen collection from a sars case was not followed, which resulted in delayed confirmation of diagnosis. streamlining of the laboratory reporting system was also required. there is a definite need to make the emopd safer for immunocompromised and susceptible patients and their attendants. our study highlights the vulnerability of emopds in india for spread of infectious diseases even in centres of excellence. the situation in smaller hospitals can only be expected to be worse. a set of standard guidelines should be evolved for various levels of hospitals in india for handling infectious diseases and pasted in the emopd. effective implementation of the idsp would be another useful measure. currently, there is a worldwide focus on improvement of quality of care in emopds. the recent sars epidemic showed that only healthcare systems that have been strengthened and can respond to events of this kind would be able to handle future contingencies. under a new accreditation standard, emopds and all departments must be prepared to handle an influx, or the risk of an influx, of infectious patients. they should collaborate with the infection control committee, disaster management committee, local board of health, and other providers to develop protocols and policies. they should hold disaster drills in which they must handle infectious patients. emopd staff, particularly the triage nurses, need training in the early recognition of presenting symptoms of infectious diseases. who has established a global alert and response network to monitor and track infectious diseases 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severe acute respiratory syndrome in hong kong equipment for sars control in patient care units and in units that process infected samples hospitals' preparation for surge of patients helps with new joint commission standards september , biological terrorism and the development of an environmental health tracking network key: cord- -v qvb i authors: persoon, ilona f.; stankiewicz, nikolai; smith, andrew; de soet, hans (j.j.); volgenant, catherine m.c. title: a review of respiratory protection measures recommended in europe for dental procedures during the covid- pandemic date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: v qvb i nan the main mode of transmission of the sars-cov- virus is via respiratory droplets and aerosols . during the covid- pandemic period, the world health organisation (who) recommends wearing respiratory protection when undertaking aerosol generating procedures (agp) to reduce the risks of cross-infection between patients and healthcare worker (hcw) and vice versa . patients who tested positive for this virus are known to carry high numbers of virus particles in their saliva and on their tongue . dentistry poses a particular challenge due to the large number of aerosol and droplet generating procedures undertaken in the oral cavity and the very close proximity (< . m) of dental hcws to the plume of aerosolised respiratory secretions. the availability of healthcare personal protective equipment (ppe) has been put under considerable strain due to the covid- pandemic . in some countries, shortages of ppe have necessitated sessional use of equipment that was previously deemed single patient use . therefore, facemask recommendations may not be based solely on maximum protection, but also on pragmatism including availability and areas of priority within a region's healthcare system. a review of protocols for dentistry during the peak of the covid- epidemic was undertaken, focussing on respiratory protection measures during dental procedures for the european continent. european dental association web sites were screened for information on guidance or protocols regarding sars-cov- and ppe. documents in languages other than english or dutch were translated into english using google translate. after obtaining the data, the results were presented to experts involved in dentistry and oral microbiology within europe for verification. three categories of respiratory protection measures were identified within the protocols; medical (surgical) facemasks, filtering facepiece particles (ffp) and ffp . of the included european countries, % recommend respiratory protection ffp / ffp when performing agp in patients with symptoms of covid- , and % recommend referral or postponing treatment (results per country are available upon request). these practices are in accordance with the who guidance . the potential for transmission from asymptomatic or pre-symptomatic carriers was identified as a concern in many of the countries, especially if an agp was necessary. when patients do not show symptoms of covid- , % of countries recommend respiratory protection ffp / ffp when performing agp. a considerable number of countries also recommend respiratory protection ffp / ffp when performing non agps, both in patients with ( %) and without symptoms of covid- ( %). these masks filter significantly more effectively and have a better fit compared to medical facemasks; studies showed % total leakage of fine particles when using ffp equivalent respirators, whereas the leakage for medical facemasks was - % . however, the effectiveness of these respirators to prevent transmission of pathogens highly depends on proper fit and use of the equipment in conclusion, the recommendations on respiratory protection when undertaking dental healthcare in european countries vary considerably. this highlights the need for a task force to re-examine the evidence base for respiratory viral transmission during dental procedures and support closer alignment of guidelines throughout the dental healthcare sectors. aerodynamic analysis of sars-cov- in two wuhan hospitals rational use of personal protective equipment for coronavirus disease (covid- ) and considerations during severe shortages consistent detection of novel coronavirus in saliva suchomel m covid- -associated shortage of alcohol-based hand rubs, face masks, medical gloves and gowns proposal for a risk-adapted approach to ensure patient and healthcare worker safety transmission of -ncov infection from an asymptomatic contact in germany temporal dynamics in viral shedding and transmissibility of covid- estimating the generation interval for coronavirus disease (covid- ) based on symptom onset data the effectiveness of respiratory protection worn by communities to protect from volcanic ash inhalation. part ii: total inward leakage tests detection of infectious influenza virus in cough aerosols generated in a simulated patient examination room effectiveness of n respirators versus surgical masks against influenza: a systematic review and meta-analysis the authors would like to express their gratitude to all key: cord- -e jrxaj authors: wu, x.; zhou, h.; wu, x.; huang, w.; jia, b. title: strategies for qualified triage stations and fever clinics during the outbreak of covid- in the county hospitals of western chongqing date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: e jrxaj nan the outbreak of sars-cov- infection in china is highly transmissible by airborne droplets and close contact with infected secretions. essential control of this disease relies on the prompt identification, appropriate risk evaluation, isolation of possible cases and prevention measures for the spread of the virus. the hospital is a high risk area for nosocomial transmission with inappropriate room setup for triaging and diagnosing febrile patients. chongqing municipality is adjacent to hubei (the most affected province), with confirmed cases and , people with close contact history of the disease in chongqing. until now, there has been a zero transmission of the infection to any medical staff here. the most vital strategy of minimising the risk of nosocomial infection starts from the triage stations and fever clinics. here we report the strategies of makeshift for qualified triage stations and fever clinics during the outbreak of covid- in the county hospitals of western chongqing. [ ] [ ] [ ] [ ] the triage station was required to be located outside the entrance of the outpatient hall with highlighted signs. this location was chosen for better ventilation and more space, mitigating close contact among people by setting one-metre interval lines for queueing. the security guard and the nurse measure the temperature of the people on line using a mobile infrared thermometer. tents are pitched for further investigation of suspected patients. one tent is for nonfebrile persons and the other is for febrile patients to enter. all people with mobile phone are required to register their identification and other basic information by scanning the qr code next to the queueing line before entry, reducing the time of collecting information, minimizing the risk of potential contamination by touching the pen and paper and also shortening the waiting time. filling in the information manually is available, with the help of nurses, for people who cannot complete the task electronically. in the tent, a second time temperature measurement using a more precise infrared thermometer is undertaken, to further assess suspected patients and to minimize the risk of contact transmission to medical staff. routine hand sanitizers are ready to be used at any time. trained physicians and nurses wearing personal protective equipment (ppe) work together for initial assessment and the differential diagnosis of the fever. a simple, but crucial, questionnaire is designed to assist diagnosing patients (figure and supplementary figure ) . [ , ] general fever clinic and specific fever clinic for the suspected after assessment, patients with fever or cold-like symptoms with epidemiological history or suspected epidemiological history are referred to the 'covid- fever clinic'; other fever patients without epidemiological history are referred to the "general fever clinic". at the clinics the suspected febrile patient undergoes detailed history taking, physical examination, blood and other specimen collection and imaging. usually, nasopharyngeal specimen are tested all of the febrile patients, regardless of epidemiological links, to ensure that cases are not mis-assigned at triage. only trained staff are engaged in specimen collection to guarantee the quality of specimen. extra backup room is kept to accommodate for any overflow of febrile patient. besides, routine use of disinfectant wipes, disinfectant spray, uv light and air disinfecting machines ensure timely cleaning and sterilization. hospitals are either redesigning and remodelling old buildings or quickly setting up temporary tents or barrack-like rooms at an open area for better classification and circuit of two passages and the three regions of standard fever clinic, dramatically reducing the risks of hospital cross infection. measures to limit contact between patients include limit-lines for access to the fever clinic. also, specific patient routes within the hospital, and a specific ct scanner, were identified for suspected patients. an emergency call is made to the radiology department to ensure that it is prepared to receive the patient, and to notify the technician to wear ppe. after imaging is completed mg/l chloride-containing disinfectant, with min ventilation time, is used prior to the next patient. if an independent laboratory, pharmacy and cashier are not available in the fever clinic, a team of trained staff is designated to deliver the specimen and medication, and to obtain mobile self-service payment. however, all fees are paid by the government once testing sars-cov- pcr is positive. [ , [ ] [ ] one cannot overemphasize the importance of the triage station and fever clinic during the contagious disease outbreak in terms of timely patient management and minimizing the risk of nosocomial transmission. thus, thanks to qualified triage station and fever clinics altogether with community isolation, quarantine, medical support, covid- has been rapidly and well controlled in all of the counties in western chongqing. [ ] funding: the study was supported by the key funding for covid- clinical investigation ( special and urgent item ) from chongqing medical university. conflicts of interest: none. [ ] wang c, horby pw, hayden fg, gao gf. a novel coronavirus outbreak of global health concern. lancet. ; ( ): - . doi: . /s - ( ) - . [ ]covid- : infection prevention and control (https://www.gov.uk/government/publications/wuhan-novel coronavirus-infection-prevention-and-control). [ ] world health organization ( ) infection prevention and control during health care when novel coronavirus (ncov) infection is suspected ( ). severe acute respiratory syndrome coronavirus (sars-cov- ) and corona virus disease- (covid- ): the epidemic and the challenges novel coronavirus infection during the - epidemic: preparing intensive care units-the experience in sichuan province therapeutic and triage strategies for novel coronavirus disease in fever clinics how to face the novel coronavirus infection during the - epidemic: the experience of sichuan provincial people's hospital. intensive care we are so grateful for the language editing by dr. sumayyah golamaully in mauritius. key: cord- -yrhlg wm authors: ha, kyoo-man title: a lesson learned from the mers outbreak in south korea in date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: yrhlg wm nan middle east respiratory syndrome (mers) viruses can spread rapidly to many people, and thus pose a global pandemic threat. mers viruses broke out in one hospital in pyeongtaek, south korea (hereinafter korea), on may , . thirty-six patients died and people were infected. the koreans experienced a national crisis, contributed to by the poor initial response of the affected hospitals, an inadequate response from the government, the economic depression that followed the outbreak, and the psychological impact of the outbreak on the korean population. to date, the korean government has not taken systematic actions to deal with global pandemics in the future. this article comments on how korea can learn from its response to a mers outbreak to be better prepared to control other epidemic and pandemic infectious diseases. we define the korean reaction (which includes four major stakeholders) as a hospital infection control issue (figure ). the four stakeholders were either directly or indirectly involved in the outbreak of mers in korea. we argue that the nation has to transform its current reaction into an emergency management issue involving all stakeholders. hospitals mainly because of poor ventilation and ineffective disinfection in one hospital, mers viruses began to spread rapidly to patients, visitors, and even to healthcare workers. a few neighbouring hospitals also showed a similar pattern of nosocomial transmission. consequently, healthcare workers made all efforts to improve infection control or hygiene; however, this took time. therefore, hospitals became major stakeholders in preventing the loss of human lives. the korea centers for disease control and prevention (kcdc) under the ministry of health and welfare (mw) insisted on not sharing mers information from the hospitals with the public at the initial stage of the outbreak under the pretext of hospital protection, although in reality this decision may have been based on nepotism. further, the ministry of public safety and security (mpss), which is a single, comprehensive emergency management agency, did not implement any specific action to prevent the loss of human lives. thus far, only the kcdc has tried to improve preparedness against similar pandemics. some koreans were involved in manipulating the facts on the mers outbreak and then spreading rumours through the internet or mobile phones. further, given the korean culture, many people did not realize that it was not advisable for them to visit the infected patients in hospitals and share their drinks or foods. also, a few infected residents attempted to go to public places without permission from the government. however, the majority of residents considered the mers outbreak to be a national emergency and thus paid attention to its progress by exchanging relevant information. other stakeholders took steps to efficiently respond to the outbreak of mers. for instance, business establishments continued to operate but measured the body temperature of their customers and distributed hand sanitizers to them, which nonetheless constituted an incomplete preventive measure. mass media also attempted to trace and reveal the sources of rumours, in the process causing political conflicts. many schools temporarily cancelled classes, although unnecessarily, so that their students could stay at home. the military isolated infected soldiers in remote facilities, but this move came rather late. korea did not give all four stakeholders equal involvement in dealing with the mers outbreak. rather, one stakeholder e healthcare workers in hospitals e played multiple roles in controlling mers viruses. thus, the situation was perceived as almost entirely a hospital infection control issue. considering that the mers outbreak was not only a health issue but also an emergency management issue, the model for controlling similar epidemics or pandemics in the future-oriented model should involve all stakeholders in an early and co-ordinated response. emergency management consists of four phases: emergency prevention/mitigation (legalization, inspection, disease prediction, etc.), emergency preparedness (emergency operation planning, training, etc.), emergency response (infection control, health treatment, etc.), and emergency recovery (insurance, medical evaluation, etc.). appropriate roles and responsibilities in all the phases have to be assigned to each of the four stakeholders in advance. although many stakeholders tried to play their own roles during the mers outbreak in korea, their responses were somewhat late and unco-ordinated, and thus contributed to the national crisis. in fact, their specific roles and responsibilities should have been assigned before the mers outbreak. in this context, nations should implement regular training in and exercise of emergency management measures. pandemics, as a type of emergency, pose three kinds of risk: loss of human lives, economic damages, and psychological impact. in the case of the mers outbreak in korea, local government and hospitals were oriented toward decreasing the number of deaths, mainly because they regarded the outbreak as an infection control issue. they did not realize the need to address the economic damage or the psychological impact on the general population, especially at the initial response stage. without a co-ordinated response, the mers outbreak caused considerable economic damage in korea. almost nobody dared to visit shopping malls for fear of infection. further, because mers scared away foreign tourists, including many chinese and some japanese visitors, the tourism industry suffered considerably. thus, the national economy was significantly depressed, and the economic growth projection fell to about %. regarding the psychological impact, most people worried about catching mers and thus wore masks whenever they went out. similarly, many primary and middle schools throughout the peninsula cancelled classes to protect their students from mers, contrary to the recommendation of the world health organization. hospitals played a major role in reducing the loss of human lives during the mers outbreak; however, this does not mean that they have done extraordinary work. after pyeongtaek st mary's hospital failed to screen the first infected patient, mers viruses spread to many parts of korea. further, the samsung medical center in seoul refused to share mers information with the public, which made the situation worse. hence, hospitals need to be more professional in dealing with infection control, in particular by educating quarantine doctors and in following the hippocratic oath. the kcdc and mw will certainly remain the major government institutions that should take charge when a pandemic occurs in korea. however, the mpss must also become proactively involved during such an outbreak. thus far, the mpss officially considers only three types of hazard under its management scope: fires, floods that accompany typhoons, and maritime accidents. as a co-operative or co-ordinating institution in relation to all hazards, the mpss must therefore extend its activities to the kcdc, other departments, and local government, and apply countermeasures against new diseases. contrary to the expectation of the government, the level of emergency awareness of korean residents increased considerably during the mers outbreak, particularly as the death toll rose. these residents should now directly demand that the government and the whole nation take more systematic actions against new pandemics toward achieving efficient emergency management. the public must also be willing to challenge cultural practices, and in particular to co-operate with restrictions on visiting hospitals. other stakeholders, including business establishments, mass media, schools, and the military played their own roles in responding to the outbreak of mers within their areas. however, they should have approached the issue more seriously from the beginning of the emergency response instead of merely acting as outsiders in a national crisis. considering that a pandemic may spread quickly to anyone, these entities should join the major stakeholders from the initial response stage. the mers outbreak in korea in may to july caused the biggest loss of human lives due to the disease outside the middle east. thus far, however, the korean government has yet to comprehensively improve its national response against pandemics. the key tenet is that korea must not consider the mers outbreak to be a hospital infection control issue. rather, the nation must regard such an outbreak as an emergency management issue involving all stakeholders, particularly in fighting against new pandemics in the international community. middle east respiratory syndrome e advancing the public health and research agenda on mers e lessons from the south korean outbreak federal emergency management agency. introduction to continuity of operations planning for pandemic influenzas mers in south korea and china: a potential outbreak threat? what can we learn from mers outbreak in south korea? none declared. none. key: cord- -mwuix tv authors: inkster, t.; ferguson, k.; edwardson, a.; gunson, r.; soutar, r. title: consecutive yearly outbreaks of respiratory syncytial virus in a haemato-oncology ward and efficacy of infection control measures date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: mwuix tv background: respiratory syncytial virus (rsv) causes significant respiratory tract infection in immunosuppressed patients. aim: to describe two consecutive yearly outbreaks of rsv in our haemato-oncology ward. methods: haematology patients presenting with respiratory symptoms were screened by polymerase chain reaction for viral respiratory pathogens using a saline gargle. findings: none of our patients had undergone bone marrow transplant but all had underlying haematological malignancies. eight patients were affected in the first outbreak (mortality rate: . %) and patients were affected in the second (mortality rate: . %). extensive infection control measures were implemented in both outbreaks and were successful in preventing further cross-transmission. conclusion: there was significant learning from both outbreaks and actions implemented with the aim of reducing the likelihood and impact of future outbreaks. respiratory syncytial virus (rsv) is an important cause of viral lower respiratory tract infection in infants and children worldwide and is a significant pathogen in immunocompromised hosts. the incubation period of rsv is typically two to eight days [ ] . route of transmission is person to person via droplets or through direct/indirect contact with contaminated hands or surrounding environment. in patients with underlying haematological conditions rsv may lead to higher mortality and prolonged viral shedding [ ] . progression to lower respiratory tract infection is estimated to occur in % of patients who have had chemotherapy for leukaemia [ ] . prior to the last outbreak of rsv in haemato-oncology patients in our health board occurred in [ ] . we describe two consecutive winter outbreaks of rsv in a haematology ward occurring in december and again in december . both outbreaks took place on a -bedded haematooncology ward in the beatson west of scotland cancer centre (bwoscc). the unit opened in and is the uk's second largest centre for specialist, non-surgical oncology and scotland's largest. the haematology ward cares for patients with haematological malignancies. allogeneic bone marrow transplant patients are nursed in a neighbouring ward and were unaffected by these outbreaks. the ward layout comprises five single rooms with en suite, one double room with shared en suite and the remainder of the accommodation is provided in three four-bedded bays with shared en-suite rooms. it is standard practice in this ward to screen haematology patients presenting with respiratory symptoms for viral respiratory pathogens using a saline gargle. patients who are unwell are told to report directly to the haematology unit rather than attend the accident and emergency department. all samples were extracted on the siegen mix using the siam viral rna kit (siegen, crawley, uk). the samples were pre-lysed and ml of the sample extracted, and nucleic acid was eluted into ml. the case definitions employed were the same for both outbreaks and are listed in box . there is variation in the published literature regarding the definition of nosocomial rsv, the interval between hospital admission and symptom onset varying from two to eight days because of the length of the possible incubation period [ , ] . we applied the lower limit of two days in our outbreak policy, taking account of our high-risk patient group. in december three patients on the haematology ward with respiratory symptoms tested positive for rsv in a h period. each of the patients had an underlying haematological malignancy. at the time of initial laboratory referral and subsequent investigation by the infection prevention and control team (ipct), one patient case had been discharged home with two remaining on the ward. one of the two remaining patients, whose symptoms had resolved by the time of referral to the ipct, was being nursed in a four-bedded bay; the other had respiratory symptoms and was in a single side room with droplet and contact precautions in place. as there were three confirmed cases (two nosocomial) linked in time, place and person, an outbreak was declared and the ward closed to admissions/transfers. on the day of ward closure a fourth patient with respiratory symptoms tested positive for rsv and was isolated with precautions in place. an outbreak control team (oct) was established. the index case was community onset and had been admitted feeling unwell, complaining of cough and green spit, and with an unwell child at home. the patient improved and was discharged home prior to the positive sample result being reported. screening of all patients and staff on the ward by pcr on gargles took place over the course of the outbreak, which lasted nine days. in total eight patients and two healthcare workers tested positive for rsv. of the patients who tested positive for rsv three were asymptomatic. three of the patient cases who tested positive for rsv required treatment with antiviral (ribavirin) and immunoglobulin. three of the confirmed patient cases died over the course of the outbreak with rsv cited on death certification. although only two staff members tested positive for rsv, a total of seven staff reported symptoms over the course of the outbreak, and this, along with ward closure, led to service disruption in this highly specialist area. patient characteristics of this outbreak are listed in table i . the majority of patients were male (six out of eight). the average age was years (range: e ) and the mortality rate was . % (three of eight patients). a full list of infection control measures employed in both outbreaks is listed in box . precautions remained in place for patient cases until two negative viral gargle samples were achieved h apart. symptomatic staff were advised to remain off duty until h asymptomatic. a patient information leaflet was produced for distribution to all patients on the ward. over the course of the outbreak the ward was visited twice daily as a minimum by a member of the ipct and this allowed for observational audit of staff practice, including use of personal protective equipment and informal teaching. the ipct completed formal infection prevention and control audit, nosocomial rsv any patient with respiratory symptoms and a positive respiratory sample for rsv if patient was hospitalized two or more days before the onset of symptoms. confirmed case of rsv any patient or staff member with respiratory symptoms and a positive respiratory sample for rsv probable case of rsv any patient or staff member with respiratory symptoms asymptomatic carrier any patient or staff member in whom rsv was detected on screening in the absence of respiratory symptoms or fever measuring both standard and transmission-based infection control precautions at the time of ward reopening, and a training package was put in place for ward staff. the end of the outbreak was declared after nine days. in december the ipct was alerted to four patients testing positive for rsv on the haematology ward over a fiveday period. again these were nosocomial infections and linked in time, place, and person; therefore an outbreak was declared and an oct established. at the time of referral two patients had been sent home well and the other two cases, both of whom were symptomatic, were cohorted together in a four-bedded bay with the remaining two beds blocked. a fifth patient tested positive prior to the first outbreak meeting and was isolated in a single side-room with precautions in place. staff recalled a positive patient seven days previously who had been discharged home. this was also determined to be a nosocomial infection and it was likely that this patient was the index case, taking the total numbers at this point to six patients. screening of the remaining patients was undertaken and a further three cases were identified, all of whom were asymptomatic. during the course of the outbreak a further three symptomatic cases were detected, taking the total number of patients to . one patient died with rsv cited on death certification. one patient was treated with ribavirin and immunoglobulin and a further three patients were given infection control measures implemented for both outbreaks À ward closed to admissions/transfers. À isolation of symptomatic cases in single side-room or cohorted with other respiratory syncytial virus-positive patients. À increased environmental cleaning: twice daily with chlorine-based detergent (actichlorÔ plus). À cough etiquette emphasized. À use of personal protective equipment (gloves, aprons, surgical masks, visors) emphasized and adequate supplies obtained. À hand hygiene emphasized. À screening of all patients. À screening of all staff ( outbreak only). À restriction of patient and staff movement. À access to adjoining ward (bone marrow transplant) restricted and entry via alternative route agreed. À reduced visiting hours and visitor numbers (no more than two per patient). if possible no child visitors aged < years. media statements released which reinforced this. À symptomatic staff to refrain from duty until h symptom-free. À enhanced observation of the ward by the infection prevention and control team and education. À frequent meetings with infection control, clinical and management staff. À written communication, so all staff were aware of situation. À psychological and practical support to ward staff dealing with patients and relatives from infection control staff. immunoglobulin alone. the end of the outbreak was declared after days. no staff screening was undertaken but symptomatic staff were excluded from work. patient characteristics are displayed in table i . male patients were predominantly affected ( out of patients). the average age of patients was years (range: e ), and the mortality rate was . % (one out of patients). we describe two outbreaks of rsv in our haematology ward, which have occurred in the last two consecutive years during the month of december. all patients in both outbreaks had underlying haematological malignancies but none had had autologous or allogeneic bone marrow transplants. the outbreaks coincided with seasonal outbreaks of rsv in the community and increased admissions in the paediatric setting. from timelines that were created, and particularly during the december outbreak, there were opportunities for crosstransmission between patients in the same bed bays. however, this did not explain the full picture, as some rsvpositive patients had no contact with other positive cases (figures and ). our hypothesis for both outbreaks is that rsv was introduced from the community by a patient, a staff member or a relative and cross-transmission then occurred in the ward setting between patients themselves, and staff members with mild symptoms. this appeared to be the case in the first outbreak where the index case was admitted symptomatic from the community. this pattern has been demonstrated in other rsv outbreaks. jensen et al. described an rsv outbreak in haematology patients involving patients and one staff member. sequencing of the isolates was consistent with transmission occurring on the ward and introduction of rsv from the community [ ] . in a e outbreak involving haematology patients, investigations showed single introduction of the outbreak strain from the community; this strain subsequent spread among patients into the unit [ ] . in addition to direct contact with symptomatic patients or staff, asymptomatic patients and prolonged excretion may have contributed to continued transmission within the unit. viral shedding in this patient group is known to occur for several weeks after the resolution of symptoms, and has been reported to be seven to days in one study [ ] . in both outbreaks we detected asymptomatic patients on screening. we also noted patients who continued to be pcr positive following resolution of symptoms and who became positive again after having negative pcr results. both outbreaks were relatively short, so it was not possible to determine for how long patients were continuing to excrete the virus. whether these patients could shed virus in sufficient amounts to contribute to further transmission is unknown. outbreak investigators in the paediatric setting have detected asymptomatic patients and have postulated that these patients may shed rsv and cause onward transmission [ , ] . due to our high-risk population we employed patient screening to detect those who were asymptomatic in both outbreaks. further research investigating the efficacy of this measure is required. during a large outbreak of rsv in a german haematology unit, % of rsv patients had recurrent positive tests even after two consecutive negative pcr tests. this led the authors to conclude that it might be appropriate to treat patients as positive for their duration of stay [ ] . mortality rates in haemato-oncology patients as a result of rsv are high. the mortality rate in outbreak was higher at . %. average age in this outbreak was also higher at years, which might have been a factor in the mortality rate. a retrospective cohort study of adult patients attending the emergency department with rsv identified lower respiratory infection, chronic lung disease and bacterial co-infection as independent predictors of life-threatening infection [ ] . risk factor analysis specific to haematology patients is difficult due to small numbers but sharing a room with a positive patient was identified as a risk factor from one study [ ] . one of the larger studies examining risk factors involved haematology patients. hypogammaglobulinaemia was identified as a significant risk factor for morbidity and mortality and was not reversible by treatment with polyvalent immunoglobulin [ ] . preexisting lung disease was also thought to be a factor but the finding was not statistically significant [ ] . in haematopoietic cell transplant recipients with rsv, lymphopenia was associated with progression to lower respiratory disease [ ] . the majority of our patients in both outbreaks were noted to be lymphopenic (table i) although this is not a rare finding in this patient population. a range of infection control precautions were employed during both outbreaks. on both occasions the ward was closed to admissions in an attempt to control the outbreak, to prevent exposure of other haematology patients and to limit the reintroduction of virus from the community. the implementation of broad precautions applicable to the entire unit is recommended during rsv outbreaks in preference to those focusing only on specific patients [ ] . a recent systematic review of control measures implemented in rsv outbreaks supported the use of multi-component measures. these measures reduced the transmission risk by %. it was not possible, however, to assess the effects of individual components [ ] . in the first outbreak in several staff members exhibited symptoms compatible with rsv infection. screening was therefore undertaken for all groups of staff in the unit. two were positive, both of whom were displaying symptoms. staff screening was not performed in the second outbreak. fewer staff were symptomatic and our experience from the outbreak the preceding year was that only the symptomatic staff tested positive. similarly, in an outbreak of rsv in adult stem cell recipients asymptomatic healthcare workers were screened and all tested negative [ ] . had the outbreak control measures failed we would have proceeded with staff screening in . during both outbreaks healthcare workers with mild symptoms remained at work and this has been described by others [ ] . human resource policies in relation to sickness absence and concerns about ward staffing may mean that staff are reluctant to take time off when symptoms are mild. when caring for rsvpositive patients our staff wore surgical masks. implementation of a universal surgical mask policy, whereby all staff in direct contact with patients wore a mask, led to a significant reduction in respiratory viral illness in a haemopoeitic stem cell unit [ ] . prophylaxis in paediatric outbreaks of rsv is well described; however, studies into its use in adults are lacking [ ] . prophylactic administration of palivizumab was administered during a nosocomial outbreak involving five stem cell transplant patients in . sixteen patient contacts were designated high risk and administered prophylaxis with intravenous palivizumab, none of whom went on to develop rsv [ ] . further studies into the benefits of prophylaxis in this patient group are needed. given that the last outbreak of rsv in haematology patients in our health board was in we were surprised to experience two significant outbreaks two years in succession. although both outbreaks were relatively short-lived there was significant morbidity, mortality and disruption to our haematology service. a review of both outbreaks has been undertaken and a number of measures implemented as a result. rsv is highly transmissible and rapid detection in this susceptible patient group is essential. we are limited by accommodation with only five single rooms; in addition our virology laboratory is situated off site. near-patient testing done at ward level for rsv and other respiratory viruses has now been implemented. this will enable prompt detection and isolation or cohorting, depending on results. human resources have agreed that staff members who are excluded during a confirmed outbreak will not have the sickness absence recorded e it is hoped that this will encourage staff members to refrain from duty when symptomatic. an early warning trigger has been implemented to inform the ward and infection control team when rsv cases in the community start to increase. consideration is to be given to admitting haematology patients to other areas when presenting with respiratory symptoms, provided specialist haematology care is not required. our board rsv policy was reviewed and now includes specific information relevant to rsv outbreaks in adults; the previous emphasis had been on the paediatric setting where outbreaks are more frequent. a report was produced following each outbreak and provided summary information as well as recommendations including: staff education, local audits of hand hygiene, and standard infection control precautions. a full staff debrief was undertaken after the first outbreak as there was naturally staff anxiety both in relation to patient outcomes and as to whether staff had been implicated in the outbreak. haematology units should be alert to the possibility of rsv outbreaks, especially during periods of high incidence in the community. both outbreaks were relatively short-lived and the initial infection control measures implemented were effective in preventing further cross-transmission. infection control measures we felt were key in managing these outbreaks were: À ward closure À isolation/cohorting of positive patients À rapid exclusion of symptomatic staff À hand hygiene and personal protective equipment. infection control measures which may be useful but require further evaluation include: À isolation of positive patients for their duration of stay À screening to detect asymptomatic patients with subsequent isolation À universal application of surgical masks. respiratory syncytial virus outbreak on an adult stem cell transplant unit contributing and terminating factors of a large rsv outbreak in an adult haematology and transplant unit respiratory syncytial virus infection in patients with haematological diseases; single centre study and review of the literature control of an outbreak of respiratory syncytial virus infection in immunocompromised adults outbreak of respiratory syncytial virus in immunocompromised adults on a haematology ward molecular characterisation of a respiratory syncytial virus outbreak in a haematology unit in heidelberg respiratory syncytical virus infection in recipients of allogeneic stem cell transplantation: a retrospective study of the incidence, clinical features and outcome transmission of respiratory syncytial virus at the paediatric intensive care unit: a prospective study using real time pcr respiratory syncytial virus outbreak in neonatal intensive care unit: impact of infection control measures plus palivizumab use factors predicting life threatening infections with respiratory syncytial virus in adult patients risk factors and containment of respiratory syncytial virus outbreak in a haematology and transplant unit respiratory syncytical virus in hematopoietic cell transplant recipients;factors determining progression to lower respiratory tract disease risk of nosocomial respiratory syncytial virus infection and effectiveness of control measures to prevent transmission events: a systematic review universal mask usage for reduction of respiratory viral infections after stem cell transplant: a prospective trial detection and control of a nosocomial respiratory syncytial virus outbreak in a stem cell transplantation unit: the role of palivizumab we would like to thank all the nursing and medical staff in the haematology unit at the beatson oncology centre. none declared. none. key: cord- - qncy nd authors: khonyongwa, kirstin; taori, surabhi k.; soares, ana; desai, nergish; sudhanva, malur; bernal, william; schelenz, silke; curran, lisa a. title: incidence and outcomes of healthcare-associated covid- infections: significance of delayed diagnosis and correlation with staff absence date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: qncy nd background: the sudden increase in covid- admissions in hospitals during the sars-cov pandemic of led to onward transmissions among vulnerable inpatients. aims: this study was performed to evaluate the prevalence and clinical outcomes of healthcare-associated covid- infections (ha-covid- ) during the epidemic and study factors which may promote or correlate with its incidence and transmission in a teaching hospital nhs trust in london, england. methods: electronic laboratory, patient and staff self-reported sickness records were interrogated from (st) march to (th) april . ha-covid- was defined as covid- with symptom onset > days of admission. test performance of a single combined throat and nose swab (ctns) for patient placement was calculated. the effect of delayed rna positivity (drp, defined as > h delay), staff self-reported covid- sickness absence, hospital bed occupancy, and community incidence of covid- was compared for ha-covid- . the incidence of other significant hospital-acquired bacterial infections (hab) was compared to previous years. results: ha-covid- ( . %) cases were identified. when compared to community-acquired admitted cases (ca-covid- ), significant differences were observed in age (p= . ), ethnicity (p< . ) and comorbidity burden (p< . ) but not in d mortality. ctns negative predictive value was . %. drp was associated with greater mortality (p= . ) and incidence of ha-covid- correlated positively with drp (r= . ) and staff sickness absence (r= . ). for the study period hab rates were similar to previous years. conclusion: early diagnosis and isolation of covid- patients would help reduce transmission. a single ctns has limited value in segregating patients into positive and negative pathways. the covid- (sars-cov- ) outbreak started in china in late december and was declared a public health emergency of international concern on th january, . the first cases identified in the uk were in international travellers but local transmission was soon observed. london experienced the largest number of covid- cases in any uk region ( ) while a large part of the total burden of disease was in south-east london. to increase capacity for intensive care of severely ill covid- patients in our hospital, elective work was minimised. subsequently specific wards and intensive care units (icus) became cohort areas for affected patients and only non covid- emergency work continued. due to the high prevalence of infection during the peak of the outbreak, one of the suggested strategies to prevent healthcare transmission was to screen all patients on admission with a single combined nose and throat swab. this was assessed for sars-cov- rna to enable segregation into covid- positive and non covid- cohort wards. recent publications have identified advanced age, comorbidities and male gender as major risk factors for severity and mortality in covid- ( , ) and the impact of ethnicity is being explored ( ) . healthcare-associated covid- infections (ha-covid- ) have been reported in other studies ( ) but the literature on epidemiology, risk factors and outcomes of acquisition is lacking. this study was performed to determine the burden, risk factors and clinical outcomes of adult ha-covid- infections and evaluate factors which may correlate with the incidence and transmission of ha-covid- . factors studied included the utility of a single combined throat and nose swab (ctns) for patient placement, delayed rna positivity (drp), selfreported covid- sickness absence among hospital staff, total hospital bed occupancy, community incidence of covid- (cic ) and the change in incidence of other significant hospital-acquired bacterial infections (hab). setting: this study was conducted at the main site of a tertiary care teaching hospital in south-east london from st march to th april . before the covid- outbreak, the capacity was beds including adult intensive care beds. the hospital caters to a wide mix of specialities including haemato-oncology, liver transplantation, neurosciences, women's health, paediatrics, renal, respiratory and endocrinology and serves a socioeconomically deprived region of london. all patients who were sars-cov- rna positive from a respiratory sample and who were admitted to hospital for at least an overnight stay were included in the study. case definitions: j o u r n a l p r e -p r o o f covid- infection: either clinical or radiological evidence of pneumonia or acute respiratory distress syndrome, or influenza-like illness with fever ≥ . °c and acute onset of at least one of the following: persistent cough (with or without sputum), hoarseness, nasal discharge or congestion, shortness of breath, sore throat, wheezing, sneezing within the phe estimated incubation period (range to days, median days) ( , ) . community-associated covid- infection (ca-covid- ): . all symptoms on admission in keeping with above symptoms of covid- and . respiratory sample positive for sars-cov- rna at some point in their admission corresponding with the above symptoms infection prevention and control (ipc) measures: all patients suspected of having a respiratory illness compatible with covid- were triaged at the emergency department. if inpatient care was required, they were admitted to a ward designated as a holding area ( en-suite single rooms) while awaiting results of investigations. if a swab was sars-cov- rna positive, then they were kept in a side room with ipc precautions or in a designated covid- cohort ward/icu. if the swab was sars-cov- rna negative, they were placed with other non-covid- patients. local sars-cov- rna testing by real time pcr with mean turn-around time of hours was introduced on th february . this enabled rapid movement of patients from the holding area. when the requirement for beds with ventilator support increased, other areas of the hospital were repurposed to accommodate icu beds. negative pressure rooms were limited in the hospital and a risk assessment was done to reduce the impact of aerosols. a separate area for donning and doffing personal protective equipment (ppe) was established for each ward. when side room availability reached capacity, parts of the ward were created as cohort areas with bed spaces segregated from the other, curtains always to be closed, and where possible, allotted a separate toilet and dedicated nurse. there is a large variation in the design of each ward in the hospital. cohort areas were segregated by at least a passageway and the beds allocated to covid- patients clearly signposted as the cohort area. for the majority of the duration of the study, whole wards were either covid- cohort wards or non covid- wards. staff members were advised to wear ppe and ffp masks as appropriate. training and mask fit testing sessions were organised continuously from february . public health england (phe) guidance and updates were followed for all other aspects of infection prevention and control. cleaning of environmental surfaces and clinical equipment was implemented as per phe recommendations. curtains were changed if a non covid- patient was to be admitted to the bed space vacated by a covid- patient. when a ha-covid- case was identified, actions included staff refresher training for correct ppe usage, rapid transfer of patients to a covid- positive cohort ward, deep cleaning (washing walls and carpets) followed by increasing the cleaning frequency until no further transmission was seen (defined as no new symptom onset within weeks of last known case and in haematology and geriatrics a cnts was tested for sars-cov- rna twice weekly for all contacts up to weeks from last positive case regardless of symptoms). virological methods: a combined throat and nose swab (ctns) in vtm, or respiratory fluid such as bronchoalveolar lavage (bal), were assessed using rdrp gene for sars cov- rna. local interpretation of pcr curves was performed using pcr: ai machine-learning software clinical, laboratory and outcome data: sars-cov- rna results data was extracted from the laboratory information management system (winpath) and clinical and demographic details from electronic patient records (epr). age, gender and ethnicity (as black asian and minority ethnicities (bame) or non-bame), chronic kidney disease (ckd), hypertension, malignancy, dementia, chronic obstructive pulmonary disease (copd), diabetes and the charlson comorbidity index (cci-age adjusted) were noted. patients without electronic clinical records were excluded. patients were followed up for days. duration of hospital stay, readmission after discharge and , and d mortality were recorded. icu admission within days of covid- diagnosis was used as a marker for severe disease and a subset analysis was performed. test performance of single cnts: this was calculated to evaluate the efficiency of a single ctns on admission to segregate patients into positive and negative pathways. true positives were all cases fitting the definition of ca-covid- and positive on the first ctns (taken within h of admission), true negatives were patients with a negative ctns swab within h of admission and had a minimum follow up stay of days wherein they remained sars-cov- rna negative and /or did not develop symptoms of covid- . all positive pcr reactivity was reviewed by virologists before releasing the results to rule out contamination. if contamination was suspected samples were retested on a new pcr run and a repeat sample was requested. hence false positives were ruled out prior to result authorisation. false negatives were all cases fitting the definition of ca-covid- (and rna positive after h) but were negative on the first ctns (within h). delayed sars-cov- rna positivity (drp) was defined as: the outcomes of patients with drp were compared with those without a delay. source and incubation period of ha-covid- and late indeterminate cases: if an index case patient was found in the same ward as a ha-covid- case (within d prior) they were recorded as a potential source. duration of exposure of each ha-covid- case to a known positive patient was calculated and the incubation period was determined using the midpoint of the exposure period up to the development of symptoms and expressed as a range from the earliest and latest contact with the known positive. asymptomatic cases were excluded from this analysis. staff self-reported absence: the workforce development database (health-roster) was interrogated for staff absences due to : covid- , : cold, cough and flu-like illness, : chest and respiratory problems. this did not include those self-isolating or shielding as per uk government advice ( ) . absences due to and above from were evaluated for comparison. staff were grouped as per patient facing roles (g -nurses, doctors, additional clinical services and allied health professionals), non-patient facing, high nosocomial exposure risk (g -estates and ancillary, scientific and technical and healthcare scientists) and non-clinical (g -administrative and clerical) to compare association with healthcare contact. only one episode of sickness was recorded per day period for each staff member. staff members deployed to other roles were excluded. records for staff not directly employed by the hospital trust (e.g. porters and catering staff) were not available. hospital bed occupancy data, cic and hab : bed occupancy was derived from the business intelligence unit of the hospital and community incidence of covid- (cic ) was derived from national population data ( ) and department of health reports of covid- cases ( ). hab included bloodstream infections due to staphylococcus aureus (mrsa and mssa), escherichia coli, klebsiella spp, pseudomonas aeruginosa, and vancomycin-resistant enterococci and toxigenic clostridioides difficile infections detected after h of admission. the incidence for the duration of this study was compared to the average incidence from and during march, april and may. statistical methods: categorical variables were compared using chi square or fisher's exact test. continuous variables not normally distributed were presented as median with interquartile range and mann whitney u test used for significance testing. logistic regression was applied to explore risk factors associated with the outcomes and route of acquisition. to build the logistic regression model, forward selection was used and variables with p< . were entered in the model. results were not adjusted for bame, because of unevenly distributed missing data. likelihood ratio test was used to determine significant effect on the outcome after adjusting for the other variables in the model. kaplan meier plots were utilised to assess mortality. pearson test was used for correlations between ha-covid- and hospital bed occupancy, drp, cic and staff self-reported covid- sickness. all data was collated in excel and analysed in stata (version ). on th feb the first case of covid- was recorded in the hospital. subsequently, until th april, , approximately people were tested, of which tested positive ( figure ). of these, ( %) were admitted to hospital within d of testing for at least an overnight stay or already admitted to hospital at the time of testing. due to the possibility of multiple acquisition sites, patients who had a second hospital admission within d prior to testing (n= ) were excluded. patients < years of age (n= ) and those where no clinical data was available (n= ) were also excluded. full classification of covid- cases based on acquisition are described in figure . a total of ( . %) admitted covid- cases were classified as ca-covid- , ( . %) as ha-covid- and ( . %) as indeterminate. fifteen ( . %) patients were classed as asymptomatic ( sars-cov- rna positive h- days of admission, cases - days post admission and cases > d of admission). for ha-covid- , time from admission to symptom onset ranged from to days (median . and iqr - days). figure illustrates the primary reason for admission of ha-covid- and indeterminate cases. incidence of ha-covid- during this period was per , bed-days. during the study period patients who stayed as inpatients > days were classed as not having acquired covid- ( tested on an average . times , range: - ). tables a and b summarise the clinical features and outcomes of ca-and ha-covid- . overall, the ha-covid- population was more likely to be > years and have a cci ≥ , but less likely to be bame. diabetes, ckd, malignancy and a longer post-covid- length of stay (median d, p< . ) were common with ha-covid- but no overall difference in mortality was observed (table a and supplemental figure s ). risk factors were similar for the patients admitted to icu (supplement table s a and s b) and there were no statistically significant differences in any outcome measures. a drp was seen in patients (table a ). in cases the cause was delay in sampling and in cases samples was taken within h but sars-cov- rna was negative. for drp patients, age > , non bame ethnicity, diabetes and malignancy, cci> were more common as was d mortality (p= . ). this association remained significant in the multivariate model (table b) . cases ( %) were not isolated appropriately as a result of the negative rna test. for the ha-covid- patients, a potential source patient was found for cases and late indeterminate and asymptomatic late indeterminate (table ) . ca-covid- with drp was the largest single contributing group of ha-covid- and late indeterminate cases ( . %). figure s a shows the incidence of self-reported staff sickness from and and figure s b shows the self-reported covid- sickness absence for groups with high (g and g combined) and low (g ) risk of nosocomial exposure. bed occupancy varied during the study period as seen in figure s , with an early fall in bed occupancy reflecting the reduction of elective activity and expedited discharge of non-covid- patients in anticipation of increasing covid- admissions. correlation between weekly incidence of ha-covid- (including late indeterminate cases) and staff self-reported sickness absence, drp cases, cic and trust covid- bed occupancy is displayed in figure . significant correlation was observed with the former two but neither with covid- bed occupancy nor the incidence in the community. the incidence of hab during the study period was not significant when compared to the average of the previous two years ( figure s ). tables s -s provide risk factors and outcome analysis including for the indeterminate cases. table s provides additional outcome measures for drp associated cases. table s and figure s provide the estimated incubation period for ha-covid- patients. a recent survey from acute hospitals in the uk reported an average of approximately - % of patients with a positive covid- whose diagnosis was identified d after admission (inter-quartile range . % to %) (written communication). in our study . % were symptomatic ha-covid- and an additional . % were symptomatic late indeterminate cases. in addition, asymptomatic cases were identified after d and were identified - d from admission. we identified asymptomatic cases as part of contact screening in high transmission risk situations, but if outbreak management programmes include consistent testing of all asymptomatic contacts, potentially more cases would be identified. both in the overall analysis and in those admitted to icu, distinct differences in the risk factors between ca-covid- and ha-covid- were observed. the ha-covid- group was older with more comorbidities and may represent the population hospitalised at that time. however, the lower d mortality ( . % vs . %) and lower proportion admitted to icu ( . vs . %) may be because ca-covid- cases were only admitted to hospital if they were severe. overall d mortality appears similar between ca-covid- and ha-covid- . we also observed a trend in ca-covid- for more cases of bame origin ( . % vs . % p< . ) but since data were missing for patients, results are not conclusive. in our setting, the sensitivity of a single ctns taken within h to predict the potential to transmit sars-cov- was . % and the negative predictive value was . %. wang et al ( ) highlighted the variability in detection of the viral rna by pcr in different sample types with maximum positivity rate in bronchoalveolar lavage ( %), followed by sputum ( %) and nasal swabs ( %). in the present study, patients had a drp result in keeping with the recent report of kucirka et al ( ) who reviewed the variation in false negative sars-cov- rt pcr results from upper respiratory tract samples. they concluded that the probability of a falsenegative result in an infected person varied with days from symptom onset; the median false-negative rate varying from % (ci, % to %) on day of symptom onset to % (ci, % to %) days after symptom onset. since patients can present at any stage of the illness, we conclude one ctns is insufficient to prevent onward transmission, if the decision to segregate patients is based on this result alone. gao et al ( ) have described two nosocomial outbreaks in wuhan where the index was a misdiagnosed case of ca-covid- . our results also suggest that . % of all ha-covid- and late indeterminate infections could be traced back to cases where the acquisition was from a community case but an rna based diagnosis could not be made within h of admission ( table ). the weekly incidence of drp also correlated with the incidence of ha-covid- . among drp cases, co-morbidities (cci> ) were higher than in those without a delay ( . % vs . % p= . ) and may explain the difficulty in making a clear diagnosis in the presence of multiple clinical features. however, the higher d mortality (p= . ) (tables a and b) in this patient group emphasises the need to identify a more accurate method of ruling out covid- in the initial stages of presentation. a combination of detailed history taking, successive swabs, deeper respiratory sample and radiology and biochemical markers should be evaluated in the future to help determine the best strategy to reduce onward transmission in hospital settings. during feb-april , reported staff sickness due to cold, cough, flu and chest and respiratory problems decreased from the second week of the study probably due to the similarity of symptoms with covid- and the introduction of a new staff sickness code (s covid- , figure s a ). covid- sickness, on the other hand, increased in the first three weeks of the study and then started decreasing from week which coincides with the government introduction of community wide restriction on movement and closure of nonessential businesses. this finding is similar to the recent report by hunter et al ( ) which found an increase in staff positivity from to % from th to st march . they compared positivity rates amongst staff in patient-facing, non-patient facing and non-clinical roles and found no significant difference between these groups suggesting nosocomial transmission from patients to staff was not an important factor during the study period. however in their study, data on clinical roles were only available for / of included staff. our study compared staff self-reported covid- sickness rates between patient-facing high nosocomial risk and non-clinical staff and found the difference increased after social distancing was implemented. we hypothesize that working for home may be an easier option for non-patient-facing staff that may not need to take sickness leave even if mild symptoms are present. previous work has shown that healthcare staffing potentially influences the incidence of hais ( ) . in the present study, the incidence of ha-covid- correlated positively with healthcare staff absence due to covid- . the reasons for this correlation are likely to be multifactorial since the reduction in healthcare staff to patient ratios may have a negative influence on appropriate ipc measures, but may independently be a reason for sars-cov- transmission from infected healthcare staff to patients. dona et al ( ) recently discussed the potential impact of covid- on hospital transmission of mdr organisms, based on how risk factors such a healthcare absence, hospital overcrowding, ppe usage and patient demographics are distributed in a healthcare setting. in our study, the effect of the measures taken and the demographics did not have a significant impact on the rate of mdr healthcare-associated infections when compared to the average of the previous two years. our study does have some limitations. staff members were tested for sars-cov- via a regulated pathway from th march . prior to this, testing was on special request only and has not been included in this report. due to the high community prevalence at the time it was not possible to determine the source of the infection linked to staff members. recent reports suggest sars-cov- can be transmitted by asymptomatic carriers ( , ) . we have observed this in ha-covid- clusters but this study did not extend to include detection of asymptomatic infections. it is possible our ha-covid- rates are lower during this period because a large proportion of elective work had stopped which limited the number of susceptible patients in the hospital. cases with suspicion of covid- but with multiple rna negative samples were out of the scope of this analysis. this study shows that hospital transmission of covid- can be initiated by carriers who may not show symptoms, and could be admitted for other reasons. screening for asymptomatic or early infection on admission is one approach recently advocated to segregate covid- and non covid- patients. however the use of a single ctns for this purpose is limited. further work on appropriate use of resources in patient pathways to limit transmission is recommended. informatics coronavirus (covid- ) in the uk: crown copyright clinical course and risk factors for mortality of adult inpatients with covid- in wuhan, china: a retrospective cohort study risk factors for severity and mortality in adult covid- inpatients in wuhan the impact of ethnicity on clinical outcomes in covid- : a systematic review two outbreaks of sars-cov- in department of surgery in a wuhan hospital transmission characteristics and principles of infection prevention and control: public health england covid- : investigation and initial clinical management of possible cases. . . diagonostics.ai. covid- : diagostics.ai nhs. self-isolation if you or someone you live with has coronavirus symptoms ons. estimates of the population for the detection of sars-cov- in different types of clinical specimens variation in false-negative rate of reverse transcriptase polymerase chain reaction-based sars-cov- tests by time since exposure first experience of covid- screening of health-care workers in england nurse staffing and hospital-acquired conditions: a systematic review multidrug resistant infections in the covid- era, a framework for considering the potential impact protecting health-care workers from subclinical coronavirus infection epidemiological and clinical characteristics of asymptomatic sars-cov- carriers key: cord- - sn coni authors: singh, rajinder pal; safri, hardeep singh; singh, sukhdev; alg, gaggandeep singh; randhawa, gurch; gill, sukhpal singh title: bearded individuals can use an under-mask beard cover ‘singh thattha’ for donning respirator masks in covid- patient care date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: sn coni tight-fitting ffp facemasks are ideal respiratory protective equipment during aerosol generating procedures in covid- environment, and require a fit test (ft) to assess mask-face seal competency. facial hair is considered to be an impediment for achieving a competent seal. we are describing an under-mask beard cover called singh thattha technique which obtained a pass rate of / ( . %) by qualitative and / ( %) by quantitative ft in full-bearded individuals. sturdier versions of ffp were more effective. individuals for whom shaving is not possible, the singh thattha technique could offer an effective solution to safely don respirator masks. tight-fitting respirator facemasks such as n or ffp masks are considered to be the gold standard respiratory protective equipment (rpe) for healthcare workers (hcw) working in aerosol generating procedure (agp) environments involving covid- . optimal use of facemasks depends on their tight seal with the wearer's skin, assessed via rpe fit testing. prior to working in agp environments, hcws must undergo and pass the mandatory rpe fit test, which is conducted either as a qualitative fit test (qft) or a quantitative fit test (qnft). qft is based on subjective assessment of facemask seal competency by detection of a test agent, usually sensed as a bitter or sweet taste, or smell by the wearer. whereas qnft gives an objective measure of face fit, by providing a numerical measure of the seal competency. fit test is conducted by a certified fit tester, and passing it depends on type of respirator mask tested. in the event of shortage of successfully fit tested facemasks, hcws must undergo repeat fit testing with other types of available facemasks. evidence suggests that facial hair reduces tight-fitting respirator facemask efficacy with worsening protection with longer facial hair [ ] . conventional fit testing in the presence of facial hair has been shown to have a high test-failure rate [ , ] . hence, in line with the available evidence, facemask manufacturers' guidance for fit testing recommends wearers are clean-shaven to enable a good seal of ffp mask over their face covering the nose and the mouth. individuals unable to shave due to personal or religious reasons are recommended to utilise alternatives such as powered air purifying respirators (papr) [ ] . however, these alternatives are expensive, limited in supply and cumbersome to use [ ]. they do not allow for fitting of surgical loupes. dentists are unable to do the all the procedures in their repertoire. re-deployment to non-agp areas incur a loss of their skill-sets and need for retraining. junior doctors have their training impacted with concerns for inadequate and prolonged training. therefore, this option of an alternative ppe may not be ideal for some individuals affected by the above-mentioned factors. there is no evidence in literature to suggest why, instead of shaving, the facial hair factor cannot be overcome with an under-mask beard cover. the purpose of the study is to describe an innovative potential solution called 'singh thattha' technique, where we have used an under-mask beard cover to overcome the facial hair factor for wearing a respirator mask in bearded individuals. the technique of applying the under-mask beard cover to cover the beard over the chin and cheeks and tie the knot at the top of the head is called 'singh thattha' technique, and pioneered by a transplant surgeon in manchester. thattha is the colloquial term used for the beard cover used and the material used for the st case was fabric made of polyester-cotton blend. using this method the candidate 'passed' the bitrex qft qualitative fit test (macfarlan smith, edinburgh, uk) in one attempt wearing a m ffp mask. it was mentioned that the 'pass' was with a beard using a beard cover. the material was subsequently switched to a flat elastic rubber sheet (pilates & yoga elastic band©) for a better seal by the author (fig- a) . the knot on top of the head could be either over the turban ( b), or over the inner head cloth ( c) depending on which gave the best fit with the ffp mask. we are reporting the outcomes of the singh thattha technique tested by qft and qnft: a. singh thattha technique was adopted by male bearded sikh dentists in the uk who subjected themselves to bitrex qft conducted by certified fit testers to existing industry standards set by british safety industry federation. data was collected by the british sikh dentists association and submitted to us for analysis. b. the technique was further subjected to robust review with a reputed fit tester through a quantitative fit test (qnft) session in shrewsbury, uk. the qnft method used was 'ambient particle counting' using accufit s/n; protocol: indg ; pass level: . informed consent was obtained, and no participant was allergic to materials used. participants included male candidates from the bearded sikh community. the results are summarised in table . the all male candidates passed qnft using the singh thattha technique. the first candidates passed using m masks, with the knot of the under-mask thattha tied on the top of the head covered by a cloth (fig- c, c) . one of these candidates also passed using a m mask with an adhesive dual mural tape (dmt) in its upper inner lining, with the knot of the under-mask thattha tied directly over the turban. the other two male candidates used ffp stealth half masks and passed the qnft with the under-mask thattha tied directly over their turban (fig- b) . small numbers precluded a statistical analysis. the novel coronavirus known as sarscov- (covid- ) pandemic has resulted in a significant loss of lives and impacted resource utilisation [ ] . in line of their duty, healthcare workers (hcws) at forefront of the pandemic have suffered significant mortality. healthcare providers have come under intense scrutiny to ensure that adequate and appropriate personal protective equipment (ppe) is provided for front-line workers. tight-fitting respirator masks, which depend on a seal of the mask with the wearer's face, are considered as ideal protective rpe for hcws working in agp environment involving covid- . however, these are not suitable for bearded individuals as evidence has shown that beards will not allow for an optimal face-mask-face seal. therefore, bearded individuals who are unable to shave due to personal reasons have to rely on alternative rpe such as expensive and cumbersome paprs, which may not be ideally suited for the work or training for some of these individuals -notably dentists and surgeons. we are offering an innovative solution using an under-mask beard cover called singh thattha technique for overcoming the beard factor to enable bearded individuals to wear a respirator mask. the under-mask beard cover (singh thattha) technique to wear an ffp mask was pioneered in manchester. the technique was adopted and tested by a large number of bearded british sikh dentists ( / ) who passed the qft using certified fit testers. the technique was further tested using robust qnft in a pilot study and all / fully bearded men passed the fit test. the relatively sturdier masks such as m , stealth half mask p , jsp force p and gsv ellipse half mask p were best-suited to achieve a competent seal using the singh thattha technique. the beard-cover we used (pilates & yoga elastic band ©) is rubber material. during the fit test the different exercises used test that the silicone mask does not slip over the skin. in fact, the resistance of the rubber and silicone actually improved the fit in these exercises with the beard cover. facial skin may sweat, but the thattha material does not and is of an added advantage. whereas other determinants of face-fit such as face architecture and mask shapes may be irreversible factors governing outcome of the fit test, the beard factor could be overcome by an under-mask beard cover. this pilot study opens up possibilities for bearded hcws looking to safely wear a tight-fitting respirator mask for whom shaving may not be a viable option. in additional to cost-saving implications for healthcare providers, this solution minimises potential risk of re-deployment of some affected individuals who either have no access to alternative ppe, or if the available ones are not conducive to performing for their specific job-roles. whilst a limitation of this study remains small numbers of individuals tested using the under-beard cover technique, it provides encouraging results to pave way for larger scale studies to be conducted. the authors plan to conduct a follow up study with the singh thattha technique involving larger numbers of bearded individuals given that the preliminary reports are quite encouraging. to summarise, the final arbiter of face-mask fit is a fit test and not the difference in the nuances of the chemistry between the 'mask with face' versus the 'mask with beard cover. facial hair, albeit an accepted risk factor for facemask leakage, can be overcome by using an under-mask beard cover. bearded individuals who are unable to shave may have a new innovative technique to be able to wear respirator masks. . whilst a limitation of this study remains small numbers of individuals tested using the under-beard cover technique, it provides encouraging results to pave way for larger scale studies to be conducted. the authors plan to conduct a follow up study with the singh thattha technique involving larger numbers of bearded individuals given that the preliminary reports are quite encouraging. public health england document: guidance covid- personal protective equipment (ppe) the effect of wearer stubble on the protection given by filtering facepieces class (ffo ) and half masks. hse three of the authors were participants in the study. one of the authors is president of sikh doctors and dentists association which funded the study, but author has no financial interest to declare. key: cord- -kig xnkb authors: donà, daniele; di chiara, costanza; sharland, mike title: multidrug resistant infections in the covid- era, a framework for considering the potential impact date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: kig xnkb nan the recent report by jolivet et al highlights the progress being made on multidrug-resistant (mdr) infections [ ] . however, this report predates the covid- pandemic and it is unclear what the impact will be on mdr infections globally. there are reports of a high use of broad-spectrum antibiotics in the hospital setting, recognised as a risk factor for hospital-acquired infections (hai) with mdr organisms [ ] [ ] [ ] . recent data have also pointed to significant rates of hospital-acquired pneumonia (hap) [ ] . high rates of admission, shortages of staff and personal protective equipment (ppe) and high acuity patients with prolonged lengths of stay in overcrowded facilities may also impact on rates of hai with mdr pathogens [ , ] . moreover, severe covid- , which particularly affects elderly patients with multiple comorbidities, may be an important factor in determining changes of colonization pressure [ ] [ ] [ ] . equally, wider recognition of the importance of nosocomial infections, with stricter hygiene policies, high use of ppe, and patients being cared for in new temporary hospitals, could all mitigate against this threat [ , ] . we have tried to summarise in table i the potential relative impact of these various factors to provide a conceptual framework for determining the overall impact [ ] [ ] [ ] [ ] [ ] . novel cost-effective surveillance programmes of mdr hai in both high-and low/middle-income countries will be even more important in the post covid- era, combined with enhanced stewardship interventions. these need to be planned for now, to facilitate future integration with any future pandemic surveillance. this research did not receive any specific grant from funding agencies in the public, commercial, or not-forprofit sectors. [ ] [ ] [ ] lower rates of admission to hospital from long term care facilities may lead to less transmission cycles between long term care facilities and hospitals [ ] [ ] [ ] impact of colonisation pressure on acquisition of extendedspectrum β-lactamase-producing enterobacteriaceae and meticillin-resistant staphylococcus aureus in two intensive care units: a -year retrospective surveillance clinical course and risk factors for mortality of adult inpatients with covid- in wuhan, china: a retrospective cohort study intensive care management of coronavirus disease (covid- ): challenges and recommendations. the lancet. respiratory medicine management of multidrug-resistant organisms in health care settings critical care response to a hospital outbreak of the -ncov infection in shenzhen bed occupancy rates and hospital-acquired infections--should beds be kept empty key: cord- -ihpden q authors: glasbey, t.; whiteley, g. title: observations on disinfectant performance date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: ihpden q nan one of the cornerstones for infection control must be adequate disinfection of environmental surfaces, particulary high touch surfaces. this becomes even more important during a pandemic such as the one we are all currently experiencing. in the recent review article 'persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents' [ ] , the authors claim that "data obtained with benzalkonium chloride at reasonable contact times were conflicting. within a min a concentration of . % revealed no efficacy, whereas a concentration of . % was quite effective". in the case of benzalkonium chloride, the reference cited for the demonstration of no efficacy dated from . in that paper [ ] , a disinfectant solution having an active ingredient concentration of . % appeared to show no efficacy against the enveloped human coronavirus, whereas it showed remarkable activity (> . log reduction) against a non-enveloped coxsackie virus. a second study cited by the authors, this time dating from , showed a > . log reduction of coronavirus in minutes, used a . % solution of a pharmacopeial grade of benzalkonium chloride (i.e. not a formulated disinfectant product) [ ] . in another paper cited by the authors, a more contemporary formulated benzalkonium chloride disinfectant, when tested at a . % concentration, gave a > . log reduction of coronavirus in minutes in both clean and dirty conditions [ ] . unfortunately, this data failed to be included, whereas the test results obtained from various ethanol-based hand rubs from the same reference were included in this kampf et al., review. the use of quaternary ammonium-based disinfectants to deactivate sars-cov- has been recommended by several jurisdictions. for example, the united states epa has provided a list of suitable disinfectant products on their list n. [ ] as of th april , this list contains recommended products, of which ( %) are products containing only quaternary ammonium active ingredients, with a further products listed containing quaternary ammonium salts formulated with at least one other class of active ingredient. by way of comparison, only products containing sodium hypochlorite as their active ingredient are listed, along with only products listing ethanol as their raw ingredient. it is acknowledged that many of the products on list n will not have direct test data against the sars-cov- virus, but each product on the list has been shown to be effective against either human coronavirus or non-enveloped viruses, which are recognised as being more resistant to disinfection than enveloped viruses (of which sars-cov- is an example). [ ] in the case of citations of the age under question we note considerable reservations. disinfectant products in most modern health systems are required to perform to minimum standards of performance on statutory test methods that have been agreed through robust peer review. these statutory testing regimes then take over from peer review as the achievements are no longer regarded as novel. this does not mean that these products do not work sufficiently, and reference to raw material alone becomes an obsolete consideration in terms of predictable performance against the test protocols. we are deeply concerned that the selective quotation of material from the underlying references provides a reader with what amounts to a biased view of the material. the paper by kampf et al., [ ] appears to move the reader to an intended product grouping rather than allowing the data to provide the essential information required for a scientifically bases conclusion. finally, we would like to address the apparent lack of peer review for this review article, which was accepted for publication on the same day it was received. whilst in a pandemic situation such as that which we find ourselves in currently, timely publication of relevant material is to be welcomed. however, if that material is drawing conclusions on disinfectant efficacy based on a very narrow dataset, peer review must surely form an essential part of the publication process. persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents the action of three antiseptics/disinfectants against enveloped and non-enveloped viruses virucidal efficacy of physico-chemical treatments against coronaviruses and parvoviruses of laboratory animals efficacy of various disinfectants against sars coronavirus epa list n: disinfectants for use against sars-cov- principles of viral control and transmission both authors are employees of whiteley corporation, a manufacturer of cleaning products and disinfectants. key: cord- -flb wwzg authors: garcía, inés suárez; lópez, maría josé martínez de aramayona; vicente, alberto sáez; abascal, paloma lobo title: sars-cov- infection among healthcare workers in a hospital in madrid, spain date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: flb wwzg aim: the aim of this study was to describe the epidemiological and clinical characteristics of covid- among healthcare workers (hcws) between february (th) to april (th), in a hospital in madrid, spain. methods: we designed a retrospective cohort study. cumulative covid- incidence was calculated for all hcws and categorized according to presumed level of covid- exposure (high, medium and low). results: among , hcw, ( . %) had covid- during the study period. cases increased gradually from march (th), peaking in march (th) and declining thereafter. the peak of cases among hcws was reached days before the peak in admitted covid- cases in the hospital. there were no significant differences in the proportion of covid- cases according to level of occupational exposure (p= . ). there were departments and professions in which more than % of the workers had confirmed covid- . we identified temporal clusters in three of these departments and one profession, with most of the cases occurring over a period of less than days. the prevalence of comorbidities was low and . % of patients had mild or moderate symptoms. eleven patients were admitted to the hospital and patient needed intensive care. none of the patients died. the median time of sick leave was (iqr: – ) days. conclusions: our results suggest that hcw-to-hcw transmission accounted for part of the cases. in spite of a low prevalence of comorbidities and a mild clinical course in most cases, covid- caused long periods of sick leave. the virus sars-cov- is the causal agent of the acute respiratory tract infection known as covid- ( ) . it is estimated that by may th , covid- had caused , , infections and , deaths( ). the first covid- case was declared in spain in january st, ( ) and since then, spain has been one of the most affected countries by the pandemic ( ) . healthcare workers (hcws) are especially vulnerable to infection by sars-cov- . in the first published series of patients from wuhan, china, % of the cases were hcws( ). the proportion of hcws was much lower ( . %) in a later case series from china including , covid- cases ( ) . in spain, % of all the covid- cases have been among hcws ( ) , and in italy, % of responding hcws were infected ( ) . very few studies have focused on sars-cov- infection among hcws. moreover, the scarce data available to date have focused on the proportion of hcws infected but have not sufficiently described epidemiological and clinical characteristics of the affected workers. there are important implications of covid- among hcws. firstly, there are consequences for their health: in the previously mentioned series from china, . % of the cases among hcws were classified as severe or critical and of the patients died ( ) . secondly, infected hcws could also transmit the infection to vulnerable patients if they are not properly and timeously isolated. thirdly, high rates of infection among hcws could cause problems due to understaffing in the health system. lastly, the workers may transmit the infection to close family contacts ( ) , other hcw ( ) , and the community. due to the important implications of covid- among hcws, and the lack of detailed information published about this issue, it is important to better characterize its epidemiology and clinical characteristics in order to inform decision-makers on appropriate prevention and management strategies. therefore, we designed a retrospective cohort study whose aim was to describe the epidemiological and clinical characteristics of sars-cov- infection among hcws in a hospital in madrid, spain. the study was performed in hospital universitario infanta sofía, a public tertiary hospital in madrid, spain. all hcws that were working in the hospital between february th to april th were included. workers from the laboratory, radiology department, security services, maintenance services, kitchen facilities, cleaning workers and porters were also excluded as they are contracted by external companies and are not employed by the hospital. variables and data collection all data were gathered retrospectively. the number of hcws according to their profession and department for the study period was obtained from the human resources department. data for covid- cases were extracted from the clinical records of the occupational health department and recorded in an anonymized database. during the study period, hcws experiencing symptoms consistent with probable covid- were instructed to present at the occupational health outpatient clinic, where they were managed according to the hospital protocol: a nasopharyngeal swab was collected and analysed with polymerase chain reaction (pcr) for sars-cov- . for symptomatic hcws with negative pcr, this test was repeated after - hours if symptoms persisted. according to the hospital protocol, hcws with positive sars-cov- pcr remained on sick leave until a negative follow-up pcr was obtained. follow-up pcrs among patients with a previous positive pcr were obtained between day and after symptom resolution and repeated thereafter until a negative pcr result was obtained. workers were allowed to return to work when they fulfilled two criteria: symptoms had resolved, and they had a negative follow-up pcr. a case of covid- was defined as any hcw presenting to the occupational health outpatient clinic with symptoms consistent with covid- and with positive sars-cov- pcr. the date of the case was defined as the date of presentation to the occupational health outpatient clinic. the following variables were obtained from the clinical records: age, sex, profession (head of department [i.e., a physician in charge of a medical or surgical department], physician, nurse supervisor, nurse/auxiliary nurse, other), department, date of presentation at the outpatient clinic, date of symptom onset, duration of sick leave, admission to hospital, presence of comorbidities (arterial hypertension, diabetes mellitus, current tobacco consumption, cardiovascular disease, and chronic obstructive bronchopulmonary disease or asthma). nine patients had no information on the day of symptom onset: for these patients, the date of symptom onset was assumed to be the date of presentation to the outpatient clinic. clinical course was divided in the following categories: mild symptoms (including myalgia, ageusia, anosmia, headache, sore throat, cough, or temperature < o c, plus no need to stay in bed), moderate symptoms (including fever ≥ o c, or need to stay in bed, with or without any of the mild symptoms), and unilateral or bilateral infiltrates in chest x-ray. hcws were stratified in three categories according to their presumed level of occupational exposure to covid- cases: high risk (hcws with usual contact with covid- patients: accident and emergency, internal medicine, intensive care, and pneumology departments), moderate risk (hcws with occasional contact with covid- patients: other medical and surgical departments not included in the high or low risk groups) and low risk (including administrative workers, social workers, hospital management, and pharmacy, pathology, and preventive medicine departments). for nurses working in the hospital wards and haemodialysis unit, the department was not available and therefore they were included in a separate category for the purpose of risk of occupational exposure. in addition to these variables, information was collected about the training in covid- prevention, and use of personal protection equipment (ppe,) in the hospital during the study period. total numbers of notified covid- confirmed by pcr were obtained from the madrid autonomous region website ( ) . statistical analysis covid- cumulative incidence during the study period was calculated for all hcw, stratified by presumed level of occupational exposure, and stratified by department and profession. for departments and professions with more than hcws, of which more than % were diagnosed with covid- , date of presentation was analysed in detail to detect possible transmission clusters. descriptive analyses were carried out using frequency distributions or median and interquartile range (iqr), as appropriate. the proportions of hcw acquiring covid- among the three categories according to risk of occupational exposure were compared with χ test. statistical analyses were carried out with stata version . (stata corporation, college station, tx, usa). the study was approved by the ethics committee of hospital universitario "la paz" (pi- ). informed consent was not required. by april th , , there were , hcws in our hospital that fulfilled inclusion criteria. among these, presented to the occupational health outpatient clinic with symptoms consistent with covid- and were tested with at least one pcr during the study period. a total of workers, which account for . % of all hcws included, had microbiological confirmation of covid- . median age was (iqr: - ) years, and cases ( . %) were women. figures a and b show the number of confirmed cases among hcws per day, along with the number of patients admitted in the hospital with covid- (figure a) and the total number of cases notified in the madrid autonomous region (figure b) during the study period. the first case among hcws was diagnosed in march th and cases increased gradually, reaching a peak in march th and declining thereafter. the peak of cases among hcw was reached days before the peak in admitted covid- cases in the hospital, which occurred on march st (figure a), and days before the peak in the notified cases in the madrid autonomous region, which occurred in march th (figure b). as expected, cases among hcws very rarely presented during weekends. the median delay between the date of symptom onset and the date of presentation to the outpatient clinic was (iqr: - ) days. the first date of symptom onset was february th and then increased gradually, reaching a peak on march th and gradually declining thereafter. the proportion of cases among hcws according to level of occupational exposure is shown in table i. there were no significant differences in the proportion of covid- cases according to level of occupational exposure (high, medium, or low) (p= . ). there were departments of more than hcws in which more than % of the workers had confirmed covid- : dermatology ( the proportion of cases according to profession are shown in table ii. there were professions in which more than % of the workers had confirmed covid- : medical heads of department ( . % with covid- ) and nurse supervisors ( . %). the number of cases according to date of presentation for the departments and professions in which more than % of the hcws had covid- are shown in figures a and b, respectively. the cases in the oncology, dermatology and neurology departments seemed to be clustered in time, with all cases presenting in a period of and days in the oncology and dermatology departments, and out of cases presenting in a period of days in the neurology department. according to work category, there also seemed to be a temporal cluster among heads of department, with out cases presenting over a period of days (figures a and b ). regarding comorbidities, workers ( . %) had arterial hypertension, ( . %) had asthma or chronic obstructive bronchopulmonary disease, ( . %) were active smokers, ( . %) had cardiovascular disease, and worker had diabetes mellitus. regarding the clinical course, ( . %) had mild symptoms, ( . %) had moderate symptoms, ( . %) had unilateral lung infiltrates in chest x-ray, and ( . %) had bilateral lung infiltrates. in addition, patients with unilateral lung infiltrates also had thromboembolic disease: patient had deep venous thrombosis and the other had pulmonary embolism. the majority of cases were managed in their home, but cases ( . %) needed admission to the hospital for a median of (iqr: - ) days. one of the patients with bilateral pneumonia needed icu admission and orotracheal intubation because of severe respiratory failure. none of the patients died. among the workers, were still on sick leave at the end of the study period. the median time of sick leave among the hcws who had returned to work was (iqr: - ) days. after symptom resolution, the median number of pcrs performed per hcw was (iqr: - ), and the median time to obtain a negative pcr result (and therefore to allow the hcw to return to work) was days (iqr: - ). training in infection control practices and use of ppe was provided by the occupational health department from february th to march th for the intensive care unit, hospitalization wards, surgical rooms, daycare hospital, obstetric ward, nurse supervisors, and the internal medicine, anaesthesia, general surgery and emergency departments. in addition one training session was provided in the pharmacy department on april nd . there were a total of training sessions involving a total of ( . %) hcws. this study has analysed the epidemiology of sars-cov- infection among hcws in a public hospital in spain during the height of the covid- epidemic. we found that . % of the hcw had microbiologically confirmed covid- . the peak of cases preceded the peak of admitted patients with covid- , with a lag of weeks. the risk of covid- did not differ significantly among three groups with different levels of occupational exposure to covid- patients, and a few clusters were detected in specific departments and professions: these facts suggest that a considerable proportion of the transmissions occurred from hcw-to-hcw, rather than from patient-to-hcw. infected workers had low prevalence of comorbidities and the clinical course was mild in most cases; in spite of this, covid- caused long periods of sick leave. the sources of hcw infection include patients with covid- , other hcws, and the community. during the covid- pandemic several reports have identified factors increasing the risk of patient-to-hcw exposure, mainly excessive workload( ), shortage of personal protection equipment (ppe), lack of training in infection control measures, or use of ppe that does not fulfil safety requirements ( , ) . also, hcws can become infected outside their workplace if there is ongoing transmission in the community( ) (community-to-hcw). however, it has been pointed out that there is potential for transmission between hcw (hcwto-hcw), with potential occasions such as clinical meetings, clinical handovers, lunchbreaks and shared use of small work spaces ( ) . nevertheless, the transmission of covid- between workers has not been sufficiently studied: we are only aware of a study in singapore that identified a cluster of intrahospital hcw-to-hcw transmission ( ) , and an anecdotal recent report from newspapers that described an outbreak in madrid, where hcws acquired covid- after a lunch that took place in a hospital with over participants, who were not wearing masks during the event ( ) . in our study, the fact that cases peaked well before the peak in admitted covid- patients and the peak of diagnosed cases in the community, the lack of differences on the risk of infection among groups with different levels of exposure to covid- , and the identification of several temporal clusters among certain groups suggest that transmission among hcws account for part of the cases. it is possible that several hcws became infected during the first days (either from undiagnosed covid- cases in the hospital, or from the community) and then in turn transmitted the infection to other hcws. three departments (oncology, dermatology and neurology) had most of the cases diagnosed in a short period of time, suggesting transmission in shared facilities or clinical meetings. there was also a temporal cluster among the heads of department, and a high proportion of the nurse supervisors affected, although the latter were not temporally related. these two groups were having daily meetings every day and also doing daily night shifts, and it is possible that there had been transmissions during the meetings or through fomites in the staff rooms or the emergency phone. in our hospital, workers were instructed to wear adequate ppe when contacting patients with confirmed or suspected covid- . however, at the time of the study the use of face masks was neither recommended by health authorities for the general population (their compulsory use was only instituted for public transport on may rd ( ) and closed spaces on may th ( )) nor specifically recommended for hcws that were not having contact with patients( ). during the period of february th to march th , training about covid- transmission and ppe was provided to hcws by the occupational health department. however, the training focused on the contact with covid- patients and did not specifically recommend wearing face masks when not interacting with patients. until approximately march th to th , hcws did not systematically wear face masks when being in contact with other hcws in the hospital facilities. after noting an increase in cases, most departments started systematically wearing face masks at all times in the hospital; shared meals during the night shifts were stopped, instructing workers to keep a distance of at least metres in the refectory; and ward rooms were disinfected on march th and th . we cannot precisely determine the influence of these measures on covid- transmission in the hospital, but we presume that they were effective since the cases in hcws started declining after march th despite an increasing number of patients admitted to the hospital with covid- . it is unlikely that a better training on the use of ppe could explain the decrease in cases among hcws, as this training was not continued after march th (except for one additional session in the pharmacy department on april nd ). the prevalence of comorbidities was low and the clinical course was mild in most of the cases; our hcw were in general healthier and had a less severe clinical course than the series published in the general population ( , ) and can probably be explained by a healthy worker effect, along as a younger age. also, the spanish ministry of health recommended that hcws with vulnerability to covid- complications (such as hcws aged over years, pregnant women, and those with certain comorbidities) who could not be relocated to avoid covid- exposure should be preventively kept away from work ( ): this was the case for hcws in our hospital. nevertheless, some cases did experience severe complications such as bilateral pneumonia, thromboembolic disease or severe respiratory failure. in addition, cases had to stay away from work for a long time, for a median time of days; this long sick leave, along with the workers preventively kept away from work, in a time of increasing healthcare demands due to the pandemic can have important effects due to understaffing, which entails an increase in workload and can produce additional stress on the already overworked staff that remains in the hospital( ). our study has two main limitations. first, we did not systematically test all the hcws in the hospital, but we limited our tests to symptomatic hcw presenting to the occupational health outpatient clinic. thus, we could have missed a proportion of workers with asymptomatic infection. second, the only available diagnostic test during the study period was sars-cov- pcr in nasopharyngeal swabs, which can have false negatives even in symptomatic cases: a recent review found a sensitivity of % (ci %: - ) ( ) . therefore, our study has probably underestimated the percentage of affected hcws. during the covid- pandemic health services had the challenge of ensuring sufficient ppes and that these were adjusted to quality standards. spanish health institutions had difficulties in providing adequate ppe to all healthcare workers during these times and we cannot exclude that some transmissions could be attributed to lack of adequate ppes or their suboptimal use. however, our results suggest that hcw-to-hcw transmission accounted for at least part of the covid- cases found in our hospital: this is a transmission route that is rarely mentioned in other studies ( ) . we believe that this possibility should be further explored in other settings, and suggest preventive measures such as the systematic use of face masks at all times in the workplace, ensuring adequate working spaces to avoid overcrowding, and keeping a safety distance in meetings, clinical handouts, and work meals that could reduce the transmission of covid- in healthcare settings. also, surveillance of potential clusters could potentially be useful for contact tracing and prompt identification of transmissions ( ) . in this study in a public hospital in spain, . % of the hcws had symptoms consistent with covid- and microbiological confirmation of infection. the facts that cases among hcws peaked weeks before the peak of admitted patients, that the risk of covid- was similar among three groups with different levels of occupational exposure, and that several temporal clusters were detected in specific departments and professions, suggest that hcw-to-hcw transmission accounted for part of the cases. in spite of a low prevalence of comorbidities and a mild clinical course in most cases, severe complications were diagnosed in some hcws and covid- caused long periods of sick leave. hospitalized patients with novel coronavirus-infected pneumonia in wuhan, china world health organization. coronavirus disease . situation report- euro surveillance : bulletin europeen sur les maladies transmissibles = european communicable disease bulletin characteristics of and important lessons from the coronavirus disease (covid- ) outbreak in china: summary of a report of cases from the chinese center for disease control and prevention informe sobre la situación de covid- en personal sanitario en españa covid- : protecting health-care workers asymptomatic sars-cov- infection in household contacts of a healthcare provider containment of covid- cases among healthcare workers: the role of surveillance, early detection, and outbreak management comunidad de madrid. informe diario de situación covid- risk factors of healthcare workers with clinical infectious diseases : an official publication of the infectious diseases society of america covid- : a new work-related disease threatening healthcare workers covid- : the daunting experience of healthcare workers in sardinia rapid assessment of regional sars-cov- community transmission through a convenience sample of healthcare workers, the netherlands beyond the assistance: additional exposure situations to covid- for healthcare workers. the journal of hospital infection un almuerzo de despedida celebrado en el gregorio marañón causa un brote de coronavirus en el hospital orden tma/ / , de de mayo, por la que se dictan instrucciones sobre la utilización de mascarillas en los distintos medios de transporte y se fijan requisitos para garantizar una movilidad segura de conformidad con el plan para la transición hacia una nueva normalidad orden snd/ / , de de mayo, por la que se regulan las condiciones para el uso obligatorio de mascarilla durante la situación de crisis sanitaria ocasionada por el covid- procedimiento de actuación para los servicios de prevención de riesgos laborales frente a la exposición al nuevo coronavirus (sars-cov- ). de marzo de procedimiento de actuación para los servicios de prevención de riesgos laborales frente a la exposición al sars-cov- . de marzo de infectious diseases society of america guidelines on the diagnosis of covid- we thank all the nurses, physicians and occupational risk prevention technicians that took care of the hcws in the occupational health outpatient clinic during the study. all authors declare that they have no conflict of interest. this study was not funded. isg asked the research question, designed the study, analysed the data and wrote the first draft of the paper. mjm gathered the data. as gathered the data. pla designed the study and gathered the data. all authors were involved in interpretation of the data and commented on interim drafts. all authors have read and approved the final version of the article. key: cord- -ltej wvo authors: nakamura, itaru; watanabe, hidehiro; itoi, takao title: protective barrier box to mitigate exposure to airborne virus particles with minimum personal protective equipment when obtaining nasal pcr samples date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: ltej wvo nan can be minimized to a gown, nonsterile gloves, and a medical mask, and only glove exchange is thought to be necessary to perform nasal sampling on the next patient. although contamination after use was indicated as a disadvantage of the aerosol box , this pcr box designed to be easily cleaned by wiping with a disinfectant after sampling. in preparation for the next epidemic, we must develop these types of protective devices, which can reduce the exposure risks and reduce the need for ppe. how to obtain a nasopharyngeal swab specimen barrier enclosure during endotracheal intubation more on barrier enclosure during endotracheal intubation no financial support was provided relevant to this article. the authors declare no conflict of interest key: cord- -fez jyn authors: colaneri, marta; seminari, elena; piralla, antonio; zuccaro, valentina; filippo, alessandro di; baldanti, fausto; bruno, raffaele; mondelli, mario u. title: lack of sars-cov- rna environmental contamination in a tertiary referral hospital for infectious diseases in northern italy. date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: fez jyn nan the world health organization defined coronavirus disease (covid- ) as the disease caused by severe acute respiratory syndrome coronavirus (sars-cov- ), a betacoronavirus belonging to the same subgenus as the severe acute respiratory syndrome coronavirus (sars-cov). human coronaviruses (hcovs) spread in a similar fashion as rhinoviruses, by direct contact with infected secretions or large aerosol droplets [ ] . health care workers are at increased risk of acquiring covid- infection, possibly due to direct contact with the patients. indeed, transmission of hcovs through environmental contamination has been reported in healthcare settings [ ] . understanding which are the potentially contaminated surfaces in a healthcare environment is crucial to protect healthcare workers from this virus showing an unprecedented exponential trend with a doubling time of . - . days [ ] . in this regard, studies suggest that surfaces and suspensions can carry hcovs, increasing the risk of contact transmission that could lead to hospital acquired hcovs infections [ , ] since february , , when the first autochthonous case in italy was confirmed, an overwhelming number of sars-cov- infections is continuously being detected, exceeding , cases at the time of writing. fondazione irccs policlinico san matteo, pavia, is a , -bed tertiary teaching hospital in northern italy and a national sars-cov- referral center. the hospital houses icu beds and infectious diseases (id) beds, the latter being distributed in two floors. in the id ward, each room has a buffer zone to allow safe donning and disposal of ppe. healthcare workers involved in the direct care of patients use the following ppe: liquid-repelling gowns, double gloves, a class filtering face-piece respirator (ffp ) and eye protection (goggles or face shield). cleaning procedures have been standardized [ ], in particular ward surfaces are cleaned with sodium hypochloride at the concentration of , ppm of free chlorine ( . %) daily and , ppm of free chlorine ( . %) in terminal sanitization. from february to , cases of sars-cov- were identified by the virology laboratory, and those with interstitial pneumonia were admitted. samples were collected on th february; by that day % of admitted patients were covid- positive with pneumonia, and were treated with c-pap or high flux oxygen. surfaces in areas considered virus free were swabbed to search for covid- rna. table indicates which surfaces and objects were subjected to swabbing and fig. stability and inactivation of sars coronavirus environmental contamination and viral shedding in mers patients during mers-cov outbreak in south korea early phylogenetic estimate of the effective reproduction number of sars-cov- survival of human coronaviruses e and oc in suspension and after drying on surfaces: a possible source of hospital-acquired infections human coronavirus e remains infectious on common touch surface materials transmission of sars and mers coronaviruses and influenza virus in healthcare settings: the possible role of dry surface contamination we thank nurses for collaboration. key: cord- -ukqux authors: curtis, l.t. title: prevention of hospital-acquired infections: review of non-pharmacological interventions date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: ukqux hospital-acquired (nosocomial) infections (hais) increase morbidity, mortality and medical costs. in the usa alone, nosocomial infections cause about . million infections and deaths per year. hais are spread by numerous routes including surfaces (especially hands), air, water, intravenous routes, oral routes and through surgery. interventions such as proper hand and surface cleaning, better nutrition, sufficient numbers of nurses, better ventilator management, use of coated urinary and central venous catheters and use of high-efficiency particulate air (hepa) filters have all been associated with significantly lower nosocomial infection rates. multiple infection control techniques and strategies simultaneously (‘bundling’) may offer the best opportunity to reduce the morbidity and mortality toll of hais. most of these infection control strategies will more than pay for themselves by saving the medical costs associated with nosocomial infections. many non-pharmacological interventions to prevent many hais will also reduce the need for long or multiple-drug antibiotic courses for patients. lower antibiotic drug usage will reduce risk of antibiotic-resistant organisms and should improve efficacy of antibiotics given to patients who do acquire infections. much of the recent research on nosocomial infections has dealt with the need for new antibiotics, better antibiotic management and better diagnostic techniques to detect infections earlier. better drug treatment and earlier infection diagnosis can certainly play a major role in reducing morbidity and mortality from hospital-acquired infections (hais). however, there are many nonpharmacological interventions that can significantly reduce the incidence of hais, but these are often overlooked in practice. this review is not exhaustive and will not attempt mathematical data analysis but will examine recent research that examines non-pharmacological interventions for reducing hais. it will also include a brief description of the morbidity, mortality and medical costs associated with nosocomial infections, along with a brief discussion of the routes by which hais spread. a bibliographic search between january and january was conducted in databases including pubmed, medline and google scholar. additional research articles were collected from conference proceedings, books and pre- journal articles as appropriate. many terms were used in the literature searches including nosocomial, hospital acquired, mrsa (meticillin-resistant staphylococcus aureus), staphyloccoccus, streptococcus, vre (vancomycinresistant enterococcus), clostridium difficile, legionella, klebsiella, tuberculosis, airborne infection, waterborne infection, hand washing, hospital cleaning, urinary catheters, central catheters, haemodialysis, ultraviolet light, hepa (high-efficiency particulate air) filtration and many others. a total of articles was included in this review. care was taken to see that a balanced representation of articles was presented. hais cause a huge amount of morbidity and mortality. klevens et al. used data from the national nosocomial infections surveillance (nnis) system, and data from the national hospital discharge survey and the american hospital association survey to estimate nosocomial morbidity and mortality. this study estimated that there were nosocomial infections in the usa in , of which were due to urinary tract infections, to surgical site infections, to pneumonia, to bloodstream infections and to other causes. it is difficult to obtain a precise estimate of deaths from nosocomial infections since patients often die from several causes and infection is often not mentioned on death certificates of patients who die of a combination of a chronic illness (such as cancer) and acute infection(s). estimated annual deaths in the usa due to hais in was . in , an estimated died in the usa of mrsa infections, of which most were nosocomial. a study of consecutive deaths in a spanish -bed tertiary care hospital reported that . % of the deaths of patients which occurred more than h after admission were due to nosocomial infections. while it has been long known that hais are very expensive to treat, cost estimates of nosocomial infections vary. a us study of admissions in us hospitals from to estimated that each nosocomial infection increased medical costs by $ , . a french study reported that hospital-acquired sepsis increased medical costs by a mean of v , . various studies have estimated that the average cost of ventilator associated nosocomial pneumonia from us$ , to $ , per case. , hospital-acquired bacteraemia has been estimated to increase medical costs in a belgian study by an average of v , and in a michigan study by $ , . , a british study reported that the average increased medical cost for each central venous catheter infection was £ , . traditionally, it has been believed that most nosocomial infections, with a few exceptions such as tuberculosis and aspergillus and viruses like respiratory syncytial virus (rsv), influenza, rhinoviruses and coronaviruses, are not spread through the air. while a large percentage of hais are spread through surface contact (such as hands) or by catheters, intravenous (iv) lines or surgical incisions, many nosocomial infections can also spread through the air. it was previously believed that most pathogenic bacteria could not survive as bioaerosols and spread significant distances to infect patients. however, many airborne pathogenic bacteria are viable but not culturable, and some experts have estimated that as little as % of viable bacteria are culturable by standard microbiological techniques. , for example, heidelberg et al. reported that viable counts of serratia marcescens, klebsiella planticola and cytophaga allerginae in -hour-old bioaerosols were, respectively, , and % of the original counts even though none of the bacteria was culturable on tryptic soy agar plates. many pathogens present on sneezes evaporate in less than a second into small droplet nuclei of about mm diameter. , such small droplet nuclei can remain suspended for hours and travel long distances before settling. a number of studies have reported airborne transmission of many pathogenic bacteria to humans including mrsa, coagulase-negative staphylococci, corynbacterium diphtheriae, neisseria meningitidis, bordetella pertussis, acinetobacter and pseudomonas. e a mouse study reported two strains of klebsiella pneumoniae which could infect and multiply in mouse lungs after airborne exposure. therefore it may be concluded that while many nosocomial bacterial infections are spread by contact or by iv routes, the airborne route is also an important source of many hais. pathogens from hospital water are another underappreciated and underdiagnosed source of hospital infection. , over published studies employing both epidemiology and molecular biology techniques [such as polymerase chain reaction (pcr) and dna probes] have confirmed that contaminated hospital water sources can cause nosocomial outbreaks from many pathogens including legionella, mycobacteria, pseudomonas, stenotrophomonas, serratia, acinetobacter, aeronomas and moulds such as fusarium, aspergillus and exophialia. , hospital water can also be contaminated with amoebae and viruses. it is estimated that waterborne nosocomial pseudomonas infections kill annually in the usa. legionella is found in many hospital water systems and can persist for years. viable legionella were found in the water systems of of ( %) us hospitals and of ( %) spanish hospitals. , environmental pulsed-field gel electrophoresis studies have confirmed that specific legionella strains can persist for as long as years in hospital water supplies. viable pathogens can grow in many sources of hospital water including drinking water, hand-washing water, ice, dialysis water, shower water, water in storage tanks and distribution systems, water from decorative pools/fountains, and carpets, furniture, ventilation ducts and building materials that have become wet. contaminated environmental surfaces (such as bedside rails) are also an under-recognised source of hospital infections. many surfaces in hospitals contain viable pathogens such as mrsa and vre. in rooms of patients with diarrhoea, viable mrsa has been collected from % of the room surfaces and viable vre has been collected from % of room surfaces. , many strains of mrsa and vre can remain viable for several weeks to several months on dry surfaces. , infections can also be spread to hospitalised patients via drugs, intravenous solutions, cleaning solutions or by foodstuffs. a review of hais obtained via contaminated substances reported that the most commonly involved items were disinfection materials (n ¼ patients), heparin solutions (n ¼ ), red blood cells, clotting factors and other blood products (n ¼ ), albuterol inhalers (n ¼ ), total parenteral nutrition (n ¼ ), propofol (n ¼ ), rantidine (n ¼ ) and ultrasound gel (n ¼ ). the remaining part of the results section will concentrate on research on interventions to reduce hais. table i gives a summary of nonpharmacological interventions that have either been proven to reduce nosocomial infections or some level of evidence suggests may be effective. hand washing, gloving, gowning and personal items frequent and adequate hand washing is the best way to prevent spread of most nosocomial infections. the extreme importance of hand washing has been known since at least , when dr ignaz semmelweis discovered that washing hands before performing obstetric exams on pregnant women reduced childbirth-related infectious mortality from more than % to less than %. however, rates of hand washing among healthcare providers usually range from only about to % per hospital patient encounter, although some studies have reported hand-washing rates as high as %. e viable pathogens are often found on hands of healthcare providers. various studies have reported the following pathogens on the respective percentage of healthcare providers' hands: acinetobacter spp. e %, clostridium difficile e %, klebsiella spp. %, mrsa up to . %, pseudomonas spp. . e %, rotavirus . e . %, vre to % and yeasts (including candida) e %. most studies have reported that increases in hand-washing rates significantly reduce rates of hais including mrsa although a few studies have reported negative results. , e alcohol-based hand-washing solutions are generally considered to be more effective than soap and water. compared with plain soap and water, some studies have reported significantly lower rates of nosocomial infections when alcohol-based solutions or chlorhexidine-or triclosan-based hand-washing agents are used. , , , an australian hospital study noted a hand hygiene programme that switched from soap to a chlorhexidine/isopropyl alcohol solution reduced mrsa bacteraemia by % (p ¼ . ) and reduced clinical isolates of lactamase-resistant e. coli and klebsiella by % (p < . ). some studies have also reported that the economic savings that alcohol or chlorhexidine hand-washing solutions provide by reducing nosocomial infections will far more than pay for the cost of the hand-washing solutions. , it is estimated that hand washing with plain soap for s removes most soil and dirt, eliminates about % of transient hand flora but a low percentage of resident hand flora. hand washing for s with a soap containing chlorhexidine or triclosan removes most soil and dirt and about . % of transient flora and about % of resident flora. hand rubbing for s with an alcohol-based gel does not remove soil or dirt, but kills about . % of transient flora and about % of resident flora. many healthcare providers prefer using alcoholbased solutions instead of soap and water, and compliance rates are generally higher when alcohol-based hand-washing solutions are used. use of alcohol-based cleaners saves time and these generally abrade and irritate the skin less than antiseptic soaps. however, some people complain that alcohol-based cleaners dry out and crack their skin. hospitals and healthcare providers may want to experiment with several alcohol or chlorhexidine-based hand cleaners. soap and water may still have to be used in cases when hands are visibly soiled. in that case, staff and visitors should wash hands carefully for at least s with soap and water. table ii lists six abridged 'golden rules' to improve hand hygiene compliance proposed by dr gunter kampf. in , the us centers for disease control and prevention (cdc) published new guidelines for hand hygiene. major changes of these guidelines over the guidelines included use of waterless alcohol-based cleaners (unless hands are visibly soiled), prohibition of artificial fingernails and an institutional mandate to provide staff education and develop a multidisciplinary programme to monitor compliance. to measure effectiveness of these new cdc guidelines, an anonymous survey of staff in hospitals was made after the new guidelines had been in force for a year. this survey found that mean hand-washing rates were only . %, and % of the hospitals had no multidisciplinary programme to improve compliance. it is not certain what type of glove provides the best protection for infection control. some studies have suggested that latex gloves are somewhat better in preventing penetration of water and virus than vinyl gloves. however, about e % of healthcare workers are sensitive to latex and sometimes experience severe respiratory reactions to it. if latex gloves are used in the healthcare setting, only the powder-free gloves should be used since these release much lower levels of latex allergens than the powdered latex gloves. nitrile gloves also have good barrier penetration but are more expensive and heavier than either latex or vinyl gloves. gowns are often used in rooms of patients with infectious disease. data on gown use and nosocomial prevention are sparse. one study reported that use of disposable gowns in an intensive care unit (icu) was associated with a % reduction in vre (p < . ). gown use in this study also produced an annual net benefit of $ , in the icu by averting an estimated vre cases. another study reported that use of gowns was associated with a modest and insignificant drop in mrsa cases. rates of gown usage by healthcare providers and staff are generally mediocre, with one study reporting mean gown usage in rooms of patients with contact precautions was only % for healthcare providers and % for visitors. shoe and head covers are often recommended for use in areas containing immunocompromised or surgical patients. although bacterial pathogens have been collected from shoes, research on the use of shoe covers and/or separate hospital shoes and spread of pathogens has been meagre. one study reported that wearing gowns and shoe covers in bone marrow surgery did not significantly reduce patient infection risk (as measured by antibiotic therapy). an experimental laboratory study involving sham surgery reported significantly lower levels of airborne bacteria when headgear was worn versus no headgear. various studies have reported that nosocomial pathogens are present on many items of healthcare providers such as laboratory coats, stethoscopes, blood pressure cuffs, ekg electrodes, pens, finger rings, neck ties, artificial nails and ambulances. e to prevent spread of nosocomial infections, these items should be disinfected or cleaned regularly. disposable one-use electrodes even a small number of nosocomial infections prevented will outweigh the cost of effective hand hygiene products. . encourage senior staff to set a good example to motivate junior staff. . have adequate staff:patient ratios. are now available. sometimes, pieces of equipment such as stethoscopes or blood pressure cuffs are dedicated to one patient only in order to limit spread of pathogens. proper cleaning techniques and proper cleaning chemicals can also significantly reduce hospital pathogen levels and risk of nosocomial infections. one study utilised a fluorescent marker solution to determine cleaning efficacy of surfaces found in patient care rooms of us hospitals. terminal room cleaning after patient discharge was able to adequately clean only a mean of % of the standardised surfaces, including less than % for toilet hand holds, bedpan cleaners, room door knobs and bathroom light switches. carling et al. recommended that hospitals monitor performance of cleaning personnel and provide feedback and training as needed to optimise cleaning effectiveness. several studies have reported that hospital cleaning personnel often receive little initial training and, after receiving instruction, often do a much better job of eliminating pathogens by their cleaning. , an illinois prospective study reported that following a cleaning educational programme, average rates of cleaning icu surfaces rose from to %. rates of vre infection were reduced by % [ % confidence interval (ci): . e . ]. a british retrospective icu study reported that significantly higher rates of mrsa infection were associated with inadequate surface cleaning and nurse understaffing. research on chemicals used to clean non-porous surfaces (such as floors, walls, tables etc.) in hospitals and their effects on reducing nosocomial infection has been sparse. in a literature review, no randomised controlled trials and only four cohort studies could be identified. three studies detected no significant differences between nosocomial infection rates when comparing surface cleaning with aldehydes, quaternary ammonium compounds, active oxygen cleaners or ortho-benzyl para-chlorophenol compared with plain detergent solutions. the fourth study reported that use of : hypochlorite (bleach) solution was associated with a significantly lower rate of c. difficile infection in bone marrow patients compared with cleaning with quaternary ammonium compounds. another study of rooms which housed vre-positive patients found that ( %) of the rooms' surfaces contained viable vre before cleaning, but ( %) had viable vre after thorough cleaning with a % bleach solution (p < . ). hydrogen peroxide vapour may be used to decontaminate rooms containing pathogens. a british study compared manual cleaning of rooms (via a protocol compliant with uk standards) with a h protocol using min of ppm hydrogen peroxide vapour to decontaminate rooms. in surgical ward rooms, % of swab samples were positive for viable mrsa before manual cleaning, and % of matched swabs were still positive for viable mrsa after cleaning. by comparison, in six other surgical rooms, viable mrsa was found on % of swabs before hydrogen peroxide treatment, but on only % of matched swabs following hydrogen peroxide treatment. during the hydrogen peroxide disinfection, hydrogen peroxide levels in adjacent rooms were no greater than ppm at head height. more study is needed on the safety and efficacy of this hydrogen peroxide vapour technology. research is currently underway to use copperoxide-impregnated textiles and paints in order to prevent spread of infections. better nutrition can also play a critical role in reducing nosocomial infections. malnutrition is very common in hospitalised patients. a review of published studies in acute care patients reported that malnutrition ranged from to % of all hospitalised patients and e % of hospitalised elderly. malnutrition was measured by such parameters as weight, weight loss, body mass index, grip strength, respiratory function, nutritional intake and blood levels of albumin, and prealbumin. many nutrients play a key role in maintaining immunity including protein, omega- fatty acids, vitamins a, b , b , c, d, and e; selenium, zinc, copper and iron. most of these nutrients become depleted following acute illness. malnutrition is a major risk factor for infection. a study of hospitalised patients reported that the odds ratio risk of hais was . times as great ( % ci: . e . ) in severely malnourished patients compared with adequately nourished patients. other studies have reported that malnourished elderly are significantly more likely to acquire nosocomial infections and are significantly more likely to acquire pneumonia compared with well-nourished elderly. , better nutrition may play a major role in reducing nosocomial infection in acutely ill hospital patients who cannot eat by the regular oral route. in recent years, 'immunonutrition' enteral formulas containing larger quantities of antioxidant vitamins, zinc and other trace metals, omega- fatty acids and amino acids like glutamine have become more commonly used. meta-analysis has calculated that enteral immunonutrition in hospitalised patients is associated with a % lower risk of nosocomial pneumonia ( studies, p ¼ . ), a % lower risk of bacteraemia (nine studies, p ¼ . ), a % lower risk of abdominal abscesses (six studies, p ¼ . ), and a % lower risk of urinary tract infections ( studies, p ¼ . ) compared with patients receiving standard enteral formula. many hospitalised patients develop serious c. difficile infections after several antibiotic courses. probiotic bacteria and yeasts can be helpful in preventing or clearing infections by c. difficile and other bacteria. meta-analysis of studies reported that supplemental saccharomyces boulardii, lactobacillus spp. or bifidobacterium spp. were associated with significantly lower levels of antibiotic-associated diarrhoea. meta-analysis of six studies indicated that s. boulardii was effective in reducing the incidence of c. difficile diarrhoea. yoghurt containing active lactobacillus spp. has been found to be effective in preventing or clearing infections caused by c. difficile and vre in hospitalised patients. , housing patients in separate rooms, pathogen surveillance and 'search and destroy' strategies for nosocomial infections housing patients in separate rooms may reduce risk of hais. a quebec observational study of a bed icu measured rates of nosocomial infections during a . -year period. the incidence of nosocomial mrsa, pseudomonas and candida infections per patient-days were respectively . , . , . for patients housed in multiple patient icu rooms and . , . , . for patients housed in single rooms (p < . for all three comparisons). however, another study conducted in two british icus reported that isolating patients had little effect on mrsa acquisition rates. screening patients at hospital admission for common pathogens like s. aureus may be an effective way to prevent the pathogens from becoming established infections. a recent study estimated the health and economic impacts of preadmission s. aureus screening and subsequent decolonisation therapy for the . million us patients who undergo elective surgery annually. an s. aureus screening and decolonisation protocol for all elective surgical patients was projected to save inpatient lives and save $ million in net medical costs annually. for some nosocomial infections such as mrsa, 'search and destroy' control strategies have been developed. such search and destroy protocols involve a number of interventions including: (i) active surveillance which includes a nasal swab for mrsa cultures upon patient admission and every third day throughout hospitalisation. (ii) contact precautions including proper gloving, gowning and mask use. (iii) treatment of carriers with antibiotics and surface disinfectants. (iv) microbiological controls: starting h after the end of treatment three control samples were taken at colonised sites. if mrsa was isolated, treatment was resumed. (v) isolation or cohorting: mrsa positive patients were placed in separate rooms or cohorted with other patients with mrsa infection. (vi) educational programme on infection controls for healthcare workers. such a search and destroy mrsa programme was found to reduce mrsa infection in a spanish icu from . to . cases per patient-days (p ¼ . ). the netherlands has been addressing the mrsa problem since the s with a programme of patient isolation, search and destroy protocols and restrictive antibiotic usage. , by , mrsa comprised less than % of clinical s. aureus specimens collected in netherlands hospitals, while mrsa comprised %, %, % and % of clinical s. aureus cultures respectively in belgium, france, germany and the usa. molecular biology techniques such as pcr and gel electrophoresis techniques have been very useful in hospital surveillance and tracking of nosocomial infections. such techniques can be used to test samples from patients, staff and environmental substrates. implementation of an enhanced infection control programme which included molecular typing to assess microbial clonality was associated with an % reduction of nosocomial infections in a large hospital (p ¼ . ). this infection control programme was calculated to annually prevent nosocomial infections and save us$ . million in net healthcare costs. inadequate nurse staffing may increase risk for nosocomial infections. a us study of patients in icu units served by nurses measured rates of nosocomial infections and nurse staffing levels. icu units with higher nurse staffing had significantly lower rates of centralline-associated infections, ventilator-associated pneumonia, ducibitus ulcers and day mortality (p < . for all comparsions). a -month study from a -bed taiwanese hospital reported that higher nursing staff levels were associated with significantly lower levels of urinary tract infections (p < . ), respiratory infections (p ¼ . ) and pressure ulcers (p ¼ . ). public reporting of hais may provide a good incentive for hospitals to reduce nosocomial infection rates. in the usa, since , a number of states have passed laws mandating reporting of hai rates. there is some concern that such reporting of infections may undercount the true nosocomial infection rates. there is also concern about the need for proper adjustment of infection rates for factors such as age, chronic health problems and preadmission health of the patients received by specific hospitals. many administrative problems have beset these mandating laws. for example, the state of illinois passed the 'hospital report card act' (sb ) in mandating public reporting of several types of nosocomial infections. however, by january none of the reporting systems had been implemented. about e % of hospital-acquired urinary tract infections originate from urinary catheters. urinary catheters should be used only if necessary and should be removed as soon as practicable. , some studies have indicated that early removal of urinary catheters can reduce urinary tract infection rates by up to %. about % of urinary hais have been linked to improper handwashing and poor aseptic techniques in cleaning the urinary meatus area and inserting and maintaining the urinary catheters. however, studies have shown that vigorous twice-daily meatal cleaning does not seem to reduce urinary infection rates. many studies and meta-analyses have reported that silver alloy/silver hydrogel-tipped urinary catheters significantly reduce urinary tract infections. a meta-analysis of eight published studies reported that use of silver-tipped urinary catheters was associated with a mean % reduction of urinary tract infections ( % ci: . e . ). a more recent study reported that using silver-tipped catheters (both short-and long-term users) was associated with a % reduction in urinary tract infections. none of the bacteria and yeasts isolated from these silver-tipped catheters developed any resistance to silver. these studies have also indicated that while silver-tipped urinary catheters cost more than standard catheters, the saving in nosocomial urinary infections far more than pays for the extra cost of the silver-tipped catheters. , however, according to meta-analysis of urinary catheters inserted for less than days, post- studies have reported that silver-tipped catheters reduce urinary tract infections by a smaller margin than in pre- studies. the reason for this possible reduced effectiveness of silver-tipped catheters after is not known. the use of nitrofurazone-coated catheters was associated with a e % reduction in urinary tract infections in three recent published studies. a number of interventions can significantly reduce the morbidity and mortality of central venous catheter (cvc)-related infections. cvcs should be used only when necessary and should be removed as soon as practical, since longer catheterisation periods significantly increase risk for bloodstream infection. three studies reported that the use of extensive barrier precautions (long-sleeved gown, sterile gloves, mask, cap and large sterile sheet drape) when inserting a central line was associated with a significantly lower rate of bloodstream infections compared with when only gloves and a small drape were used. these studies also found that extensive barrier precautions were very cost-effective in terms of saving costs of nosocomial infections. other studies have reported that subclavian central venous insertion is associated with significantly lower bloodstream infection rates compared with femoral insertion. meta-analysis of eight studies reported that use of antiseptic chlorhexidine-containing solutions to prepare the catheter site was associated with a % lower risk of catheterrelated bloodstream infections compared with when iodine based solutions were used ( % ci: . e . ). the institution of multiple interventions at the same time ('bundling') may be the best strategy to reduce cvc-related infections. a huge study of catheter-related bloodstream infections was conducted in icus and analysed patientcatheter-days. an education programme was conducted in icus that included hand washing, using extensive barrier precautions when inserting a cvc, cleaning skin with chlorhexidine, and avoiding the femoral site and the use of unnecessary catheters. catheter-related bloodstream infections were . / catheter-days at baseline to . / at e months follow-up ( % reduction, p < . ). another study reported that a multidimensional educational programme for central catheter insertion and maintenance reduced bloodstream infections from . to . / catheter-days ( % reduction, p < . ) and produced a net saving of from $ . to . million in months secondary to reduced bloodstream infection rates. the use of coated cvcs can also significantly reduce the risk of nosocomial infections. a twoyear study at a large michigan hospital reported that using chlorhexidine/silver sulfadiazene-coated catheters reduced bloodstream infections in hospitalised patients by % (p < . ). metaanalyses and many studies have reported that the use of cvcs coated with chlorhexidine/silver sulfadiazene significantly reduces rates of catheterrelated infections and significantly lowers hospital costs. cost savings were estimated to be $ for each chlorhexidine/silver sulfadiazene-coated catheter used. use of new agents such as lysostaphin in catheters and catheter lock solutions may also reduce infection. lysostaphin is an enzyme which effectively breaks up and kills staphylococci in biofilms on catheters. haemodialysis patients are at high risk of many nosocomial infections including s. aureus, coagulasenegative staphylococci, many types of gramnegative bacteria and candida. temporary catheters have the greatest risk of infection and should not be used any longer than necessary. a review of eight studies calculated that mean rates of bacterial infections in haemodialysis patients were about . / days when temporary catheters were used, . / days with cuffed temporary catheters, . / days with polytetrafluoroethylene grafts, and . / days when arteriovenous fistulas are used. renal patients are at significant risk for hepatitis c (hcv) transmission from haemodialysis procedures. risk of hcv transmission can be significantly reduced by using separate haemodialysis machines and equipment for hcv þ and hcv À patients, proper gloving and other barrier precautions by healthcare workers, proper cleaning of machines and sending all tubing and dialysis units for either disposal or disinfection and reprocessing after each use. a spanish study reported that hcv þ prevalence fell from . % ( patients) in to . % ( patients) (p < . ) in following the institution of universal precautions and increased cleaning along with the separation of hcv þ and hcv À patients. no serconversions were noted during this time in hcv À haemodialysis patients following separation of hcv þ and hcv À haemodialysis. preventing ventilator-associated pneumonia although prompt use of proper antibiotics is the cornerstone for treating ventilator-associated pneumonia (vap), there are many non-pharmacological interventions which can significantly reduce risk of vap incidence. longstanding methods of reducing risk of vap include: (i) avoiding tracheal intubation whenever possible and using noninvasive positive pressure ventilation instead; (ii) placing the patient in semi-erect position of e above horizontal reduces risk of aspiration-related vap; and (iii) using enteral feeding rather than parenteral feeding whenever possible. recent meta-analysis has also indicated that the following interventions are associated with significantly lower levels of vap: (i) kinetic bed therapy ( studies; rr: . ; % ci: . e . ); (ii) subglottic secretion drainage (five studies; rr: . ; % ci: . e . ); (iii) heat and moisture exchangers vs heated humidifiers (eight studies; rr: . ; % ci: . e . ); (iv) oral decontamination with chlorhexidine (seven studies; rr: . ; % ci: . e . ). five studies employing multiple interventions were able to significantly reduce rates of vap by e %. one of these studies involved four hospitals and employed an intensive educational programme for icu nurses and respiratory therapists coupled with posters and fact sheets posted in the icu. following these broad based interventions, vap rates fell from . to . / ventilator-days ( % reduction, p < . ). about e % of all surgical patients develop a significant infection at the wound site. while antibiotics play a major role in preventing and treating surgical infections, many other factors are important in preventing surgical infections. higher rates of surgical infections are associated with operations of two or more hours, a contaminated or dirty procedure, or inadequate scrubbing procedures. traditionally patients have been shaved at surgical sites, but it is now believed that clipping hair is better since shaving leaves small cuts in the skin. a review of three trials involving surgical patients reported that there were significantly more surgical site infections when patients were shaved versus clipped (rr: . ; % ci: . e . ). cleaning surgical sites with antiseptics such as iodine compounds or chlorhexidine has long been recommended to reduce risk of surgical infection. however, meta-analysis of six studies found that bathing or swabbing sites with % chlorhexidine solutions was associated with only a marginal decline in surgical site infection rates compared with bathing with plain soap or placebo solutions (rr: %; % ci: . e . ). warming the patient before or during surgery has also been shown to significantly reduce rates of surgical infection. warming may reduce surgical infection rates by improving blood circulation and immune function in the surgical areas. an ultraclean air-filtered operating room coupled with use of whole-body ventilated exhaust suits by operating personnel was associated with a % drop in deep sepsis rates compared with standard operating room procedures (p < . ). multiple interventions simultaneously may prove to be the most effective way to reduce surgical infections. institution of a comprehensive surgical infection control programme was associated with a % drop in surgical-related infections for coronary artery bypass graft patients (or: . ; % ci: . e . ). this infection control programme included prospective surveillance and reporting, chlorhexidine showers, discontinuation of shaving, elimination of ice baths for cardioplegia solution, limitation of operating room traffic, reducing use of flash sterilisation and elimination of postoperative tap-water wound washing for four days. laparoscopic surgery should be done instead of open surgery whenever possible, since laparoscopic surgeries generally have significantly lower rates of infection, adhesions and other complications. many studies and meta-analyses have reported much lower infection rates when laparoscopic surgery is performed instead of open surgery for many types of abdominal procedures including perforated peptic ulcer surgery, cholecystectomy, splenectomy, lysis of small intestine adhesions causing obstruction, appendectomy, rectal cancer surgery and ventral hernia repair. e relatively few studies have been conducted involving sterilisation of surgical instruments and medical devices such as endoscopes. cleaning must also precede sterilisation or high-level disinfection. surgical and medical instruments may be sterilised or disinfected by a number of methods including autoclaving, ethylene oxide chambers, or solutions containing phenolics, aldehydes, quaternary ammonium compounds, hydrogen peroxide, peracetic acid or chlorine compounds. all of these techniques have advantages and disadvantages. autoclaving provides excellent sterilisation but not all equipment can withstand the heat. ethylene oxide chambers provide excellent disinfection but they must be monitored for potential ethylene oxide gas leaks. disinfectant aldehydes such as glutaraldehye and ortho-phthaladehyde can cause respiratory, skin and eye irritation. peracetic acid systems provide good sterilisation but are relatively expensive and can only be used for immersible instruments. preventing waterborne hospital infections a number of interventions have been proven effective in reducing rates of hospital waterborne infections. numerous studies have found that replacing tap water with sterile water for drinking, bathing and procedures can significantly reduce rates of many hospital infections including crytosporidium, legionella, aeromonas and stenotrophomonas. sterile sponges can be used for bathing. boiling and water filtration in hospital water systems can also sterilise water, but these systems need to be monitored closely because many problems can develop which cause these systems to fail. daily cleaning of patient shower areas with a detergent and phenolic compound has been shown to significantly decrease airborne levels of moulds including aspergillus. heating water to more than c has been shown to significantly reduce levels of legionella spp. in storage tanks and hospital water systems; however, water heating alone will not usually eliminate all legionella in a contaminated hospital water system. some studies have found that the uv-light water treatment can greatly reduce levels of legionella in hospital water systems. copperesilver-based ionisation systems can also significantly reduce waterborne concentrations of legionella, moulds and gram-negative bacteria such as p. aeruginosa and actinetobacter baumannii. e a spanish hospital saw legionella infection rates fall from . to . cases per discharges following installation of a copperesilver ionisation system (p < . ). routine surveillance of hospital water supplies for legionella is highly recommended in cases of confirmed legionella infections; however, it is controversial as to whether such routine testing is needed in hospitals with no legionella infection history. , all water leaks and water damage should be repaired and remediated within h to prevent growth of pathogenic bacteria and moulds. hospitals should avoid using indoor decorative fountains since they encourage legionella and the splashing water facilitates ready aerosolisation of the organism. hepa filtration is relatively inexpensive and probably should be used for all hospital rooms. various studies have found that the hepa filtration in hospitals can significantly reduce airborne levels and/or infection rates for several aerosolised pathogens. many studies have reported that the hepa filters in patient rooms can significantly reduce both airborne aspergillus concentrations and rates of human aspergillus infections. e meta-analysis of six non-randomised controlled trials reported that hepa filtration for neutropenic patients was associated with a significant drop in mortality due to mould infections (rr: . ; % ci: . e . ). meta-analysis of six randomised controlled studies reported that hepa filtration for neutropenic patients was associated with only a marginal drop in overall mortality (rr: . ; % ci: . e . ). use of portable hepa filters has been found to significantly reduce airborne levels of mrsa and p. aeruginosa in hospitals. , a porcine study reported that hepa filtration was associated with significantly lower rates of porcine respiratory syndrome virus (prsv). hepa air filtration has been shown to reduce airborne concentrations of droplet nuclei (which transport tuberculosis) by %. recently, a new hospital air filtration system has been developed by airinspace technologies (montigny le bretonneux, france). this portable immunairä system forms a protective hood around the patient, filters air at air changes per hour and uses a 'cold plasma' system to destroy microbes. early tests have indicated that such a system has a more than % single-pass efficiency in destroying bacteria, viruses and moulds such as aspergillus. more study of this and other air filtration systems is needed. provision of adequate outdoor air ventilation rates is also essential to dilute out and control hospital pathogens. a study with army recruits reported significantly higher rates of acute respiratory disease when housed in poorly ventilated barracks compared with well-ventilated barracks. the american society for heating, refrigerating and air conditioning engineers (ashrae) has proposed standards of at least four outdoor air changes per hour (ach) for hospital rooms, outdoor ach for operating rooms and six outdoor ach for icus. , hospitals undergoing construction or renovation have increased dangers for airborne and dustborne pathogens and may require additional outdoor ach as well as barrier protections. , uv light machines in rooms or in ventilation systems can effectively kill mycobacteria, legionella and many viruses, but uv light is not effective in killing many species of bacteria and moulds. special interventions for control of tuberculosis tuberculosis (tb) remains a serious health problem in both the developed and developing world. recent cdc guidelines have recommended a number of administrative, engineering and personal protection measures to control tb spread in healthcare settings. recommended administrative controls include tb testing for all patients at risk of tb, implementing a written tb control plan in the hospital and housing infected patients in separate rooms. all rooms housing tb patients should have at least outdoor ach, have a negative pressure of at least . inch water, and the rooms of patients with actual or suspected tb should be checked visually with tests such as smoke tests. hepa air filters in patient rooms and uv irradiation in the ventilation systems or upper part of rooms is also strongly recommended to reduce airborne tb levels. hepa masks or other respiratory protection need to be worn by healthcare workers and visitors to rooms of infectious tb patients. proper cleaning and disinfecting of instruments used by tb patients are also essential. controlled studies for individual interventions of tb control programmes are lacking. however, risk of tb transmission can be greatly reduced when many infection control measures are applied simultaneously. a -bed hospital in atlanta, georgia, used a variety of controls for tb including administrative (patient isolation, staff tb education programme, tb tests to staff every six months and hiring a nurse epidemiologist), negative-pressure tb rooms, and hepa masks by all healthcare workers in respiratory protection areas. over a -month period, the number of tb exposure incidents fell from . to . per month (p < . ). the rate of tuberculin skin test conversions among healthcare workers also fell from . % to . % in this period (p < . ). many non-pharmacological interventions have been shown to significantly reduce rates of hais, but are often overlooked in clinical practice. widely varied interventions such as proper hand washing, better nutrition, housing patients in separate rooms, sufficient numbers of nursing staff, coated urinary and cvcs, hepa air filters, copperesilver water ionisation and numerous interventions for ventilated and surgical patients have all been documented to significantly reduce risk of nosocomial morbidity and/or mortality. many of these studies have also indicated that these infection control interventions will more than pay for themselves in terms of reduced total medical costs. the hospital environment is a complicated ecosystem and many interventions are needed for optimal infection control. while many hospitals are using a number of these infection control strategies, relatively few hospitals are employing most of the broad range of infection control methods available today. multiple interventions ('bundling') often give better results than single interventions. most bundling studies have used only two to five infection control interventions at the same time. larger interventional studies should be undertaken which employ large numbers of infection control methods simultaneously. such multifaceted infection control protocols will probably result in larger declines in nosocomial infection rates than strategies employing only one to five interventions. however, it is difficult to sort out the efficacy of individual interventions when many interventions are simultaneously used. aboelela et al. have suggested that in studies with many interventions, groups of several interventions or bundles can be studied as one intervention. current levels of multidrug-resistant bacteria will increase in the future as antibiotics are heavily used in both human and veterinary medicine and relatively few new antibiotics are being developed. multifactorial non-pharmacological infection control strategies will not only substantially reduce the numbers of nosocomial infections, but should also significantly reduce hospital antibiotic usage. lower overall antibiotic use will reduce risk of antibiotic-resistant organisms and should improve efficacy of antibiotics given to patients who do acquire nosocomial infections. multiple-intervention infection control strategies should significantly reduce mortality, morbidity and overall medical costs. there needs to be more support for improved hospital infection control on the part of patient advocacy groups, nursing, medical and public health associations, hospital administrators, health insurance companies, business and labour groups, the media and public officials. research and implementation of multifaceted hospital infection control strategies should clearly be one of the highest priority items facing healthcare in the early st century. estimating health-care associated infections and deaths in u.s. hospitals invasive methicillin resistant staphyloccocus aureus infections in the united states proportion of hospital deaths potentially attributable to nosocomial infections the costs of nosocomial infections epidemiology and economic evaluation of severe sepsis in france: age, severity, infection site, and place of acquisition (community, hospital or icu) as determinants of workload and cost clinical and economic consequences of ventilator associated pneumonia: a systemic review decreasing ventilator-associated pneumonia in a trauma icu costs associated with hospital acquired bacteraemia in a belgian hospital the attributable mortality and costs of primary nosocomial bloodstream infections in the intensive care unit central venous catheter infection in adults in acute hospital settings the airborne transmission of infection in hospital buildings: fact or fiction? effect of aerosolization on culturability and viability of gram-negative bacteria airborne contagion and air hygiene how far droplets can move in indoor environments e revisiting the wells evaporationefalling curve consideration of barrier protection and latex protein allergy in the evaluation of medical gloves to gown or not to gown: the effect on acquistion of vancomycin resistant enterococci a cost benefit analysis of gown use in controlling vancomycin resistant enterococcus transmission: is it worth the price? the role of gowns in preventing nosocomial transmission of methicillin resistant staphylococcus (mrsa): gown use in mrsa control compliance of routine use of gowns by healthcare workers (hcws) and non hcw visitors on entry into the rooms of patients under contact precautions evidence of control and prevention of surgical site infection by shoe covers and private shoes e a systemic literature review the role of protective clothing in infection prevention in patients undergoing autologous bone marrow transplantation surgical area contamination e comparable bacterial counts using disposable head and mask and helmet aspirator systems, but dramatic increase upon omission of head-gear: an experimental study in horizontal laminar air-flow the medical overcoat e is it a transmitting agent for bacterial pathogens? stethoscopes and nosocomial infection epidemiology of colonisation of patients and environment with vancomycin resistant enterococci potential micro-organism transmission from the re-use of m red dot adhesive electrocardiograph electrodes using marker pens on patients: a potential source of cross infection with mrsa impact of ring wearing on hand contamination and comparison of hand hygiene agents in a hospital neck ties as vectors for nosocomial infections artificial nails: are they putting patients at risk? a review of the research can methicillinresistant staphylococcus aureus be found in an ambulance fleet? identifying opportunities to enhance environmental cleaning in acute care hospitals effect of a training program for hospital cleaning staff on prevention of hospital acquired infection reduction of clostridium difficile and vacomycin-resistant enterococcus contamination of environmental surfaces after an intervention to improve cleaning methods reduction in acquisition of vancomycin-resistant enterococcus after enforcement of routine environmental cleaning measures mrsa acquisition in an intensive care unit does disinfection of environmental surfaces influence nosocomial infection rates? a systematic review environmental control to reduce transmission of clostridium difficile tackling contamination of the hospital environment by methicillin resistant staphylococcus aureus (mrsa): a comparison between conventional terminal cleaning and hydrogen peroxide vapour decontamination copper-oxide impregnated textiles with potent biocidal activities malnutrition in acute care patients: a narrative review contribution of selected vitamins and trace elements to immune function malnutrition is an independent risk factor associated with nosocomial infections relations between undernutrition and nosocomial infection in elderly patients risk factors for nosocomial pneumonia in a geriatric hospital: a case-control, one-center study immunonutrition in the intensive care unit. a systemic review and consensus statement meta-analysis of probiotics for the prevention of antibiotic associated diarrhea and the treatment of clostridium difficile disease use of probiotic lactobacillus preparation to prevent diarrhoea associated with antibiotics: randomised double blind controlled trial probiotic treatment of vancomycin-resistant enterococci: a randomised controlled trial single rooms may help to prevent nosocomial bloodstream infections and cross-transmission of methicillin-resistant staphylococcus aureus in intensive care units isolation of patients in single rooms or cohorts to reduce spread of mrsa in intensive-care units: prospective two-centre study budget analysis of rapid screening for staphylococcus aureus colonization among patients undergoing elective surgery in us hospitals methicillin resistant staphylococcus aureus control in an intensive control unit: a year analysis methicillin resistant staphylococcus aureus control in hospitals: the dutch experience low prevalence of methicillin-resistant staphylococcus aureus (mrsa) at hospital admission in the netherlands: the value of search and destroy and restrictive antibiotic use application of molecular techniques to the study of hospital infection medical and economic benefits of a comprehensive infection control program that includes routine determination of microbial clonality nurse working conditions and patient safety outcomes relationships between nurse staffing and patient outcomes coming soon: state reports on infection rates hospital safety reports past due: officials debate reasons for three studies delays decreasing urinary tract infection in a large academic community hospital preventing catheter-related bacteriuria. should we? can we? how? urosepsis in the critical care unit the efficacy of silver alloy-coated urinary catheters in preventing urinary tract infections: a meta-analysis effect of silvercoated urinary catheters: efficacy, cost-effectiveness, and antimicrobial resistance systematic review: antimicrobial urinary catheters to prevent catheterassociated urinary tract infection in hospitalized patients prevention of central venous catheter-related infections: what works other than impregnated or coated catheters? prevention and control of nosocomial infections using maximal sterile barriers to prevent central venous catheter-related infection: a systematic evidence-based review use of maximal sterile barriers during central venous catheter insertion: clinical and economic outcomes complications of fermoral and subclavian venous catheterization in critically ill patients: a randomized controlled trial chlorhexidine compared with povidone-iodine solution for vascular catheter-site care: a meta-analysis an intervention to decrease catheter-related bloodstream infections in the icu effect of an education program on decreasing catheter-related bloodstream infections in the surgical intensive care unit health care-associated infections: major issues in the early years of the st century are antiseptic-coated central venous catheters effective in a real-world setting? prevention of nosocomial bloodstream infections: effectiveness of antimicrobialimpregnated and heparin-bonded central venous catheters cost-effectiveness of antiseptic-impregnated central venous catheters for the prevention of catheter-related bloodstream infection lysostaphin disrupts staphyloccocus aureus and staphylococcus epidermis biofilms on artificial surfaces hemodialysis vascular catheter-related bacteremia effect of isolation measures on the incidence and prevalence of hepatitis c virus infection in hemodialysis preventing ventilator associated pneumonia: an evidence-based approach to modifiable risk factors prevention of ventilatorassociated pneumonia: analysis of studies published since an educational intervention to reduce ventilator-associated pneumonia in an integrated health system risk factors for surgical site infections preoperative hair removal to reduce surgical site infection preoperative bathing or showering with skin antiseptics to prevent surgical site infection effects of preoperative warming on the incidence of wound infection after clean surgery: a randomised controlled trial results of a comprehensive infection control program for reducing surgical-site infections in coronary artery bypass surgery laparoscopic repair of perforated peptic ulcer: a meta-analysis comparison of the risk of surgical site infection after laparoscopic cholecystectomy and open cholecystectomy perioperative outcomes of laparoscopic versus open splenectomy: a meta-analysis with an emphasis on complications laparoscopic lysis of adhesions a meta-analysis of laparoscopic versus open appendectomy in patients suspected of having acute appendicitis laparoscopic versus open appendectomy in children: a meta-analysis laparoscopic versus open appendectomy for rectal cancer: a metaanalysis pooled data analysis of laparoscopic vs. open ventral hernia repair: years of patient data accrual disinfection and sterilization in health care facilities: what clinicians need to know cleaning patient shower facilities: a novel approach to reducing patient exposure to aerosolized aspergillus species and other opportunistic molds hospital acquired legionellosis: solutions for a preventable infection evaluation of ultraviolet light for disinfection of hospital water hospital acquired legionnaires disease in a university hospital: impact of the coppere silver ionization system impact of copper and silver ionization on fungal colonization of the water supply in health care centers: implications for immunocompromised patients in vitro efficacy of copper and silver ions in eradicating pseudomonas aeruginosa, stenophomonas maltophilia and acinetobacter baumannii: implications for on-site disinfection for hospital infection control surveillance of hospital water and primary prevention of nosocomial legionellosis: what is the evidence? cleaning and restoration certification (iicrc). iicrc standard and reference for professional mold restoration s . east mill plain boulevard impact of air filtration on nosocomial aspergillus infections control of construction associated nosocomial aspergillosis in an antiquated hematology unit efficacy of high-efficiency particulate air filtration in preventing aspergillosis in immunocompromised patients with hematologic malignancies the influence of high-efficiency particulate air filtration on mortality and fungal infection among highly immunocompromised patients: a systematic review reduction in mrsa environmental contamination with a portable hepa-filtration unit airborne dissemination of epidemic pseudomonas aeruginosa in the nottingham cystic fibrosis population: a role for portable hepa filtration? abstract presented at the federation of infection societies meeting in further evaluation of alternative air-filtration systems for reducing the transmission of porcine reproductive and respiratory syndrome virus efficacy of portable filtration units in reducing aerosolized particles in the size range of myobacterium tuberculosis evaluation of a new mobile system for protecting immune-suppressed patients against airborne contamination building-associated risk of febrile acute respiratory diseases in army trainees control and management of hospital water quality ventilation for acceptable indoor air quality control and prevention of healthcareassociated tuberculosis: the role of respiratory isolation and personal respiratory protection guidelines for preventing the transmission of mycobacterium tuberculosis in health care settings preventing the nosocomial transmission of tuberculosis effectiveness of bundled behavioural interventions to control healthcareassociated infections: a systemic review of the literature acknowledgements i thank all of the infection control researchers who have published useful papers. none declared. none. key: cord- - npxrrhr authors: lee, m.k.; chiu, c.s.; chow, v.c.; lam, r.k.; lai, r.w. title: prevalence of hospital infection and antibiotic use at a university medical center in hong kong date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: npxrrhr hospital infection prevalence surveys were performed in our -bed university medical centre in hong kong from to . we investigated the rates of four major hospital-acquired infections (hais) (pneumonia, symptomatic urinary tract infection, surgical site infection and laboratory-confirmed bloodstream infection) in order to identify current distribution and any changes after years. a one-day point prevalence study was performed on september . all inpatients were surveyed for hais, community-acquired infections (cais), risk factors, pathogenic isolates and antibiotics prescribed. infections were diagnosed according to centers for disease control and prevention (cdc) criteria. in total, patients were surveyed; of these, had hais ( % prevalence) and ( %) were receiving antibiotics. the commonest hai was pneumonia ( . %) followed by bloodstream infection ( . %) and symptomatic urinary tract infection ( . %). the prevalence of postoperative surgical site infection was . %. the nosocomial prevalence rate was highest in the intensive care unit, followed by the pediatric and neonatal intensive care units, children's cancer centre/bone marrow transplant unit and orthopaedics with traumatology. meticillin-resistant staphylococcus aureus and pseudomonas aeruginosa were the commonest pathogens. the rates are significantly lower than previously and reflect the increased resources for infection control made available following the outbreak of severe acute respiratory syndrome (sars). hospital-acquired infections (hais) are common causes of morbidity and mortality among hospitalized patients. surveillance for nosocomial infections (nis) is an important component of an effective infection control programme. the national nosocomial infections surveillance (nnis) system coupled with feedback and interventions successfully reduced the infection rate among participating hospitals. unfortunately such prospective surveillance is costly and labour intensive. prevalence surveys are relatively inexpensive and easy to perform, although rates obtained are higher than comparable incidence rates and may be statistically less stable. despite their limitations they provide a useful estimate of hai. french et al. conducted serial point prevalence surveys in our hospital years ago. these proved to be a practical and useful way of documenting the trend of hais and assessing the impact of an infection control programme. conducting a prevalence survey also raises awareness among healthcare professionals of infection risks in hospital settings. , the objectives of this study were to determine the rate of nosocomial infection and the use of antibiotics. knowledge of the current situation and major changes in distribution of nosocomial infections should help to prioritize resource allocation, allow a more effective infection control policy and enable a targeted prospective surveillance programme. the prince of wales hospital (pwh) is a -bed teaching hospital in hong kong. our laboratory is accredited by the national association of testing authorities (nata) and offers a wide range of bacteriology and virology services. the study was performed on september, . all inpatients at : as documented by the hospital computer system were included except those who were temporarily under observation in the accident and emergency department. cdc definitions for nosocomial infections were used. hai was defined as occurrence of infection after hospital admission, without evidence that the infection was present or incubating ( h) on admission. four major infections were surveyed: pneumonia, symptomatic urinary tract infection (suti), surgical site infection (ssi) and laboratory-confirmed bloodstream infection (lcbsi). infections of more than one site in the same patient were counted as separate infections. only active infections (i.e. those undergoing antimicrobial treatment, symptomatic or considered ongoing by medical staff) were included. demographic information, admission diagnosis, use of medical device and antibiotic were recorded by the ward nursing staff who had attended briefing sessions on each ward on the point prevalence survey with instructions on correct filling of a data collection form. other relevant data were recorded by our investigators (infection control nurses and medical microbiologists: total ¼ ) on a separate standardized data collection form. they visited each ward and examined the clinical records, microbiology results and drug charts. a return visit was made if patient or medical record was not available. completed data collection forms were checked on the same day by the survey coordinator to avoid absence of data. microbiological data were collected up to two weeks after the study period. statistical analysis was conducted using spss software (spss, inc., chicago, il, usa). p < . was considered statistically significant. the results were fed back to the hospital infection control committee and individual departments after the survey. in all, patients were surveyed and their distribution by specialty is shown in table i . ages ranged from day to years. the mean and median age was . and years respectively; % were male and % were female. hospitalization ranged from to days. most patients ( . %) were admitted for two days or less, nearly % admitted for days or less. the mean and median durations of hospitalization were . and four days respectively. in patients, devices were present. peripheral intravenous catheter (n ¼ ), urinary catheter (n ¼ ) and central venous catheter (n ¼ ) were the most common. of these, patients had one device, had two and patients had three. twenty patients were receiving mechanical ventilation. forty-four hais were diagnosed in patients. two patients had acquired the infections in another hospital and were excluded, leaving hais in patients giving a % hai rate. the most common hai was pneumonia ( . %), followed by ssi ( . %), lcbsi ( . %) and finally suti ( . %) ( table i) . there were two cases ( %) of ventilator-associated pneumonia (vap) among the cases of hospitalacquired pneumonias (hap). fifty-seven percent of hospital-acquired urinary tract infections were catheter related. the icu had the highest prevalence rate of nosocomial infection ( . %), followed by the pediatric/neonatal icus, children's cancer centre/ bone marrow transplant unit (ccc/bmt) and orthopaedics and traumatology (table i) . the prevalence of ssi among those patients who had undergone operation was . % (table i) . approximately % of the surgical patients underwent operations classified as 'contaminated' or 'dirty' were diagnosed with ssi. four percent and % of those who had 'clean' and 'cleanecontaminated' operations had ssis (table i) . patients with nosocomial infection had a median hospital stay of days compared to days for non-infected patients. duration of hospital stay, operation, invasive ventilation and intravascular device were independent risk factors for hai (p < . ) (table ii) . sixty-six patients were diagnosed with cai. the prevalence rate was . %. together with hai ( patients with hai and two other patients with hai from other hospitals), the overall prevalence rate of infection in hospital was . %. among patients with hai, . % had relevant microbiology and serological tests performed and . % had positive cultures. the commonest organisms isolated were pseudomonas aeruginosa and meticillin-resistant staphylococcus aureus. a total of patients ( %) were receiving antibiotics; ( . %) received one antibiotic, ( . %) received two and ( %) received three or more. the five most commonly prescribed antibiotics were amoxicillin-clavulanate, metronidazole, cefuroxime, cloxacillin and gentamicin (table iii) . the commonest antibiotic combinations were cefuroxime þ metronidazole (n ¼ ), gentamicin þ penicillin (n ¼ ), ampicillin þ cloxacillin (n ¼ ), ampicillin þ cefuroxime þ metronidazole (n ¼ ) and gentamicin þ vancomycin (n ¼ ). though some of our findings are similar to those in other parts of the world, they are useful for local healthcare workers. the last survey in our hospital was performed over years ago and some interesting changes in nosocomial infection rate and antibiotic use were found. differences in methodologies and patient population do not allow stringent comparison of prevalence between different surveys and meaningful comparison of infection rates requires adjustment for intrinsic and extrinsic risk factors. the impact of case mix on infection rates was well illustrated with the example of hospital size in the study by sax's group. detailed information on patient demographics, duration of hospital stay and invasive devices/antibiotic use has been illustrated for reference in this single hospital study. the cdc definition of infections was adopted. although it was not used in the previous surveys, it is now one of the most widely used and objective standards. all our investigators were qualified medical and nursing staff with relevant infection control training. inter-observer bias was minimized by ensuring that the investigators agreed on the interpretation of the diagnostic criterion before the survey. however, gastmeier et al. showed that despite the use of specific cdc criteria, there could still be subjectivity in the diagnosis of nosocomial infections. the investigator effect was not known in the current survey. only four major infections were studied. the prevalence of hai was %. in point prevalence surveys using the cdc diagnostic criteria and involving the four major sites of infection (suti, lrti, ssi and bsi) conducted in france, italy, norway and lebanon, the prevalence of hai ranged from . to . %. , e the inclusion of all sites of infection tends to increase the overall prevalence rate by e % as compared with studies that included only major sites. , thus, if corrected, the hai prevalence rate estimated for all sites would be e %. this rate was much lower than those found in e in pwh ( . %), as well as in other countries ( . e . %). , , e apart from the overall rate, rate reductions were found in hap (from . to . %), ssi (from . to . %), and uti (from . to . %) without making case-mix adjustments (figure ). this probably relates to improved infection control following the sars crisis in hong kong, as evidenced by increased resources and heightened awareness among healthcare workers (hcws). our hospital had one infection control nurse per beds after as compared to the previous ratio of : . infection control programmes, such as 'alert organism' reporting, biannual hand hygiene audit, regular infection control educational/training to hcws and ssi surveillance have since been implemented. heightened infection control awareness was demonstrated by the high compliance rate in hand hygiene audit among hcw. the low prevalence may also relate to a short duration of hospital stay and rapid transferal to convalescence hospitals after initial diagnosis and stabilization. the prevalence of nosocomial pneumonia, lcbsi and ssi was similar to that reported in european surveys. the prevalence of nosocomial lcbsi was relatively high, possibly due to a high overall blood culture rate and simple application of the diagnostic criteria. the rate of nosocomial urinary tract infection (uti) was lower than the . e . % reported from other surveys. , e , e the greatest problem with defining suti is that if the urine is not analyzed, uti cannot be diagnosed. secondly, the definition did not take into account urinary catheters, as symptoms of uti other than fever cannot be assessed in catheterized patient. the frequency of suti therefore depended upon: (i) frequency of catheter use: % of the patients had an indwelling urinary catheter; (ii) urine analysis protocol: in our hospital, urine is only analysed when the signs and symptoms indicate a uti or when a catheterized patient develops a fever. symptoms of uti in patients with a serious major disease of other organs may have been ignored; and (iii) physician's diagnosis: data collection based on doctor's diagnosis may not have been sensitive enough to record all utis. furthermore asymptomatic bacteriuria was not evaluated. these factors may account for the underestimation of rate of uti compared with other studies. the distribution of nosocomial infection among different specialties was similar to published european studies. the prevalence of nosocomial infection was greatest in icu at . %, which compared with . % years ago, and was similar to that of other studies. , , , the special pediatric unit ranked second for nosocomial infection. hai, not limited to ssi, has been shown to be twice as common in postoperative patients. , thirty-eight percent of patients received at least one antimicrobial agent, more than in other studies ( . e %), but only % had an infection according to the cdc criteria. e , indications for antibiotic prescription were reviewed retrospectively in order to investigate this discrepancy (table iii) . prophylactic use ( . %) and treatment for infections that were not being investigated in the current survey ( %) may have accounted for antibiotic use in % of patients. the remaining % may have represented treatment of infections not fulfiling the cdc criteria or inappropriate antibiotic prescription. recent surveys showed that suboptimal antimicrobial prescription is frequent in our hospital. though appropriateness of antibiotic prescription was not the aim of current study, unnecessary antibiotic combinations were noted (table iii) . broad-spectrum antibiotics, e.g. imipenem, meropenem and cefepime, accounted for about % of the antibiotics being prescribed on the day of survey. audit of 'big-gun' antibiotics in local university hospitals revealed that e % of the prescriptions were not justified or suboptimal. , the upcoming antibiotic stewardship programme targeting this group of drugs should help to optimize use of antimicrobials in the hospital. in summary, provision of better resources appears to have had a definite effect in reducing hais. the icu, special pediatric and surgical/ orthopaedic units warrant targeted surveillance of nosocomial infection followed by a relevant infection control programme. another target would be improvement in nosocomial bloodstream infection by promoting proper intravenous catheter care. repeated prevalence surveys are useful for monitoring trends in rates of both hai and effectiveness of such intervention strategies. the efficacy of infection surveillance and control programs in preventing nosocomial infections in us hospitals feeding back surveillance data to prevent hospital acquired infections prevalence, incidence and duration repeated prevalence surveys for monitoring effectiveness of hospital infection control prevalence of nosocomial infections in hospitals in norway the french prevalence survey study group. prevalence of nosocomial infections in france: results of nationwide survey in national nosocomial infection study site definition manual inter-hospital differences in nosocomial infection rates: importance of casemix adjustment experience with two validation methods in a prevalence survey on nosocomial infections prevalence of nosocomial infections in representative german hospitals prevalence of nosocomial infections in italy: result from the lombardy survey in national prevalence survey on hospital infection in norway a one-day prevalence survey of hospital acquired infections in lebanon prevalence of nosocomial infections in spain: epine study e prevalence of hospital infection at the prince of wales hospital a three-year survey of nosocomial and community-acquired infections, antibiotic treatment and re-hospitalization in a norwegian health region hospital-acquired infections in italy: a region wide prevalence study prevalence of hospital-acquired infection in a lithuanian hospital prevalence of nosocomial infection and antibiotic use at a university medical center in malaysia surveillance in infection control: are we making progress? prevalence of hospitalacquired infection in a tunisian hospital antibiotic guidelines and optimization programme optimising antimicrobial prescription in hospitals by introducing an antimicrobial stewardship programme in hong kong: consensus statement we are grateful to the nursing staff of the pwh, and especially to our microbiologists and icns, who assisted in the surveys. key: cord- -odqo o w authors: gibbons, john p.; hayes, joshua; skerritt, conor j.; o’byrne, john m.; green, connor j. title: custom solution for ppe in the orthopaedic setting: retrofitting stryker flyte t ® ppe system date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: odqo o w the covid- pandemic has meant that there is growing pressure on hospital resources not least the availability of appropriate personal protective equipment (ppe), specifically, facemasks and respirator masks. within the field of orthopaedic surgery, it is a common sight to see orthopaedic surgery carried out in “space suits” (ss) which comprise of a helmet, hood and surgical gown. in this study the authors made modifications to two different ss systems to incorporate high-efficiency particulate air (hepa) filters to the inlets to the fan to assess their potential as a method of providing a reusable system for ppe for the surgeon with regard to protection from a respiratory droplet spread virus. the testing was carried out using particle counter upstream and downstream on a manikin wearing two different ss systems with and without modifications to the inlet. the results show that using a layer of hepa filter cut to size, and sealed to the inlet for the fan in the helmet will reduce the downstream particulate at the user’s mouth by over . % which is equivalent to that of a respirator mask. hepa filter material is relatively cheap and can be used repeatedly making this a viable alternative to disposable, and even re-sterilized, respirator masks in the setting of a respiratory droplet spread viral pandemic. the emergence of the novel coronavirus covid- as a pandemic affecting most of the world's population has led to concern regarding an international shortage of personal protective equipment (ppe). the world health organisation (who), in recent guidance with respect to rational use of ppe, stated that: "the current global stockpile of ppe is insufficient, particularly for medical masks and respirators" ( ). current advice from a number of bodies is that the use of ffp or n respirator masks with eye protection as well as gloves and gowns for specific procedures of which orthopaedic surgery is included ( ) ( ) ( ) . more recently, guidance for all healthcare workers (hcws) has advised that any person working within metres of any patient who is suspected or confirmed covid positive, should be using a respirator mask ( ) ( ) ( ) . the use of respirator masks, such as n and ffp which provide at least % and % filtration of particles . μm, is advised based on the best and most broadly available masks to hcws in terms of filtration of particles and that they offer a seal to the face. it is, however, not without its own limitations, as these masks are not custom made for face-fit to the individual, and require a face-fitting procedure, which has been shown to have limitations ( ) . the mean diameter of the coronavirus has been reported to be nm ( ) . the filter efficiency of the n and ffp respirator masks relate to their ability to effectively filter submicron particles and are standardised against uncharged particles of sodium chloride measuring nm or airborne staphylococcus aureus ( , ) . there are studies that have questioned the validity of using these masks in providing protection against viruses and that the performance of such masks may underestimate the penetration of nanosized virions ( ) . high-efficiency particulate air (hepa) filters are standardised against the same particle size for their certification and are . % efficient in their filtration, a study by nasa showed that hepa filters are also efficient for particles in the size range of virions at one magnitude less in size, c. nm ( ) . the possibility of a global shortage of ppe, including facemasks, has led to bidding wars amongst governments to acquire ppe for the health care workers, the irish government have stated this in no j o u r n a l p r e -p r o o f uncertain terms ( ). we are now very much reliant on external supplies of ppe, it is imperative that we design methods to be more self-reliant should this particular pandemic endure or resurface, and be prepared for future pandemics. there are protocols being developed with regards to the standardization of sterilization of face masks that show acceptable retention of the efficiency of the filtration after cycles ( , ) . there are limitations with regard to re-sterilization, namely, that the masks may suffer mechanical damage during the process, disposable masks are often not face-fit for the individual and the fit may be damaged by the process. sterilization of a mask is not performed if there is gross contamination of the mask, which, in the setting of orthopaedic surgery would render most masks not re-usable as there is often gross contamination of the ppe with blood spatter and splash-back from lavage. orthopaedic surgery generates aerosolised human tissue, including bone and blood, through the use of power tools during procedures. these aerosol generating procedures (agps), and the inability to re-sterilise common respirators due to contamination with blood was what prompted the current authors to look at using the existing "space-suits" (ss) used in orthopaedic surgery as an alternative for re-usable masks. the research question in this paper is if retrofitting a stryker® helmet with a hepa filter at the inlet draped in the usual hood and gown would improve the ss to a point of being comparable to a n or equivalent mask. this is a proof of concept study using a manikin to isolate the effectiveness of the retrofitted helmet with regard to the ability to filter air coming into the ss. the experimental set up of this research involved a manikin (head and torso mounted on a stand to measure cm in height) used for cpr training as the subject in all tests. the manikin was cleaned with chlorohexidine scrub prior to the experiment, all orifices other than the mouth and nose on the manikin were sealed with m steri-drape™. the particle detector was placed at the mouth and sealed with leucoplast sleek tape around the detector and mouth isolating it from the internal tubing j o u r n a l p r e -p r o o f of the manikin as well as taping over the nostrils of the manikin, (see figure ). the detector tubing was fed out through the bottom of the manikin and sealed with m steri-drape™. the testing was performed in the orthopaedic theatre initially but the background particle count was found to be too low to discern a difference at the downstream penetration detector that would be reliable. the testing was then performed in the adjoining anaesthetic room and all doors and exhaust vents were closed but not sealed. an ambient recording was made to ensure that the distribution of background particulate was equal at both points for the detector in relation to the manikin without any donned ppe, which was confirmed. the ppe systems used in this study were the stryker flyte t ® and t ® ( ) . both systems have a grill over the fan inlet which prevents the hood material being sucked into the inlet. the t helmet has a grill overlying the fan inlet that is not amenable to removal and replacement without damaging the plastic housing for this system. the grill was cut off and a housing containing a hepa filter with a rubber gasket seal was mounted over the fan inlet (see figure a ). the t helmet has a similar grill but can be removed and replaced without damage to the housing. figure b illustrates the experimental set up for the modified t system. this allowed for a hepa filter to be placed over the inlet and sealed at the periphery to the helmet and then the grill replaced to prevent the hood being sucked onto the fan (see figure ). the hepa filter material was taken from the soniq ii™ system( ). the particulate testing was carried out by a certified engineer who commissions ventilation systems for surgical healthcare infrastructure in this jurisdiction. the detection equipment used, aerotrak® handheld particle counter model , (tsi, minnesota, usa), is industry standard; it generates a . l/min intake and was set to read channels to enable reading of all particles in the size range j o u r n a l p r e -p r o o f . - μm. the testing protocol for each measurement of particulate penetration recorded at the mouth detector involved upstream challenge samples taken for seconds each at either the inlet to the stryker hood or the same point in space relative to the head for testing without the hood on. samples were taken upstream to ensure that the upstream challenge was consistent and this required that all four readings are within % of the mean, which they were for all tests. the downstream detector reading was also taken over seconds and at least three readings were taken for each experimental set up outlined below and ten readings were taken for the configurations using the modified hoods. the particulate counts were collected and tabulated using microsoft excel® and statistical analysis was performed with comparison of test configurations using student's t-test. the test configurations were performed using the following set up: ambient test -testing of background particulate to ensure similar readings at upstream and downstream with no ppe on the manikin. this test is required to ensure no difference in ambient distribution of particles around the manikin, which was confirmed. configuration : a stryker t ® helmet and hood and a standard surgical gown around the neck without the fan running. configuration : a stryker t ® helmet with the same hepa filter material cut to fit over the inlet of the t fan and sealed with sealant tape to the helmet housing to prevent any filter bypass, (see figure ) and then draped with hood and standard surgical gown around the neck with the fan running at medium speed. in order to investigate gas levels within the modified t system and the non-modified t system with use, the second author, j.h., wore the each of the ss with serial collection of data from a standard anaesthetic machine used in the operating theatre (ge datix ohmeda asyis & ge carescape b , finland). the experiment was carried out in an operating theatre with a functional laminar airflow system. a narrow ( . mm diameter) pvc co sample tube, connected to a multi-gas analyser (ge carescape e-caio respiratory module, finland) was placed inside the hood at the level of the participants mouth to continuously measure etco (end tidal carbon dioxide) and eto (end tidal oxygen). this side-stream gas analyser draws ml/minute from the user's airway gas, where the co concentration is calculated via absorption of infrared light, according to the beer-lambert law, and oxygen concentration is calculated using paramagnetic analysis. no additional mask was worn. measures for etco , eto and fio were recorded at -minute intervals with both the modified t system hood and the non-modified helmet. j o u r n a l p r e -p r o o f system without filter and the two generations of stryker flyte system with hepa filters modifications were performed for total of readings. table presents the statistical analysis using a student ttest and the significance of the differences observed. figure for the stryker flyte t ® system, the ss alone provides a similar degree of protection as the previous generation of ss at . % (σ= . %), which was not significantly different from the t system. similar to the t system above, once the fan was turned on the penetration downstream increased to . % (σ = . %), again this was not statistically significantly different to the t system with the fan operating. with the modification of the hepa filter to the inlet of the t helmet as described, the downstream penetration was reduced to . % (σ = . %) which is significantly better than all other test configurations and offers a particulate filtration similar to ffp and n or other equivalent respirator mask. figure illustrates the downstream penetration for each experimental set up for each of the channels recorded by the aerotrak® particle counter, showing that there was less than . % penetration at all particle sizes for the modified t system. an additional experiment was run with the addition of an impenetrable cover over the hood except for the area over the inlet did not significantly improve the efficiency leading one to conclude that the positive pressure experienced in the ss provides enough pressure to negate any possible infiltration of particulate though the hood material not directly over the fan inlet. the results of the gas measurement testing are outlined in table and illustrated in figures - . etco remained steady state throughout the recording. the level of etco was higher in the modified t system compared to the non-modified t system (see figure ). fio appeared to be slightly lower under the modified t system compared to the non-modified t system. fico , the inspired concentration of carbon dioxide, is normally . it was observed that the use of both systems results in an increase in fico (see figure ) . the normal fio level is % and the readings demonstrated that there is a reduction in fio with both modified and non-modified ss use (see figure ). the user did report mild discomfort when wearing the modified hoods however this was rated equivalent to wearing a regular ffp mask. the results of this study show that the ss operating without a fan offer close to % reduction in downstream penetration of particles, however, once the fan is turned on the downstream penetration increases to - % for the t and t systems respectively. when the modifications using hepa filter at the inlet to the fans described in this study are implemented there is a significant reduction in downstream penetration, specifically, for the t system the downstream percentage penetration is less than . % which is comparable with that offered by respirator masks. the hepa filters have a significantly greater life-span compared with respirator masks even with the potential re-sterilization of masks ( , ) . this is a pilot study of the potential modification of ss with hepa filters and would require further testing to confirm a recommended life-span for operating, establishing timing of regular quality assurance checks on the efficacy of the filters, and possible further modification of the inlet to protect the hepa filter material ( , ) . derrick et al previously looked at the feasibility of the ss with regards to their use as a method of ppe ( ) . they had concluded that the stryker t ® suit alone was insufficient to protect the hcw in j o u r n a l p r e -p r o o f relation to submicron particles ( ) which is confirmed in the results of this study for non-modified ss. their comparative was using volunteers using either a stryker t ® ss to that of a combination of a n filtering facepiece respirator combined with a surgical facemask and a full-face shield. in their methodology the detector was placed in the breathing zone for the ss, cm below the bottom edge of the transparent face piece whilst for the facepiece respirator the probe was passed through both the respirator and covering surgical mask cm to the right of the valve. there are a number of confounders to the results observed that could result from such in vivo testing, being: . the detector in the surgical mask is not necessarily replicating the possible true particles entering the mouth allowing for possible entrainment of surrounding air if there is even the slightest breach in the face-fit ( ); . similarly, the detector for the ss was placed in the breathing area, not at the mouth, and their study design would not account for the possibility of particles from the subject's hair or skin counting towards the readings given that the ss offers a positive pressure environment from the top of the hood downwards. currently, for most jurisdictions, the recommendation is for the use of respirator facemasks when dealing with suspected or confirmed cases of sars-cov- ( ). a respirator mask is reliant on the adequacy of the face-fit, however, studies have shown that the adequacy of a face-fit even in controlled environments is variable and can depend on the respiratory rate of the user as well as the position of the user( ). there is previous work with regard to ss in relation to the effect of the positive pressure exerted within the suit; and the pressure that this can exert all the way down to any breach including the glove sleeve interface ( , ) . although these tests were carried out on a static manikin, the air provided to the user is that of a highly filtered positive pressure source with less than . % particle penetration which is not reliant on a face-fit, rather, the mechanical seal that is then protected by the plastic housing in the helmet that remains static. the reason that a manikin is used in this study is to assess the efficiency of the ss as a form of ppe using the detection methods for downstream penetration of the ambient environment. a manikin reduces the shedding of the millions of particles that would occur from forced air being pushed over the users head/hair/face, as well as the particles breathed out by a living person, hence changing the microenvironment within the ss, that would not be accounted for upstream and therefore give a systematic bias that could influence the findings that would pull into question the efficiency of the filtration system between the outside environment and inside the ss. we feel that this is a valid method to assess the modified ss at acting as a form of ppe for the user by reducing the confounding factor of having a person breathing and shedding particles that would inherently change the microenvironment inside the ss downstream of the hepa filter that is responsible for protecting the user. another possible benefit to the use of these modified ss in the orthopaedic setting during this pandemic and in the setting of any possible blood borne viruses is that the ss would provide further reassurance to the operating surgeon who may be cutting bone and creating aerosolised blood and tissue material. although the possibility of transmission of sars-cov- is not yet known, coronavirus rna has been detected in blood donation samples and there is a theoretical risk of transmission( , a more recent study, by erickson et al. has used a -d printed inlet manifold with hepa filters, retrofitted to the helmet, to provide a hepa filtered airflow to the user ( ) . this study did not provide details on the particulate filtered but stated that it was independently verified to meet hepa standards ( ) . the system used adds to the overall volume and weight of the hoods and has two plastic hoses that exit the toga posteriorly that could jeopardise sterility of a surgical field. in contrast the setup described for the t system in this study does not add any further encumberment to the user and under the hood there can be no difference in the outward appearance compared to a non-modified ss. it appears that both modified stryker hoods are safe to use with no appreciable interval increase in etco or fico with time. etco , an approximation of arterial carbon dioxide concentration, appears to be slightly higher with use of the modified t system, however, it does not continue to increase with time. we speculate that the increase in fico may be due to a reduced fresh gas flow as a result of the additional hepa filter. this does not appear to impact respiration over a prolonged period as there was no significant interval deterioration in gaseous exchange noted over the duration of the study. similarly, the normal fio level is % and the readings demonstrated that there is a reduction in fio with both modified and non-modified systems. however, although the fio is reduced in both systems the reductions are steady state with respect to time suggesting that there is adequate ventilation sufficient to keep up with the oxygen consumption of the user. the purpose of this study was to evaluate if the ss could be used as a reasonable alternative to facemask ppe. this study uses the well-established ss used in routine orthopaedic surgery to potentially provide a solution to such a shortage. by fitting a ss with a hepa filter that can be used for months at a time before needing to be assessed or changed, the orthopaedic surgeon can be one less hcw for facemask ppe requirements and use. this study is a proof of concept study and by no means rigorous in the testing and validation required for mass roll-out, but it does, validate and provide evidence that this solution could be used safely as ppe in the setting of a respiratory droplet spread, viral pandemic. the gown material without a hepa filter and not operating the fan provides some protection to the user with c. % downstream penetration, however, the concerns of the fan raised in previous studies are valid, whereby, the suction effect allows an increase in particulate detected downstream to %. the ss must be operated with the fan on and so the addition of a hepa filter at the intake significantly reduces the particulate count to less than % for the configuration with a hepa filter housing mounted to the helmet. the downstream penetration is even better, at less than . % downstream j o u r n a l p r e -p r o o f penetration, with a hepa filter cut to the shape of the inlet and with edges sealed to the t helmet. the level of particulate penetration is at the level of a ffp mask (> % filtration of . μm particles), or equivalent can provide and greater than that of the recommended n respirator. for the purposes of reducing reliance on the supply of facemasks that are used in all areas of healthcare during such a pandemic the modification of the ss may present a viable alternative that would be palatable to orthopaedic surgeons. of personal protective equipment for coronavirus disease ( covid- ) and considerations during severe shortages: interim guidance management of patients with urgent orthopaedic conditions and trauma during the coronavirus pandemic. british orthopaedic association intraoperative recommendations when operating on suspected covid infected patients. royal college of surgeons in ireland evaluating the national ppe guidance for nhs healthcare workers during the covid- pandemic guidance on the use of surgical masks in the healthcare setting in the context of the covid- pandemic health service executive when to use a surgical face mask or ffp respirator do n respirators provide % protection level against airborne viruses, and how adequate are surgical masks? ultrastructural characterization of sars coronavirus respiratory protection against bioaerosols: literature review and research needs submicron and nanoparticulate matter removal by hepa-rated media filters and packed beds of granular materials. . . rte. hse seeks to accelerate ppe deliveries but warns supply remains challenging is there an adequate alternative to commercially manufactured face masks? a comparison of various materials and forms sterilization of disposable face masks by means of standardized dry and steam sterilization processes; an alternative in the fight against mask shortages due to covid- flyte personal protection system: stryker orthopaedic instruments hepa filter replacement experience in a biological laboratory survival of microorganisms on hepa filters surgical helmets and sars infection does the use of laminar flow and space suits reduce early deep infection after total hip and knee replacement? the ten-year results of the new zealand joint registry does modern space suit reduce intraoperative contamination in total joint replacement? an experimental study coronavirus disease : coronaviruses and blood safety severe acute respiratory syndrome coronavirus rna detected in blood donations helmet modification to ppe with d printing during the covid- pandemic at duke university medical center: a novel technique there was no funding received for the production of this paper by the present authors.j o u r n a l p r e -p r o o f key: cord- -jjiox it authors: mastromarino, p.; conti, c.; donato, k.; strappini, p.m.; cattaruzza, m.s.; orsi, g.b. title: does hospital work constitute a risk factor for helicobacter pylori infection? date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: jjiox it the aim of this study was to assess whether clinical work constitutes a risk factor for helicobacter pylori infection among employees in hospitals. the prevalence of h. pylori infection was analysed in individuals employed in a university teaching hospital according to three categories of hospital workers: (a) personnel from gastrointestinal endoscopy units (n= ); (b) personnel from other hospital units with direct patient contact (n= ); and (c) staff from laboratories and other units with no direct patient contact (n= ). stool samples from each subject were examined with a validated enzyme-linked immunosorbent assay for the presence of h. pylori antigens. a questionnaire inquiring about sociodemographic and occupational characteristics was completed by each participant. the prevalence of h. pylori infection was . % in group a, . % in group b and . % in group c (p< . ). among the different healthcare categories, nurses had a significant higher prevalence of h. pylori infection (p< . ). no significant association was found between the length of employment or exposure to oral and faecal secretions, and h. pylori infection. hospital work involving direct patient contact seems to constitute a major risk factor for h. pylori infection compared with hospital work not involving direct patient contact. helicobacter pylori infection probably represents the most common bacterial infection of the human species with a prevalence of - % in developed countries and up to % in developing countries. , a wide body of evidence now indicates that h. pylori is the major aetiological agent of chronic active gastritis, and gastric and duodenal ulcers, and represents a major risk factor for the development of gastric cancer. h. pylori is almost always acquired in childhood and, if untreated, infection is usually lifelong. the only consistent source of h. pylori is the gastric mucosa of human beings. an environmental source of infection has not been identified. person-to-person spread therefore seems to be the most likely mode of transmission. evidence that supports person-to-person transmission includes the clustering of h. pylori infection in families, [ ] [ ] [ ] in institutions for the mentally handicapped , and in submarine crews. as well as in the human stomach, viable h. pylori cells have been detected in faeces and oral secretions. , therefore, possible routes of person-to-person transmission are gastric to oral, faecal to oral, or oral to oral. , , healthcare workers who come into contact with patients and contaminated secretions could be at increased risk of infection by h. pylori. the majority of studies on the risk of infection for healthcare workers have focused on endoscopists and endoscopy room staff. these studies, mainly performed by serological diagnosis, have yielded conflicting results about the rate of h. pylori infection among professionals performing gastroendoscopic procedures. some studies have not found a statistically significant difference in the infection rates compared with controls, [ ] [ ] [ ] [ ] [ ] [ ] while others have. [ ] [ ] [ ] [ ] [ ] [ ] consequently, a consensus has not been reached regarding the occupational risk for acquiring h. pylori infection. in these studies, different groups of subjects have been used as controls: blood donors; healthy non-medical professionals; , , and non-endoscopy medical personnel. , the h. pylori infection rate among patients undergoing endoscopy for upper gastrointestinal symptoms in italy is as high as . %; therefore, medical and nursing staff involved in endoscopic procedures could have a high risk of occupational exposure. the purpose of this study was to determine whether different staff groups of healthcare workers, either with or without direct patient contact, are at equal risk of acquiring h. pylori infection. for epidemiological studies of h. pylori, the non-invasive stool antigen test (hpsa) is a useful and appropriate diagnostic method that is both practical and highly sensitive. therefore, we used the hpsa test that, in contrast to serology, reflects the current status of tested individuals with regard to the presence or absence of h. pylori infection. the target population consisted of the personnel working at the umberto i hospital, a university teaching hospital located in rome, italy. from january to july , subjects underwent the hpsa in order to assess h. pylori infection status. individuals who had taken antimicrobial and antacid drugs during the three weeks preceding the test were excluded from the study. participation in the study was voluntary and anonymous. a questionnaire was completed by participants before collection of the faecal specimen. the questionnaire included the following items: age; sex; profession; department of employment; length of employment; exposure to gastrointestinal or oral secretions; history of upper gastrointestinal pain, dyspepsia or ulcer disease; and use of non-steroidal anti-inflammatory drugs or medication for any gastrointestinal complaints, such as antacids or histamine- -blocking agents. for endoscopists, additional items were: average number of gastroendoscopic examinations performed or assisted per week; and use of infection prevention procedures including routine wearing of gloves and mask during endoscopic procedures. stool specimens were obtained from each participant. the specimens were stored at k c. h. pylori stool antigen was measured using an antigen enzyme immunoassay (eia; premier platinum hpsa; meridian diagnostics, inc., cincinnati, oh, usa). the test using polyclonal antibodies to h. pylori was performed as indicated by the manufacturer, and the results were read by spectrophotometry. specimens with absorbance values (a / ) of z . were positive, those with values of z . and ! . were equivocal, and those with values of ! . were negative. the eia has a reported sensitivity of . %, a specificity of . % and showed . % correlation with h. pylori infection (data provided by meridian diagnostics, inc.). descriptive analysis was used to tabulate the data and make comparisons. all tests and p values were two-tailed. a p value of less than . was considered to be statistically significant. the outcome variable was the infection with h. pylori. multi-variate analysis was performed using logistic regression to analyse the independent effect of each variable on the outcome and possible interaction. study population and h. pylori infection two hundred and forty-nine subjects (mean age . years, sdz . years, age range - years), all working in the hospital, were included in the study population and divided into three groups: h. pylori prevalence in the three subgroups by sociodemographic characteristics is shown in table i . among the subjects, ( . %) tested positive for h. pylori. logistic regression analysis showed that crude h. pylori prevalence was significantly higher in both groups a (orz . ; % ci . - . ; pz . ) and b (orz . ; % ci . - . ; pz . ) compared with group c (table ii) . these odds ratios do not change substantially when adjusted for sex, age and education level. as shown in table i , there was no sex difference in h. pylori prevalence. although not statistically significant, h. pylori prevalence in the overall population increased with age (infected people: mean age . years, sd . years vs uninfected people: mean age . years, sd . years). in the endoscopy units, physicians and nursing personnel less than years of age had a lower prevalence of h. pylori infection ( . % vs . %, p! . ). therefore, concentrating on endoscopy status and age, when adjusted for exposure to endoscopy, workers aged r years had a significantly higher risk of infection (orz . ; % ci . - . ; pz . ). when adjusted for age, the h. pylori infection risk in groups a and b was higher than that in group c (orz . ; % ci . - . ; pz . vs orz . ; % ci . - . ; pz . ). education level was used as a surrogate measure of socio-economic status as reported previously. , an inverse relationship between educational attainment and infection in the overall population was seen in univariate analysis, showing more risk for healthcare personnel with % years of education compared with staff with a university education (table ii) . as reported in table i , in the subgroup of general medical staff, personnel with a university education showed a significantly lower prevalence of infection (p! . ) compared with personnel with a lower education level. the level of education was not related to h. pylori infection in staff with no patient contact. there was no significant difference in prevalence according to length of employment in the overall population or in the three subgroups. also, exposure to oral and faecal secretions was not associated with infection status (table iii) . figure presents the h. pylori prevalence in endoscopy personnel and general medical staff by age group (! vs r years old). both physicians and nurses working in an endoscopy unit showed an age-related difference in the prevalence of h. pylori infection. physicians less than years of age had significantly lower prevalence than older subjects ( . % vs . %, p! . ), whereas the difference did not reach statistical significance among nurses ( . % vs . %, pz . ). in contrast, the rate of infection in general medical staff did not show any significant difference with age. although not statistically significant, a difference between endoscopist and non-endoscopist physicians aged r years was observed ( . % vs . %, pz . ), whereas younger physicians of the two groups showed a similar prevalence of h. pylori infection ( . % vs . %). on the contrary, endoscopy nurses aged r years did not differ in their h. pylori prevalence from general nurses of the same age, whereas surprisingly, among nurses ! years, the prevalence was higher among general nurses. for endoscopists, the number of endoscopies performed per week and the time working in the endoscopy unit were considered to be possible risk factors. in both cases, there was no significant association (table iv) . regarding infection prevention, all endoscopy personnel wore gloves during every endoscopic procedure, and . % of the personnel used a mask. among physicians, . % always wore a mask during endoscopic practice, and among nursing personnel, . % used a mask during endoscopy and during the cleaning of endoscopes. no association between the use of a mask and the prevalence of h. pylori infection was observed. a history of gastritis and/or h. pylori infection were more frequent in endoscopy ( % and %) and general medical personnel ( % and %) compared with staff with no patient contact ( % and %). thirteen endoscopy personnel with a previous history of gastritis and/or h. pylori infection had received specific antimicrobial therapy; however, three of them were infected with h. pylori ( %). in the general medical staff group, healthcare workers reported previous therapy for h. pylori infection, five of whom were positive for h. pylori faecal antigen ( %). none of the six healthcare workers in the group with no patient contact that were treated for h. pylori infection were infected. gastrointestinal symptoms were noted by workers: % of endoscopy personnel, % of general medical staff and % of personnel with no patient contact. the most commonly reported gastrointestinal symptoms were abdominal pain in subjects, dyspepsia in subjects and nausea in subjects. twenty-six healthcare workers reported more than one gastrointestinal symptom. a statistically significant difference in the prevalence of infection was found between symptomatic and asymptomatic endoscopy personnel, whereas in general medical staff and in personnel with no patient contact, the difference was not significant (figure ). healthcare workers who are routinely exposed to patients and contaminated secretions are at increased risk of infection with parenteral viruses and other micro-organisms including emerging infectious diseases, as the recent severe acute respiratory syndrome outbreak confirmed. although a high h. pylori infection rate has been reported frequently in gastrointestinal endoscopy personnel, very few studies have been carried out on the prevalence of infection in different groups of hospital employees. , , no data are available on the h. pylori infection rate of healthcare workers exposed to h. pylori-contaminated secretions without patient contact, such as laboratory staff, in comparison with medical personnel (physicians and nurses) who had contact with patients. our study shows a significantly lower h. pylori infection prevalence in laboratory personnel compared with other hospital professional categories despite the fact that many of the laboratory personnel worked in a clinical microbiology laboratory where h. pylori was cultured, and most of the laboratory workers analyse faeces and oral samples in which the micro-organism may be present. laboratory workers, when handling potentially infectious samples, are aware of the need to use universal precautions. our results demonstrate that the prevalence of h. pylori infection is high and similar in gastrointestinal endoscopy personnel and other medical staff with direct patient contact, underlining the importance of contact with patients rather than the endoscopy activity itself as a risk factor for the acquisition of infection. similar conclusions were reported by braden et al. who found high h. pylori infection rates in physicians and nurses with contact to patients in general but not additionally in personnel with explicit exposure to gastric secretions during endoscopy. among healthcare workers with a previous history of recovered h. pylori infection, we observed a high prevalence of re-infection in the endoscopy and general medical staff groups. no infection was observed in h. pyloritreated workers with no patient contact, suggesting a higher chance of re-infection in personnel with direct patient contact. multi-variate logistic regression analysis showed that in our local community, h. pylori infection prevalence was highest in nurses. an increased infection rate in nurses has also been reported by gasbarrini et al. but only following univariate analysis. we observed similar prevalence of infection in nurses working in an endoscopy unit or other clinical departments. therefore, strict and continuous contact with patients seems to be a risk factor for h. pylori infection because the infected patients may release and spread the micro-organism from saliva, stool and vomitus. indeed, it has been demonstrated that emesis can be a potent mechanism for discharging millions of h. pylori cells into the environment, and positive h. pylori cultures have also been obtained from air sampled during vomiting. our results suggest that professional category exposure involving direct patient contact rather than educational attainment of healthcare workers can constitute a risk factor for h. pylori infection. in agreement, the rate of infection in laboratory personnel (contrarily to general medical staff) was low and was not influenced by educational level (technicians, . %; graduates, . %). among endoscopy workers, older personnel (r years) showed a significantly higher h. pylori infection rate compared with younger personnel. on the contrary, in general medical staff and staff with no patient contact, the h. pylori infection incidence was not influenced by age. although the study design did not allow this aspect to be investigated specifically, it may be hypothesized that since the h. pylori identification by warren and marshall in , endoscopy personnel have probably acquired safer working habits and thus younger workers may have had a lower risk of infection. moreover, the high prevalence in older endoscopy staff suggests that the period in which the exposure during endoscopy occurred could have enhanced acquisitional risk. the high prevalence of infection in general nurses of the two age groups (! and r years) suggests that infection control measures adopted in non-endoscopy departments are probably not as efficacious towards h. pylori, a micro-organism that colonizes the stomach for years or decades causing asymptomatic infections in most cases. our results indicate that % of asymptomatic healthcare personnel are infected by h. pylori, and % of infected workers have never had symptoms related to the gastrointestinal tract. in conclusion, the results of our study indicate that hospital work involving direct patient contact is associated with h. pylori infection, and suggest that safe working habits used by laboratory personnel or endoscopy staff, due to awareness of the existence of h. pylori, could prevent transmission of infection. the high infection rate observed in nurses suggests an increased risk of occupational exposure and calls for more strict precautionary guidelines to reduce the transmission of h. pylori to healthcare staff. epidemiology of and risk factors for helicobacter pylori infection among asymptomatic subjects in populations the transmission of helicobacter pylori: a critical review of the evidence helicobacter pylori and the pathogenesis of gastroduodenal inflammation helicobacter pylori and gastroduodenal disease an international association between helicobacter pylori infection and gastric cancer helicobacter pylori in children with peptic ulcer and their families intrafamilial clustering of helicobacter pylori infection helicobacter pylori: clonal population structure and restricted transmission within families revealed by molecular typing the prevalence of helicobacter pylori infection among inhabitants and healthy employees of institutes for the intellectually disabled high prevalence of helicobacter pylori antibodies in an institutionalized population: evidence for person-toperson transmission elevated risk of helicobacter pylori infection in submarine crews characterization of a culture method to recover helicobacter pylori from the feces of infected patients fecal and oral shedding of helicobacter pylori from healthy infected adults the transmission of helicobacter pylori: which theory fits the facts? review article: the transmission of helicobacter pylori from stomach to stomach campylobacter pyloridis serology among gastroendoscopy clinic staff prevalence of helicobacter pylori antibodies in the serum of gastroenterologists in austria risk of infection with helicobacter pylori and hepatitis a virus in different groups of hospital workers epidemiology of helicobacter pylori infection with special reference to professional risk endoscopy is not a risk factor for helicobacter pylori infection but medical practice is prevalence of helicobacter pylori infection in medical professionals in spain prevalence of helicobacter pylori infection in endoscopy and non-endoscopy personnel: results of field survey with serology and c-urea breath test occupational exposure to helicobacter pylori for the endoscopy professional: a sera epidemiological study risk among gastroenterologists of acquiring h. pylori infection: case-control study seroprevalence of immunoglobulin g antibodies against helicobacter pylori among endoscopy personnel in japan helicobacter pylori prevalence in endoscopy and medical staff seroprevalence of helicobacter pylori infection in medical staff in shanghai a serologic survey of helicobacter pylori infection in italian patients endoscoped for upper gastrointestinal symptoms. the italian helicobacter pylori study group prevalence and risk factors for helicobacter pylori infection among healthcare workers at a teaching hospital in rome: the catholic university epidemiological study hepatitis b virus, hepatitis c virus and human immunodeficiency virus infection in healthcare workers: a multiple regression analysis of risk factors a survey of latent tuberculosis among laboratory healthcare workers in new york city a major outbreak of severe acute respiratory syndrome in hong kong helicobacter pylori infection in intensive care: increased prevalence and a new nosocomial infection gut decontamination of critically ill patients reduces helicobacter pylori acquisition by intensive care nurses unidentified curved bacilli in the stomach of patients with gastritis and peptic ulceration this work was supported by a grant (n. ) from ministero del lavoro e della previdenza sociale (italy). we appreciate the contribution of all those who generously participated in this study. key: cord- -y fyslgo authors: zorko, david j.; gertsman, shira; o’hearn, katie; timmerman, nicholas; ambu-ali, nasser; dinh, tri; sampson, margaret; sikora, lindsey; mcnally, james dayre; choong, karen title: decontamination interventions for the reuse of surgical mask personal protective equipment: a systematic review date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: y fyslgo background: the high demand for personal protective equipment during the novel coronavirus outbreak has prompted the need to develop strategies to conserve supply. little is known regarding decontamination interventions to allow for surgical mask reuse. aim: identify and synthesize data from original research evaluating interventions to decontaminate surgical masks for the purpose of reuse. methods: we searched medline, embase, central, global health, the who covid- database, google scholar, disasterlit, preprint servers, and prominent journals from inception to april , for prospective original research on decontamination interventions for surgical masks. citation screening was conducted independently in duplicate. study characteristics, interventions, and outcomes were extracted from included studies by two independent reviewers. outcomes of interest included impact of decontamination interventions on surgical mask performance and germicidal effects. findings: seven studies met eligibility criteria: one evaluated the effects of heat and chemical interventions applied after mask use on mask performance, and six evaluated interventions applied prior to mask use to enhance antimicrobial properties and/or mask performance. mask performance and germicidal effects were evaluated with heterogenous test conditions. safety outcomes were infrequently evaluated. mask performance was best preserved with dry heat decontamination. good germicidal effects were observed in salt-, n-halamine-, and nanoparticle-coated masks. conclusion: there is limited evidence on the safety or efficacy of surgical mask decontamination. given the heterogenous methods used in studies to date, we are unable to draw conclusions on the most efficacious and safe intervention for decontaminating surgical masks. as the global spread of novel coronavirus (sars-cov- ) continues to escalate, so has the demand for personal protective equipment (ppe), creating global shortages in the supply of n filtering face respirators (ffrs) and surgical masks. n ffrs are recommended by the world health organization (who) and the centers for disease control and prevention (cdc) for use by healthcare providers (hcps) caring for coronavirus disease (covid- ) patients requiring airborne precautions and during aerosol-generating procedures [ , ] . therefore, n ffrs are most commonly needed for hcps in acute care and inpatient settings. in contrast, surgical masks are recommended for use by hcps to protect against the risk of droplet transmission in a broader range of inpatient healthcare settings, as well as outpatient settings (e.g. covid- assessment centres, long-term care facilities, and community care settings) [ ] [ ] [ ] . as the supply of n ffrs is threatened, hcps may resort to use of surgical masks for airborne precautions [ , [ ] [ ] [ ] . surgical masks are also recommended for use by patients with suspected or confirmed covid- to prevent potential spread in a variety of healthcare settings [ , ] . several institutions now recommend that everyone entering the hospital setting wear a surgical mask [ ] . these practices have created an unprecedented demand for surgical masks; unfortunately, the capacity for surge production of ppe is not sustainable in the long-term [ ] [ ] [ ] . as most facemask ppe are designed for single-use, mask rationing and conservation is now a top priority globally [ ] . mask reuse is now suggested as a crisis capacity strategy to conserve available supplies during a pandemic [ , [ ] [ ] [ ] , and much attention has now turned to decontaminating facemasks. several strategies have been evaluated, including ultraviolet germicidal irradiation (uvgi), chemical disinfectants, and microwave-and heat-based methods; however, most of this literature has focussed on the decontamination of n ffrs [ ] [ ] [ ] . the evidence on the efficacy and safety of decontamination and reuse of surgical masks is unclear. the objective of this systematic review was to evaluate and synthesize the evidence on decontamination interventions for the purpose of surgical mask ppe reuse. this systematic review protocol was designed a priori, registered on prospero (april th , ; crd ), and uploaded as a pre-print on open science framework (april th , ; https://osf.io/ wt /) [ ] . the reporting of this systematic review is in accordance with the preferred reporting items for systematic reviews and meta-analyses (prisma) statement (appendix a) [ ] . studies were eligible for inclusion if the following criteria were met: ) the study was original research, including systematic reviews; ) the study evaluated surgical facemask ppe or their components; ) the study evaluated any intervention(s) to decontaminate, sterilize or treat surgical masks (applied either before or after their use) for the purposes of reuse as ppe; ) at least one of the following efficacy or safety outcomes of interest was reported: a) mask performance (i.e. filtration efficiency and airflow resistance); b) reduction in pathogen load; c) in vivo infection rates following use of decontaminated masks; d) changes in physical appearance (i.e. mask appearance or physical degradation); e) adverse effects experienced by the wearer (e.g. skin irritation); or f) feasibility of the intervention (e.g. time, cost, resource utilization). we excluded editorials, case reports, narrative reviews, study protocols, clinical practice guidelines, grey literature, book chapters, and patents. two health sciences librarians (ls, ms) searched the following electronic databases from their dates of inception to april th citations were imported into endnote and duplicates were removed. citations were uploaded to insightscope (www.insightscope.ca) for title/abstract screening and full text review. citation screening for title/abstract and full text review stages was conducted independently and in duplicate by a team of reviewers recruited from mcmaster university, the university of ottawa, and the university of manitoba. prior to gaining access to the full set of citations, each reviewer read the systematic review protocol and was required to achieve a sensitivity of at least % when screening a test set of citations (containing five true positives and true negatives). reviewers achieving less than % sensitivity on the test set were provided with additional training. at both title/abstract and full text review, citations were excluded only if both reviewers agreed to exclude; disagreements were resolved by the study leads (dz, kc) where necessary. upon completion of full text review, the study co-lead (dz) reviewed all retained citations to identify potential duplicates and confirm eligibility. the reference lists of all citations included for full text review were searched for potential eligible citations that may have evaded the initial database search. data were collected using electronic data extraction forms (microsoft excel) modified from previous systematic reviews [ , ] for this protocol and piloted by two investigators (dz, sg) on two eligible studies. data was extracted from the full text publication and any related publications, referenced published protocols, or supplementary materials. data extraction was completed in duplicate by two independent reviewers. where necessary, graphical data was extracted using sourceforge plot digitizer (http://plotdigitizer.sourceforge.net) and checked by the second reviewer for accuracy. disagreements were resolved by the study leads (dz, kc), where necessary. we planned to use recommended risk of bias tools where appropriate [ ] ; however, in the absence of a standard risk of bias tool for laboratory studies, we applied objective assessment criteria developed for this purpose [ ] . risk of bias was assessed by two reviewers independently and in duplicate at the study level by outcome in the following domains: study design, methodological consistency, population heterogeneity, sampling bias, outcome evaluation, and selective reporting (appendix c). the primary outcome for this study was efficacy and safety of the decontamination intervention, as determined by any of the following: mask performance (filtration efficiency [fe] and airflow resistance); reduction in pathogen load; in vivo infection rates following use of treated masks; mask appearance or physical degradation; or adverse effects experienced by the wearer. fe refers to the percentage of particles filtered at either a specific particle size or a range of particle sizes depending on the testing agent and standard used [ ] . study results reporting percentage particle penetration were converted to fe units (i.e. fe% = -particle penetration) for comparability [ ] . airflow resistance is measured as the pressure drop across the mask, quantifying initial resistance to airflow in millimetres of water column height pressure per square centimeter (mmh o/cm ) [ ] . reduction in pathogen load was reported as a log reduction factor from a time zero post-inoculation to a subsequently measured time point. if log reductions were not reported by the study, we calculated them using the study data provided (e.g. colony counts), where possible. a log reduction factor ≥ was used as a reference indicating good germicidal effect [ ] . the secondary outcome was feasibility of the intervention, such as the time, cost and resources required to implement the intervention. where results were presented for multiple experimental conditions, we reported the summary of results conducted at the harshest testing conditions, to allow a conservative interpretation of the outcomes evaluated [ ] . primary outcome data was analysed descriptively and presented using absolute values and as a percent change where possible. no three studies evaluated the same intervention, nor applied similar test agents or conditions when evaluating outcomes. this precluded our planned quantitative analysis of outcomes [ ] ; therefore, selected results from included studies were summarized descriptively. nine of reviewers achieved the % sensitivity threshold on the test set. the two reviewers who did not achieve the % threshold were provided additional training regarding the screening protocol prior to citation screening. the review team achieved kappa values of . and . for title/abstract and full text screening respectively. study leads resolved conflicts in . % title/abstract and . % full text screening citations. of records identified through the initial database search, unique citations were reviewed and full-texts were assessed for eligibility. twenty-six full texts were excluded for ineligibility, leaving seven unique studies for inclusion in our analysis (prisma diagram, figure ). no additional citations were identified on review of reference lists. characteristics of included studies are summarized in table i . only one of the seven included studies evaluated interventions applied after surgical mask use (i.e. decontamination interventions) [ ] . the remaining six studies evaluated interventions applied to masks or mask components prior to use to enhance antimicrobial properties and/or fe for potential reuse or extended use (i.e. pre-contamination interventions) [ ] [ ] [ ] [ ] [ ] [ ] . interventions in these studied were tested on whole masks, pieces of whole masks (referred hereafter as mask pieces) or pieces of individual mask layers (referred hereafter as mask layer pieces). risk of bias assessments for the included studies are described in appendix d. lin et al. [ ] evaluated five decontamination interventions on mask pieces of two surgical mask types commonly used in taiwanese hospitals (gauze double-layer electret masks and oimo spunlace non-woven masks; models unspecified): dry heat (via rice cooker), high-pressure moist heat (i.e. autoclave), and three chemical agents ( % ethanol, % isopropanol, and . % sodium hypochlorite [i.e. bleach]). study methods and findings are summarized in table ii . mask pieces were assessed for fe, airflow resistance, and physical characteristics following decontamination. fe was presented graphically for a range of particle sizes ( . μm to . μm); we summarized the results for fe at . μm, a standard particle size for particulate fe testing [ ] . at baseline, gauze and spunlace mask pieces had fes of approximately % and %, respectively. fe in both mask pieces decreased after each decontamination intervention, but dry heat decontamination of gauze mask pieces demonstrated the smallest change (absolute fe reduction of . %). moist heat and chemical decontamination interventions all resulted in greater absolute fe reductions ( % to %). bleach was the most damaging method, resulting in a . % absolute fe reduction in spunlace mask pieces and destruction of gauze mask pieces. airflow resistance was assessed at a flow rate of . l/min [ ] . statistically significant changes in pressure drop were reported following all decontamination interventions, except for dry heat and ethanol on gauze mask pieces [ ] . airflow resistance results were not reported for bleach on gauze mask pieces (mask destroyed), or isopropanol for either mask type. physical characteristics were reported only for gauze mask pieces; the autoclave deformed and caused observable folds in the mask filter, and bleach destroyed the mask. physical characteristics following decontamination with other interventions, or in spunlace mask pieces, were not reported. germicidal effects of the five decontamination methods were not assessed. six studies evaluated five unique pre-contamination methods applied prior to mask use: four were antimicrobial interventions (nanoparticle emulsion [ , ] , quaternary ammonium agent five studies evaluated the effects of their intervention on fe, airflow resistance, or both, applying different testing techniques (table iii) evaluated fe of gs -coated mask layer pieces using aerosolized bacteria ( . μm to . μm particle diameter) and gs -coated masks using nacl ( . μm particle diameter), respectively. they found no statistically significant change in fe in gs -coated masks or mask layer pieces ( . % to . % fe increase in polypropylene filter layer, . % fe reduction in mask; p=ns). li et al. [ ] used a potassium-fluorescein solution (particle size not reported) to evaluate fe in nanoparticle-coated full masks by: ) the percentage potassium content of each mask layer relative to the potassium content of the whole mask; and ) a seven point scale rating fluorescent stains on mask users faces. they found that the percentage potassium content of each mask layer was similar compared to uncoated masks (+ %, - % and + . % absolute difference from control for outer, middle and interior mask layers, respectively), and similar ratings of fluorescent stains. airflow resistance was non-significantly increased (+ . ml/s/cm ; p=ns). shen et al. [ ] used an aerosolized pathogen simulant ( . μm particle diameter) and also quantified fe as the proportion of particle content on each mask layer to that of the whole mask. they reported significant decreases in particle content on the repellant-coated outer mask layer coated with repellant (p< . ), but no changes to particle content on mask layers proceeding the filter layer (suggesting no changes to fe of the mask as a whole). airflow resistance was not assessed. (table iii) however, the germicidal effect of dry heat in surgical masks is unclear. bleach is not a safe method of decontaminating surgical masks; mask performance is significantly altered and safety data from n ffr studies suggest potential health risks associated with off-gassing [ ] . with respect to pre-contamination interventions, salt film, gs , nanoparticle emulsion and n-halamine mask coatings were reported not to have detrimental effects on mask performance. n-halamine and nanoparticle emulsion showed strong germicidal effects in masks (log reduction factors ≥ ), which is consistent with their application in medical devices [ ] , and food and water treatment [ ] . salt films also demonstrated strong germicidal effects, but their application has been experimental to date [ ] . an important consideration is that pathogen load was evaluated at different post-inoculation incubation time points in each study (i.e. minutes to hours); it is well-established that viral load reductions can occur by virtue of time [ ] . ideal ppe decontamination methods should not only demonstrate effective reductions in pathogen load, but also preserve mask performance without causing any residual chemical hazard to the wearer [ ] . results of included studies should be interpreted cautiously for the following reasons: ) some of the mask types used in these experiments appear to have baseline fes below reference standards which may have affected the results observed [ ] ; ) experiments and test conditions applied to mask pieces or individual layers cannot necessarily be extrapolated to whole masks; and ) testing methods and outcome assessments were heterogenous. unlike n ffrs, surgical masks are not certified under standardized national institute for occupational safety and health regulations. the food and drug administration (fda) recommends that several standards (astm f , astm , mil-m c, or modified greene and vesley method) may be applied to surgical masks, complicating the evaluation of mask performance in this review [ ] . there are many test conditions that can impact fe, such as particle size, particle charge (i.e. whether charge neutralized or not), and face velocity (i.e. flow rate); however, the fda and astm do not have uniform recommended standards [ ] . the evidence that we have collated in this systematic review is therefore important and essential. this systematic review reveals that the body of evidence on decontamination interventions for surgical masks is scant compared to n ffrs. three recent systematic reviews have revealed unique studies evaluating microwave irradiation, heat, chemical disinfectants, and uvgi for decontamination of n ffrs [ ] [ ] [ ] . uvgi and vaporous hydrogen peroxide showed favourable evidence for germicidal effects without significant changes in mask performance; however, we were not able to find any publications evaluating these methods in surgical masks. the lack of research on surgical masks may stem from assumptions that methods effective in n ffrs can be extrapolated to surgical masks, and some institutions are already applying the same decontamination methods to both [ ] . considering this systematic review demonstrates that mask types can perform differently after decontamination, and that surgical masks and n ffrs perform differently with aerosol challenges [ , ], we cannot conclude that decontamination methods can be effectively or safely applied to all mask types. furthermore, common components of surgical masks such as cellulose-based materials, are known to degrade vaporous hydrogen peroxide and reduce the efficacy of sterilization [ ] . there is also limited data evaluating the effectiveness of any ppe decontamination intervention against sars-cov- [ , ] , although more studies are underway. independent research on surgical masks is therefore critical in order to inform clinicians, infection control experts, and public health administrators on how best to advise safe decontamination and reuse practices. our systematic review has several important strengths. to our knowledge, this is the first systematic review of decontamination interventions in surgical mask ppe and provides important information describing the nature of interventions and outcomes evaluated to date. our review highlights the variability in study methods and outcome reporting. as a result, we identified the following core outcomes to consider when conducting research in this field, to encourage consistent methodology and transparent reporting: mask performance (fe, airflow resistance), decontamination effects (germicidal effects, in vivo infection rates), physical characteristics of decontaminated masks, adverse effects to mask users, and intervention feasibility. we also developed a systematic tool with which to assess risk of bias in this body of literature. our review also has limitations. we were unable to conduct any meta-analyses due to the paucity of studies and their heterogeneous methodologies and outcome assessments. outcomes described this systematic review required summarizing study results from multiple experiments; we rationalized the selective reporting of results in our methods to encourage conservative interpretation of the findings. given the rapidly evolving landscape of ppe literature during the sars-cov- pandemic, we plan to update this systematic review at regular intervals for new relevant evidence as it becomes available (i.e. living systematic review) [ ] . there is inadequate evidence on the safety or efficacy of any decontamination intervention for extended use or reuse of surgical masks in the clinical setting. further research should therefore be conducted specifically in surgical masks, that include decontamination interventions demonstrating promise in n ffrs (e.g. uvgi, vaporized hydrogen peroxide). to ensure the safety of hcps and all end users, the same rigorous standard of research should be applied to surgical masks as with n ffrs, given its much broader applications as ppe. we recommend that future studies consider applying core outcomes and test conditions that are in accordance with acceptable industry standards in their design, to enable transparency of reporting and comparisons of efficacy between interventions. . (+ . ), p< . fe, filtration efficiency; ns, not statistically significant. a fe to testing agent used, expressed as a percentage. a higher percentage filtration efficiency indicates better mask performance. results in study were presented as percentage particle penetration, and converted to filtration efficiency (fe % = -particle penetration) for consistency of reporting in this systematic review. b airflow resistance assessed the "breathability" of the mask at tidal breathing. a lower airflow resistance means better breathability. for disease control and prevention. interim infection prevention and control recommendations for patients with suspected or confirmed coronavirus disease (covid- ) in healthcare settings world health organization. rational use of personal protective equipment for coronavirus disease ( covid- ) and considerations during severe shortages: interim guidance facemasks for the prevention of infection in healthcare and community settings advice on the use of masks in the context of covid- : interim guidance potential demand for respirators and surgical masks during a hypothetical influenza pandemic in the united states personal protective equipment supply chain: lessons learned from recent public health emergency responses. health secur hospital preparedness for severe acute respiratory syndrome in the united states: views from a national survey of infectious diseases consultants universal masking in hospitals in the covid- era centers for disease control and prevention. strategies for optimizing the supply of facemasks sourcing personal protective equipment during the covid- pandemic heat-based decontamination of n filtering facepiece respirators (ffr): a systematic review decontaminating n masks with ultraviolet germicidal irradiation (uvgi) does not impair mask efficacy and safety: a systematic review efficacy and safety of disinfectants for decontamination of n and sn filtering facepiece respirators: a systematic review decontamination interventions for the reuse of surgical mask personal protective equipment (ppe): a protocol for a systematic review the prisma statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration tools for assessing risk of reporting biases in studies and syntheses of studies: a systematic review a comparison of facemask and respirator filtration test methods american society for testing and materials (astm) f - . standard specification for performance of materials used in medical face masks validation and application of models to predict facemask influenza contamination in healthcare settings the chemistry and applications of antimicrobial polymers: a state-of-the-art review notice -important regulatory considerations for the reprocessing of single use n respirators during the covid- response n mask decontamination using standard hospital sterilization technologies do n respirators provide % protection level against airborne viruses, and how adequate are surgical masks? terminal sterilization of medical devices using vaporized hydrogen peroxide: a review of current methods and emerging opportunities detection limit of assay not reported; log reduction factor cannot be calculated. f colony-forming unit reduction percentages reported in study. results converted to log reduction factors. g absolute values for lung viral titers reported in study (strain not reported) with post-inoculation incubation of - log reduction in lung viral titer g uncoated: . (n ) mg/cm : . , p < . mg/cm : . , p < . mg/cm : . , p < . all surviving mice had reduced, but detectable, lung viral titers.bdl, below detection limit; cfu, colony forming units; fe, filtration efficiency; gs , goldshield quaternary ammonium agent; h n ca/ , h n influenza virus (a/california/ / ); h n pr/ , h n influenza virus (a/puerto rico/ / ); h n vn/ , h n influenza virus (a/vietnam/ / ); kcl, potassium chloride; n , time zero from which log reduction factor was calculated; nacl, sodium chloride; ns, not statistically significant. a fe to testing agent used, expressed as a percentage. a higher percentage filtration efficiency indicates better mask performance. b airflow resistance assessed the "breathability" of the mask at tidal breathing. a lower airflow resistance means better breathability. c study reported pressure drop and flow rate in inches of water and cubic feet per minute per square foot, respectively. results converted to si units. d colony-forming units or plaque-forming units reported in study, as applicable. results converted to log reduction factors. key: cord- -s h p s authors: carter, b.; collins, j.t.; barlow-pay, f.; rickard, f.; bruce, e.; verduri, a.; quinn, t.j.; mitchell, e.; price, a.; vilches-moraga, a.; stechman, m.j.; short, r.; einarsson, a.; braude, p.; moug, s.; myint, p.k.; hewitt, j.; pearce, l.; mccarthy, k. title: nosocomial covid- infection: examining the risk of mortality. the cope-nosocomial study (covid in older people). date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: s h p s introduction: hospital admissions for non-covid- pathology have significantly reduced. it is believed that this may be due to public anxiety about acquiring covid- infection in hospital and the subsequent risk of mortality. there is an urgent need for clarity regarding patients who acquire covid- in hospital (nosocomial covid- infection [nc]), their risk of mortality, compared to those with community acquired covid- (cac) infection. methods: the cope-nosocomial study was an observational cohort study. the primary outcome was the time to all-cause mortality (estimated with an adjusted hazards ratio [ahr]), and secondary outcomes were day- mortality and the time-to-discharge. a mixed-effects multivariable cox’s proportional hazards model was used, adjusted for demographics and comorbidities. results: our study included patients from hospital sites throughout the uk, and one in italy, and collected outcomes on patients admitted up to (th) april, . . % of covid- infections were acquired in hospital. ( . %) patients with covid died. the median survival time in nc patients was days, which compared to days in cac patients. in the primary analysis, nc infection was associated with reduced mortality (ahr= . , %ci . - . ). secondary outcomes found no difference in day- mortality (aor= . , %ci . - . ), but nc patients required longer time in hospital during convalescence (ahr= . , %ci . - . ). conclusion: the minority of covid- cases were the result of nc transmission. whilst no covid- infection comes without risk, patients with nc had a reduced risk of mortality compared to cac infection, however, caution should be taken when interpreting this finding. in the united kingdom, authority to conduct the study was granted by the health research authority ( /hra/ ), and in italy by the ethics committee of policlinico hospital modena (reference / /oss/aoumo). cardiff university was the study sponsor. the novel coronavirus sars-cov- is implicated in causing the disease covid- and its associated complications. while most infected people develop mild flu-like symptoms, some have significant respiratory complications and go on to develop multiorgan failure ( ) and death ( ) . despite robust infection control efforts, hospital-acquired (herein described as nosocomial) covid- infection have been reported ( - ) . heightened anxiety amongst the general public has resulted in individuals' reluctance to attend hospital for diagnostic tests or treatments. this may account for the significant reduction in acute hospital attendances ( ) and possibly contributed to the high excess mortality toll. the hallmark of sars-cov- is its highly contagious nature; it remains viable and infectious on surfaces for up to three days ( ) . its main mode of transmission is through droplets and close contact with people with the disease ( ) . incubation is estimated at - days (who), but this can take up to days ( ) . nosocomial infection is defined as an infection that is acquired in hospital by a patient who was admitted for a reason other than that infection (at least days prior to a positive covid- diagnosis), and in whom the pathogen was not incubating at the time of admission. risk factors for developing a nosocomial infection include; age > years, immunosuppression, admission to intensive care, history of trauma, antibiotic use and use of an indwelling catheter ( ) . prior to the current covid- pandemic, nosocomial infections (most commonly from respiratory and urinary tracts and surgical wounds) already posed significant healthcare and economic burdens in both developed and resource-poor countries, with an average estimated prevalence of . % worldwide ( ) . in general, nosocomial infections are not life threatening. however, a large study in the united states reported that non-ventilator associated nosocomial pneumonia occurred in . % of all hospital admissions, with a mortality rate of . % ( ) . in addition, patients diagnosed with a nosocomial infection are likely to spend . times longer in hospital ( ) . sars (severe acute respiratory syndrome, ) and the mers (middle east respiratory syndrome, ) had estimated nosocomial infection prevalence of % and % respectively ( ) . in comparison, chinese estimates of the prevalence of nosocomial covid- are as high as % ( ) ( ) ( ) . there is no current published data for nosocomial versus community acquired covid- in uk hospitals, leaving uncertainty around morbidity or mortality and heightened public anxiety. a robust evidence base will help direct policy-makers and aid the dissemination of public health advice. the cope (covid- in older people study) study was designed to assess a number of clinical parameters and biomarkers as prognostic tools for patients with covid- . the aim of this secondary study was to assess the burden of nosocomial covid- (nc) infection and determine if patients with nc exhibited poorer outcomes to those who experienced community acquired covid- (cac) infection. data were obtained as part of a multi-centre international cohort study: the cope study in older people study), which assessed clinical and biomarkers as prognostic indicators of mortality. in the united kingdom, authority to conduct the study was granted by the health research authority ( /hra/ ), and in italy by the ethics committee of policlinico hospital modena (reference / /oss/aoumo). cardiff university was the study sponsor. this manuscript follows the strobe statement for reporting of cohort studies ( ). investigators at each site collated electronic and manual patient records. prior to participating, all study personnel completed specific data collection training. local policies on data protection were followed in order to record data securely at each site. full study details can be found within the cope protocol ( ) . we utilised an established network of clinical teams with an interest in frailty from ten uk sites and isolation of suspected and confirmed cases, and had a policy of having no outside visitors during the period of data collection ( ) . all hospitals deliver urgent and emergency care to patients diagnosed with covid- . data were collected from patients admitted with cvid from th february and th of april . further details of the study design are found within the protocol ( ) , and the main study findings are reported in the cope study report ( ) . in the original protocol we estimated a % mortality in the frail, and % in those not frail (hazard ratio [hr] of · ). in order to detect this difference with % power and with a % significance, at least patients were to be included. the sample size was increased to assess cfs categorised into four groups (rather than frail vs not frail) ( ) . we attempted to include all consecutive patients admitted to hospital aged years or older with a diagnosis of covid- . diagnostic criteria were swabs confirming the presence of sars-cov- , or a clinical diagnosis (made by the site clinical team and based on signs, symptoms and/or radiology) consistent with covid- . patients were screened and excluded due to: not having a clinical (or laboratory) diagnosis; clinical documentation not available; or no available clinical resource for data capture. clinical teams at each site screened in-patient admission lists for eligibility and had access to infection control records of positive covid- laboratory testing. screening logs of eligible participants were retained at each site. outcomes: the primary outcome was the time-to-mortality from the date of admission (or date of diagnosis, if diagnosis was five or more days after admission). for example, all nc patients were diagnosed or more days after admission, and were analysed as the time from diagnosis to outcome (death or discharge). the cac were analysed from the date of diagnosis to outcome (since they had a positive diagnosis between five and days after admission could not be confirmed as true nc), with the remaining cac analysed as the difference from admission to outcome. the time to event was censored at death or discharge. secondary outcomes: day- mortality and the time-to-discharge (herein described as the length of stay). we collected variables with prognostic utility ( , - ) which included: patient age sex; c-reactive protein (crp) on admission (; estimated glomerular filtration rate (egfr) on admission; smoking status (never, previous, or current); frailty; and previous or current history of: coronary artery disease, diabetes mellitus, and hypertension. frailty was measured using the pre-admission clinical frailty score (cfs) representing a patients' frailty two weeks prior to admission. the cfs is widely used within the uk to aid clinical management. the cfs is used as an ordinal hierarchical scale that numerically ranks frailty from to , with a score of being very fit, well, managing well, vulnerable, mildly frail, moderately frail, severely frail, very severely frail and terminally ill. for the purposes of the analyses scores were grouped into a clinically meaningful groups: - , - , - and - ( ). baseline demographic and clinical characteristics were partitioned by mortality, and location of infection to describe the included participants. time to mortality (primary outcome) and length of stay (secondary outcome) were analysed with mixed-effects multivariable cox's proportional baseline hazards regression models. the analyses were fitted with a random effect to account for hospital variation ( ) , and adjusted for the base model of: patient age group; sex; smoking status; crp; diabetes; hypertension ; coronary artery disease; and the cfs. the adjusted hazard ratios (ahr) were estimated with associated % confidence intervals ( %ci). the baseline proportionality assumption was tested visually with loglog residuals. each time to event analysis was reported with a kaplan meier survival plot. the secondary outcome of day- was analysed using a mixed-effects multivariable logistic model, fitting each hospital as a random intercept effect, and adjusted with covariates consistent with the primary outcome. the adjusted odds ratio (aor) were estimated and presented with associated %ci. missing data were explored for patterns of missingness. the primary outcome analysis was repeated within each of the co-morbidity subgroups to assess the impact of nc within each subgroup. analysis was carried out using stata version ( ) . kaplan meier survival plots were generated in r ( ) . the cope study screened , participants from general medical, surgical, geriatric, respiratory, and infectious diseases wards, as well as intensive care units where applicable. these wards solely managed suspected or confirmed covid- patients. patients were excluded from the study after screening, with the remaining , participants included. there were ( . %) patients from the uk, and ( . %) from italy (table ) . most were diagnosed laboratory testing ( . %) and ( . %) by clinical diagnosis. data quality was high and a complete case dataset was obtained for over % of included patients. there were cases of missing smoking status, which were imputed as never smokers, and cases of missing crp, which were median imputed. other missing covariates occurred in no more than patients. given the minimal degree of missing data, the complete case population was used within each analysis, and the number included shown as the population under investigation. the median patient age was years old (iqr, - ), and were male ( . % table . by end of study period, . % of patients with nc were dead versus . % cac patients. the median time-to-mortality was days in the nc versus days in the cac group ( figure ). in the multivariable analysis we found that nc infection was associated with reduced mortality (ahr= . , %ci . - . ; p= . , table ). it was also found that increased mortality was this study is the first to report outcomes for patients with nc infection. of all covid- cases included . % of infections were due to transmission in hospital. overall mortality rate was . % with a reduction in mortality with an nc infection. patients with nc infection experienced a longer length of stay in hospital. the proportion of nosocomial infections with covid- found within this study was lower than the % previously reported by wang and colleagues ( ) . although direct comparisons are difficult, wang had a small sample size (total patients) which included healthcare worker infections. excluding these, the rate of patient nc infection was similar to our study ( . % versus . %). compared to other reported rates of nc infection during historical global pandemics, it appears that nc infection rates are much lower during the covid- pandemic, with the majority of inhospital covid cases originating from the community. in western healthcare, infection control policies have been developed for many years which have positively impacted the response to the rapidly evolving pandemic situation. this multicentre study is predominantly uk based and it is important to recognise that data from eastern populations may not be applicable to western populations based upon individual genetic differences, available healthcare resources and preparedness of healthcare providers to respond to overwhelming demands on services. the first covid- positive patient was reported to the world health organisation (who) on st december in wuhan, china. the uk and italy reported their first cases on st january . it is possible that countries affected later were able to anticipate resources required and recognised the importance of being able to implement those plans quickly and have a different nc rate. this allowed patients with either diagnosed or suspected to have covid- to be isolated, managed with an increased awareness of cross infection, with preventative measures such as personal protective equipment, in dedicated 'covid- ' wards. the public health message during the united kingdom's lockdown was to stay at home, leaving home only for essential travel, in order to maintain social distancing measures. understandably there is much anxiety amongst the general public, particularly amongst those with pre-existing healthcare conditions. this has led to % fewer ed attendances reported in march compared to march in england alone ( ) . furthermore, the office for national statistics (ons) reported the highest death rate in england & wales since (week ending rd april ), , more than the -year average. worryingly only , of these are attributed to , raising the concern that these additional deaths may have been related to a public reluctance to seek medical attention. our findings have demonstrated that mortality rates are no worse if covid- was acquired in hospital, compared with those who have acquired the disease in the community. highlighting that patients should be reassured when seeking medical attention for non-covid- conditions. this nc group of patients were older and frailer, with a non covid- pre-existing reason for hospital admission, all leading to and a median hospital stay in excess of one month. with daily inpatient assessment it is likely that prompt recognition of covid- like symptoms occurred leading to prompt laboratory and clinical diagnosis of covid- infection. in contrast the cac patients may have tolerated their symptoms at home for a period of time before requiring hospital admission. there is also a possibility that reluctance to seek medical attention may have compounded their potentially delayed presentation to hospital. this difference in clinical management may have led to the nc patients to have timely supportive treatment, as opposed to those coming in from home who may have presented late with more severe illness led to a reduced mortality in the cac patients. it is possible that normal targeted and individualised care for longer term patients were reconfigured to focus on acute admission assessment and critical care. although not assessed in this study and difficult to assess objectively, the influence of nursing in isolation and prohibition of hospital visitors is likely to have had a negative psychological impact for this patient group. this is a large multicentre observational cohort study including over , adult in patients. our definition of nc was conservative, so the infection rate should be considered . % or greater. since hospital workers or patient visitors with covid- were not included in the definition of nc infection, or were patients with a positive diagnosis less than days prior to their admission. or asymptotic patients were discharged without a positive diagnosis (most likely in younger or less severe patients). a further limitation of this observational study is that we could not allow for casemix differences between the nc and cac groups, including mildly symptomatic or asymptomatic patients diagnosed covid- as part hospital screening programmes. furthermore, we did not assess the cause of death for patients from both nc and cac groups, although it is assumed that covid- formed at least part of the cause of death for all those who died. with low hospital acquired infection rates, this study demonstrates that effective infection control policies are in place in western hospitals. it is now the responsibility of public and professional bodies to actively encourage patients to seek acute medical attention when required and to consider the risks and benefits of reintroducing elective services. organisational response to emerging evidence should be proactive, considered and continuous. it is imperative that complacency is avoided in response to reduced published daily mortality figures in order to prevent a second wave. in a large study, we found that the minority of covid- hospital episodes were the result of nosocomial transmission. whilst no covid- infection comes without risk, those patients with nc infection had no greater risk of mortality, and potentially lower risk than people admitted to hospital with covid- . the older person's surgical outcomes collaboration (opsoc) over the last seven years have engaged with patients over study design, interventions, and dissemination. the cope study was discussed by patients at the study set up about the outcomes to be collected at the protocol stage. this particular study was set up, and conducted in a timely manner, to address if attending hospital during the first (or subsequent) waves of the epidemic was likely to lead to infection, and if that infection would have an increased risk of experiencing a clinical event. there was no funding for the cope study. no conflicts exist from any of the authors clinical course and risk factors for mortality of adult inpatients with covid- in wuhan, china: a retrospective cohort study world health organisation minimising intra-hospital transmission of covid- : the role of social distancing risk of nosocomial infection of coronavirus disease : an experience in a general ward setting in hong kong sars-cov- transmission in patients with cancer at a tertiary care hospital in wuhan, china the incubation period of coronavirus disease (covid- ) from publicly reported confirmed cases: estimation and application aerosol and surface stability of sars-cov- as compared with sars-cov- clinical management of severe acute respiratory infection when patients novel coronavirus ( -ncov) infection is suspected: interim guidance risk factors and prevention strategies of nosocomial infection in geriatric patients world health organisation department of communicable disease surveillance and response. prevention of hospital-acquired infections a practical guide nd edition the epidemiology of nonventilator hospital-acquired pneumonia in the united states infection control and prevention: a review of hospital-acquired infections and the economic implications nosocomial infections among patients with covid- , sars and mers: a rapid review and meta-analysis clinical characteristics of hospitalized patients with novel coronavirus-infected pneumonia in wuhan, china prevention and treatment of cross infection of novel coronavirus pneumonia in thoracic surgery ward clinical practice of prevention and treatment of novel coronavirus infection in the medical personnel and surgical patients in the department of thoracic surgery of hospitals in wuhan cope study: covid- in older people -the influence of frailty and multimorbidity on survival. a multi-centre covid- : infection prevention and control guidance the influence of frailty on survival following covid- . the cope study (covid in older people): a multi-centre, international observational cohort study. the lancet public health clinical features of patients infected with novel coronavirus in wuhan clinical characteristics of coronavirus disease in china clinical predictors of mortality due to covid- based on an analysis of data of patients from wuhan, china. intensive care med parametric frailty and shared frailty survival models statacorp. stata statistical software: release . college station, tx: statacorp llc r: a language and environment for statistical computing. r foundation for statistical computing v deaths registered weekly in england & wales, provisional. week ending rd supplementary figure : time to mortality analysis, carried out in each subgroup. the findings present the adjusted multivariable hazard ratio for patients with a nosocomial infection versus a community acquired covid- infected patients note: multivariable analyses adjusted for age group, sex, smoking status, hypertension, diabetes, cad, kidney function, crp and cfs. *subgroup omitted due to low number of observations. key: cord- - jwawrm authors: choi, s.; jung, e.; choi, b.y.; hur, y.j.; ki, m. title: high reproduction number of middle east respiratory syndrome coronavirus in nosocomial outbreaks: mathematical modelling in saudi arabia and south korea date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: jwawrm background: effective countermeasures against emerging infectious diseases require an understanding of transmission rate and basic reproduction number (r( )). r( ) for severe acute respiratory syndrome is generally considered to be > , whereas that for middle east respiratory syndrome (mers) is considered to be < . however, this does not explain the large-scale outbreaks of mers that occurred in kingdom of saudi arabia (ksa) and south korean hospitals. aim: to estimate r( ) in nosocomial outbreaks of mers. methods: r( ) was estimated using the incidence decay with an exponential adjustment model. the ksa and korean outbreaks were compared using a line listing of mers cases compiled using publicly available sources. serial intervals to estimate r( ) were assumed to be six to eight days. study parameters [r( ) and countermeasures (d)] were estimated by fitting a model to the cumulative incidence epidemic curves using matlab. findings: the estimated r( ) in korea was . in the best-fit model, with a serial interval of six days. the first outbreak cluster in a hospital in pyeongtaek had an r( ) of . , and the largest outbreak cluster in a hospital in samsung had an r( ) of . . assuming a six-day serial interval, the ksa outbreaks in jeddah and riyadh had r( ) values of . and . , respectively. conclusion: r( ) for the nosocomial mers outbreaks in ksa and south korea was estimated to be in the range of – , which is significantly higher than the previous estimate of < . therefore, more comprehensive countermeasures are needed to address these infections. background: effective countermeasures against emerging infectious diseases require an understanding of transmission rate and basic reproduction number (r ). r for severe acute respiratory syndrome is generally considered to be > , whereas that for middle east respiratory syndrome (mers) is considered to be < . however, this does not explain the large-scale outbreaks of mers that occurred in kingdom of saudi arabia (ksa) and south korean hospitals. aim: to estimate r in nosocomial outbreaks of mers. methods: r was estimated using the incidence decay with an exponential adjustment model. the ksa and korean outbreaks were compared using a line listing of mers cases compiled using publicly available sources. serial intervals to estimate r were assumed to be six to eight days. study parameters [r and countermeasures (d)] were estimated by fitting a model to the cumulative incidence epidemic curves using matlab. findings: the estimated r in korea was . in the best-fit model, with a serial interval of six days. the first outbreak cluster in a hospital in pyeongtaek had an r of . , and the largest outbreak cluster in a hospital in samsung had an r of . . assuming a six-day serial interval, the ksa outbreaks in jeddah and riyadh had r values of . and . , respectively. conclusion: r for the nosocomial mers outbreaks in ksa and south korea was estimated to be in the range of e , which is significantly higher than the previous estimate of < . therefore, more comprehensive countermeasures are needed to address these infections. ª the healthcare infection society. published by elsevier ltd. all rights reserved. the emergence of infectious diseases associated with middle east respiratory syndrome (mers), severe acute respiratory syndrome and ebola has created unprecedented public health challenges. these challenges are complicated by the lack of basic epidemiological data, which makes it difficult to predict epidemics. thus, it is important to quantify actual outbreaks as novel infectious diseases emerge. disease severity and rate of transmission can be predicted by mathematical models using the basic reproduction number (r ) [ ] . for example, r has been used extensively to assess pathogen transmissibility, outbreak severity and epidemiological control [ e ] . in previous studies, r for mers has ranged from . to . [ e ], which suggests that the mers coronavirus (mers-cov) has limited transmissibility. however, these studies typically considered community-acquired mers infections. in this context, nosocomial infections can exhibit different r values as the transmission routes for community-acquired and nosocomial infections often differ [ ] . recent studies have examined large nosocomial outbreaks of mers-cov infection in jeddah and riyadh within the kingdom of saudi arabia (ksa). one study reported higher nosocomial r values than those from community-acquired infections when using the incidence decay with exponential adjustment (idea) model, which yielded values of . e . in jeddah and . e . in riyadh [ ] . the idea model is simple because it does not consider the population-level immune status, which makes it especially useful for modelling emerging infectious diseases in resourcelimited settings. the mers outbreak in south korea was associated with nosocomial infections. at that time, the korea centre for disease control and prevention (kcdc) assumed that the outbreak had an r < . thus, the initial countermeasures were not sufficiently aggressive to prevent the spread of mers-cov infection to other hospitals. therefore, the idea model was used to evaluate and compare the mers r values from the outbreaks in both ksa and south korean hospitals. ksa data were obtained using a line listing of mers-cov cases that was maintained by andrew rambaut (updated on th august ). the line listing was created using data from the ksa ministry of health and world health organization (who) report [ ] . since only % of cases in the ksa listing included the onset date, hospitalization dates or reported dates were used instead. the korean data were obtained from the kcdc. among the mers cases, had confirmed onset dates. the eight cases with unknown onset dates were assigned dates based on laboratory confirmation. all cases in ksa and korea were confirmed based on laboratory findings. study parameters [r and countermeasures (d)] were estimated by fitting a model to the cumulative incidence epidemic curves using matlab (mathworks, natick, ma, usa). the data were narrowed down to the nosocomial cases alone. cases with unknown transmissions were considered to be nosocomial if: (a) the patient was in contact with a healthcare worker and/or hospitalized patients; or (b) the patient was a healthcare worker. cases were excluded if they could not be verified as nosocomial (e.g. zoonotic transmission, family contact or community infection). the idea model was used to estimate r as reported previously [ ] , together with publicly available data. the idea model is based on the concept that the number of incident cases (i) in an epidemic generation (t) can be counted as: when an outbreak occurs, epidemic control measures can be implemented, which can, in turn, change r . therefore, the relationship between i and r with d is defined as follows: r and d are estimated by fitting i from eq. ( ) to the observed cumulative incidence data of mers using the leastsquares data-fitting method. since the idea model is parameterized using epidemic generation time, incidence case counts were aggregated at serial intervals of six, seven and eight days in the present study [ ] . two large outbreaks were considered in each country studied: the outbreaks in riyadh and jeddah for ksa; and those in pyeongtaek st. mary's hospital and samsung seoul hospital for south korea. the term 'resnorm' is defined as the norm of the residual, which is the squared -norm of the residual; it measures the difference between observed data and the fitted value provided by a model. however, as residuals can be positive or negative, a sum of residuals is not a good measure of overall error in the fit. therefore, a better measure of error is the sum of the squared residuals (e), which is calculated as follows: the functions to be fit were the given input data (xdata), the observed output data, (ydata) and f(x, xdata), where xdata was an epidemic generation, ydata was the observed cumulative incidence data, and f(x, xdata) was eq. ( ). since the generation times and the estimated values differ according to serial interval times, resnorm changes accordingly. therefore, to compare resnorm with the serial interval time, relative resnorm was defined as follows: the idea model was fitted to the cumulative south korean mers-cov case data from the onset date of the first case to the onset date of the last case. the outbreak start date was defined as th may because that was the symptom onset date for patient , who was the index case and caused the outbreak in the pyeongtaek hospital. all data used in these analyses were de-identified publicly available data obtained from who, the ksa ministry of health website or kcdc datasets. as such, these data were deemed to be exempt from institutional review board assessment. ksa outbreaks were relatively large, with cases (over the course of days) in jeddah and cases (over the course of days) in riyadh. the korean outbreaks involved cases (over the course of days), including cases (over the course table i ). the idea model was fitted to the daily ksa and korea mers-cov case data according to the onset date. figure displays the cumulative mers-cov case data for the ksa and the south korea mers outbreaks. the date of symptom onset for patient was th may ; however, he was admitted to the pyeongtaek hospital on th may . therefore, the outbreak was assumed to start on th may via a simulation of the pyeongtaek hospital outbreak. the outbreak start date for the samsung hospital was determined to be th may , following the same logic ( figure ). figure shows the results of the ksa outbreak. squares, circles and asterisks represent data aggregation of the number of cases by serial intervals of six, seven and eight days, respectively; the curves represent model fits for best-fit parameters. the estimated r values for jeddah and riyadh were in the range of . e . and . e . , respectively, using serial intervals of six to eight days. the estimated r values for the korea mers outbreak were . , . and . for serial intervals of six, seven and eight days, respectively (figure ). since most cases were related to nosocomial infections, r for each hospital was also considered. the outbreak in the samsung hospital was larger than that in the pyeongtaek hospital (the first korean outbreak). the pyeongtaek hospital exhibited best-fit r values of . , . and . for serial intervals of six, seven and eight days, respectively, while the samsung hospital exhibited greater r values of . , . and . for serial intervals of six, seven and eight days, respectively. figure shows that the idea model provided well-fitted curves for the cumulative data regarding south korean mers symptom-onset dates for all cases. although the idea model seemed to be appropriate, the original data never fit the model precisely. therefore, the appropriateness of the model was assessed. , using the incidence decay with exponential adjustment model. red squares, jeddah, six days; red circles, jeddah, seven days; red asterisks, jeddah, eight days; blue squares, riyadh, six days; blue circles, riyadh, seven days; blue asterisks, riyadh, eight days. evaluated using the relative resnorm to find the best-fit parameters. the results indicated that the best-fit r and serial interval values were . and seven days for all cases, . and eight days for the pyeongtaek hospital, and . and six days for the samsung hospital, respectively. d increased with each serial interval because the daily effort of d was aggregated by serial interval. the clusters of mers-cov cases in ksa healthcare facilities occurred from late march to late may , while the korean outbreaks occurred from mid-may to early july . these hospital-based outbreaks exhibited characteristics different from those of community-based outbreaks (higher r values and case fatality rates) [ , ] . the estimated r is a basic epidemiological variable that is important for selecting appropriate countermeasure efforts. however, an emerging infectious disease often has unknown epidemiology, making it difficult to model mathematically. several methods have been proposed to address this issue, including the idea model. the richards model can also estimate r using the cumulative daily number of cases and the outbreak turning point (or the peak, t i ) [ ] . in this context, hsieh used the richards model to estimate r values for the korean outbreak as . e . . however, the richards model does not consider any countermeasures implemented during an outbreak; therefore, it can only be used after an outbreak has peaked. the present study used the idea model to estimate r values from the mers outbreaks in ksa and south korea. the idea model exhibited a good fit: the estimated r values for south korea were . e . , and the best-fit r was . for a serial interval of seven days. conversely, r values for riyadh and jeddah were . e . and . e . , respectively, using serial intervals of six to eight days. majumder et al. [ ] figure . best-fit reproduction number (r ) by serial intervals of middle east respiratory syndrome in south korea, , using the incidence decay with exponential adjustment model. green squares, total, six days; green circles, total, seven days; green asterisks, total, eight days; red squares, pyeongtaek, six days; red circles, pyeongtaek, seven days; red asterisks, pyeongtaek, eight days; blue squares, samsung, six days; blue circles, samsung, seven days; blue asterisks, samsung, eight days. intervals of six to eight days. however, the estimated r values from the present study were much higher than the previously reported values of < for mers (the threshold for an epidemic) [ ] . regardless, the korean government assumed that the outbreak had an r value < based on the previous research. the initial criterion for quarantine, therefore, was limited to cases of 'close contacts', which were defined as people who were within m of a mers patient for ! h [ ] . these quarantines e established using an incorrectly assumed r e resulted in more mers patients and greater hospital-to-hospital transmission [ ] . a serial interval is the interval between successive cases of an infectious disease. this time period depends on the temporal relationship between the infectiousness of the disease, the clinical onset of the source case, and the incubation period of the receiving case [ ] . as mers becomes infectious with the onset of clinical symptoms, the mers latency period equals the incubation period. therefore, the shortest serial interval could be the same as the incubation period, and the longest serial interval could be the sum of the incubation period and the maximum duration of infectiousness. during the korean mers outbreak, several superspreading events occurred because the mers cases were not isolated immediately upon presentation of clinical symptoms [ ] . thus, these cases contacted susceptible individuals for up to one week after the onset of their clinical symptoms. however, most mers cases with laboratory confirmation were isolated immediately after onset of clinical symptoms [ , ] . in this study, as the incubation period was two to days (median: six days), the serial interval was slightly longer than the incubation period. the idea model with several serial intervals (four to days) was used and found that intervals of six to eight days provided the best fit. for ksa data, even though the reported date was used instead of the onset date, r was not affected because aggregated data by serial intervals was used in the analysis. the idea model is limited by the fact that d cannot be compared with d of another model. in this context, an increasing d in accordance with increasing serial intervals indicates that the countermeasure efforts are increasing. however, the size of d cannot be compared between two or more models of different outbreaks. nevertheless, the strength of the idea model is its simplicity because r can be estimated using the cumulative number of cases according to the serial interval alone. in conclusion, the estimated r values from the ksa outbreaks (riyadh and jeddah) ranged from . to . , whereas the estimated values from the south korean outbreaks ranged from . to . . based on these findings, it appears that nosocomial mers-cov outbreaks in ksa and south korea had higher r values than the previously assumed values of < . although community-acquired infections are caused by contact, nosocomial infections are caused by a combination of contact and aerosol transmission; therefore, r values for nosocomial infections can be higher than those for communityacquired infections. hence, more comprehensive countermeasures are needed to address nosocomial mers infections and prevent spread. mathematical models to characterize early epidemic growth: a review transmission dynamics of the etiological agent of sars in hong kong: impact of public health interventions emergency response to a smallpox attack: the case 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pyeongtaek st. mary's hospital mortality risk factors for middle east respiratory syndrome outbreak, south korea middle east respiratory syndrome coronavirus (mers-cov) nosocomial outbreak in south korea: insights from modeling a dynamic compartmental model for the middle east respiratory syndrome outbreak in the republic of korea: a retrospective analysis on control interventions and superspreading events mers outbreak in korea: hospital-to-hospital transmission the interval between successive cases of an infectious disease risk factors for transmission of middle east respiratory syndrome coronavirus infection during the outbreak in south korea control of an outbreak of middle east respiratory syndrome in a tertiary hospital in korea mers-cov outbreak following a single patient exposure in an emergency room in south korea: an epidemiological outbreak study all relevant data are available at http://rambaut.github.io/ mers-tools/cases .html. key: cord- - tu c m authors: romano-bertrand, sara; aho-glele, ludwig-serge; grandbastien, bruno; gehanno, jean-françois; lepelletier, didier title: sustainability of sars-cov- in aerosols: should we worry about airborne transmission? date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: tu c m nan sars-cov- is predominantly transmitted by respiratory droplets and contact with contaminated surfaces but the role of aerosol is debated. the usual personal protective equipment (ppe) recommended for healthcare workers (hcws) include gown or apron, gloves, protective goggles, head cover and face mask. for the later, the world health organization recommends wearing of an anti-projection or surgical mask when caring for covid- patients, and a respirator (filtering facepiece particles (ffp) or n mask) only in case of aerosol-generating procedures (agps) (https://apps.who.int/iris/bitstream/handle/ / /who- -ncov-ipcppe_use- . eng.pdf). this is based on previous knowledge [ ] and the doctrine that: a patient positive for sars-cov- is contagious by respiratory secretions (> μm in size) that disseminate only on short distance (< m); sars-cov- carried on large droplets settles onto local surfaces and is not stable in the air; sars-cov- aerosol dispersion is possible during agps which extensively expose hcws and therefore hcws need to wear a respirator for a higher respiratory protection during agps. however, an experimental study of van doremalen et al, [ ] assessed the sustainability of sars-cov- in aerosols (< μm at % of hygrometry (expressed in %rh for relative humidity)) performed using a high-powered machine that does not reflect normal cough conditions (https://www.who.int/publications-detail/modes-of-transmission-of-virus-causing-covid- -implicationsfor-ipc-precaution-recommendations). they showed that sars-cov- remained viable and infective at least hours in aerosols, which opened the debate on sars-cov- transmission through longdistance aerosols (> m), and questioned the appropriateness of respiratory protection for hcws. an individual who is well, emits to particles per liter of expired air, including % of < μm-size particles [ ] . when speaking, the rate of emitted particles can reach , particles per minute, with a size up to μm. a cough generates to particles of size between . and μm (with a predominance of < μm particles size) [ ] , while a sneeze produces around particles between . and μm in size (https://www.anses.fr/fr/system/files/air et ra.pdf). however, the particles size evolves based on temperature and humidity. large particle size can rapidly desiccate at high temperature and low humidity, subsequently remaining suspended in the air [ ] . models assessing viral infectivity in aerosols and droplets, focused mainly on influenza virus, showed that respiratory droplets, usually of size between to μm at their emission, can rapidly shrink even more when poorly concentrated in organic substances, depending on humidity [ ] . droplets containing mixtures mimicking respiratory mucus decrease from μm to . μm under rh%, which significantly extended their time to settle from a height of . m, from min to min [ ] . on the other hand, even if the humidity appears as an important parameter to consider in the potential distance and time of droplets dissemination, it may not modulate the stability of respiratory viruses in aerosols in presence of organic material. a study comparing infectivity of both fine aerosols and stationary droplets containing pandemic influenza a (h n ) according to seven different conditions of humidity at °c showed no significant differences of infectivity for both aerosols and droplets containing respiratorylike secretions [ ] . furthermore, even if influenza is considered as a droplet-mediated disease, a study showed that % of viral rna emitted from patients was carried on particles of < μm of diameter, suggesting the potential for airborne transmission [ ] . under real-life conditions in healthcare settings, a study assessed the extended sars-cov- dispersion within the hospital environment, by sampling air and surfaces in room of three covid- patients, before routine cleaning for one of them (patient ) [ ] . all environmental samples collected after cleaning in rooms of patients and were negative, while sars-cov- was retrieved from % of surfaces sampled in the room of patient . the authors were not able to identify sars-cov- in air but detected it onto air exhaust outlets, suggesting that the virus in droplets was displaced by airflows and reached the vents [ ] . aerodynamic analysis of sars-cov- in two hospitals caring for covid- patients in wuhan showed that sars-cov- was present in air (including small particles size) especially in confined spaces [ ] . but the important limitation of these two studies is that the authors did not demonstrate that sars-cov- was viable and infectious [ , ] . another study of the indoor air in healthcare settings caring for covid- patients in iran did not detected sars-cov- in air samples collected to m from the patients' beds with confirmed covid- in ventilated rooms [ ] . however, these results are not transposable to poorly ventilated environments, and airborne transmission may occur in confined spaces in absence of respiratory protection. the important issues of clinical relevance that remain to be addressed are: what is the infective dose to contaminate a person by inhalation? what is the impact of air ventilation on indoor contamination during the patient hospitalization? the viral load detected by rt-pcr in respiratory specimens can be highly variable between patients [ ] and the relationship between viral load in respiratory tract and emitted droplets from patient, along with the viability of sars-cov- in patient-generated aerosols remain to be demonstrated. furthermore, the increased infective risk for hcws seems limited to when agps are performed compared to normal ward based care, provided the hcw is wearing a mask [ ] . by considering all these elements, a potential airborne transmission of sars-cov- cannot be excluded, especially in confined spaces, and needs further investigation. this was already the conclusion of roy should be considered as droplet preferentially even if airborne transmission under rare specific circumstances has been described [ ] . to date, implementing both droplets and contact precautions for hcws seems adequate in significantly reducing the risk of infection by sars-cov- during clinical care, as previously demonstrated for sars-cov- [ ] . to efficiently prevent from contamination, wearing a face mask must be combined with other ppe [ , ] . the growing anxiety regarding the availability of ppe, especially face masks, urges to rationalize their indications. in order to prevent a supply shortage, the requirement of face mask may be argued on the level of required effectiveness. respirator (ffp or n masks) must be only reserved to hcws when performing agps [ ] . a precise list of agps should be dressed in order to strictly address the indications of respiratory masks. funding: no funding to report. conflict of interest: none to declare. hospital hygiene and infection control team epidemiology and infection control department. dijon university hospital, rue paul gaffarel service de médecine préventive hospitalière hygiène, prévention et contrôle de l'infection (hpci), centre hospitalier universitaire vaudois physical interventions to interrupt or reduce the spread of respiratory viruses: systematic review aerosol and surface stability of sars-cov- as compared with sars-cov- study on transport characteristics of saliva droplets produced by coughing in a calm indoor environment how far droplets can move in indoor environments--revisiting the wells evaporation-falling curve mechanistic insights into the effect of humidity on airborne influenza virus survival, transmission and incidence influenza virus infectivity is retained in aerosols and droplets independent of relative humidity measurements of airborne influenza virus in aerosol particles from human coughs air, surface environmental, and personal protective equipment contamination by severe acute respiratory syndrome coronavirus (sars-cov- ) from a symptomatic patient aerodynamic analysis of sars-cov- in two wuhan hospitals a field indoor air measurement of sars-cov- in the patient rooms of the largest hospital in iran viral load of sars-cov- aerosol generating procedures and infective risk to healthcare workers: sars-cov- -the limits of the evidence airborne transmission of communicable infection -the elusive pathway viral load distribution in sars outbreak escalating infection control response to the rapidly evolving epidemiology of the coronavirus disease (covid- ) due to sars-cov- in hong kong key: cord- -qxn td authors: ibfelt, t.; engelund, e.h.; schultz, a.c.; andersen, l.p. title: effect of cleaning and disinfection of toys on infectious diseases and micro-organisms in daycare nurseries date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: qxn td background: the rising number of children in daycare nurseries increases opportunities for the transmission of infectious diseases. pathogens may be transmitted directly from child to child via sneezing, coughing and touching, or indirectly via the environment. toys are among the fomites with the highest pathogen load, but their role in disease transmission is unknown. aim: to determine if washing and disinfection of toys can reduce sickness absence and microbial pathogen load in the nursery environment. methods: twelve nurseries (caring for children) were randomized to intervention and control groups. the intervention consisted of washing and disinfection of toys and linen every two weeks for three months by a commercial cleaning company. the extent and causes of sickness absence among the children were recorded in both groups before and after introduction of the intervention. ten sampling points in each nursery were examined for bacteria and respiratory viruses. results: the presence of respiratory virus dna/rna was widespread, but very few pathogenic bacteria were found in the environment. the intervention reduced the presence of adenovirus [odds ratio (or) . , % confidence interval (ci) . – . ], rhinovirus (or . , % ci . – . ) and respiratory syncytial virus (or . , % ci . – . ) compared with the control group, but the intervention had no effect on sickness absence or disease patterns in the nurseries. conclusion: although cleaning and disinfection of toys every two weeks can decrease the microbial load in nurseries, it does not appear to reduce sickness absence among nursery children. children, especially children aged three years and under, have a high frequency of infectious disease episodes. children in daycare nurseries have more infections than children cared for elsewhere, e mainly because of direct transmission between children, contact or respiratory droplet transmission, and inadequate hand hygiene. although indirect transmission of infection via the nursery environment has not been studied extensively, it is likely to play a role. previous research on bacteria in the nursery environment has shown positive cultures in e % of samples, depending on location, but almost all bacteria isolated were of low pathogenicity. e quantitative polymerase chain reaction (pcr) to determine the diversity of bacteria in the nurseries has shown that the most common bacteria in the nursery environment are coagulase-negative staphylococci (cons), bacillus spp. and pseudomonas-like bacteria, all of which rarely cause disease in healthy children. less is known about viruses in the nursery environment in spite of the frequency of viral respiratory infections caused by rhinovirus, bocavirus, adenovirus and respiratory syncytial virus (rsv). e in a study of the prevalence of different respiratory viruses on surfaces in nurseries during the winter of e , using the same technique as in this study, respiratory viruses were found to be widespread in the environment, especially on toys (publication pending). this study found that toys were not washed or disinfected systematically. the danish health board recommends monthly cleaning, but it is not known whether regular cleaning of toys in nurseries can affect the pathogen load and reduce infection. the aim of this study was to determine whether regular systematic cleaning and disinfection of toys would decrease the prevalence of bacteria and respiratory viruses in the nursery environment, and reduce sickness absence in danish nurseries. twelve nurseries from the municipality of copenhagen were recruited in autumn . the number of divisions in each nursery ranged from two to six, and the number of children ranged from to . the total number of children was , and their ages ranged from six months to three years. nurseries were questioned about their policies and procedures for hygiene and cleaning of toys before commencement of the study, and randomized to intervention (n ¼ ) and control (n ¼ ) groups. the intervention took place from january to march . a commercial cleaning company (berendsen a/s, søborg, denmark) collected toys and linen every two weeks from nurseries in the intervention group for cleaning in their industrial cleaning facility. linen and toys suitable for washing machines were washed at c and subsequently disinfected with turbo oxysan (ecolab, valby, denmark). toys that were not suitable for washing machines were either immersed in a disinfectant [sirafan m, ecolab ( e % benzalkonium chloride, e % didecyldimethylammonium chloride and e % alcohol ethoxylates)] or cleaned manually with a microfibre cloth using the same disinfectant (sirafan m, ecolab). the toys were subsequently rinsed with water, air dried and returned to the nurseries. cleaning of toys was staggered to ensure that the children had some toys to play with while others were being cleaned. absence data and disease patterns were recorded for each child on a daily basis from december to march . the number of absent children and the reason for absence (as reported by the parents) was recorded by the staff within the following categories: respiratory infections, gastrointestinal infections, other illnesses, or day off. sampling was performed before and after the intervention in december and april . ten predefined sampling points (seven in the playroom and three in the toilet area) were sampled in each of the nurseries. the playroom sampling points were undersides of tables, plastic toys, wooden toys, food toys, teddy bears, pillows and sofas. the toilet sampling points were toilet seats, changing mats and basin taps. the sampling area for most sampling points was  cm, but where it was not possible to sample a  cm square (e.g. on smaller toys), the whole object was swabbed. sampling was performed using: ( ) a dry, sterile, cotton-tipped swab, immersed in ox serum broth after sampling (department of clinical microbiology, herlev hospital, herlev, denmark); and ( ) a double-sided dipslide (  mm) with tryptic soy agar (tsa) agar on one side and violet red bile glucose agar on the other side, with both sides containing a neutralizer against disinfectants (model no. dpsldtv, m, copenhagen, denmark). the dipslides were incubated for h and the ox serum broth was incubated for seven days at e c. following incubation, the ox serum broth was plated on to a blood agar plate (item no. , ssi-diagnostika, copenhagen, denmark) and a lactose agar plate (item no. , ssi) and incubated for h. total bacteria count was determined using the tsa side of the dipslide and the supplied key from the manufacturer, and reported as colonyforming units (cfu)/cm . the different species from both dipslides and the ox serum broth were identified using conventional identification and matrix-assisted laser desorption/ ionization-time of flight (maldi-tof) (bruker daltonics scandinavia ab, frederikssund, denmark). maldi-tof was only used for potential pathogens (all faecal bacteria, staphylococcus aureus and nasopharyngeal bacteria). bacteria (and fungi) were divided into four groups: skin bacteria (cons, micrococcus spp., poprionibacterium spp. and s. aureus), water and soil bacteria and fungi (acinetobacter spp., pseudomonas-like spp., aeromonas spp., comamonas spp., bacillus spp. and moulds), nasopharyngeal bacteria (streptococcus pneumoniae, moraxella spp. and non-haemolytic streptococci) and intestinal bacteria (all enterobactereaceae and enterococcus spp.). escherichia coli and enterococcus spp. were used as indicators of faecal contamination. respiratory viruses were sampled from the same sampling points as the bacterial samples. each point of  cm was sampled using a  mm polyester foam swab (model - , vwr, herlev, denmark). swabs were immersed in sterile rnase-free water before sampling. after sampling, each swab was placed in a -ml sterile plastic container with ml nuclisens lysis buffer (biomérieux, marcy l'etoile, france). on arrival at the laboratory, the tubes were placed on a shaking table for min and the lysis buffer was transferred to a . -ml cryotube and stored at À c until analysis. virus dna and rna from the sample were extracted using a minimag apparatus and nuclisens extraction reagents (biomérieux). the purified dna/ rna, eluted in ml of elution buffer (biomérieux), was stored at À c until quantitative pcr amplification and analysis. selected and bocavirus. quantitative pcr was performed using ml of extracted nucleic acids and the ftd respiratory pathogens plus multiplex pcr kit (fast track diagnostics, junglinster, luxembourg) with the recommended enzyme kit (agpath-id one-step rt-pcr reagents, life technologies, naerum, denmark). pcr amplification and reading was performed using rotorgene q (qiagen inc., venlo, the netherlands) and analysis was performed using rotorgene software. total bacterial growth was read from the tsa side of the dipslide and calculated in cfu/cm . results from the dipslides and the ox serum broth were pooled for each sample point, and given as binary results depending on the presence or absence of the target organisms. the same binary method was used for respiratory virus detection. logistic regression models were used to examine the odds of bacterial and viral presence before and after the intervention. differences in total growth were analysed using student's t-test. differences in sickness absence between groups were analysed using a modified chi-squared test. all calculations were performed using statistical package for the social sciences version (ibm corp., armonk, ny, usa). p . was considered to indicate significance. no difference in hygiene standards was found between the control group and the intervention group. no nurseries in either group had a scheduled plan for cleaning toys or washed the toys systematically. very few potentially pathogenic bacteria were found in the samples. out of samples, there were potential pathogens ( %) in the pre-intervention samples (six in the control group and nine in the intervention group) and ( %) potential pathogens in the post-intervention samples (eight in the control group and three in the intervention group). these were bacteria of low pathogenicity such as enterobacter spp., e. coli and nonhaemolytic streptococci. the highest prevalence was found on pillows and sofas, followed by changing mats and various toys. mean (ae standard error) bacterial growth was . ae . cfu/ cm . highest bacterial growth was found on teddy bears ( . ae . cfu/cm ), followed by sofas ( . ae . cfu/cm ), pillows ( . ae . cfu/cm ), toilet seats ( . ae . cfu/cm ), plastic toys ( . ae . cfu/cm ), wooden toys ( . ae . cfu/ cm ), playroom tables ( . ae . cfu/cm ), changing mats ( . ae . cfu/cm ), food toys ( . ae . cfu/cm ) and basin taps ( . ae . cfu/cm ). no difference in total growth or potential pathogen presence was found between the intervention group and the control group. a mean of three different respiratory viruses was found at each sampling point. the prevalence rates for the different respiratory viruses are listed in table i on the other hand, metapneumovirus was found significantly less often in the control group than in the intervention group. the intervention had no effect on the detection of other viruses. the fomites with the highest presence of respiratory virus were pillows and sofas, followed by toys and playroom tables. when looking at the samples from the toys alone, there was a significant decrease following the intervention in the intervention group compared with the control group for rhinovirus (or . , % ci . e . ; p ¼ . ) and rsv (or . , % ci . e . ; p ¼ . ), but not adenovirus. as in all samples, the presence of metapneumovirus was significantly decreased in the control group compared with the intervention group. no differences were found for the other viruses on the toys. the prevalence rates of the four most prevalent viruses on the toys are shown in figure . the proportion of healthy children in the control group decreased from % to % in the post-intervention period, whereas it was unchanged in the intervention group; however, the difference between the groups was not significant. mean absence (ae standard error) due to respiratory infections decreased after the intervention in both the intervention and control groups (from . % ae . % to . % ae . % in the intervention group and from . % ae . % to . % ae . % in the control group). however, gastrointestinal infections increased after the intervention (from . % ae . % to . % ae . % in the intervention group and from . % ae . % to . % ae . % in the control group). other illnesses also increased in both groups after the intervention (from . % ae . % to . % ae . % in the intervention group and from . % ae . % to . % ae . % in the control group). no significant differences in any of the disease categories were found between the groups. when looking at the timeline of infectious diseases in the two groups before and after the intervention, there is no striking effect of the intervention on total sickness absence, respiratory infections or gastrointestinal infections (figures e ). there was a significant difference (p ¼ . ) in total sickness absence between the groups, but the control group had the lowest sickness absence ( . % vs . % in the intervention group). no difference was found between the groups when analysing respiratory or gastrointestinal infections in the pre-and postintervention periods. the bacteria found in this study were mainly nonpathogenic; only % of the bacteria were potential pathogens. this is in accordance with a study by lee et al., who investigated the bacterial diversity in a nursery through a combination of cultures and s rrna sequencing. prevalent bacteria cultured were bacillus spp., staphylococcus spp. and pseudomonas spp., while s sequencing analysis was dominated by pseudomonas spp. and oxalobacteria spp. the present study found a very low prevalence of potential pathogens ( %), and this was lower than reported in many other studies; for example, laborde et al. reported faecal coliform rates of e % on toys, sinks and tables in toddlers' classrooms; and ekanem et al. reported a faecal coliform rate of % on classroom objects. the discrepancies may be due to different sampling techniques, different sampling points and different sampling areas. it may be more efficient to sample larger areas using cloths in order to maximize the chances of finding pathogenic bacteria present in the environment. respiratory virus rna/dna was widespread in the environment, especially for viruses causing the common cold, such as rhinovirus, adenovirus, coronavirus and bocavirus. other studies have found similar pathogens in the throats of children with respiratory infections. , , these studies found rhinovirus, rsv, coronavirus and adenovirus to be the most prevalent viruses. this corresponds well with the present results, where bocavirus was the most prevalent virus, followed by coronavirus, adenovirus and rhinovirus. rsv detection was lower, but this may have been because the severity of rsv infection keeps children away from nurseries. the similarity between the present findings in the environment and findings in children's throats indicates that viruses are transmitted to the environment. the weakness of the pcr technique is that viral nucleic acid is detected rather than 'live' viruses, and the prevalence of infectious viruses may be overestimated. to assess this, the viruses would have to be grown in cell cultures. this was not possible due to time and economic constraints. moreover, some viruses, such as norovirus, cannot be cultured. the main endpoint in this study was the number of days of absence due to sickness. this study did not find a decrease in total sickness absence or in sickness absence due to respiratory infection. to the authors' knowledge, this is the first study to measure the isolated effect of cleaning toys on infectious diseases in nurseries. however, a few studies have 'touched upon' the subject. krilov et al. showed a significant decrease in the number of infections in a specialized preschool following the implementation of an infection control programme. this programme included cleaning toys, but this was combined with other measures such as hand hygiene and environmental cleaning. numerous studies have shown the presence of coliforms and different pathogenic bacteria and viruses on toys in hospitals and other clinical settings. e consequently, the general recommendations to date have been that toys should be cleaned regularly in order to prevent infections. the data from this study, however, do not support these recommendations. possible reasons for failure to observe an effect of cleaning toys include: too great an interval between washes; not washing all toys at the same time; and the effect of person-to-person transmission overshadowing the effect of cleaning. this raises the question of whether commercial cleaning of toys is costeffective. it is likely that the most effective ways to prevent infections in daycare nurseries are rigorous hand hygiene and other well-established infection control measures, or simply to keep the children at home for longer when they are ill. e the latter is confirmed by the absence timelines in this study (figures e ) , which included the period before and after the christmas holiday in december. during this holiday, the nurseries were closed for two weeks. there was a marked decrease in sickness absence after the holiday in both groups, with the percentage of children with respiratory infection decreasing from . % to . % in the intervention group and from . % to . % in the control group. if feasible, absence from nurseries might be the best way to reduce the spread of infection in children. in conclusion, this study showed that respiratory virus dna and rna are widespread in the nursery environment. fortnightly cleaning and disinfection of toys reduced the frequency of detection of some respiratory viruses, but not the bacterial load, and did not reduce the number of days of absence due to respiratory infection or sickness as a whole. as this is the first study of its kind, further studies are needed to confirm or refute the findings. studies over a longer period of time may be necessary to control for seasonal fluctuation in infection rate and virus types. acute respiratory infections in day care diarrheal illness among infants and toddlers in day care centers. ii. comparison with day care homes and households forms of care and children's infections. . occurrence and causal factors childhood upper respiratory tract infections: to what degree is incidence affected by day-care attendance? microbiological analysis of food contact surfaces in child care centers effect of fecal contamination on diarrheal illness rates in day-care centers microbial evaluation of foodservice surfaces in texas child-care centers culture-independent analysis of bacterial diversity in a child-care facility epidemiology of multiple respiratory viruses in childcare attendees presence of viral and bacterial pathogens in the nasopharynx of otitis-prone children a prospective study epidemiology of viral respiratory tract infections in a prospective cohort of infants and toddlers attending daycare the occurrence of influenza a virus on household and day care center fomites prevalence of rotavirus on high-risk fomites in day-care facilities survival and detection of rotaviruses on environmental surfaces in day care centers the frequency, level, and distribution of fecal contamination in daycare center classrooms transmission dynamics of enteric bacteria in day-care centers frequent respiratory pathogens of respiratory tract infections in children attending daycare centers impact of an infection control program in a specialized preschool viral contamination of environmental surfaces on a general paediatric ward and playroom in a major referral centre in riyadh toys in a pediatric hospital: are they a bacterial source? bacterial colonization of toys in neonatal intensive care cots toys e friend or foe? a study of infection risk in a paediatric intensive care unit the impact of selected environmental factors on the morbidity of children in day care centers a review of enteric outbreaks in child care centers: effective infection control recommendations a randomized, controlled trial of a multifaceted intervention including alcohol-based hand sanitizer and hand-hygiene education to reduce illness transmission in the home an open randomized controlled trial of infection prevention in child day-care centers mandatory handwashing in elementary schools reduces absenteeism due to infectious illness among pupils: a pilot intervention study the authors wish to thank charlotte foged (rigshospitalet) and resadije idrizi (dtu food) for excellent technical assistance, and ecolab denmark, berendsen denmark and m denmark for the free supply of materials and cleaning. ecolab denmark, berendsen denmark and m denmark supplied materials and cleaning free of charge, but had no influence on the analysis of the data or the writing of the manuscript. key: cord- - u zxsam authors: fisher, d.; tambyah, p.a.; lin, r.t.p.; jureen, r.; cook, a.r.; lim, a.; ong, b.; balm, m.; ng, t.m.; hsu, l.y. title: sustained meticillin-resistant staphylococcus aureus control in a hyper-endemic tertiary acute care hospital with infrastructure challenges in singapore date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: u zxsam background: meticillin-resistant staphylococcus aureus (mrsa) has been entrenched in singapore hospitals since the s, with an excess of non-duplicate cases of infections ( bacteraemia episodes) each year in our -bed university hospital. approximately % of our hospital beds are used as isolation facilities. aim: to study the impact of an mrsa control bundle that was implemented via gradual geographic extension across hospital wards. methods: the bundle included active surveillance on admission and transfer/discharge to identify ward-based acquisition of mrsa, isolation and cohorting of mrsa-infected patients, enhanced hand hygiene initiatives, and publicly displayed feedback of mrsa acquisition and hand hygiene compliance rates. implementation was between october and june in order to provide lead-time for the incremental development of infrastructural capacity, and to develop an ethic of infection prevention among staff. results were analysed via interrupted time-series analysis. findings: mrsa infections fell midway through the implementation, with mrsa bacteraemia declining from . [ % confidence interval (ci): . – . ] cases per inpatient-days in the first quarter of to . ( % ci: . – . ) cases per inpatient-days in the first quarter of . mrsa acquisition rates fell a year after the programme had been fully implemented, whereas hand hygiene compliance rose significantly from % ( % ci: – ) in the first quarter of to % ( % ci: – ) in the first quarter of . conclusion: successful staged implementation of an mrsa bundle in a hyper-endemic setting is sustainable and represents a model that may be adapted for similar settings. sustained meticillin-resistant staphylococcus aureus control in a hyper-endemic tertiary acute care hospital with infrastructure challenges in singapore introduction since the worldwide establishment of healthcareassociated meticillin-resistant staphylococcus aureus (mrsa), sustainable reductions have been demonstrated in several parts of the world. the netherlands has maintained mrsa levels of < . % and managed outbreaks successfully using a search and destroy policy. scandinavian countries and western australia cite similar success stories, as has the veteran affairs chain of hospitals in the usa after the establishment of an mrsa bundle. e more reports from across australia, france, and the uk have also shown significant reductions in mrsa infections in the last few years. e effective interventions for controlling mrsa transmission in a hospital setting are well known and include active surveillance, improving hand hygiene compliance, and isolating all mrsa cases, whereas general strategies such as obtaining focused and committed hospital leadership are critical towards lowering implementation barriers and improving sustainability. , , , such successes are rare in asia and parts of the world where mrsa is hyper-endemic, and where high antimicrobial resistance rates in other nosocomial bacteria result in competition for limited resources and isolation facilities e infrastructural hurdles that have been difficult to overcome. , estimates of the burden of mrsa in singapore and at the national university hospital of singapore (nuh) have been published in separate reports which describe the issue microbiologically, and clinically. , more than mrsa infections including at least bloodstream infections were previously seen per year at nuh. the sheer volume of cases coupled with infrastructural and societal constraints traditionally has hindered mrsa control efforts here. few beds are available for contact isolation despite negative pressure isolation rooms being built after the severe acute respiratory syndrome (sars) outbreak in . there is insufficient capacity to isolate all mrsa patients, as they constitute up to % of all inpatients, and prioritizing mrsa would impair the ability to isolate or cohort patients with other transmissible diseases. adding to the problem is the average daily bed occupancy rate exceeding % e the result of a recent, rapid population boom in singapore. in , the senior hospital management at nuh, in response to endemic rates of mrsa infections of % and large numbers of clinical infections, called for a more aggressive response. we describe our strategy to contain mrsa in a hyper-endemic hospital with infrastructural constraints and its implementation, as well as analyse its impact via time-series analysis. we conducted a prospective interrupted time-series study at nuh e a -bed acute care tertiary university in singapore. the intervention (described further below) was implemented via gradual geographic extension between october and june . the intervention comprised a series of mrsa control measures put together as a bundle, and included: À active surveillance for mrsa carriage. this consisted of swabs of nares, axillae and groin (plus any wounds) cultured on chromogenic agar mrsa select (bio-rad laboratories, marnes-la-coquette, france). patients not known to have mrsa had entry swabs, while those who had been in a hospital ward > h, had no prior positive mrsa cultures (screening or clinical) and had not died, also had exit swabs upon discharge or transfer from the ward. À promotion of hand hygiene. this was done primarily via educational and socio-behavioural measures. hand hygiene education focused on the world health organization (who) 'five moments for hand hygiene', which was audited. continuous reminders were developed, including via posters in wards, computer screensavers, and audio on ward entry. hospital-wide training programmes ran in and annually to coincide with the who world hand hygiene day. all frontline clinical staff had to participate in a compulsory min training programme and assessment over one week on both years. a sticker placed on the staff identification tag confirmed certification. all new staff received the same programme at orientation. to further reinforce the message, the clinical examination template in the national university of singapore final mbbs degree stipulated a deduction in marks for failed hand hygiene. À auditing of hand hygiene compliance. this was performed primarily by appointed ward liaison nurses that had been trained by infection control nurses, supplemented and cross-checked by medical and nursing students who were engaged via innovative educational programmes in which they were trained as auditors and observed staff in their work covertly. À isolation or cohorting of mrsa-positive patients. such patients were placed in isolation or, more usually, in a designated cohort cubicle, established on each ward. periodic snapshots of cohorting compliance were undertaken. a close relationship between the bed management unit and the project stakeholders was developed to facilitate the siting of mrsa-positive patients. À public and regular feedback of results. data on hand hygiene compliance and mrsa acquisition were posted on ward-based 'dashboards' that had been requested by hospital administration. the signage was publicly displayed, ward-specific and updated monthly. À other measures included a bare-below-the-elbows policy for all clinical staff, coloured bracelets to identify all colonized and infected patients, and cash rewards (of around us$ ) for exemplary performances by wards or departments with regards to hand hygiene compliance and mrsa transmission rates to enjoy a celebratory lunch or similar. À to ensure that any progress made was primarily due to the mrsa bundle and not changes in prescribing habits, surveillance of major classes of antibiotics (fluoroquinolones, carbapenems, third or fourth generation cephalosporins and vancomycin) was undertaken from using pharmacy-based electronic data. this was expressed as defined daily doses (ddd) per inpatient-days. in order to fully implement this in an mrsa-hyper-endemic hospital with infrastructural and resource constraints, the mrsa bundle was implemented via planned gradual geographic extension over years e a few wards at a time. this would allow lead-time for the incremental development of infrastructural capacity in a number of areas including the number of microbiology laboratory technical staff and an infection control data management system. it was also believed that a gradual introduction would help the growth of an ethic of infection prevention among staff. to improve the odds of sustainability, two actions were undertaken simultaneously. first, an overall mrsa taskforce was formed that included members of the senior hospital management, comprising the chair of the medical board, chief operations officer, director of nursing, the infection control chair and a full-time mrsa data manager among others. second, an assessment of the local clinical and economic impact of mrsa infections was undertaken. the key indicators for improvement included: collectively, these indicators would represent the overall burden of mrsa infections in the institution, the likelihood of mrsa acquisition in mrsa-naïve patients during their hospitalization, and the overall infection control adherence among healthcare staff. process indicators included cohorting compliance rates and active surveillance testing rates as well as the results of hand hygiene compliance audits. preliminary analysis of pre-intervention time-series yielded non-significant autoregressive coefficients, suggesting that the observed autocorrelations at lag across the entire time-series resulted from gradual changes in disease incidence rather than inherent correlations between time-windows. subsequent analysis accounted for autocorrelation by modelling changes in the mean incidence or proportion as a function of time. the numbers of mrsa clinical cases and mrsa bacteraemia cases per quarter were modelled as poisson with mean m(t) per hospital inpatient-day. extending the model to negative binomial to account for super-poisson heterogeneity did not improve the fit. the quarterly number of positive exit swabs among initially non-colonized patients was assumed to be binomial with proportion p(t). both models used linear (on a log or logit scale) changes in location with time, with a single change in gradient allowed. for the number of mrsa or bacteraemia cases, the models have the form: log mðtÞ ¼ a À bðt À sÞ ðt>sÞ À gðs À tÞ ðt < sÞ where a quantifies average incidence at the temporal change point, s, while b(g) characterizes per-quarter increase (decrease) in incidence after (before) s, and (a) ¼ if a is true and otherwise. a similar model, replacing log m(t) by logit p(t), was used for within-hospital colonization and handwashing performance. the parameters a, b, g and s, were inferred independently of the time-course of interventions, thereby to assess the plausibility that interventions coincided with the inferred changepoint, s. because the likelihood surface suggested that the maximum likelihood estimate of s, in particular, may not be normally distributed, bayesian methods were used to derive % confidence intervals (cis), taking uniform prior distributions over the parameter support, using markov chain monte carlo samplers with , samples and every th retained, with multivariate normal proposals with covariance tuned on trial runs. approximate p-values were obtained by extending credible intervals by analogy to the relationship between p-values and the end-points of confidence intervals. point estimates reported were maximum likelihood estimates or posterior modes. all analysis was performed in the r statistical environment. the programme was initiated in october in a single orthopaedic ward, followed by a subsequent roll-out to all targeted wards within the hospital that was completed by june (figure ). by the end of june , all adult intensive care units, and up to % of general wards including the majority of surgical general wards, had been included in the programme. figure shows the incidence-density of all mrsa clinical isolates since , all mrsa blood isolates since , and mrsa acquisition rates since . there is strong evidence of a rising incidence of all mrsa clinical cases until a peak in the first quarter of ( % ci: q - to q - ) with a notable decline thereafter ( figure a) ; this peak is consistent with the completion of the roll-out by the end of the second quarter of (p ¼ . ) but not with the first roll-out of the programme in the fourth quarter of (p ¼ . ). the decline after the change-point was . times ( % ci: . e . ) as rapid as the preceding rise. the mrsa acquisition rate is presented in figure b empirical and modelled mrsa bacteraemia rates are presented in figure c . here, there was a significant fall from . cases ( % ci: . e . ) per inpatient-days in the first quarter of to . cases ( % ci: . e . ) in the first quarter of , but no evidence of the fall levelling off, with the % ci for a change-point spanning almost the entire period of recorded data. the evolution of hand hygiene compliance is displayed in figure d . compliance rose significantly since audits started, from % ( % ci: e %) in the first quarter of to % ( % ci: e %) in the first quarter of . there was, however, evidence that compliance stalled around the last quarter of ( % ci: q - to q - ) with a rate of change after that time that was not statistically distinguishable from (p ¼ . ). throughout the period of the study, the changes in consumption of the antibiotics measured did not correlate with the improvement in mrsa rates (figure ) , and therefore antibiotic prescription per se did not affect mrsa rates at our institute. our results reinforce the concept that an 'mrsa bundle' comprising standard well-known mrsa control measures is able to bring down mrsa transmission and infection rates substantially, even in a setting where mrsa is hyper-endemic. , , this study has shown significant declines in mrsa acquisitions, all clinical specimens and also bacteraemias. concurrently there was no decline in antibiotic prescribing habits. adding to the likelihood that the interventions caused the mrsa improvements is the fact that vancomycin-resistant enterococci and clostridium difficile rates have increased at our hospital (unpublished data) while multidrug-resistant gramnegative infection rates have remained stable. our approach can perhaps be extrapolated to other similar settings, as it shows how implementation barriers in terms of manpower, cultural and infrastructural constraints can be overcome using a gradual and staged roll-out of the mrsa bundle, with active involvement of senior hospital management. kotter broadly mapped out the process of initiating and sustaining change efforts more than a decade ago. sustainability is critical in such efforts, and requires cultural change. data management and communication was key to sustaining the change. one full-time member of staff was appointed to collate and feed performance metrics back to ward-based healthcare workers, nurse managers, the infection control team and senior management. ward-specific hand hygiene compliance data from trained auditors and mrsa acquisition rates were posted graphically each quarter in publicly displayed dashboards on each ward. efforts toward prevention of mrsa acquisition and infection have become embedded in the culture of clinical medicine at nuh. the plateau seen in the data after significant gains suggests that the improvements are sustainable but that better results are unlikely in the absence of further intervention. potential further interventions beyond those already implemented include those related to technological advancement or cutting edge research. screening of healthcare staff was not implemented because of both operational concerns e a significant proportion of staff are likely to be colonized but it would be impossible to lay all of them off work during the period required for mrsa decolonization as well as the concern that mrsa recolonization would be common in a hyper-endemic setting. nonetheless, this will be considered in the future as mrsa rates fail to decline further. decolonization (of patients or staff) remains controversial beyond some preoperative indications and further work in this regard is underway at our institution. it is conceivable that reducing the reservoir of mrsa may prevent transmission, and therefore infection rates. the predictable development of mupirocin resistance is of particular concern and evaluating carbapenem use alternative agents is another priority for research in mrsa control globally. current efforts are labour-intensive and carry a risk of fatigue. maintenance of data allows the tracking of progress and may help to prevent history from repeating itself if a trend toward the original baseline appears. patients who are colonized but do not develop infection are invisible in the absence of active surveillance, so this monitoring of acquisition (without infection) allows a more 'upstream' view of the progress of infection control interventions. manual hand hygiene audits using trained auditors are inefficient because they are labour intensive, and are made inaccurate by the hawthorne effect and necessarily small sample sizes, generally only on weekdays and daytime hours. technological solutions are evolving and could potentially feature in the infection control programme of tomorrow. functionality and evidence of cost-effectiveness remain barriers to such technology. active surveillance testing was a cornerstone of our bundle. whereas we used culture-based techniques, molecular testing would be more timely and sensitive, albeit it carries a risk in the regional setting of potentially missing certain mrsa strains with arginine-catabolic mobile elements (acme) inserted into orfx, and incurring greater operational costs. there are several limitations of this work. first, this was a non-randomized before-and-after study design involving a single institution. however, this is a common issue in infection control studies and not one that is easily overcome because of the nature of such studies. during this period, there was no concomitant decrease in other nosocomial antibiotic-resistant pathogens such as carbapenem-resistant acinetobacter baumannii or extended-spectrum beta-lactamase-producing enterobacteriaceae (data not shown) that would suggest an overall decline in antimicrobial resistance rates. clinical practices also did not change substantially. second, the nature of the intervention is such that several measures were included in a single 'bundle', and the individual effect of each measure cannot be determined. nonetheless, such 'care bundles' are now accepted in clinical practice, and their effects are greater collectively than when introduced as separate measures. in conclusion, hospitals confronting hyper-endemic mrsa with high infection rates and infrastructural and/or resource constraints can introduce sustainable improvement, provided that a proactive team including senior management leadership is driving it. data maintenance of process and outcome measures and good communication are essential. low prevalence of methicillin-resistant staphylococcus aureus (mrsa) at hospital admission in the netherlands: the value of search and destroy and restrictive antibiotic use increasing incidence but decreasing in-hospital mortality of adult staphylococcus aureus bacteraemia between methicillin resistant staphylococcus aureus in norway methicillin-resistant staphylococcus aureus veterans affairs initiative to prevent methicillin-resistant staphylococcus aureus infections outcomes from the first years of the australian national hand hygiene initiative national program for prevention of healthcare-associated infections and antimicrobial resistance e : positive trends, but perseverance needed trends in sources of methicillinresistant staphylococcus aureus (mrsa) bacteraemia: data from the national mandatory surveillance of mrsa bacteraemia in england evaluation of the national clean your hands campaign to reduce staphylococcus aureus bacteraemia and clostridium difficile infection in hospitals in england and wales by improved hand hygiene: four year, prospective, ecological, interrupted time series study getting started kit: reduce methicillinresistant staphylococcus aureus (mrsa) infection; how-to guide. cambridge, ma: institute for healthcare improvement emergence and resurgence of meticillin-resistant staphylococcus aureus as a public-health threat high burden of antimicrobial resistance in asia antimicrobial drug resistance in singapore hospitals methicillin-resistant staphylococcus aureus control in singapore e moving forward overcrowding and understaffing in modern health-care systems: key determinants in meticillin-resistant staphylococcus aureus transmission evaluation of mrsa select, a new chromogenic medium for the detection of nasal carriage of methicillin-resistant staphylococcus aureus the challenge of introducing a hand hygiene standard to clinical examinations teaching hand hygiene to medical students using a hands-on approach economic and clinical impact of nosocomial methicillin-resistant staphylococcus aureus infections in singapore: a matched caseecontrol study r: a language and environment for statistical computing. vienna: r foundation for statistical computing leading change: why transformational efforts fail methicillin-resistant staphylococcus aureus throat colonization among healthcare workers during an outbreak in singapore general hospital routine hand hygiene audit by direct observation: has nemesis arrived? arginine catabolic mobile element in methicillin-resistant staphylococcus aureus (mrsa) clonal group st -mrsa-iii isolates in singapore: implications for pcr-based screening tests care bundles; the holy grail of infectious risk management in hospital? this work was funded internally by the national university hospital. key: cord- - j t ha authors: gohil, s.; donaghy, b.; tature, d.; kowal, j.; lea, s.; lai, f.y.l.; range, s.; tang, j.w. title: seasonal respiratory virus testing in management of adult cystic fibrosis patients date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: j t ha nan sir, testing for respiratory virus infections (rvis) is performed less frequently in patients with cystic fibrosis (cf), although they are known to contribute to bacterial infections and exacerbations by various mechanisms [ e ] . thus, routine screening for such viruses may enhance the management of these patients [ ] . here we describe the incidence of rvis over one season in our adult cf patients. between february and march , there were two consecutive seasonal influenza outbreaks on our adult respiratory and cf patient ward. this prompted a pdsa (plan, do, study, act) quality service improvement evaluation to assess the utility of routine respiratory virus testing in the management of adult cf patients during a respiratory exacerbation. this had several aims, including: earlier rvi detection, early targeted antiviral treatment (for influenza alone), checking vaccination history and correlation with the test result (for influenza alone), and exploring the possible role of occupation in the exposure and acquisition of rvis. routine screening for seasonal rvis for all adult cf patients took place between november and april . respiratory virus swabs were taken by the cf nurses from all inpatients, ward attenders and outpatients with cf, and sent to the diagnostic laboratory for testing using a commercial respiratory virus multiplex polymerase chain reaction assay. of adult cf patients presenting with an exacerbation, had an rvi and had more than one exacerbation. of the patients with more than one exacerbation, four were diagnosed with an rvi during one of these encounters. of the patients with an rvi, nine had non-influenza infections (two entero-/rhinoviruses, five nl and one hku coronaviruses, one human metapneumovirus), three had influenza infections alone (two influenza a/h n , one influenza b), and one was multiply infected with influenza b, corona-oc and entero-/ rhinoviruses. of the nine patients infected with non-influenza viruses, four were treated empirically with oseltamivir (one commenced oseltamivir treatment but did not complete the course, two completed oseltamivir treatment, one received post-exposure prophylactic oseltamivir). all four patients with laboratory-confirmed influenza received oseltamivir treatment. of the patients who had no detectable rvi, one had commenced oseltamivir treatment empirically but did not complete the course, and four had completed oseltamivir treatment. symptomatic cases were more likely to have been prescribed empirical oseltamivir treatment than asymptomatic cases, as per local seasonal influenza clinical guidelines. regarding influenza vaccination history, of patients had no detectable rvi, of whom had been vaccinated against influenza in the preceding six months. of the five unvaccinated patients, when asked why they had not attended for vaccination, one was unconcerned, three could not access the vaccine, and one had become unwell post vaccination in a previous season so had declined vaccination this season. of the four patients who had laboratory-confirmed influenza, three were not vaccinated due to a lack of concern and one had been vaccinated earlier in the season but became infected with late-season influenza. a history of influenza vaccination was found to be significantly higher (p< . ) in the rvi-negative cases, indicating that this was a protective intervention. we also investigated whether these adult cf patients had occupations that put them in frequent contact with potentially respiratory-virus-infected people. of the patients with a laboratory-confirmed rvi, six were unemployed, one worked from home and six worked in occupations with frequent public interactions. of the patients without any rvis, worked in occupations with regular public contact, five were unemployed, one was at college (with frequent contact with other students) and one worked from home. no significant (p> . ) differences were identified between occupational status and positive or negative rvi status. in summary, routine rvi screening allowed early influenza and non-influenza virus detection in % and % of patients, respectively. early rvi detection allows the prompt treatment of any influenza cases, reducing the potential severity of possible secondary bacterial infective exacerbations. it also enables the timely implementation of appropriate infection control measures. influenza vaccination appears to be effective in reducing the risk of developing influenza virus infection, although this could be improved further with enhanced patient education and access to vaccination. late-season waning of influenzavaccine-induced immunity should also be taken into account when the timing of the seasonal influenza immunization is being planned [ ] . occupational status does not appear to affect the risk of acquiring an rvi. following this service evaluation (pdsa cycle ), routine rvi testing is now being considered for all adult cf patients presenting with an exacerbation during the annual influenza season. repeat cycle testing (pdsa cycle ) during the next influenza season on more patients will further assess the utility of this approach. although clinical teams have traditionally focused more on bacterial and fungal infections in cf patients, rvis can contribute to the severity of these other non-viral infective episodes. early rvi diagnosis, treatment (currently only available for influenza) and appropriate isolation may reduce the subsequent impact on non-viral secondary infections. the diagnosis and management of respiratory viral infections in cystic fibrosis bronchotracheal response in human influenza adherence of pseudomonas aeruginosa to tracheal cells injured by influenza infection or by endotracheal intubation viral infections trigger exacerbations of cystic fibrosis in adults and children within-season influenza vaccine waning suggests potential net benefits to delayed vaccination in older adults in the united states none declared. none. key: cord- - kye w g authors: kumar, parmeshwar; killedar, makhdoom; singh, gagandeep title: adaptation of the ‘assembly line’ and ‘brick system’ techniques for hospital resource management of personal protective equipment, as preparedness for mitigating the impact of the covid- pandemic in a large public hospital in india date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: kye w g nan the covid- pandemic had a slow start in india due to strict restrictions and screening imposed on foreign travel, but by the first week of march , it was clear that the surgical store of our hospital needed to rapidly ramp up its inventory of personal protective equipment (ppe), well ahead of an anticipated increased transmission. ppe items provided by our regular vendors were not available as complete kits. in addition, some important items such as coveralls were not being routinely procured. logistical delays from the nationwide lockdown, financial constraints like fluctuating pricing and demands for advance payment as well as regulatory pressure due to caps imposed on purchase quantity and pricing, made it difficult to procure ppe. the supply chain disruption consequent upon limited supply of raw material with manufacturers and export bans imposed by other countries added to the complexity of the issue. managing the supply chain of ppe in this scenario was difficult and made it necessary to evolve new systems and guidelines to mitigate these conditions. our hospital responded by bringing together a team consisting of hospital administrators, microbiologists, and clinicians. an equitable model for appropriate use of ppe in various healthcare settings was created, which also reassured and boosted the morale of healthcare workers. it was decided to assemble ppe kits in-house from piecemeal purchases of individual items of appropriate quality. an assembly line was put in place where components of the ppe kit were added in sequence until the final completed product was packed and ready for distribution. the processes adopted involved the following principles. the reputation of our institute, large size of advance orders and extensive reach available from previous history of purchases allowed us to attract a choice of vendors. a few components not routinely available in adequate numbers, like hood caps and long shoe covers, were custom-made by reliable manufacturers. the patient waiting hall was reconfigured to become the staging area for incoming vendor inventory (figure ). data entry operators and patient care coordinators were enlisted as assembly line workers. faculty members volunteered to be assembly line supervisors. in the indian armed forces, a 'brick system' has been in vogue since the colonial era. a brick is an operationally self contained box for a manpower based unit. it is typically used inventory management of the personal kit issued to each fighting unit and also used by the united nations peace keeping forces (the un brick) [ ] . the system also envisages different types of kits required at different levels. this method was modified by a hospital administrator having previous experience in the indian army medical corps. the number of beds in a given medical unit and the human resources needed to operationalise it were considered a functional unit. the number of ppe kits required per day was ascertained. for laboratories, the monthly requirement was considered. the requisite number of in-house ppe kits for the various wards were then assembled into one brick(a carton) and supplied to that unit on a daily basis. the brick system aids in inventory management by rationalising the indents, keeping track of future requirements and projecting the purchasing of components far ahead of time. bricks of varying sizes and levels help in rationing of ppe between different wards based on differentiating essential and elective patients. availability of smaller bricks helps in downsizing of certain wards in terms of patient admissions or rostering of health care workers based on ppe availability. computerised records of each brick helps in storage, retrieval, issue and consumption patterns. keeping the system ready for all eventualities, based on reports from other countries [ ] , disinfection and reuse scenarios were envisaged. modifications to a number of hospital rooms were carried out for disinfection of different kit components, if found necessary in future. hydrogen peroxide vapour based disinfection rooms [ , ] revenue procurement practices in the indian army. institute for defence studies and pursuit of ppe dupont personal protection covid- supply update (rev / ) and fact sheet downloads at evaluation of five decontamination methods for filtering facepiece respirators key: cord- -cmeiqvnp authors: van straten, b.; de man, p.; van den dobbelsteen, j.; koeleman, h.; van der eijk, a.; horeman, t. title: sterilization of disposable face masks by means of standardized dry and steam sterilization processes; an alternative in the fight against mask shortages due to covid- date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: cmeiqvnp nan b. van straten , , p. de man , j. van den dobbelsteen , h. koeleman , a. van der eijk , t. horeman the covid- pandemic causes imminent shortages of face masks in hospitals globally. in preparation for that scarcity we performed a study to investigate the possibility of reprocessing disposable ffp face masks in order to verify their re-usability with a method that could be applied in practice using already available equipment. therefore single use ffp masks (type + mtm) were sterilized with a -minute procedure at ⁰c, using a dry sterilization process as well as with a regular steam process with the masks in sterilization/laminate bags. the effectiveness of these processes are sufficient to inactivate the coronavirus based on knowledge of inactivation of such viruses. [ , ] a blind comparison of unused sterilized masks was performed with respect to visual inspection, consistency, face fit and breathing resistance. the results of this comparison were that the investigators were unable to distinguish unused new (slightly curved and folded) masks from reprocessed sterilized masks. we then tested the functionality of the unused and sterilized masks in several ways. first of all permeability properties for bacteria were tested by spraying a bacteria solution of staphylococcus epidermidis (atcc ) on the masks while air was being drawn through the masks. unused and multiple sterilized masks showed no differences in the amount of passed bacteria (data not shown). in these experiments it was also observed that the reprocessing procedures of the masks did not appear to affect the water-repellent mask properties. we then assessed pressure/flow and performed particle tests. before sterilization, the batches were individually packed in laminate bags and sterilized with steam sterilization by means of ⁰c in getinge autoclaves and in combination with permeable laminate bags, halyard type clfp x wi-s . the autoclaves were activated on a ⁰c program and validated accordingly. after sterilization, the samples were tested at delft university of technology and at reinier de graaf hospital, and benchmarked with new mouth masks. a custom test set-up was built to measure the pressure drop over the maskers and outflow with regard to the permeability of the masks. a direct comparison between new and sterilized masks did not show substantial differences. finally, the filtration capacity of the masks was evaluated using a calibrated lighthouse solair particle counter (lighthouse, san francisco). it was shown that the mask permeability of small particles did not change after multiple heat sterilization procedures (table i) . we openly shared our positive experiences with the steam sterilization process with other hospitals in the netherlands that are also preparing for the outbreak. we were informed that their attempts to steam sterilize mouth masks at ⁰c gave poor results as masks started to deform and became sticky while the elastics lost its resilience. in addition, we tested gamma radiated masks this process did hamper the filter capacity (table i) . the results of our experiences and experiments indicate that our sterilization process did not influence the functionality of the masks tested. in case of an acute shortage of ffp masks, steam sterilization (e.g. in laminate sterilization wrappings) of used masks at ⁰c in laminated bags, is a simple, useful cost-effective and quick procedure that can be used to make used masks available for safe reuse. the sterilization process of available standard autoclaves in hospitals may have to be adjusted in order to use this sterilization method. we also emphasise that we performed these experiments with m masks only. however, our method seems to be a potentially useful way to reuse mouth masks; other hospitals facing a shortage of masks may wish to test and validate this approach to reusing masks. coronavirus disinfection in histopathology inactivating porcine coronavirus before nuclei acid isolation with the temperature higher than °c damages its genome integrity seriously key: cord- -wyglrpqh authors: meyers, craig; kass, rena; goldenberg, david; milici, janice; alam, samina; robison, richard title: ethanol and isopropanol inactivation of human coronavirus on hard surfaces date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: wyglrpqh background: the covid- pandemic has greatly increased the frequency of disinfecting surfaces in public places causing a strain on the ability to obtain disinfectant solutions. an alternative is to supply plain alcohols (etoh and ipa) or sodium hypochlorite (sh). aim: there are few data showing the efficacy of multiple concentrations of etoh, ipa, and sh on a human coronavirus (hcov) dried on surfaces using short contact times. methods: multiple concentrations of etoh, ipa, and sh to inactivate high numbers of hcov under real-life conditions were tested. high concentrations of infectious hcov were dried on porcelain and ceramic tiles, then treated with multiple concentrations of the alcohols for contact times of sec, sec, and min. center for disease control (cdc) recommended three concentrations of sh were also tested. reductions in titres were measured by using the tissue culture infectious dose (tcid( )) assay. findings: concentrations of etoh and ipa from % to % were very efficient at inactivating high numbers of hcov dried on tile surfaces even with a sec contact time. concentrations of % dehydrated the virus, allowing infectious virus to survive. the cdc recommended / and / dilutions of sh were efficient at inactivating high numbers of hcov dried on tile surfaces, whereas, a / dilution had substantially lower activity. conclusions: etoh, ipa, and sh at multiple concentrations efficiently inactivated infectious virus on hard surfaces, typical of those found in public places. often no remaining infectious hcov could be detected. with the rapid spread of sars-cov- around the world, there was a concomitant rapid increased need of effective sanitizers/disinfectants. with the major method of transmission being through aerosolized respiratory droplets, and virus on surfaces remaining viable for hours and even days - , there arose a constant need to properly disinfect surfaces. healthcare institutes, businesses, and homes quickly found themselves in need of reagents to disinfect surfaces. during this pandemic, the necessity to disinfect surfaces at an increased rate resulted in product shortages. the environmental protection agency (epa), in order to make everyone aware of, and have access to, potentially effective surface disinfectant products for use against the possible presence of sars-cov- on surfaces, provided a list of "disinfectants for use against sars-cov- " . under their guidelines, the epa allows a manufacturer to provide data that shows that their product(s) is (are) potentially effective against harder-to-inactivate viruses. after receiving approval from the epa, the manufacturers can market claims for use against sars-cov- . while this list can potentially provide important information to users it has several shortcomings. first, for many of the disinfectants on the list, it is difficult, if not impossible, to obtain the experimental protocols used to determine the effectiveness of the disinfectant. second, the fda, epa, and the department of health and human services (dhhs) all require that standards for meeting efficacy data requirements include testing virucidal effects on a carrier (surface), as opposed to a suspension assay [ ] [ ] [ ] . third, the surface or carrier test also requires the drying of virus onto the carrier in the presence of a protein "soil"; then the virus is recovered and assayed for infectivity [ ] [ ] [ ] . fourth, many of the contact times reported on the epa's list are not realistic for practical use. a contact time of over min is often not pragmatic under normal situations in healthcare institutes, business, or homes. it is also questionable if the viruses used to make these claims are really harder-to-inactivate viruses. this list was developed to provide needed guidance at the beginning of a situation, such as the present pandemic. for that early need, it was an important aid. however, the list was meant to be a stop gap until more evidence-based studies could be completed. with the rapid loss of ready available disinfectants, many public places have found that the only products available in needed quantities are common alcohols, ethanol (etoh) and isopropyl alcohol (ipa), without additives. here we demonstrate the efficacy of etoh and ipa, two basic disinfectants that are relatively easy to obtain, and are relatively safe for use in public areas. we tested a wide variety of concentrations of the two alcohols commonly used in disinfectants and sanitizers. to satisfy the requirements of hard surfaces as carriers, we used ceramic and porcelain tiles that are commonly found in public places. all assays were performed in the presence of a 'soil', bovine serum albumin (bsa). for all of our assays, we used high titre stocks of hcov- e, as a surrogate for sars-cov- . while there are clear differences in the pathology of these viruses, they are in the same virus family, having very similar structures, and both are human respiratory pathogens. sars- has been shown to survive longer in a dried state for up to days where hcov- e survived only up to days , but disinfectant comparisons were not performed. using the surrogate has allowed us to rapidly test and provide science-based answers in the search for an effective surface disinfectant, using contact times that better reflect real-life situations. huh cells were grown in dulbecco modified eagle's medium (dmem) supplemented with % fetal bovine serum (fbs) (dmem ) and u/ml pen/strep, and the cells grown in % co at ˚c. infectious stocks of human coronavirus e (hcov e) were prepared by seeding t flasks with x huh cells, which were incubated overnight. on the following day, the media was changed to dmem with % fbs (dmem ) and a cells were infected with virus using a multiplicity of infection (moi) of . . the infected flasks were incubated for two days in % co at ˚c. on the second day, the flasks were frozen at - ˚c for at least h, then thawed in a ˚c water bath taking care to remove them from the water bath before they were completely thawed. thawing was then completed at room temperature. the cell suspensions were transferred to a ml polypropylene tube and sonicated on ice in a cup sonicator at watts peak envelope power, bursts of s each. the lysates were clarified by centrifugation at , rpm for min at ˚c, and the supernatant poured into a fresh ml tube. virus solutions were aliquoted into - . ml portions, and several smaller aliquots were then frozen for long term storage at - ˚c. one of the smaller aliquots was used to determine the titre of the stock by the tissue culture infectious dose (tcid ) assay. huh cells were harvested, counted, and resuspended into dmem to a concentration of . x cells/ml. then, µl of the cell suspension was added to each well of the -well plate. plates were incubated overnight in % co at ˚c. serial -fold dilutions of virus were added to each column of wells containing cells. an extra row of mock-infected cells were included across the bottom as controls. the plates were then incubated for days in % co at ˚c. on the third day, the wells were examined for the presence of cytopathic effects (cpe) and the tcid calculation was done using the reed-muench method , based off the number of wells positive for cpe at each dilution. the disinfectants used in the study were ethanol (etoh) (fisher scientific), isopropanol (ipa) (sigma -aldrich), glutaraldehyde (gta) (cidex and cidexplus; advanced sterilization products), orthophthalaldehyde (opa) (cidex opa; advanced sterilization products), and sodium hypochlorite (sh) (activate; deardorff fitzsimmons corp.). each disinfectant was prepared according to manufacturer's recommendation and stated dilution immediately before testing. porcelain and ceramic tiles were purchased from a local building supply company and used as carriers for the disinfection assays (fig ) . carriers were prepared by soaking in % hydrogen peroxide for min, neutralization in sterile water containing u/ml of catalase for min, and j o u r n a l p r e -p r o o f rinsing in sterile water for min before being dried in a sterile petri dish , . two hundred µl of an organic load or soil of % bsa was added to the virus suspension and µl of this virus solution was spread onto a single carrier side with a sterile pipette tip. the inoculated carriers were allowed to dry in a laminar flow cabinet for min. immediately after drying, ml of the liquid disinfectants were added to the surface of the carrier, covering the entire area containing the dried virus. carriers were then incubated at room temperature for contact times of s, s, and min. virus was then scraped off the carrier into a -ml amicon ultra centrifugal filter ( , mw cut-off [mwco]) and immediately ml of neutralizer was added to the filters. the filters were centrifuged at , rpm for min. the filters were washed a total of x with dmem and centrifuged at , rpm for min. the virus-containing eluents were then assayed for infectivity using the tcid method. at least four replicate assays were done for each disinfectant and contact time. controls for virus recovery after drying on a carrier were included for every set of assays performed. in every case, we never observed a significant decrease (< . log ) in infectious virus due to drying the virus on either type of tile. neutralizers used were dmem for etoh and ipa, and % glycine for sh, gta, and opa. table i shows that in general, both etoh and ipa were highly effective at inactivating hcov. etoh concentrations of %, %, %, and %, and ipa concentrations of %, %, and % were all able to produce greater than log inactivate of hcov, and in some cases, we were unable to detect any remaining infectious virus. greater than . % reduction of infectious virus was observed at all contact times, including the shortest time of s. in many instances, we were unable to detect any residual infectious virus (table i) . however, in a few cases with contact times of or s, some of the replicates reached only a log reduction (table i) , although this level still means that over . % of the infectious virus was destroyed. interestingly, at the highest concentrations tested, % etoh and % ipa, we observed significant reductions in inactivating, with some contact times producing less than a log reduction of infectious virus. because of our previous experience in testing bleach (sh) [ ] [ ] [ ] [ ] , and the potential for people to have it available for use in disinfecting surfaces, we decided to include sh in these evaluations. common concentrations of bleach purchased by the general public contain between % and % sh, and it is recommended to be used at a / to a / dilution. we used . % sh diluted / (~ . %) as we have done previously as a positive virucidal control , , . as expected, . % sh was highly effective at inactivating hcov, producing greater than a log decrease in infectious virus. we were unable to observe any sign of remaining infectivity at all contact times of min, s, and s (table i) . because there are recommendations to use bleach at / and / dilutions for sanitizing surfaces , , we decided to also test the / dilution. at a / dilution or ~ . % sh, we observed significant decreases in its ability to inactivate hcov (table i) . sometimes, the inactivating dropped below a log decrease. we also tested a / dilution or ~ . % sh (table i ). the efficacy of . % sh was similar to that of . % sh, both producing greater than a log decrease in infectivity with contact times of s and s. with both . % and . % sh there was no evidence of any remaining infectious virus (table i) . because of its prominent role for the last several decades as a hospital sterilant, we also tested j o u r n a l p r e -p r o o f (gta). as expected, gta proved to be highly effective at inactivating hcov, producing greater than log decrease in infectious virus at all contact times (table i) . in the midst of a pandemic, the supply chain may not be able to provide traditional disinfectants fast enough to meet needs. basic alcohols, etoh and ipa, are likely easy solutions to fill unmet needs. clear evidence-based answers to important questions of contact times, effect of carrier types, and the influence of soil contamination on disinfectants used on a new infectious organism are minimal or nonexistent. our goal was to create a more real-world situation to evaluate the efficacy of available disinfecting agents. as we are finding out in the present pandemic situation, these may be the only products available during times of shortages. we used a wide range of concentrations, porcelain and ceramic tile carriers, which are common surfaces in public places, and contamination with organic soil, and short contact times that represent the reality of practices used in disinfecting public spaces. our studies demonstrate that etoh and ipa at concentrations ranging from % to % are highly effective at inactivating hcov on tile surfaces even with contact times as low as sec. while we saw slight differences between the two carriers, these were inactivating over . % or . % of the virus. noteworthy differences were observed when we used % etoh or % ipa. it is likely that a minimum concentration of water is required to catalyze microbial penetration, allowing these agents to optimally perform their destructive effects. higher concentrations may dehydrate the virus, allowing significant levels to remain viable , . therefore the adage that "more is better" is not necessarily true for alcohols. because many public spaces have bleach on hand, we also tested bleach at three recommended concentrations , . concentrations of . % and . % both inactivated . % or more of the virus within short contact times. however, . % sh was much less effective at inactivating the virus. several studies have reported the efficacy of various disinfectants in inactivating cov, including animal - and human [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] cov. these studies are discussed in a review . the majority of these studies did not use the carrier method of drying the virus onto a solid surface. it has been recently shown that hcov can remain infectious in aerosols for hours and on surfaces for days , demonstrating the importance of testing the efficacy of a disinfectant in the manner in which it will be used, i.e., to disinfect solid surfaces. of those studies that used the carrier method, some dried the virus on petri dishes , , while others used stainless steel as their carrier , , . similar to the use of stainless steel, we used carriers that represented real-life situations. porcelain and ceramic tiles are common surfaces in many public places, and during a pandemic, would be surfaces that require constant disinfection. in our study, we saw only small effects, of less than log of inactivating, between the two tile types, for only a few of the disinfectant concentrations and contact times tested. previously published studies particularly relevant to our results used different concentrations of etoh and ipa [ ] [ ] [ ] , . all but one of these studies used the suspension technique, so those testing high concentrations of etoh or ipa were unable to factor in the rapid dehydration phenomenon which is characteristic of these agents. the only study that performed testing by drying the virus on a carrier, only used % etoh . results from these studies aligned well with our results presented here, but none covered the range of concentrations we covered, with the majority only testing a few concentrations. in addition, only one study used the carrier model. two studies that tested bleach as a surface disinfectant both showed, as we did, that diluting sh -fold resulted in poor inactivating of two animal cov, mouse hepatitis virus and transmissible gastroenteritis virus , or inactivating hcov e . in addition, one of these studies also tested sh diluted -fold and observed a . % reduction in virus titre similar to the results we observed. sars-cov- is the third pathogenic hcov with significant mortality in the past years to spread in the human population , . after its emergence, it quickly spread around the world. while there is a potential for other mechanisms of transmission, aerosolization and fomites are considered the most probable means. some of the most common symptoms of sars-cov- disease are associated with the formation of aerosols. persons infected but showing only mild or no symptoms can also readily spread the virus by aerosols . aerosols directly and indirectly readily contaminate surfaces in all public places, on which the virus can stay infectious for days . this resulted in persons responsible for the safety of many public places, including healthcare institutes, businesses, and homes, trying to find solutions to their need to disinfectant surfaces much more often. this led to a rapid strain on the supply chain in providing sufficient quantities of normally used disinfectant compositions. one answer was the use of readily available agents such as common alcohols (etoh and ipa) and diluted bleach. this study provides important information on the efficacy of these agents at different concentrations to inactivate hcov. chemical disinfection of non-porous inanimate surfaces experimentally contaminated with four human pathogenic viruses broad-spectrum microbicidal activity, toxicologic assessment, and materials compatibility of a new generation of accelerated hydrogen peroxide-based environmental surface disinfectant inactivation of sars coronavirus by means of povidone-iodine, physical conditions and chemical reagents the action of three antiseptics/disinfectants against enveloped and non-enveloped viruses in vitro bactericidal and virucidal efficacy of povidone-iodine gargle/mouthwash against respiratory and oral tract pathogens rapid and effective virucidal activity of povidone-iodine products against middle east respiratory syndrome coronavirus (mers-cov) and modified vaccinia virus ankara (mva) inactivation of severe acute respiratory syndrome coronavirus by who-recommended hand rub formulations and alcohols efficacy of various disinfectants against sars coronavirus stability and inactivation of sars coronavirus virucidal activity of world health organization-recommended formulations against enveloped viruses, including zika, ebola, and emerging coronaviruses persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents aerosol and surface stability of sars-cov- as compared with sars-cov- the antiviral action of common household disinfectants and antiseptics against murine hepatitis virus, a potential surrogate for sars coronavirus evaluating the virucidal efficacy of hydrogen peroxide vapour inactivation of surrogate coronaviruses on hard surfaces by health care germicides virucidal efficacy of physico-chemical treatments against coronaviruses and parvoviruses of laboratory animals identification of a novel coronavirus in patients with severe acute respiratory syndrome isolation of a novel coronavirus from a man with pneumonia in saudi arabia presumed asymptomatic carrier transmission of covid- none of the authors have any financial and personal relationships with other people or organizations that could inappropriately influence or bias of this work. this study was funded in part by the huck institutes of the life sciences' coronavirus research seed fund (crsf). key: cord- - qlo mun authors: park, sung‐soo; oh, hye-young; hong, duck‐jin title: mass screening of healthcare personnel for sars-cov- in the northern emirates date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: qlo mun nan while healthcare personnel (hcp) potentially has an increased risk of infection with the severe acute respiratory syndrome coronavirus (sars-cov- ) in the era of the pandemic [ ] , the approach to testing hcp for the virus has not been uniform [ ] . given the significant percentage of asymptomatic coronavirus disease (covid- ) infection [ ] , universal testing of hcp could allow infected workers to be identified and isolated early, reduce in-hospital transmission, mitigate potential workforce depletion, and enhance healthcare workers' safety [ ] . this study aimed to evaluate the effectiveness of the universal staff screening for covid- and identify any risk factor for viral infection. the hospital invited hcp to screen for sars-cov- three times between rd april and th may , regardless of symptoms. the presence of sars-cov- was confirmed by real-time reverse transcription-polymerase chain reaction (rt-pcr). the staff were encouraged to notify the occupational health nurse for sars-cov- test any time if they had any suspicious symptoms of covid- or close contact with covid- patients. once a member of staff was confirmed as a covid- case, a structured survey and contact tracing were followed. all clinical staff in the hospital were recommended to wear a surgical mask from th march , onwards. external visitors were prohibited from entering the hospital starting on th march . all patients were admitted to negative pressure rooms first after routine screening rt-pcr test for sars-cov- from th april . covid- patients were transferred to the there were sharp rises in the rate of positive coronavirus tests up to . % and . % at the second and third screening, respectively (table i) as the travel ban and lockdown had been imposed since late march in the uae [ ] , a high incidence of covid- in support staff might be related to shared accommodation and crowded commuter vehicles, which is supported by the survey. most migrant workers in gulf countries are confined to small rooms which are shared with up to a dozen workers [ ] . it is comparable to the findings of the previous studies that household contact or extra-occupational exposure might j o u r n a l p r e -p r o o f have a role in transmission dynamics among hcp [ , ] . the limited accessibility of the healthcare system for these staff might also contribute to their higher infection rate. they must visit a different medical clinic when they are ill, unlike other employees. screening found few covid- patients in the non-support staff, which implies that strict infection preventive measures could contain in-hospital transmission effectively if transmission outside hospital settings is under control. the limitation of the study is that it is hard to generalise the results due to the middle east setting and covid- free status of the institution. also, since the screening was done during the coronavirus lockdown, the epidemiology could change when restrictions are lifted. the proportion of asymptomatic covid- cases supports the utility of the universal screening of hcp. however, as mass screening for a long time seems unsustainable, targeted screening for high-risk groups might be an alternative in the second wave of covid- . j o u r n a l p r e -p r o o f risk of covid- among front-line healthcare workers and the general community: a prospective cohort study effective control of sars-cov- transmission between healthcare workers during a period of diminished community prevalence of covid- covid- : four fifths of cases are asymptomatic, china figures indicate covid- : the case for healthcare worker screening to prevent hospital transmission united arab emirates ministry of interior labor camps in the gulf states. viewpoints: migration and the gulf characteristics and transmission dynamics of covid- in healthcare workers at a london teaching hospital transmission to healthcare personnel: the global act-hcp case-control study soohyun ha and zahra ahmed mohammed saeed, for their hard work to increase sars-cov- test capacity. the authors thank katrine k. gatchalian and hyojung kim, for assistance in extracting data from covid- test registry and sowmya a. fernandes j o u r n a l p r e -p r o o f none declared. none.j o u r n a l p r e -p r o o f key: cord- -sk pqjrh authors: o’hearn, katie; gertsman, shira; webster, richard; tsampalieros, anne; ng, rhiannon; gibson, jess; sampson, margaret; sikora, lindsey; mcnally, james dayre title: efficacy and safety of disinfectants for decontamination of n and sn filtering facepiece respirators: a systematic review date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: sk pqjrh background: decontaminating and re-using filtering facepiece respirators (ffrs) for healthcare workers is a potential solution to address inadequate ffr supply during a global pandemic. aim: the objective of this review was to synthesize existing data on the effectiveness and safety of using chemical disinfectants to decontaminate n ffrs. methods: we conducted a systematic review on disinfectants to decontaminate n ffrs using embase, medline, global health, google scholar, who feed, and medrxiv. two reviewers independently determined study eligibility and extracted predefined data fields. original research reporting on n ffr function, decontamination, safety, or ffr fit following decontamination with a disinfectant was included. findings and conclusions: a single cycle of vaporized hydrogen peroxide (h( )o( )) successfully removes viral pathogens without affecting airflow resistance or fit, and maintains an initial filter penetration of < %, with little change in ffr appearance. residual hydrogen peroxide levels following decontamination were within safe limits. more than one decontamination cycle of vaporized h( )o( ) may be possible but further information is required on how multiple cycles would affect ffr fit in a real world setting before the upper limit can be established. although immersion in liquid h( )o( ) does not appear to adversely affect ffr function, there is no available data on its ability to remove infectious pathogens from ffrs or its impact on ffr fit. sodium hypochlorite, ethanol, isopropyl alcohol and ethylene oxide are not recommended due to safety concerns or negative effects on ffr function. shortages of personal protective equipment (ppe), including n filtering facepiece respirators (ffrs), are common during pandemics. the centres for disease control and prevention (cdc) recommends n ffrs, which filter % of airborne particles [ ] , as the preferred ppe when entering the room of a patient with suspected or confirmed covid- , and that an n ffr should be worn during all aerosol generating procedures [ ] . unfortunately, during the ongoing covid- pandemic, some hospitals and healthcare workers are faced with an inadequate supply of n ffrs [ , ] while also dealing with an increase in sars-cov- positive patients. project n , a covid- initiative that transfers ppe from manufacturers and other disciplines to healthcare institutions in need, received requests for over million units of equipment from , health centres globally since march th [ ] . consequently, addressing the n ffr shortage has become a matter of increasing urgency as cases of covid- continue to rise. a potential solution to ffr shortages would be to decontaminate and re-use ffrs. however, prior to utilizing this strategy, it is essential to demonstrate that decontamination does not compromise structural integrity, fit, filter efficiency (aerosol penetration), and airflow resistance of the ffr [ ] . several decontamination methods have been previously investigated, including energetic (e.g. microwave irradiation, ultraviolet germicidal irradiation (uvgi)) [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] , gaseous (e.g. ethylene oxide, vaporized hydrogen peroxide) [ , , , , ] , and liquid protocols (e.g. hydrogen peroxide, sodium hypochlorite) [ , , [ ] [ ] [ ] , , , ] . the cdc recently released crisis standards of care decontamination recommendations, with a brief summary of evidence for several of these approaches [ ] . however, detailed information on the safety and efficacy of a variety of decontamination methods is essential to allow hospital decision makers to j o u r n a l p r e -p r o o f evaluate the evidence and determine the feasibility of rapidly implementing different protocols at their institutions. to help inform ffr-reuse policies and procedures, our team has conducted three systematic reviews to synthesize existing published data regarding the effectiveness of uvgi [ ] , heat and microwave irradiation [ ] , and chemical disinfectants for decontamination of national institute for occupational safety and health (niosh)-approved n ffrs. this review will focus on chemical disinfectants, with the following objectives: ( ) to assess the impact of the each disinfectant method on ffr performance, with a specific focus on aerosol penetration and airflow resistance; ( ) to determine the effectiveness of each disinfectant method at reducing viral or bacterial load; ( ) to describe observations related to changes in physical traits following decontamination with a disinfectant; ( ) to determine the impact of each disinfectant on ffr fit; and ( ) to describe findings or observations related to potential health risks or irritation from residual disinfectant remaining on ffrs following decontamination. the study protocol and objectives were established a priori and registered on prospero on april th , (crd ), and reported here according to the prisma guidelines for systematic reviews (appendix a) [ ] . the protocol was also uploaded as a pre-print to osf on april th , (https://osf.io/ usx /). studies were eligible for inclusion in this systematic review if they satisfied all of the following criteria: ( ) original publication or systematic review; ( ) study reported on decontamination procedures for niosh-approved n (including sn ) ffrs or their components; ( ) at least one of the decontamination procedures evaluated used one of the j o u r n a l p r e -p r o o f following chemical disinfectants: sodium hypochlorite; liquid hydrogen peroxide, vaporized hydrogen peroxide, hydrogen peroxide gas plasma, or ionized hydrogen peroxide; ethanol or isopropyl alcohol; ( ) the study reported on at least one of the following outcomes of interest: (i) impact of the disinfectant on ffr performance, with a specific focus on aerosol penetration and airflow resistance (pressure drop); (ii) effectiveness of the disinfectant at removing viral or bacterial load; (iii) observations related to changes in physical traits following decontamination with a disinfectant; (iv) impact of each disinfectant on ffr fit; or (v) findings or observations related to user safety or irritation. only studies published in english or french were included. studies published prior to , the year that the n ffr was invented [ ] , were excluded. we included peer-reviewed literature and pre-prints. editorials, narrative reviews, book chapters, patents, and non-peer-reviewed commissioned reports were excluded. the following databases were searched by two health sciences librarians ( health, medrxiv and osf preprints were searched march , for the term "n " and records pertaining to decontamination were selected and downloaded. citations were uploaded to insightscope (www.insightscope.ca) for title and abstract screening and full text review. at both title/abstract and full text screening levels, citations were assessed in duplicate and independently. before citation screening was initiated, each reviewer was asked to read the published protocol for this systematic review to familiarize themselves with the review objectives and citation screening process. next, to ensure that the reviewers understood the citation eligibility criteria, the study lead (ko) created a test set of citations. the test set included true positives (i.e. citations that met the eligibility criteria to be included in this systematic review) and true negatives (i.e. citations that did not meet eligibility criteria to be included in this systematic review) [ ] . each reviewer (jg, rn) was then required to complete the test set by assessing the same citations. reviewers had to achieve a sensitivity in excess of % on the test set before they were given access to title/abstract screening. at both title/abstract and full text review, records were removed only if both reviewers agreed to exclude. cases with screening conflicts were resolved by review by the study lead (ko). at the completion of full text review, the study lead (ko) reviewed the eligible citations to identify potential duplicates and confirm eligibility. the reference lists of included studies were reviewed to identify any potentially relevant studies not included in the screening set. j o u r n a l p r e -p r o o f a data extraction tool was developed in redcap [ , ] by the study lead (ko) and piloted on five eligible studies. eligible studies were divided equally among the reviewers for duplicate, independent data extraction into redcap and microsoft excel, followed by conflict resolution by the study lead. when necessary, data was extracted from figures using sourceforge plot digitizer (http://plotdigitizer.sourceforge.net/). outcome data is reported for niosh-approved n (particulate, including surgical) ffrs or their components only. other respirator types (e.g. r or p-filter type) were not included in the analysis. ffr "component" was defined as a piece of an n ffr that had been cut out with all layers still intact. intervention arms described by authors as vaporized hydrogen peroxide, hydrogen peroxide gas plasma, and ionized hydrogen peroxide were analyzed together and, for convenience, are collectively referred to as vaporized hydrogen peroxide for the remainder of this review. risk of bias was assessed for each study by outcome using a predetermined evaluation matrix which included evaluation based on study design, methodological consistency, population heterogeneity, sampling bias, outcome evaluation, and selective reporting (appendix c). all statistical analysis were performed using the r statistical programming language [ ] . data was meta-analyzed using a random effects model with the r package 'metafor' [ ] . random effects meta-analyses were employed to present either the pooled absolute value pre / post chemical disinfectant intervention or relative change (from control or no treatment arm). for both the aerosol penetration and airflow resistance outcomes, the data was presented as an absolute value. for the germicidal outcome, the data was presented as a relative log change j o u r n a l p r e -p r o o f in viral load. the majority of studies evaluated the germicidal effect of chemical disinfectants using viruses; to improve comparability studies on bacteria or bacteriophage decontamination were removed from the germicidal analysis and are instead presented descriptively. random effects meta-analysis was used to calculate the effect size for each type of chemical disinfectant. heterogeneity was assessed by calculating an i statistic from a fixed effect model. the standard deviation for each control and treatment arm within a chemical disinfectant class was calculated from the pooled absolute values post intervention. the sample size represents the total number of replicates for all n ffr models included. a total of records were identified through the initial database search. after removing duplicate citations in endnote, there were citations remaining. both reviewers correctly identified all true positives and true negatives in the test set. title and abstract screening excluded , with the review team achieving a kappa of . . at the full text level, the reviewers excluded six of the records, with a kappa of . . an additional three pre-print articles were identified following the initial search, screened in duplicate and included in the analysis, resulting in a total of eligible articles [ , , [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] . an overview of the search process, results and reason for exclusions are shown in the prisma diagram ( figure ). nine studies originated from the united states, three from east asia, and the remaining one originated from canada. the studies included a total of intervention arms, including sodium hypochlorite (n = ), liquid hydrogen peroxide (liquid h o , n = ), vaporized hydrogen peroxide (vaporized h o , n = ), ethanol (n = ), isopropyl alcohol (n = ), ethylene oxide j o u r n a l p r e -p r o o f (eto, n = ), or other (n = ). thirty-five n models were evaluated across the studies. the most common models studied were the m (n = ), m (n = ) and the m (n = ). the number of articles evaluating the main study outcomes were aerosol penetration (n = ), airflow resistance (n = ), germicidal activity (n = ), fit (n = ), changes in physical traits (n = ), and safety/irritation (n= ). a summary of the intervention arms, outcomes, and number of n ffr models evaluated is presented in table i . the majority of studies reported on outcomes following a single cycle of decontamination. bergman et al. [ ] evaluated aerosol penetration and airflow resistance following three decontamination cycles, and kenney et al. [ ] reported on changes in physical traits following five cycles. fischer et al. [ ] and kumar et al. [ ] reported on ffr fit following three decontamination cycles and , , , and cycles respectively. three studies were published as pre-prints [ , , ] , the remaining were peer-reviewed publications. there were five studies identified that evaluated aerosol penetration following decontamination with a disinfectant [ , , , , ] , including intervention arms that evaluated sodium hypochlorite (n = ), liquid h o (n = ), vaporized h o (n = ), ethanol (n = ), isopropyl alcohol (n = ), and eto (n = ) (table ii) . the majority of studies measured initial aerosol penetration. this was done using a continuous airflow of l/min and an aerosol of sodium chloride with a count median diameter of . ± . µm, geometric size deviation of < . and mass median aerodynamic diameter ~ nm in accordance with cfr . for niosh certification testing [ ] . the exception was lin et al [ ] who used a challenge aerosol with a count median diameter of ± and a geometric size deviation of . ± . . analysis was limited to studies that used a testing aerosol that adhered to niosh certification testing j o u r n a l p r e -p r o o f standards. some of the included studies, such as viscusi et al [ ] and bergman et al [ ] , evaluated different concentrations of sodium hypochlorite or different methodologies for vaporized h o and therefore had more than one arm included. we choose not to provide a pooled estimate of aerosol penetration between chemical sterilization, as this metric would not be relevant for decision makers. instead, we calculated mean difference from the random effects model and the i from a fixed effects model for each decontamination type ( figure ). studies on sodium hypochlorite showed no change in aerosol penetration post-sterilization, with low study heterogeneity. studies on ethylene oxide and liquid h o provided consistent findings of no change in aerosol penetration post-sterilization, with low between study heterogeneity. studies on vaporized h o showed no change in aerosol penetration post sterilization, with large between study heterogeneity driven by three decontamination cycles using the sterrad® s h o gas plasma sterilizer in bergman et al [ ] . studies on isopropyl provided consistent findings that aerosol penetration post-sterilization was impaired and exceeded % (pooled aerosol penetration estimate . % ( % ci . , . ). a summary of the aerosol penetration results for each chemical disinfectant type is provided in table iii . three studies reported on airflow resistance [ , , ] , including intervention arms that evaluated sodium hypochlorite (n = ), liquid h o (n = ), vaporized h o (n = ), ethanol (n = ) and eto (n = ) ( table ii ). the mean difference for sodium hypochlorite was . mm h o ( % ci - . , . ) with an i of ~ .%. it was not possible to include the results from lin et al [ ] in the analysis for sodium hypochlorite as there was no standard deviation (sd) for the treatment arm. the mean difference for eto was . table iii . eight studies evaluated the germicidal impact of one or more disinfectants, including two studies on bacteria [ , ] , five studies on viruses [ , , [ ] [ ] [ ] , and one study on bacteriophages [ ] . intervention arms included in the eight studies were sodium hypochlorite (n = ), vaporized h o (n = ), ethanol (n = ) and eto (n = ) (table iv) . no studies evaluated germicidal removal following decontamination with liquid h o or isopropyl alcohol. while all of the studies showed a reduction in viral load post decontamination, there were large differences in the magnitude of the effect, ranging from log . to . ( figure ). n ffrs that were inoculated with sars-cov- virus, then sprayed with % ethanol until saturation showed viral levels below the limit of detection of the assay (< . tcid /ml) at five, ten, and minutes post-sterilization [ ] . however, ethanol was not as effective at eradicating bacteria. immersion in an ethanol solution for minutes at concentrations of , , and % resulted in relative survival rates of bacillus subtilis of ± %, . ± . %, ± % and ± % respectively. by hours post-sterilization, survival rates declined to ± %, . ± . %, ± % and ± % [ ] . eto decontamination removed all viable vesicular stomatitis virus (vsv) from four n ffr models. in the same study, a single cycle of vaporized h o also removed all viable vsv and sars-cov- [ ] . one cycle of vaporized h o also resulted in bacteriophage levels (< pfu) [ ] or viral levels (< . tcid /ml) [ ] below the detectable limit of the assay on one n ffr model each, and no growth of h n on two n ffr models at seven days following decontamination with vaporized h o [ ] . a summary of the germicidal results for each disinfectant type is presented in table iii . six studies were identified that evaluated changes in ffr physical traits following decontamination (table v) . sodium hypochlorite and liquid h o consistently resulted in changes in ffr appearance, including tarnished metallic nosepieces [ , , , ] , oxidized staples [ , ] , yellowing of nose pads [ , ] , bleeding or fading of lettering [ , ] , stiffening of filter media and elastic straps [ ] , or dissolving nosepieces [ ] . the majority of studies that evaluated physical appearance following exposure to vaporized h o , isopropyl alcohol, ethanol and eto reported that ffr appearance was unchanged. changes in ffr odor was evaluated in three studies following disinfectant treatment with sodium hypochlorite, eto, liquid h o and vaporized h o . sodium hypochlorite left a characteristic bleach odor on the ffrs [ , , ] . none of the other chemical disinfectants assessed resulted in changes in ffr odor. a summary of the results of evaluations on changes in physical traits for each disinfectant type is presented in table iii . two studies evaluated ffr fit following decontamination, and included the following intervention arms: eto (n = ), vaporized h o (n = ) and ethanol (n = ). kumar et al. evaluated ffr fit using the portacount fit tester and two exercises (normal and deep breathing) following multiple decontamination bouts [ ] on new (unworn) ffrs. four ffr models were exposed to multiple bouts of decontamination (eto: and cycles; vaporized h o : , , and cycles using the vhp ard system; , , and cycles using the sterrad nx sterilizer). a single fit test was then performed with each of the four ffr models for each of the decontamination methods and number of cycles described above. all four ffr models passed the fit test (achieved a fit factor > as per occupational safety and health administration (osha) standards) following one, three, five and ten decontamination cycles of vaporized h o using the vhp ard system, but not with the standard cycle of the sterrad nx sterilizer (fit factor > after one cycle, but < following five, ten and cycles). a passing fit factor score was achieved following both one and three decontamination cycles of eto. fischer et al. evaluated ffr fit following three cycles of two-hour wear and decontamination using a m aura +/ . after each wear-decontamination cycle, six fit tests were performed using six replicate ffrs. a fit factor > was achieved following one, two and three vaporized h o wear-decontamination cycles. the fit factor ranged from to after one wear-decontamination cycle, to after two cycles and to after three cycles. the six replicate ffrs achieved a fit factor > following one ethanol weardecontamination cycle (fit factor range to ), but two out of the six replicate ffrs did not achieve a passing fit factor score following two ethanol wear-decontamination cycles (fit factor j o u r n a l p r e -p r o o f range . to ), and four replicate ffrs had a fit factor < following three cycles (range . to ) [ ] . a summary of the fit test results for each disinfectant type is presented in table iii . potential health risks associated with disinfectant decontamination was evaluated in three studies. viscusi et al. [ ] reported that, while letting sodium hypochlorite treated ffrs air-dry inner surface at two hours was . p.p.m. and undetectable at three hours [ ] . a summary of the results of evaluations for potential safety risks is presented in table iii . a detailed risk of bias assessment can be found in appendix d. overall risk of bias for aerosol penetration was low in all studies. risk was moderate in one study for airflow resistance j o u r n a l p r e -p r o o f due to population heterogeneity (i.e. ffrs not obtained from the same lot) and potential selective reporting. moderate risk of bias for all germicidal outcomes was primarily due to the use of visual assays and population heterogeneity, while moderate risks for fit evaluations were due to population heterogeneity and missing methodological details. physical trait assessments had moderate to high risks of bias for various reasons, but unblinded outcome evaluation was common across all studies. for safety/irritation evaluations, no controls were used and two studies lacked enough details to assess all risk categories, resulting in moderate to high risks of bias for this outcome. this is the first systematic review to synthesize the existing evidence on using chemical disinfectants to decontaminate n ffrs. we found that a single cycle of vaporized h o successfully removes viral pathogens without affecting airflow resistance or fit, and maintains an initial filter penetration of < %, with little change in ffr physical traits. further research is required before the acceptability of decontamination using liquid h o can be determined. sodium hypochlorite, ethanol, isopropyl alcohol and eto are not recommended due to safety concerns and/or adverse effects on ffr function. this systematic review identified five studies that reported on changes in aerosol penetration following decontamination with a chemical disinfectant. niosh has established a % filter efficiency standard (i.e. aerosol penetration of < %) for n ffr [ ] . results showed that filter efficiency > % was generally maintained following decontamination with sodium hypochlorite, liquid h o , vaporized h o and eto under laboratory test conditions. however, while the majority of studies evaluating sodium hypochlorite and vaporized h o reported a post-decontamination aerosol penetration of < %, there were conflicting findings in one study j o u r n a l p r e -p r o o f for each method. four of the five studies that evaluated sodium hypochlorite reported that filter penetration of < % was maintained following submersion ( . to . %, min submersion) [ , , ] or wiping ( times) with hypochlorite wipes [ ] ; however, the study by lin et al., which used a different aerosol penetration testing protocol, reported penetration values that exceeded % for particle sizes > nm ( . %, min submersion) [ ] . vaporized h o maintained filter performance in the majority of the studies where it was evaluated, with the exception of bergman et al. [ ] . in this study, three -minute cycles with the sterrad® s [ ] . using niosh testing standards, the report showed that filter efficiency of the m ffr was . % ± . following fifty cycles of vaporized h o , safely exceeding the niosh requirement of %. findings from the included studies showed that submersion in ethanol and isopropyl alcohol resulted in significantly higher filter penetration values that exceeded the levels permissible by niosh. this is not surprising, as solvents such as isopropyl alcohol have been shown to j o u r n a l p r e -p r o o f eliminate the electrostatic charges on the ffr filter [ , ] , and the filter efficiency of an uncharged media is typically ten-fold lower than a charged media [ ] . in addition to standards for aerosol penetration, niosh has also established standards for airflow resistance of n ffrs (peak average inhalation of a successful decontamination protocol must also remove infectious pathogens from the [ ] . the ability of vaporized h o to eradicate virus and bacteria from n ffrs could be further enhanced by allowing the ffr to sit for an extended time period between re-use. it is well established that bacteria and virus levels on surfaces decrease over time [ , ] . for example, the infectiveness of sars-cov- declines by at least one log every hours across a variety of surfaces [ ] . therefore, building a "holding period" into the decontamination protocol, where ffrs sit for - days following exposure to vaporized h o , would further guarantee the absence of viable viral particles. ffr fit is an important outcome of interest when considering whether a decontamination protocol is acceptable to use. improper fit results in an inadequate seal of the ffr against the wearer's face, reducing the ffr's ability to prevent particle penetration [ ] . two studies evaluated ffr fit following decontamination. ffr fit was not affected by one cycle of decontamination with ethanol [ ] or by multiple cycles of eto or vaporized h o [ , ] . the multiple decontamination cycle results from kumar et al. [ ] should be interpreted with some caution, however, as ffr fit was evaluated using only normal breathing and deep breathing exercises. the additional exercises from the ohsa protocol that involve movement of the mouth, head and body (to mimic movements performed by health care workers) were not included in the evaluation. therefore, it is not clear if a fit factor > would have still been achieved had the full ohsa protocol been used. additionally, the ffrss that were evaluated were new and had not been worn by health care workers prior to decontamination, or between decontamination cycles. there is evidence that ffr fit deteriorates through repeated donning and doffing [ ] , therefore the number of decontamination and re-use cycles that can be applied to a ffr will be limited by physical stress imposed by both decontamination and donning and doffing. the fda-commissioned bioquell report [ ] also evaluated fit following multiple fischer et al. [ ] are more representative of the real world, as it involved three cycles of decontamination and two-hour wearing. the ffr model they evaluated ( m aura +/ ) maintained a fit factor > following three cycles of vaporized h o ; however, they used a small sample size (six replicates of one ffr model). further testing should be conducted using ffrs worn by health care workers prior to and between decontamination cycles in order to confirm whether ffrs maintain fit in the real-world setting following multiple decontamination cycles with vaporized h o . sodium hypochlorite consistently resulted in significant changes to ffr appearance. some of the changes reported were substantial enough that they could result in changes in ffr fit or comfort, such as stiffening of filter media and elastic straps and dissolving of half of the ffr nosepiece. sodium hypochlorite also resulted in a bleach odor on the ffrs that would be unpleasant to the wearer. some chlorine off-gassing was observed on ffrs that had been submerged in sodium hypochlorite and rehydrated, which the authors felt could be significant given that rehydration of the ffr could be compared with moisture in the exhaled breath of an individual wearing the ffr [ ] . therefore, as low-level exposure to chlorine may occur when wearing an ffr that has been decontaminated by submersion in sodium hypochlorite, sodium hypochlorite is not recommended for ffr decontamination and reuse. there are also potential safety concerns with the use of eto. eto in itself is hazardous and a known human carcinogen, and decontamination with eto requires a lengthy aeration process to remove residual eto [ ] . following a -hr aeration cycle, salter et al. did not find any eto on six ffrs models, but did find traces of a hazardous contaminant, ethylene glycol monacetate [ ] . whether residual eto remains on n ffrs when using a shorter aeration cycle, such as the four-hour cycle used by viscusi et al. [ , ] , is unknown. given the potential safety concerns and the impracticality of a lengthy aeration cycle, the results of this review do not endorse eto sterilization for n decontamination, which is consistent with the cdcs recommendations [ ] . residual levels of liquid and vaporized h o were reported in one and two studies respectively, though they remained within established safety limits, and in the case of vaporized h o , decreased over time. a "holding period" following decontamination, as described above, would provide extra assurance that hydrogen peroxide levels were under the permissible exposure limit set by ohsa ( ppm) [ ] . the moderate overall risks of bias noted for germicidal outcomes are largely due to the use of unblinded assays to quantify bacterial and viral loads; although these are generally accepted as appropriate means of pathogen quantification, counting of plaques and colonies may be subjective. assessments of physical appearance and odor were unblinded in all cases and results were often reported as additional comments about observations of damage, rather than through a systematic procedure for all ffr models, which makes it unclear to what degree sampling and assessment biases may have influenced these outcomes. the potential for bias in evaluations of post-decontamination safety was increased by the lack of control group in any study which reduces confidence in accuracy of the machine measurements. although this systematic review provides valuable information regarding the use of chemical disinfectants for the decontamination of n ffrs, a number of limitations must be acknowledged. each study used a different combination of ffr types. in order to address this, we aggregated across ffr types within each study, treating the pooled replicates across ffr types as our statistically independent sampling unit. this is appropriate for our research question aimed at performance of ffrs in general (where we assume little difference between ffr types). if there are large differences between ffr types, our approach might artificially inflate our sample size; if this were the case it would unlikely change our findings, due to the consistency of these studies conclusions and low heterogeneity. for ease of completion, our review was limited to studies available in english or french, therefore evidence available in other languages is not included in our analysis. with the exception of the fit data from fischer et al. [ ] , all of the reported outcomes were evaluated on new, unworn ffrs. it is not clear whether extended ffr use prior to decontamination would alter our findings. future work evaluating decontamination of n ffrs should perform testing in real-world conditions, using n ffrs that have been worn by health care workers in the clinical setting prior to decontamination. finally, we did not have access to unpublished data, such as quality assurance work performed at hospitals or work performed by industry and submitted to regulatory agencies. for example, the fda recently reissued emergency use authorizations (eua) and no longer authorize decontamination or reuse of respirators that have exhalation valves. in the current published literature, the reasons for this eua are not evident [ ] . we identified thirteen studies that evaluated decontamination of niosh-approved n ffrs using a chemical disinfectant. of these, the most promising chemical disinfectant evaluated j o u r n a l p r e -p r o o f was vaporized h o . a single cycle of vaporized h o successfully removes viral pathogens without affecting airflow resistance or fit, and maintains an initial filter penetration of < %, with little change in ffr appearance. residual hydrogen peroxide levels following decontamination were within safe limits. more than one decontamination cycle of vaporized h o may be possible but further information is required on how multiple cycles would affect ffr fit in a real world setting before the upper limit can be established. although immersion in liquid h o does not appear to adversely affect ffr function, there is no available data on its ability to remove infectious pathogens from ffrs or its impact on ffr fit. sodium hypochlorite, ethanol, isopropyl alcohol and eto are not recommended due to safety concerns or negative effects on ffr function. this systematic review provides valuable data on the efficacy and safety of decontaminating n ffrs using chemical disinfectants. at the time of this review, published data only supports one disinfectant approach. literature in this area is rapidly evolving as researchers work to recognize solutions to widespread shortages in n ffrs. these circumstances are amenable to a living review that allows for the rapid identification and incorporation of important new data. recognizing this need, our group has initiated a living review with an open-access database [ ] ; the most recent scoping review update on -jun- identified new publications evaluating decontamination of niosh-approved n ffrs using chemical disinfectants [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] , none of which would significantly alter the findings of this systematic review. it is important that future studies on decontamination employ approved n ffrs and techniques for testing (e.g. niosh testing standards for aerosol penetration and airflow resistance). this is particularly relevant when evaluating germicidal effects, where significant heterogeneity in pathogen selection, application procedures, and assays were observed. it would be prudent for researchers working in this area to both consider the available literature on disinfectant efficacy and consult with their regulatory agencies about the most up to date testing requirements. j o u r n a l p r e -p r o o f no change in aerosol penetration, aerosol penetration < % maintained following one (n = ) and three decontamination cycles (n = ) aerosol penetration exceeded % for of ffr following decontamination cycles (n = ) no change in airflow resistance, niosh standards maintained (n = ) no viable virus, or virus or bacteriophage below detectable assay limit (n = ) fit factor > achieved following , , , cycles with the vhp ard system, but only following one cycle using the sterrad nx (n = ) b fit factor > achieved following x h wear + decontamination cycles (n = ) slight tarnishing of metallic nosebands (n = ) no changes in physical appearance (n = ) no changes in odor (n = ) did not deposit significant quantities of toxic residues on the ffrs (n = ) j o u r n a l p r e -p r o o f fit factor > achieved for replicate ffrs following decontamination cycle, but not all replicates achieved a fit factor > following and decontamination cycles (n = ) no changes in physical appearance (n = ) not assessed aerosol penetration exceeded % for particle penetration (n = ) aerosol penetration post-sterilization exceeded % for particles larger than nm (n = ) do n respirators provide % protection level against airborne viruses, and how adequate are surgical masks? interim infection prevention and control recommendations for patients with suspected or confirmed coronavirus disease (covid- ) in healthcare settings personal protective equipment supply chain: lessons learned from recent public health emergency responses hospital preparedness for severe acute respiratory syndrome in the united states: views from a national survey of infectious diseases consultants the national covid- medical equipment clearinghouse conserving supply of personal protective equipment-a call for ideas evaluation of multiple ( -cycle) decontamination processing for filtering facepiece respirators. digitalcommons@university of nebraska -lincoln impact of three cycles of decontamination treatments on filtering facepiece respirator fit evaluation of five decontamination methods for filtering facepiece respirators impact of three biological decontamination methods on filtering facepiece respirator fit, odor, comfort, and donning ease effect of decontamination on the filtration efficiency of two filtering facepiece respirator models development of a test system to apply virus-containing particles to filtering facepiece respirators for the evaluation of decontamination procedures cleaning of filtering facepiece respirators contaminated with mucin and staphylococcus aureus effectiveness of three decontamination treatments against influenza virus applied to filtering facepiece respirators effects of ultraviolet germicidal irradiation (uvgi) on n respirator filtration performance and structural integrity ultraviolet germicidal irradiation of influenzacontaminated n filtering facepiece respirators effects of relative humidity and spraying medium on uv decontamination of filters loaded with viral aerosols development of a test system to evaluate procedures for decontamination of respirators containing viral droplets analysis of residual chemicals on filtering facepiece respirators after decontamination hydrogen peroxide vapor sterilization of n respirators for reuse filter quality of electret masks in filtering . - nm aerosol particles: effects of five decontamination methods relative survival of bacillus subtilis spores loaded on filtering facepiece respirators after five decontamination methods cdc. decontamination and reuse of filtering facepiece respirators decontaminating n and sn masks with ultraviolet germicidal irradiation (uvgi) does not impair mask efficacy and safety: a systematic review microwave-and heat-based decontamination of n filtering facepiecerespirators (ffr): a systematic review preferred reporting items for systematic reviews and meta-analyses: the prisma statement the untold origin story of the n mask quality control for crowdsourcing citation screening: the importance of assessment number and qualification set size the redcap consortium: building an international community of software platform partners research electronic data capture (redcap)--a metadata-driven methodology and workflow process for providing translational research informatics support r: a language and environment for statistical computing. r foundation for statistical computing conducting meta-analyses in r with the metafor package disinfection of n respirators by ionized hydrogen peroxide in pandemic coronavirus disease (covid- ) due to sars-cov- assessment of n respirator decontamination and re-use for sars-cov- n mask decontamination using standard hospital sterilization technologies electronic code of federal regulations ( cfr . ). filter efficiency level determination test-non-powered series n, r, and p filtration national institute for occupational safety and health. niosh guide to the selection and use of particulate respirators final report for bioquell hpv decontamination for the reuse of n respirators the effects of particle charge on the performance of a filtering facepiece effect of solvent exposure on the filtration performance of electrostatically charged polypropylene filter media information and faqs on the performance, protection, and sterilization of face mask materials survival of influenza viruses on environmental surfaces the survival and inactivation of enteric viruses on soft surfaces: a systematic review of the literature aerosol and surface stability of sars-cov- as compared with sars-cov- effect of fit testing on the protection offered by n filtering facepiece respirators against fine particles in a laboratory setting impact of multiple consecutive donnings on filtering facepiece respirator fit strategies for optimizing the supply of n respirators: crisis/alternate strategies covid- ) update: fda reissues emergency use authorizations revising which types of respirators can be decontaminated for reuse live scoping review of n and surgical facemask decontamination and reuse: a scoping review protocol aerosolized hydrogen peroxide decontamination of n respirators, with fit-testing and virologic confirmation of suitability for re-use during the covid- pandemic an efficient ethanol-vacuum method for the decontamination and restoration of polypropylene microfiber medical masks & respirators analysis of steramist ionized hydrogen peroxide technology in the sterilization of n respirators and other ppe: a quality improvement study characterization of a novel, low-cost, scalable vaporized hydrogen peroxide system for sterilization of n respirators and other covid- related personal protective equipment decontamination of face masks and filtering facepiece respirators via ultraviolet germicidal irradiation, hydrogen peroxide vaporisation, and use of dry heat inactivates an infectious sars-cov- surrogate virus development of a highly effective low-cost vaporized hydrogen peroxide-based method for disinfection of personal protective equipment for their selective reuse during pandemics effectiveness of ultraviolet-c light and a high-level disinfection cabinet for decontamination of n respirators effects of sterilization with hydrogen peroxide and chlorine dioxide on the filtration efficiency of n , kn , and surgical face masks scalable in-hospital decontamination of n filtering facepiece respirator with a peracetic acid room disinfection system validation of n filtering facepiece respirator decontamination methods available at a large university hospital effect of various decontamination procedures on disposable n mask integrity and sars-cov- infectivity key: cord- - nzjrvla authors: avo, cameron; cawthorne, katie-rose; walters, joanne; healy, brendan title: an observational study to identify types of personal protective equipment breaches on inpatient wards date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: nzjrvla nan in response to the covid- pandemic, uk infection prevention & control (ip&c) guidelines have been published on using personal protective equipment (ppe) in various healthcare settings [ ] . improper ppe use can compromise the protection afforded by it [ ] . the ip&c guidelines [ ] highlight actions which may constitute a ppe 'breach'. in response to a cochrane review [ ] calling for research into barriers to proper ppe use, we investigated the most common types of breaches observed across several inpatient wards. the results highlight areas of practice that could be improved to optimise ppe use and reduce nosocomial transmission of infection [ ] . we conducted a behavioural observation study to investigate whether, based on national guidelines [ ] , healthcare workers wear correct ppe, what breaches occur, and how frequently. this study was completed in a large acute hospital in may during the covid- pandemic. national guidelines [ ] recommend different ppe requirements according to two different settings, which we have classified as 'all ppe' zones and 'mask only' zones. 'all ppe' zones constitute any room housing covid-positive patients, or when within metres of any patient. 'all ppe' zones require a fluid-resistant surgical face mask (frsm), disposable apron, disposable gloves, and, subject to risk assessment, eye protection. 'mask only' zones represent any area which is not 'all ppe' but where staff are working (e.g. the reception desk), and only frsms are required. examples of ppe 'breaches' can be seen in figure . the observations were carried out on three medical wards (one designated for covid-positive patients and two without identified covid-positive patients). permission to conduct an observation was obtained from each ward manager but staff were not informed of the purpose of the study. to minimise the hawthorne effect, observers were unknown to ward staff and the observation period was limited to minutes. for each worker, ppe use was evaluated for the session of work undertaken, and any observed breaches were recorded. if, within the -minute period, an individual left and re-entered a zone, they were counted as a separate worker as this represents another working session. eye protection was not reported as part of the 'required' ppe on non-covid wards as this could not be objectively measured in the context of individual risk assessments. across sixteen -minute observations, members of staff were observed: in 'all ppe' zones and in 'mask only' zones. a previous study showed that only % of healthcare workers donned all recommended ppe for droplet precautions [ ] . in our study, we found that workers donned the required ppe on . % of occasions in 'all ppe' zones and . % in 'mask only' zones. 'all ppe' zone compliance was % on covid-designated wards and % on non-covid wards. though eye protection was discounted in non-covid 'all ppe' zones, it was noted that visors were not used by any staff in these areas. it is likely that some individual risk assessments would have indicated wearing eye protection. this suggests that further ip&c interventions are likely required to improve compliance with ppe use. having recorded absolute numbers of ppe breaches, data were normalised to the number of staff observed in each zone across wards so that results were comparable (figure ) . normalisation was necessary as our methodology tracked staff as groups, rather than individual staff members. in the 'mask only' zone, the most common breach was touching the mask, with a normalised frequency of . occurrences per individual. the data showed that breaches were scattered across staff groups, and it was reported that breaches were common amongst all observed staff rather than specific individuals. as such, these results suggest that around % of staff breach their mask by touching it. in the 'all ppe' zone, the most common breaches were failing to remove disposable aprons ( . ) or gloves ( . ) between patients. [ ] . these breaches were observed during a number of -minute observations across several inpatient wards, covering both 'all ppe' and 'mask only' zones. 'all ppe' zones were defined as bays or cubicles housing covid-positive patients, or an area within metres of any patient; 'mask only' zones were defined as areas beyond 'all ppe' zones where staff may be working. in 'all ppe' zones, staff are required to don a fluid-resistant surgical mask (frsm), disposable gloves, a disposable apron, and, subject to risk assessment, an eye protective visor; in 'mask only' zones, only a frsm is needed. eye protection was not counted as part of the 'required' ppe on non-covid wards as this could not be objectively measured in the context of individual risk assessments. data from the 'all ppe' and 'mask only' zones were normalised to the number of staff observed in the 'all ppe' zone ( ) and 'mask only' zone ( ), respectively. covid- : infection prevention and control guidance identification and characterization of failures in infectious agent transmission precaution practices in hospitals: a qualitative study barriers and facilitators to healthcare workers' adherence with infection prevention and control (ipc) guidelines for respiratory infectious diseases: a rapid qualitative evidence synthesis improving the use of personal protective equipment: applying lessons learned are health care workers protected? an observational study of selection and removal of personal protective equipment in canadian acute care hospitals contact precautions for multidrug-resistant organisms: current recommendations and actual practice practical experiences and suggestions for the 'eagle-eyed observer': a novel promising role for controlling nosocomial infection in the covid- outbreak special thanks are extended to dr ian blyth for his guidance early in the study, dr eleri davies for her review of the manuscript, and rebekah velounias for her assistance with the data analysis. we would also like to thank the ward managers and staff for allowing us to carry out our observations. audits into ppe typically offer a binary view of whether it is used or not [ ] . this is problematic as infection transmission risk is not eliminated simply by wearing correct ppe. workers must also refrain from breaching ppe in a way that might increase the risk of transmission. this study provides an insight into how workers behave whilst wearing ppe. investigating common breaches identifies possible routes of infection, establishes recommendations for improving ppe design, and enables ip&c teams to educate healthcare workers accordingly. further work is needed to evaluate methods for reducing ppe breaches.an example might be the "eagle-eyed observer" approach, as suggested by peng et al. [ ] , which could detect ppe breaches and encourage correction. during training, more attention could be given to the use of ppe besides what types are needed and when. improvements in ppe design with enhanced comfort will also likely increase compliance and reduce the risk and frequency of breaches. key: cord- -kg pg y authors: wong, s.-c.; auyeung, c.h.-y.; lam, g.k.-m.; leung, e.y.-l.; chan, v.w.-m.; yuen, k.-y.; cheng, v.c.-c. title: is it possible to achieve percent hand hygiene compliance during the covid- pandemic? date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: kg pg y nan enforced the practice of the who "my five moments for hand hygiene", together with our institutionally-promoted th moment -"hand hygiene before touching your mucous membrane". we continued performing hand hygiene audits according to the who protocol. since the sars-cov- is predominantly transmitted via droplet and contact routes, hand hygiene with appropriate ppe are key infection control measures to protect hcws. we therefore expected hand hygiene compliance among our hcws to increase further during the covid- pandemic. it is unexpected to observe relatively lower hand hygiene compliance among hcws working in ward b, of which some of the beds are used for caring suspected or confirmed covid- patients. we understand that it may not be realistic to achieve % hand hygiene compliance in all units, but lapses in hand hygiene may pose a risk to hcws, especially during the covid- pandemic. therefore, we have introduced a buddy system to implement a model of directly-observed degowning (dodg) to minimize the risk of self-contamination. the model of dodg has been taught to all hcws who require working in aiirs during our face-to-face training sessions. in this model, the hcw is observed by other colleagues during the degowning procedure. hand hygiene, as well as appropriate degowning, are ensured by real-time reminders. this intervention may be a reason why we have achieved zero nosocomial infection by sars-cov- among hcws from the pre-pandemic phase of covid- , and until now. hand hygiene among hcws has become even more important in the context of the covid- pandemic, especially with evidence of sars-cov- transmission while presymptomatic or asymptomatic. although we have enforced dodg and directlyobserved hand hygiene during the critical moments in patient care practice, leaders' commitment to build up a good hand hygiene culture can protect our hcws and patients in all circumstances including the covid- pandemic. we thank our healthcare workers to fight against the covid- pandemic. financial support. pediatric unit a is located in ward a, caring patients with cardiac diseases. pediatric unit b is located in ward b, caring patients with infectious diseases. airborne infection isolation rooms are only available in ward b, which is designated for the management of suspected or confirmed covid- patients. situation report - . world health organization escalating infection control response to the rapidly evolving epidemiology of the coronavirus disease (covid- ) due to sars-cov- in hong kong impact of observing hand hygiene in practice and research: a methodological reconsideration infection control challenge in setting up a temporary test center at the international airport for rapid diagnosis of coronavirus disease (covid- ) due to sars-cov- absence of nosocomial transmission of coronavirus disease (covid- ) due to sars-cov- in the pre-pandemic phase in hong kong hand hygiene and the novel coronavirus pandemic: the role of healthcare workers evidence supporting transmission of severe acute respiratory syndrome coronavirus while presymptomatic or asymptomatic directly observed hand hygienefrom healthcare workers to patients hand hygiene compliance among healthcare workers in two paediatric units before and during covid- pandemic all authors report no conflicts of interest relevant to this article. key: cord- -dhfl et authors: srivastava, s.; shetty, n. title: healthcare-associated infections in neonatal units: lessons from contrasting worlds date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: dhfl et neonatal intensive care units are vulnerable to outbreaks and sporadic incidents of healthcare-associated infections (hais). the incidence and outcome of these infections are determined by the degree of immaturity of the neonatal immune system, invasive procedures involved, the aetiological agent and its antimicrobial susceptibility pattern and, above all, infection control policies practised by the unit. it is important to raise awareness of infection control practices in resource-limited settings, since overdependence upon antimicrobial agents and co-existing lack of awareness of infection control is encouraging the emergence of multi-drug-resistant nosocomial pathogens. we reviewed articles regarding hais from both advanced and resource-limited neonatal units in order to study risk factors, aetiological agents, antimicrobial susceptibility patterns and reported successes in infection control interventions. the articles include surveillance studies, outbreaks and sporadic incidents. gram-positive cocci, viruses and fungi predominate in reports from the advanced units, while gram-negative enteric rods, non-fermenters and fungi are commonly reported from resource-limited settings. antimicrobial susceptibility patterns from surveillance studies determined the empirical therapy used in each neonatal unit. most outbreaks, irrespective of the technical facilities available, were traced to specific lack of infection control practices. we discuss infection control interventions, with special emphasis on their applicability in resource-limited settings. cost-effective measures for implementing these interventions, with particular reference to the recognition of the role of the microbiologist, the infection control team and antibiotic policies are presented. summary neonatal intensive care units are vulnerable to outbreaks and sporadic incidents of healthcare-associated infections (hais). the incidence and outcome of these infections are determined by the degree of immaturity of the neonatal immune system, invasive procedures involved, the aetiological agent and its antimicrobial susceptibility pattern and, above all, infection control policies practised by the unit. it is important to raise awareness of infection control practices in resource-limited settings, since overdependence upon antimicrobial agents and co-existing lack of awareness of infection control is encouraging the emergence of multi-drug-resistant nosocomial pathogens. we reviewed articles regarding hais from both advanced and resource-limited neonatal units in order to study risk factors, aetiological agents, antimicrobial susceptibility patterns and reported successes in infection control interventions. the articles include surveillance studies, outbreaks and sporadic incidents. gram-positive cocci, viruses and fungi predominate in reports from the advanced units, while gram-negative enteric rods, non-fermenters and fungi are commonly reported from resource-limited settings. antimicrobial susceptibility patterns from surveillance studies determined the empirical therapy used in each neonatal unit. most outbreaks, irrespective of the technical facilities available, were traced to specific lack of infection control practices. we discuss infection control interventions, with special emphasis on their applicability in resource-limited settings. cost-effective measures for implementing these interventions, with particular reference to the recognition of the role of the microbiologist, the infection control team and antibiotic policies are presented. ª the hospital infection society. published by elsevier ltd. all rights reserved. the neonatal intensive care unit is an ideal situation to incorporate good infection control policy and practice, since it lends itself not only to the spread of severe infections but also to successful interventions. a collaborative effort between neonatologists and clinical microbiologists who take on the role of infection control can successfully mount a defence against healthcare-associated infections (hais) . clinical liaison between microbiologist and clinician is well established in developed countries, whereas in the developing countries such practices are yet to be widely recognized. one reason could be that microbiology results are often delayed in less technologically advanced laboratories, thus forcing the clinician to make empirical treatment decisions without consulting or depending on the microbiologist. however, technical advancement is not a prerequisite for appropriate selection of empirical antimicrobial agents, infection control practices or formulating antibiotic policies. in an environment where resources are scarce, it only requires determination and professional cooperation for suitable interventions to work. this review on healthcare-associated neonatal infections studies the definitions, associated risk factors and the aetiological agents involved with their antimicrobial susceptibility patterns in two contrasting worlds. we discuss the microbiological and infection control intervention strategies that might help, even in resource-limited settings, to prevent the morbidity and mortality associated with hai. levels of neonatal care may be classified as shown in box . a large proportion of neonates in developing countries ( %) and in rural india ( %) are born at home, with poor facilities for safe and clean delivery by unskilled 'dais' or village health workers. , even larger hospitals with a high delivery rate do not have access to level ii neonatal care. no sick newborn care unit (scnu), government or private, is available at district level in many provinces. the equipment and infrastructure are often limited and doctors are forced to select which babies will be admitted and offered facilities such as ventilators. few state-owned centres are equipped with neonatal intensive care units (nicus) and these are scattered across the country. thus, in developing countries we are dealing with neonates with completely different demographic characteristics. whereas the minimum gestational age of live-born babies managed in a nicu in developed countries is weeks with birthweights as low as g, the average gestational age of live-born babies in developing countries is ! weeks with birthweights ! g. in a study on anthropometry and body composition of south indian babies at birth, the mean ae standard deviation (sd) birthweight of all newborns was . ae . kg. financial constraints in developing countries limit the use of technical interventions, due to which very few neonates undergo invasive medical or surgical procedures, unlike reports from developed countries. the available microbiological diagnostic facilities also vary from centre to centre. semiautomated and automated culture systems are available only in a handful of tertiary care centres. the cost of providing these services to patients is borne by the family and is often prohibitive; most clinicians treat patients empirically. microbiological results are particularly important in neonates as signs of sepsis are often non-specific. hence, while financial constraints are difficult to resolve, we still have the option to utilize cost-effective, alternative interventions such as infection control, which by reducing the incidence of infection will decrease the overall morbidity and mortality in sick neonates. successful field trials for home-based neonatal care have already been reported. we need to extend these achievements to healthcare settings. we searched for articles on the pubmed database, using the index terms 'hospital acquired infection', 'neonate', 'nosocomial infection neonate', 'neonatal care level', 'neonatal care india'. reference lists of all articles retrieved were searched to obtain literature for the review. the articles were scrutinized to obtain a comparable and standard definition of nosocomial infection in neonates, inclusion and exclusion criteria used, aetiological agents involved, antimicrobial susceptibility patterns and infection control interventions. within these search results, we reviewed articles mentioning infection control and antibiotic policies, with special reference to neonatal units in developing countries. full text articles were scrutinized for a majority of english language papers; for a small number of articles we relied only on the published abstract. for foreign language studies we were able to quote only from the abstract published in english. the foetus is exposed to a sterile environment in utero, provided no invasive procedures have been carried out on the mother, the membranes are intact until the onset of labour and there is no prolonged rupture of membranes. during the process of delivery, the neonate is exposed to several sources of microbes. these include the maternal genital tract followed by ambient air or water depending on the type of delivery, handling by healthcare personnel and the instruments used at resuscitation. rotimi and duerden studied the development of bacterial flora of neonates during the first week of life. the predominant organisms in the gut, by the end of the first week, were anaerobes. bifidobacteria were isolated from all the neonates. bacteroides and clostridia were isolated from . %. enterococci were isolated from all neonates, enterobacteria from . %, anaerobic cocci from . %. staphylococcus aureus was the predominant species isolated from the umbilicus; it was isolated from . % of neonates on the first day rising to % by the sixth day and represented % of isolates from this site. viridans streptococci ( . % of isolates) were the commonest species recovered from the mouth. they were present from h after birth. the authors also studied the development of microbial flora of preterm neonates. the numbers of infants studied were too small to draw any firm conclusions; their flora predominantly reflected the maternal genital tract. in contrast, preterm and full-term babies born by caesarean section were slow to acquire colonizing flora as compared to those born vaginally. the skin of infants born by caesarean section is sterile soon after birth compared to neonates born by vaginal delivery. bowel colonization of infants born by caesarean delivery is also delayed. colonization with bifidobacterium-like bacteria and lactobacillus-like bacteria reached levels similar to vaginally delivered infants at month and days, respectively. many hais result directly or indirectly from patient colonization; studies have shown that hospitalized patients are colonized rapidly with hospital flora. colonizing flora such as candida albicans in the gastrointestinal tract, vagina or perineal area, can precede infection when normal body defences are impaired through underlying disease, immunomodulating therapy, the use of invasive devices, or when the delicate balance of the normal flora is altered through antimicrobial therapy. however, antimicrobial therapy to eradicate colonizing micro-organisms such as pseudomonas aeruginosa is not beneficial and can propagate drug-resistant pathogens. immune status of the neonate a newborn infant, particularly the preterm infant and to some extent the low birthweight infant, does not have a mature immune system and is often unable to mount an effective immune response. natural barriers, such as the acidity of the stomach or the production of pepsin and trypsin that maintain sterility of the small intestine, are not fully developed until e weeks after birth. membrane protective iga is missing from the respiratory and urinary tracts, and unless the newborn is breast-fed, is absent from the gastrointestinal tract as well. on a cellular level, there is decreased ability of leukocytes to concentrate where necessary. these leukocytes are less bactericidal and phagocytic. at the humoral level, the newborn has low or non-existent levels of the immunoglobulin antibodies igm, ige and iga. the neonate is born with igg antibodies acquired from the mother. however, it is important to note that passive transfer of maternal antibodies does not take place till weeks of gestation. this has implications for preterm infants born e weeks of gestation; they are susceptible to infection despite the mother's antibody status. there is a slow rise of immunoglobulin levels after months of age to levels of older children. before embarking on a review of nosocomial infections, we reviewed the definitions of nosocomial infections used in various studies. at the outset, the national nosocomial infections surveillance system (nnis) of the centers for disease control and prevention (cdc), usa defines nosocomial infection as a localized or systemic condition ( ) that results from adverse reaction to the presence of an infectious agent(s) or its toxin(s) and ( ) that was not present or incubating at the time of admission to the hospital. limitations encountered during the review process in the neonate, the definition of an hai is complicated by the fact that neonates can acquire infection from the maternal genital tract during birth. for this reason, neonatal infections are often classified as early onset (usually e days after birth) and late onset (> days after birth). some authors also classify them as h after birth and > h after birth. it is interesting to note that the cdc includes infections acquired from the maternal genital tract in their surveillance of nosocomial neonatal infection. several investigators have found these criteria unsatisfactory. for the purposes of this review, we have considered only those studies that have excluded infections acquired directly from the maternal genital tract; we found that the definition of nosocomial infections varied between studies and were often related to time of acquisition. the dutch group have modified the cdc criteria to include infections occurring in the neonatal unit e h after admission. in some studies, infections which manifested after the patient was in the hospital for ! h and those infections which developed within a period of days after discharge from the hospital were considered nosocomial. e in other studies, all neonates residing for ! days in a hospital unit were included. e nosocomial transmission of candida in neonates was considered if the neonate showed negative surveillance cultures at birth and positive cultures from one week later, until death or discharge. shankar et al. also recommend using surveillance cultures to differentiate endogenous colonization from nosocomial acquisition. we believe that a consistent and universally accepted case definition of hai in the neonate is important because it offers uniformity of data across centres and facilitates a standardized measurement of outcomes. many studies that we reviewed did not have clear-cut case definitions with clearly stated inclusion and exclusion criteria; when they did, they varied from centre to centre. other common limitations were inadequate sample size, , , e or variability of denominator data wherein some authors reported number of infections per patients (attack rate) or the number of infections per patient-days (incidence density). , annual incidence per live births and per nicu discharges have also been used. absence of robust statistical analysis and the inclusion of anecdotal case reports were also limitations. , e some authors acknowledge the lack of technical equipment to report viral, fungal and parasitic causes of hais. neonates present with their own unique risk factors that predispose them to acquisition of hai. the vulnerability of the neonate, particularly the preterm neonate, is directly linked to an immature immune system. this is the single most important host-related factor that predisposes them to infection. neonatal age itself is a risk factor for hai [odds ratio (or) . ; % confidence interval (ci): . e . ; p < . ]. in another study, admission to the neonatal unit, rather than age at admission, was associated with increased risk of hai (p < . ). the overall nosocomial infection rate was positively correlated with average length of stay in high-risk nurseries (r ¼ . , p < . ). preterm gestational age (< weeks) was a risk factor in e % neonates with bacterial, viral and fungal hai. , e the percentage of neonates with low birthweight ( . e . kg) and with very low birthweight ( . e . kg) who acquired hai was . and . to . % respectively. , infection, including hai, was the most common cause of death in extremely low birthweight (< . kg) neonates and septicaemia (bacterial and fungal) was the most common presentation ( . %). , male sex was a predisposing factor for nosocomial infections (p < . ). , the male predominance in neonatal sepsis has suggested the possibility of an x-linked factor in host susceptibility. , underlying medical conditions such as chronic lung disease, gastro-oesophageal reflux, history of neonatal respiratory distress, maternal infection and congenital heart disease predisposed to hais in . e . % of neonates. e a high complexity score, which categorizes procedures by severity of illness and technical complexity, was associated with increased incidence of hai in neonates after cardiac surgery (or: . ; % ci: . e . ; p < . ). prism (pediatric risk of mortality) score of > was also related to neonatal hai (crude or: . ; % ci: . e . ; p < . ). the clinical risk index for babies (crib) score shows that nosocomial bacteraemia is independently associated with low birthweight and preterm neonates. lack of maternal antibodies was a risk factor for infection with unusual rotavirus strains. factors relating to healthcare personnel, practices and the environment are often overlooked, and yet remain the most obvious and inexpensive area of intervention. indeed, the most common route of spread of nosocomial pathogens is personto-person transmission within the unit and during transfer of patients between units. such incidents have been linked with outbreaks of bacterial and viral infection in the nicu. , e the most common iatrogenic factor contributing to neonatal hais is hands of healthcare workers. , , , e intervention in the form of simple handwashing procedures and infection control practices has prevented outbreaks, as reported in many studies. , , , e , , during the process of delivery, the neonate is exposed to several sources of microbes. medical devices such as umbilical catheters, central venous catheters, urinary catheters and endotracheal tubes are commonly used in the nicu. , , , , , central venous catheters contributed to . % of hais in one study and was a significant risk factor (p < . ) in others. , , , the nosocomial infection rate was higher in neonates subjected to device use (r ¼ . , p < . ). about . % of catheterized patients developed hospital-acquired urinary tract infection (uti). the duration of ventilation was also related to the acquisition of hai. reuse of single-use items, a common though unsound practice in many units, has led to outbreaks of hai. endotracheal tubes and mucous extraction suction catheters soaked in hibitane were associated with hai in the labour room and the special care baby unit. baby placement services, resuscitation equipment and cleansing solutions have also been implicated in hai. an environmental risk factor often overlooked is related to the seasonal variation in the incidence of neonatal hai. factors such as warm climate have been associated with a rise in colonization rates with enterobacter spp. increased humidity and increased environmental dew point at the time of use of nursery air conditioners propagates airborne dissemination of acinetobacter spp. and has been associated with acinetobacter-related bloodstream infections. bacteria in ambient air have been reported to colonize the conjunctiva in neonates. agent factors contributing to hai relate to the aetiological agents implicated in infection. infection with drug-resistant organisms plays a significant role in the outcome of hai in all patients, irrespective of their gestational age and underlying condition. hospitalization leads to colonization of the skin and gastrointestinal tract with resistant flora found in hospitals and subsequent bloodstream infection, when the skin or mucosa is abraded. studies have reported that administration of prophylactic antibiotics to neonates can increase the incidence of hai with drug-resistant pathogenic micro-organisms. about . e % of neonates presenting with hai had received prior broadspectrum antibiotics. , , clinical presentation of hais in neonates a summary of the most commonly reported neonatal hai is described in table i . , , , , , , , , , , , a review of the findings of these studies is hampered by the variation and sometimes lack of denominator data. the reader is advised to study these reports with caution, taking into consideration the limitations mentioned earlier. healthcare-associated infections in the neonatal unit cover the entire spectrum of organisms: bacterial, fungal, viral and rarely parasitic. a review of healthcare-associated bacterial (table ii) , , , , , , , , , , , e fungal (table iii) , , , , , e and viral (table iv) , , , , , , e infections is summarized in the relevant tables. fortunately parasitic nosocomial infections are rare. there have been isolated reports of babesiosis transmitted by blood transfusion in neonates. among four neonates transfused with blood from asymptomatic babesia-infected donors, two ( %) became parasitaemic, of whom only one developed symptoms of babesiosis. it is interesting to note that gram-negative fermenters (e. coli, klebsiella spp.) and nonfermenting gram-negative rods such as acinetobacter spp. and pseudomonas spp. have established themselves as predominant causes of serious neonatal infections in the indian subcontinent (table ii) . in contrast, the predominant organisms isolated from invasive neonatal infections in technologically advanced countries are gram-positive cocci (coagulase-negative staphylococci, group b streptococcus). the reason for this difference is probably multifactorial and could be due to gestational age of the babies involved, the use of invasive devices (central vascular catheters and shunts), ambient moisture, humidity and the prevalent flora in the unit. evidence supporting these risk factors has been discussed elsewhere in the review and probably merits further evaluation. of all the fungal infections reported in neonatal patients, candida spp. cause significant mortality and morbidity in the neonatal unit (table iii) and will be discussed in some detail here. although the source of c. albicans infection in the nicu is often considered to be endogenous, molecular typing studies have shown that nosocomial transmission of c. albicans is the predominant mode of acquisition. , the nosocomial acquisition of c. albicans is related to cross-contamination via the hands of healthcare workers or parents and the use of contaminated equipment. , in one study, retrograde medication syringe fluids were significantly more likely to be contaminated with candida than other fluids being administered to the infants (p < . ). candidaemia was significantly associated with total parenteral nutrition (p ¼ . ) and retrograde medication administration (p ¼ . ). central vascular catheters, steroid administration, endotracheal intubation and h -blockers have also been reported as risk factors for systemic fungal infections in neonates. , other risk factors include prematurity, low birthweight and use of broad-spectrum antibiotics. complications of candidaemia such as endocarditis and uveitis have been reported in neonates. the onset of endocarditis was related to persistant candidaemia. fungal endocarditis was present in . % neonates with persistent disease (> days of candidaemia) and . % patients with non-persistent disease (or: . ), while uveitis developed in . % patients. mortality in neonates with persistent disease was comparable to the mortality in neonates with non-persistent disease. viruses account for about % of infections in hospitalized neonates. the most common viral infections are due to enterovirus/parechovirus (table iv) . enteroviruses were responsible for the highest mortality and development of serious sequelae. respiratory syncytial virus (rsv) is the second most common virus causing infections in hospitalized neonates ( e %). , , , e respiratory viruses were diagnosed in . % of neonates on mechanical ventilators; the most frequent was rsv ( . %), followed by influenza a virus ( . %). in another study, nosocomially acquired rsv infection was present in % of neonates, . % had an underlying condition predisposing to severe disease and % died. human parainfluenza type is the most common cause of bronchiolitis and pneumonia after respiratory syncytial virus. parainfluenza type virus was isolated in six of neonates cultured (five symptomatic patients and one asymptomatic patient). eighteen of nursing personnel had been ill during the previous week, concomitantly with cough and nasal congestion. nosocomial transmission of rotavirus in neonates has been reported. , , the onset of acute diarrhoea due to rotavirus in two neonates was followed by five neonates developing gastroenteritis with the same strain of rotavirus. in another study, in % of inpatients with nosocomial gastroenteritis, the causative agent was rotavirus and % of those were premature neonates. hais and resistance to antimicrobial agents compared to community-acquired infections, hais are often caused by multi-drug-resistant pathogens. in this section we concentrate on reports from the subcontinent and other resource-poor settings. in a retrospective study of bacterial isolates from cases of neonatal septicaemia over a period of years, there was a significant rise in the incidence of drugresistant acinetobacter spp. and p. aeruginosa. the incidence rate of acinetobacter septicaemia in another study was . / live births. other studies have also documented acinetobacter spp. as emerging neonatal pathogens. , , susceptibility tests showed that acinetobacter isolates were resistant to two or more antibiotics, most notably to ampicillin ( . %), cephalexin ( . %), gentamicin ( . %) and cefotaxime ( . %). most isolates were susceptible to amikacin ( . %), ciprofloxacin ( . %) and piperacillin ( . %). only about % of bacterial aetiological agents of neonatal hai would be covered by an empirical regimen of ampicillin and gentamicin. gramnegative organisms causing hai in neonates were cause of candidaemia, endophthalmitis, endocarditis, meningitis, peritonitis. source of infection was central venous catheter. rhodotorula mucilaginosa outbreak (n ¼ ) of indwelling catheter-related septicaemia in nicu. related to birthweight, gestational age, duration of parenteral nutrition, antibiotic therapy and prophylactic fluconazole. rhizopus microsporus outbreak of cutaneous infection in preterm neonates (n ¼ ) . source traced to wooden tongue depressors used in the nursery as splints for intravenous and arterial cannulation site. the combination of warm, humid conditions in neonatal incubators, particularly in association with occlusive dressings, also favours cutaneous fungal infections. nicu, neonatal intensive care unit. a non-albicans candida spp. included c. parapsilosis, c. tropicalis, c. lusitaniae, c. glabrata, c. krusei, c. guillermondii. less susceptible to the commonly used antibiotics, such as ampicillin ( . %), amoxicillin ( . %), gentamicin ( . %), ceftazidime ( . %) and cefotaxime ( . %). these organisms were more susceptible to imipinem ( . %), amikacin ( . %), ofloxacin and ciprofloxacin ( . %). , other workers found third-generation cephalosporins and aminoglycosides such as netilmicin to be effective in the treatment of neonatal sepsis. at the same time, studies have also shown that administration of antimicrobial prophylaxis, presumed to prevent hais, can be a putative risk factor in itself for hai. , , single-centre studies have shown that probiotics containing anaerobic bacteria may reduce the rate and severity of necrotizing enterocolitis. antifungal agents fluconazole has been recommended as prophylaxis against systemic fungal infections in preterm low birthweight infants. , however, other workers have found no resurgence of fungal infection after cessation of prophylactic fluconazole use. there is also concern about emergence of resistance to fluconazole. in an investigation into the resurgence of bloodstream infections due to c. parapsilosis in one unit, after the institution of fluconazole prophylaxis, primary resistance to fluconazole was not detected. others propose a twice weekly dosing of prophylactic fluconazole to decrease candida colonization, invasive infection, cost and patient exposure in high-risk preterm infants weighing < g at birth; the lower and less frequent dosing may even delay or prevent the emergence of antifungal resistance. there are reports of c. albicans resistance to fluconazole ( . %) and amphotericin-b ( %) in studies from india. newer antifungal agents, including voriconazole and caspofungin, show promise in the treatment of potentially fatal fungal infections in neonates and additional controlled studies are indicated to evaluate their role. the existing evidence base for infection control practices specifically for the neonatal unit is described in table v . , , , , , e , , , , , , e important lessons in infection control can be learnt from published accounts of specific outbreaks. in addition to the outbreaks documented in tables iii and iv , we have selected other outbreak reports that we believe reinforce the infection control message (table vi) . , , , , , , e environmental surveillance is not routinely recommended since pathogens present in the inanimate nicu environment, e.g. floors, walls, sink-drains or furniture are not associated with , , , e nosocomially acquired infection among / neonates with rsv. infection control measures successful. rotavirus , , , , , nosocomial transmission of rotavirus in / neonates with diarrhoea. winter peak. high morbidity. among patients with nosocomial rotavirus diarrhoea, % were preterm neonates. cytomegalovirus (cmv) , transfusion-acquired cmv in / neonates. adenovirus gastroenteritis was the main clinical presentation in preterm infants. parainfluenza, type , outbreak in nicu (n ¼ ). linked to hcw. controlled by glove, gown and cohorting. herpes simplex virus, rhinovirus, rubellavirus infections reported in the nicu. influenza a virus neonates on mechanical ventilation were nosocomially infected with influenza a virus. human coronaviruses patient-to-staff and staff-to-patient transmission in nicu. universal precaution with surface disinfection and handwashing prevent spread of infection. echovirus type coxsackie b nosocomial outbreak (n ¼ ) in special care nursery. transmission by staff. nicu, neonatal intensive care unit; hcw, healthcare worker. hais. only three nicu sites, namely baby placements, resuscitation equipment and various cleansing solutions, were found to be significantly associated with hais (p < . ) in one study. the relative risk of infection was greatest if baby placement sites were colonized (odds ratio ¼ . ; p < . ). this reinforces the need for scrupulous cleaning regimens rather than adopting a policy of routine environmental surveillance. however, environmental cultures may play a role in specific outbreak situations. outbreak strains of salmonella worthington were isolated from the baby warmer mattress, baby cot, suction machine bottle and wall of the refrigerator. the role of surveillance cultures to predict the onset of nosocomial infections in neonates undergoing invasive procedures, such as exchange transfusion, has been studied. the authors found that except for staphylococci, the flora from umbilical stump and umbilical vein blood in asymptomatic neonates was similar to the flora from infected neonates. 'intensive care' need not be synonymous with 'invasive care'. in the presence of constraints such as lack of trained staff, intermittent power supply or lack of disinfection between their use, incubators and other medical devices can be a risk factor for hai. in these situations kangaroo care provided by the mother has emerged as a cost-effective and widely accepted style of caring for an infant in hospital. in a study from india, there was significant improvement among the kangaroo care group compared with the conventional group, in terms of hypothermia ( / vs / , p < . ), higher oxygen saturations ( . vs . %, p < . ) and decrease in respiratory rates ( . vs . , p < . ). however, there was no statistically significant difference in the incidence of hyperthermia, sepsis, apnoea, onset of breastfeeding and hospital stay in the two groups. further studies are needed to evaluate the role of kangaroo care and the incidence of hai in neonates. the role of microbiology in the detection, epidemiological analyses and prevention of hais cannot be overemphasized, whether the unit is one that benefits from being resource rich or resource poor. in a setting where most physicians are reluctant to use first-line agents, due to misleading or lack of sufficient susceptibility data, a qualified microbiologist is indispensable. communication between microbiologist and neonatologist helps in deciding the most probable pathogen and in initiating the most appropriate antimicrobial therapy. the formulation of a mutually agreed antibiotic policy at community, institutional and national levels is imperative. an infection control team (ict) comprising an infection control nurse or an infection control trained link nurse in the nicu, a neonatologist/ physician and a microbiologist must actively participate in outbreak management and infection control policy issues. in turn, it is mandatory that microbiologists balance their focus equally on diagnostic as well as clinical microbiology. microbiological influence and involvement can be enhanced if the microbiologist joins regular clinical ward rounds and helps to raise awareness among healthcare professionals regarding all aspects of infectious disease management. education and training is an important remit of the ict. besides training of healthcare staff we believe it is important to provide training to empower the mother. as the main carer in the family her education is vital; if she can be made aware of the rationale behind the microbiologist or neonatologist's advice, she will be in a stronger position to participate in the wellbeing of herself and the baby. even as huge efforts are underway to halt the misuse of antimicrobial agents, issues regarding antimicrobial resistance in pathogens are less important to the lay public. as long as these essential drugs are available over-the-counter in many countries, all efforts in any other part of the world toward preventing their misuse will be undermined. in addition, a number of privately funded laboratories have sprung up in several cities and towns in developing countries. they lack quality assurance and the personnel who work in identifying pathogens and reporting susceptibility are not trained adequately in quality control methods. in resource-limited settings, as in technologically advanced units, advising that we wash our hands and use the most appropriate antimicrobial agent may be more valuable than suggesting expensive tools for molecular testing. we provide a simple, resource-efficient template for the instigation and maintenance of infection control in the clinical setting (box ). in the present era of global information sharing, professionals working in the area of infection control need not feel isolated. there are several useful web tools that provide practical information and guidance; our own outbreak investigation klebsiella spp. outbreak of septic arthritis (n ¼ ) linked to contaminated cover sheets. epidemiological evidence of an association between acquiring p. aeruginosa bloodstream infection in neonates and exposure to nurses with long and artificial fingernails. short natural fingernails is a policy that is essential to reduce the incidence of hai in neonates. an outbreak of invasive s. marcescens in the nicu (n ¼ ) . molecular tests showed that a vast majority of clinical and environmental isolates (from hands of nurse, handwashes and disinfectants) belonged to the same clonal type. cohorting of non-infected neonates, isolation of colonized and infected neonates, glove use and handwashing controlled the outbreak. outbreak (n ¼ ) of s. marcescens in the nicu. epidemic strain isolated from handwashes and doors of incubators. strict handwashing, disinfection of incubators, cohorting and isolating patients controlled further transmission. acinetobacter spp. during an outbreak, isolates with similar antibiogram were recovered from intravenous catheter and washbasin. , neonatal cross-infection due to contaminated equipment resulted in sepsis and central nervous system disease. outbreak of seven cases, six fatalities. equipment and environment were the source of outbreak. outbreak was controlled through cleaning and fumigation. transmission among nursery staff. enterotoxigenic e. coli (etec) outbreak involved preterm neonates (n ¼ ); surveillance cultures of swabs from the utensils used to prepare milk feed, culture of the formula feed and all items handled by one particular cook were undertaken. the cook's hand swabs and faecal sample yielded growth of etec. the outbreak was controlled by appropriate therapy and institution of proper measures of hygiene. enterobacter spp. outbreak (n ¼ and n ¼ ) of enterobacter cloacae septicaemia traced to preceding bladder catheterization and/or parenteral nutrition solution, respectively. , policy is available free of charge at www.infectioncontrolservices.co.uk/. . ensure a strict protocol for hygienic handwashing and provision of clinical handwash basins or sinks . involve the microbiologist in the planning stages or when refurbishing the unit; advice on physical setting of the unit and general layout of cots, bays, sinks will impact on infection control . provision of side rooms and bays for the isolation of infected babies or protection of healthy neonates . provide training and advice regarding environmental cleaning; ensuring that all surfaces are maintained clean and dry . create an infection control policy document and a rational antibiotic policy that is constantly reviewed . appoint an infection control team (ict) comprising a microbiologist, neonatologist, infection control nurse/liaison nurse trained in infection control . support the ict in the management of infectious diseases and in promoting infection control practices . provide education and training of unit staff in infection control . take the lead in outbreak investigation and control . install a laboratory surveillance system for alert organisms (i.e. 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extremely low birth weight infant evaluation of bacteriological research data and laboratory symptoms of infection in the diagnosis of congenital and acquired infections sex differences in susceptibility to infections epidemiology and clinical presentation of respiratory syncytial virus infection in a tunisian neonatal unit from risk factors for hospital-acquired infections in the neonatal intensive care unit enterobacter bacteremia in pediatric patients a hospital outbreak of extended-spectrum beta-lactamase-producing klebsiella pneumoniae investigated by rapd typing and analysis of the genetics and mechanisms of resistance the relationship between pediatric risk of mortality (prism) score and nosocomial infections in neonatal intensive care unit lack of maternal antibodies to p serotypes may predispose neonates to infections with unusual rotavirus strains use of pulsed-field gel electrophoresis to investigate an outbreak of serratia marcescens infection in a neonatal intensive care 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in the pediatric patient: a prospective study risk factors associated with candidaemia in the neonatal intensive care unit: a caseecontrol study role of bacteriological monitoring of the hospital environment and medical equipment in a neonatal intensive care unit association between climate and enterobacter colonization in swedish neonatal units epidemiology and diagnosis of hospital-acquired conjunctivitis among neonatal intensive care unit patients sepsis in the newborn study on antimicrobial susceptibility of bacteria causing neonatal infections: a year study ( e ) neonatal nosocomial sepsis in a level-iii nicu: evaluation of the causative agents and antimicrobial susceptibilities prospective surveillance of vancomycin-resistant enterococci in a neonatal intensive care unit neonatal group b streptococcal bacteraemia in india: ten years' experience incidence and antifungal susceptibility of candida species in neonatal septicemia duration and outcome of persistent candidaemia in newborn infants recurrent candidaemia in a neonate with hirschsprung's disease: fluconazole resistance and genetic relatedness of eight candida tropicalis isolates rhodotorula mucilaginosa outbreak in neonatal intensive care unit: microbiological features, clinical presentation, and analysis of related variables nosocomial infection with rhizopus microsporus in preterm infants: association with wooden tongue depressors clinical and epidemiologic characteristics of viral infections in a neonatal intensive care unit during a -year period nosocomial respiratory syncytial virus infection in a newborn nursery hospital-acquired viral pathogens in the neonatal intensive care unit incidence of respiratory viruses in preterm infants submitted to mechanical ventilation outbreak of respiratory syncytial virus infection in a neonatal intensive care unit neonatal rotavirus infection in belem, northern brazil: nosocomial transmission of a p[ ] g strain rotaviruses as a cause of nosocomial, infantile 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review of eighty-four cases the bacterial flora of neonates in intensive care-monitoring and manipulation computerized detection of nosocomial infections in newborns neonatal sepsis: the antibiotic crisis molecular epidemiology of an outbreak of serratia marcescens in a neonatal intensive care unit outbreak of acinetobacter spp septicemia in a neonatal icu neonatal crossinfection with listeria monocytogenes nosocomial outbreak of diarrhoea by enterotoxigenic escherichia coli among preterm neonates in a tertiary care hospital in india: pitfalls in healthcare risk factors for enterobacter septicemia in a neonatal unit: caseecontrol study enterobacter cloacae sepsis outbreak in a newborn unit caused by contaminated total parenteral nutrition solution feasibility of kangaroo mother care in mumbai key: cord- -g fuax p authors: haig, c.w.; mackay, w.g.; walker, j.t.; williams, c. title: bioaerosol sampling: sampling mechanisms, bioefficiency and field studies date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: g fuax p investigations into the suspected airborne transmission of pathogens in healthcare environments have posed a challenge to researchers for more than a century. with each pathogen demonstrating a unique response to environmental conditions and the mechanical stresses it experiences, the choice of sampling device is not obvious. our aim was to review bioaerosol sampling, sampling equipment, and methodology. a comprehensive literature search was performed, using electronic databases to retrieve english language papers on bioaerosol sampling. the review describes the mechanisms of popular bioaerosol sampling devices such as impingers, cyclones, impactors, and filters, explaining both their strengths and weaknesses, and the consequences for microbial bioefficiency. numerous successful studies are described that point to best practice in bioaerosol sampling, from the use of small personal samplers to monitor workers' pathogen exposure through to large static samplers collecting airborne microbes in various healthcare settings. of primary importance is the requirement that studies should commence by determining the bioefficiency of the chosen sampler and the pathogen under investigation within laboratory conditions. from such foundations, sampling for bioaerosol material in the complexity of the field holds greater certainty of successful capture of low-concentration airborne pathogens. from the laboratory to use in the field, this review enables the investigator to make informed decisions about the choice of bioaerosol sampler and its application. recent outbreaks such as severe acute respiratory syndrome (sars), h n influenza, and the h n avian influenza pandemic have raised concerns among infection control teams about the importance of the aerosol transmission of pathogens and have been an impetus to investigate the transmission dynamics of bioaerosols including influenza. e studies of suspected airborne transmission routes of various pathogens have been undertaken with differing degrees of success. bioaerosol material is derived from biological origins, including aerial suspensions of bacteria, viruses, fungi, enzymes, and pollen. the size range varies from submicron-sized viral particles to fungal spores and pollen grains up to mm in diameter. if carried by a favourable air flow, bioaerosol material may be distributed over large distances with potentially fatal results. for example, a community-wide outbreak of legionnaires' disease, which resulted in fatalities, had an outbreak source in industrial cooling towers km from the affected community. however, bioaerosols may be relatively delicate structures susceptible to damage due to environmental conditions, such as desiccation. there are several different types of bioaerosol sampler available to investigators, which broadly fall into four categories including impingers, cyclones, impactors, and filters ( figure ). impingers and cyclones collect airborne particles into a liquid collection medium, whereas impactors collect particles on to solid/semi-solid mediums and filters trap bioaerosol material on fine fibres or porous membrane surfaces. the mechanisms of each collection method and their associated benefits/drawbacks are discussed in detail in the subsequent section. this paper constitutes a review of bioaerosol sampling mechanisms and seeks to address practical issues such as choosing a bioaerosol sampling device, bioefficiency, and operational considerations. a comprehensive literature search was performed, using electronic databases to retrieve english language papers on bioaerosol sampling within hospitals and the wider environment. the databases searched were science direct, medline (web of science), proquest, and taylor & francis online. the primary search criterion was bioaerosol with secondary search criteria being sampling, hospital, pathogen, infection, environment, cyclone, impactor, impinger, and aerosol. the final search was on january th, . initially papers were included from to present day; however, having received expert advice, the search was revised to included papers from onwards. patents and foreign language papers were excluded from the literature review. the search yielded publications, of which were included in the review. the software programme endnote was used for reference management. bioaerosols may be collected using passive or active sampling systems as described in the following sections, with active sampling devices involving a mechanical component. , passive sampling passive sampling is arguably the most readily available, economic, and unobtrusive method of bioaerosol sampling and relies on particles settling by means of gravity, on a collection substrate housed in a settle plate. the collected particles are usually quantified in terms of the number of colony-forming units (cfu) within the area of the settling plates for the duration of a specified time-period (for example in units of cfu/m /h). as no mechanical aids, such as a pump, are required, passive sampling has the benefit of not disturbing the surrounding air. the settling velocity of a particle describes the speed of the particle as it descends in still air and is dependent on particle size and density. smaller, lighter particles will remain airborne for longer than larger, denser particles; and if the air speed exceeds the settling velocity the particle will remain suspended indefinitely. in addition, as airflow, even within an enclosed room, will be driven by subtle variations in temperature, the source volume of air for the passively collected sample will be unknown. the combination of these factors has allowed passive sampling to be regarded as both quantitatively and qualitatively inaccurate, and as a subordinate collection method to active sampling. however, this is an oversimplification to the invariably complex nature of bioaerosol sampling. if the area of interest is the dust contamination of surfaces, for example wounds or surgical instruments, then the assessment of the microbial fallout, as opposed to particles remaining suspended in the air, is the imperative. substantial effort has been made to standardize the use of settle plates in the investigation of microbial surface contamination, with consideration given to plate size, position, and length of exposure. the / / scheme refers to the positioning of mm diameter petri dishes at a height of m above floor level, m from a wall, and with an exposure time of h. this standardized method also allows for description of the microbial contamination of the surrounding atmosphere through the use of an index of microbial air contamination (ima). more recently an investigation into contamination in modern operating theatres (ots) with turbulent airflows suggested that the ima value could lead to an underestimation of the risk. in a study which compared air and surface sampling for aspergillus sp. using contact plates within a hospital ward, a significant difference between the collection of airborne and surface spores was noted, with aspergillus accounting for > % of the fungi isolated in the air but < % of fungi isolated from surfaces. this study underlined the need to be aware of the fact that pathogens which have settled on to a surface (subsequently collected on a contact plate) or settle plate may not give an accurate reflection of the suspended airborne concentrations of that pathogen. another study concluded that although settle plates could demonstrate a close correlation with bioaerosol collection undertaken by active samplers, there were exceptions, with settle plates shown to be less sensitive to the collection of fungal spores. to countermand this deficiency an increase of the exposure time of settle plates from to h was proposed. by contrast, using a min settle plate exposure time, a study in post-flood central thailand demonstrated that settle plates can be used as an alternative to active sampling systems. the study did, however, acknowledge that the higher than average fungal bioaerosol presence may have limited the generalizability of their findings. surface sampling in intensive care units has been undertaken using tryptic soy agar contact plates accompanied by air sampling using a sampl'air lite (aes chemunex, bruz, france). the total viable count of collected microbes varied between the surface and air sampling methods, which suggested that the source of the contamination may be different. surface contamination is especially influenced by human activity such as touch. surface and air sampling both concluded that the bed areas were consistently highly contaminated. the effectiveness of nitrocellulose membranes as an alternative to replication detection and organism counting (rodac) plates for surface sampling has been demonstrated. the membranes have the advantage of being more effective at removing microbes, while also enabling samples to be taken from curved surfaces. passive sampling can also be used to describe more unusual methods of collection of bioaerosol material such as solid phase microextraction (spme). microbial volatile organic compounds (mvoc) have been successfully collected using an mm stableflex carboxen/polydimethylsiloxane fibre contained in a commercial housing. active sampling cannot be discussed without reference to a particle's mass and inertia. the mass of a particle is equal to its volume multiplied by its density, so it is possible for two particles to have the same mass but differing volumes and densities. if, however, two particles have the same density but differ in volume, then the larger particle will have a greater mass than the smaller particle. the inertia of a particle can be described as follows: consider two particles with differing masses being carried by an air flow inside a pipe. on reaching a bend in the pipe, the particle with the smaller mass will be able to travel along the airflow streamline and continue beyond the bend, whereas the particle with the larger mass will be unable to turn as quickly and will hit the wall and potentially become attached (figure ). when a particle collides with a wall because its mass is too great to allow it to travel with the airflow, the collision is known as inertial impaction. if particles of varying size all have the same density then the larger particles will succumb more readily than the smaller particles to inertial impaction, hitting the wall at a bend in the pipe. hence the smaller particles will be collected in the sampling devices but the larger ones will not. there are several active sampling devices including impingers, cyclones, and impactors, which will be discussed in detail later. however, all active bioaerosol sampling systems consist of five fundamental elements which are necessary to undertake accurate sampling: . inlet to the sampling device . transport of the air sample through the device . particle size selection (not always present) . collecting medium . pump and calibrated flow monitoring. first, the design of the inlet combined with the air flow rate is essential in the collection of a representative sample that correctly reflects the concentration and size distribution of the airborne particles. in a moving air stream, such as a ventilation duct, this is achieved by isokinetic sampling. this method considers the ratio of duct and sampling probe diameters, air flows, and inlet orientation to the air stream to ensure successful capture of particles regardless of size or inertia, thus providing a representative sample. sampling in still air is also affected by particle inertia, with larger particles being susceptible to evading probe collection; as the particle nears the inlet its velocity increases, thus increasing its stopping distance which may permit the particle to bypass the probe, distorting the concentration in the sample collected. the situation in still air is more straightforward but the probe inlet must be positioned horizontally to prevent an over/underestimation sampling bias. air streamline figure . inertial impaction in a pipe. once the air sample is within the device, the sample path should be as straight and direct as possible in order to minimize losses in the conducting tubing. where this is not possible, for example in a cascade impactor, particle loss will occur through inertial impaction on the bends between collection stages. in devices with sampling probes, particle loss may also occur in the probe head or flexible connective tubing, as particles will be lodged on to the side wall and will not reach the sampling medium. examples of this include liquid-based bioaerosol samplers, which also experience collection losses through evaporation of the collecting liquid and adhesion of the particles to the device walls. when this occurs the particles do not enter the collection liquid and the sampling process may therefore yield lower or false-negative results. regardless of the mechanism of particle loss, predicting the quantity of losses is problematic, as much depends on the interaction of the air/liquid flows, particle inertia and the design of the sampler. an estimation of losses can be achieved through appropriate laboratory validation, which is discussed in more detail below. identification of particle size selection is not always available in a sampling device; however, there are several ways of selecting by particle size, either by using a pre-classifying cyclone or a series of impaction plates. collection of the bioaerosol samples is normally on to agar or a filter or into liquid, with liquid collection placing less stress on the bioaerosol particles as they are not dried out and are more likely to maintain their viability than the other two methods. calibrated flow monitoring and the pump are crucial to the collection procedure as they ensure that the sampling device operates with an accurate air flow rate. each device will have an optimum speed at which the air flow should pass through the inlet and subsequent tubing to ensure that the bioaerosol particles will be collected with maximum efficiency. bioaerosol samplers vary considerably in size from large static samplers to smaller, portable personal samplers. large static samplers operate with higher flow rates of about . e l/min, allowing them to collect larger volumes of air more rapidly than personal samplers operating at about e l/min. e impingers impingers operate by channelling particle-laden air flow through nozzles that exit into a chamber containing liquid (example shown in figure a ). as the particles exit the nozzles in a jet of air they enter the collection chamber ( figure ). the distance from the nozzle outlet to the surface of the liquid along with the air flow rate influences the diameter of the particles that will be collected. collection on to liquid prevents desiccation of the collected particles; however, shear forces in the jet in conjunction with the turbulence caused by the air being forced into the chamber may result in loss of viability. this bioefficiency (the ability of the sampling device to maintain the viability of the bioaerosol during and after sampling) may also be reduced through evaporation, re-aerosolization (loss of previously collected particles) and adherence of particles to the internal walls of the collection chamber. , e bioaerosol impingers that are widely used include the all-glass impinger (ace glass inc., vineland, nj, usa), the bio-sampler (skc inc., covington, ga, usa) and the multistage liquid impinger (burkard manufacturing co. ltd, rickmansworth, uk) among others. , e cyclones in a cyclone sampler (figure b) the particle-laden air is forced by the shape of the collection chamber into a spiral, swirling flow ( figure ). within this airflow, particles experience a centrifugal force proportional to their diameter, density, and speed. this centrifugal force carries particles with sufficient inertia towards the cyclone wall where they are separated from the air flow into a liquid. this generally means that larger particles are more likely to be collected than smaller particles, and, as with all samplers, a calibrated airflow is essential to maintain the correct collection efficiency. on reaching the bottom of the cyclone, the air flow reverses its direction and carries the smaller, uncollected particles out of the cyclone through a vortex finder positioned in the cyclone roof. to increase the bioefficiency, a film of liquid is injected near to the cyclone's inlet, resulting in wetting of the cyclone walls; the liquid is then collected at the base of the cyclone for analysis. , collecting the particles on a liquid film maintains their viability but shear forces may still reduce bioefficiency. collection losses may again arise from evaporation of the collection liquid, resulting in the re-aerosolization of liquid air streamline previously collected material or through liquid carryover where the liquid injected into the cyclone travels over the cyclone roof and vortex finder wall before escaping from the system, carrying with it collected particles. , cyclones vary considerably in size and airflow rate, with both the cyclone geometry and the airflow rate affecting the collecting efficiency. depending on the scale of the cyclone they can be used for collecting large volumes of air while operating at high flow rates or as miniature cyclones that can be worn on a person's clothing in potentially hazardous environments, with the collected material being analysed at the end of each day to assess exposure. cyclones are also frequently used as pre-classifiers, removing larger particles from an airflow before further size classification by other types of sampler. cyclones that are widely used include the coriolis Ò m (bertin technologies, saint quentin en yvelines, france), sass (research international, inc., monroe, wa, usa), burkard cyclone sampler (burkard manufacturing co. ltd, uk) along with several other cyclones specifically designed for bioaerosol sampling. , , e impactors in common with cyclones, impactors use the inertia of a particle to facilitate collection. the air sample is passed through an array of nozzles that channel a jet of particle-laden air across a gap towards an agar culture plate, which lies perpendicular to the nozzle outlet. the air flow of the jet will follow a set of curves known as streamlines through the sampler; these curves lie tangentially to the velocity vectors of the flow. the plate deflects the streamlines by , with the air flowing past the plate and through the passageway between the plate and the device walls ( figure ). the particles with sufficiently low inertia will be carried by the streamlines and escape capture. however, particles with higher inertia will be unable to follow the curve of the streamlines, and, under the influence of the centrifugal force, will impact on the agar plate. the collection efficiency of an impactor is therefore primarily dependent on the diameter and density of the particle and the diameter of the nozzle, along with the air velocity of the jet (hence the need to calibrate the air flow through the device). the efficiency of an impactor should have a sharp cutoff curve, with the ideal impactor acting like a sieve, with all particles above a certain size, known as the cut-off size, being captured by the agar plate. this feature makes impactors highly suitable as particle size classifiers, with particles greater than a given size being separated from the air flow, while smaller particles remain airborne. a single-stage impactor has one cut-off size, so only requires one set of nozzles and an agar plate (see example in figure c ). cascade impactors can be used to gain information on the particle size distribution of an aerosol, with the particle-laden air flow being passed through successive tiers of nozzles and impaction plates. each tier, known as a stage, will collect particles of a specific size with the smaller particles remaining airborne and passing on to the next stage. at each subsequent stage, the nozzle diameter will become progressively smaller, hence the jet velocity increases, and the particle cut-off size is reduced. finally the air flow will pass through a filter to allow remaining small particles to be captured. by weighing the impaction plates from each stage and the filter, before and after sampling, the fraction of the total mass in each particle size range can be established. after cultivation the number of cfu should be enumerated and the counts corrected by positive-hole correction method, which accounts for deposition of multiple bioaerosol particles at the same deposition area. e in practice, each stage in a cascade impactor will not behave entirely like a sieve, and some particles will be deposited in the passageways between the stages or may bounce off the impaction plates and avoid capture. the airflow over the impaction plates may also be disturbed by the build-up of deposited particles, leading to altered collection efficiencies; however, this can be overcome by the use of multi-jet impactors with > nozzles. the bioefficiency of impactors is air streamlines collection substrate reduced due to the shear forces on the bioaerosol particles within the jet and on impaction with the agar plates. the microbial species under investigation along with jet velocity and jet-to-plate distance have been found to play an important role in the enumeration of bioaerosols. desiccation of the pathogen will also reduce bioefficiency, which can be overcome by mineral-oil-spread agar plates. despite the drawback of reduced viability, impactors are frequently used in sampling for many airborne pathogens. , , virtual impactors also use the centrifugal force and inertia to separate particles depending on their diameter. however, virtual impactors do not collect on to an agar plate but instead have a collection probe operating with a minor flow. this works by particles entering the impactor and being carried by the major flow around a bend ( figure ). the smaller particles are able to follow the streamlines around the curve while the particles larger than the cut-off diameter of the apparatus have sufficient inertia to carry them into the collection probe. the minor flow in the collection probe carries these larger particles on to a collection filter. likewise the smaller particles are collected on a filter in a separate part of the device. virtual impactors usually have only one or two stages, as each separation stage requires control of both the major and minor flow rates. the use of a collection probe rather than an agar plate avoids issues of particle bounce and deposition build-up; however, virtual impactors suffer collection losses near to the size of the cut-off diameter at the inlet of the probe. a useful feature of these devices is that the airflow in effect concentrates the particles larger than the cut-off size into a smaller volume of air, making virtual impactors useful as particle concentrators. slit impactors operate using the same principles of centrifugal force and particle inertia as described with regard to other impactors. rotating agar plates are especially useful as they provide a record of bioaerosol concentration over a specified time-period to enable certain activities to be monitored. bioaerosol particles enter the apparatus through a slit, causing the particles to impact on the slowly rotating agar plate below. the smallest particles will escape capture by following the streamlines of the air flows over the plates through the passageways to the outlet. impactors may also take the form of sticky plastic rods, such as rotorods (ted brown associates, los altos hills, ca, usa), or sticky glass plates where the airflow rate through the device can be adjusted in order to vary the collected particle size diameter, for example versatrap spore trap cassette (skc, inc.). examples of impactors include various single-stage and multi-stage anderson impactors, aerotech n- impactor (aerotech laboratories, coventry, uk), air test omega (lcb, la salle, france), air samplair mas- (merck, lyon, france), and bioimpactor - (aes), biostage impactor (skc, inc.) among many others. , e filters personal samplers are small, portable devices that are attached to workers' clothing to provide a representative sample of the exposure of the individual to hazardous aerosol. as with larger devices, personal samplers require a pump to draw air through the device, with a sample head, foam, or cyclone being used as pre-selectors for particle size. the bioaerosol particles are collected on to filters from where they can be transferred on to plates or dissolved into a liquid solution for culturing, or examined by microscopy (e.g. immunofluorescence). sampling by filtration is commonplace in aerosol collection but less popular for the collection of bioaerosol particles due to the loss of bioefficiency through desiccation of the pathogen; however, there have been notable successes with filter collection of bioaerosols. , fibrous filters consist of layers of fine fibres with relatively substantial gaps between the fibres that allow the filter to be between % and % air. as particles pass through the filter they are captured by the fibres. membrane filters have a complex pore-like structure and a porosity of about e % less than fibrous filters. as particle-laden air enters the membrane filter, the particles are deposited on the pore structures, with the benefit that particles much smaller than the pore diameters may be successfully captured. personal samplers with various filters include the inhalable gsp samplers (cis; bgi, inc., waltham, ma, usa) used with teflon and polycarbonate filters, pas- sampling heads containing polytetrafluoroethylene (ptfe) filters (millipore, merck, france) and the button aerosol sampler containing gelatin filters (skc, inc.). , , other bioaerosol sampling techniques less widely used bioaerosol sampling techniques include electrostatic precipitation and condensation techniques. on entering the inlet of an electrostatic precipitator, the bioaerosol particles are electrically charged at the inlet before progressing through an electric field, where they are separated from the air flow and deposited on to charged plates. although there is active research into the natural charge on bioaerosol particles and the efficiency and design of electrostatic precipitators, there is concern that the electric field undermines air streamlines collection probe figure . particle-laden airflow in a virtual impactor. the viability of microbes and that more extensive investigations are required into this sampling technique. , e sampling of bioaerosol through condensation techniques involves the air sample being processed through a humidifier. subsequently the warm, humid air is rapidly cooled with the bioaerosol particles acting as condensation nuclei. although this method can be used effectively to amplify small microbes, hence improving their chances of detection, the system is complex to use and heat transfer to the microbes may result in a loss of viability. , , choosing the bioaerosol sampler considerations when choosing a bioaerosol sampler include the type and size of micro-organisms under investigation, the environment where the sampling is to be undertaken, and cost. other factors, more specific to active samplers, should include ease of cleaning/disinfection and precautions that need to be implemented to prevent exhaust air from contaminating the sampling environment. manufacturers' websites usually provide information regarding the suitability and cost of their devices; however, more revealing is the practical use made of bioaerosol samplers by investigators in the field. sampling for airborne pathogens that may pose a health risk is not limited to healthcare environments. wastewater treatment plants (wwtps), farms and slaughterhouses, public and residential buildings, compost facilities and the general outdoor environment have all been the focus for bioaerosol studies and much can be learned from such research. , , , , , e if the research is focused on an individual's risk of exposure to harmful airborne microbes, then the obvious choice of device is the personal sampler. these samplers can be worn on the person's clothing and have proven successful in capturing fungi, bacteria, and even viruses. , , , one notable study investigated the potential for workers at a danish wwtp to be exposed to aerosolized noroviruses (novs), adenoviruses (advs), endotoxins, moulds, and bacteria. this is consistent with previous studies reporting increased occurrence of gastrointestinal illness among wwtp workers compared with control groups. , the study used inhalable gsp samplers (cis; bgi, inc.) to monitor the exposure of sixteen workers. teflon filters were fitted to the gsp samplers to allow endotoxin capture, whereas polycarbonate filters were successfully used for bacteria, mould, and virus collection. this study was the first to detect viruses, specifically norovirus gi, using gsp samplers. the exposure risk experienced by workers in a slaughter house was also undertaken with the wearing of personal samplers. the samplers consisted of pas- sampling heads containing mm pore size polytetrafluoroethylene (ptfe) filters (merck millipore sas, molsheim, france) attached in the breathing zone and were connected to portable sampling pumps (gilian , sensidyne, inc., st petersburg, fl, usa). the ptfe filters successfully captured wu polyomavirus and human papillomavirus along with other pathogens. one drawback of this study, which was focused on analysing the inhaled breath of the workers, was that it became apparent that the filters were also sampling exhaled breath. this would have been overcome by the use of larger static samplers placed away from workers' immediate environment that were able to sample a bulk background air volume. on occasion, using more than one type of sampler may be necessary to overcome specific sampler limitations. personal samplers have also been used as static samplers in a variety of situations. gelatin filters ( mm pore size) fitted to a button inhalable aerosol sampler (skc, inc.) have successfully captured influenza a virus (h n ) nucleotides, dermatophagoides allergens (der f and der p ), and bacillus subtilis in a laboratory setting; whereas other studies have used gelatin filters with iom personal samplers (skc, inc.) to successfully capture airborne legionellae from a wwtp and shower rooms in nursing homes and methanobrevibacter species and saccharopolyspora rectivirgula (causative agents of farmer's lung) in a dairy barn. , however, gelatin filters were noted to perform poorly in high-humidity environments, as they dissolved when sampling in a shower room for > min. gelatin filters fitted to iom samplers have been shown to have good efficiency in capturing total and viable legionellae but perform very poorly in capturing culturable samples. midget impingers (skc, inc.) have been successfully used to assess the effectiveness of a selection of surgical face masks against aerosolized influenza. having undertaken field work, it may be possible to correlate field data to laboratory results to assess the potential risk to workers' health of exposure to other degrees of contamination. a study investigating organic dust toxic syndrome (odts) in a seed handling factory used gsp inhalable samplers attached to workers' clothing to collect bioaerosol samples during h shifts. in the laboratory it was determined that a rotating drum (hse rotating drum dustiness tester, j.s. holdings, hertfordshire, stevenage, uk) containing contaminated dust could successfully aerosolize bacteria and fungi. by comparing results with the samples collected by the personal samplers, it was possible to calculate the concentration of airborne microbes to which the workers would be exposed from the tested dust. one major limitation with personal samplers is their relatively low flow rate, which can be as low as l/min. , , , therefore longer sampling times are more appropriate to sample a significant volume of air and this may lead to loss of bioefficiency through desiccation of the pathogen, however the loss of bioefficiency is dependent not only on sampling time, but also the microbial species and relative humidity. , in comparison with personal samplers larger static samplers, with their associated higher flow rates, enable the capture of larger, more representative air samples over the same time interval. their associated flows rates vary considerably from about . l/min for the biosampler (skc, inc.) and the agi- (ace glass, inc.) through l/min for the coriolis cyclone (bertin technologies) and the mas- /a (merck), to l/min for a described impactor. , , larger samplers have been used extensively in healthcare environments and in other indoor and outdoor environments to successfully capture viruses, bacteria, and spores. , e investigating the aerial transmission dynamics of influenza gained impetus during the recent h n avian influenza pandemic; however, prior to this and during the h n pandemic, work was undertaken to assess the risk to healthcare workers carrying out aerosol-generating procedures (agps) on h n positive patients. e using glass may three-stage impingers (produced at health protection agency, porton down, uk), air was sampled m from the head of the h n -positive patient while agps were being undertaken. the impinger operated at l/min for min intervals and classified the particles into three aerodynamic size ranges (> . mm, e . mm and . e mm) to assess the respiratory fraction. the air was collected into ml of phosphate-buffered saline and samples analysed using quantitative reverse transcriptionepolymerase chain reaction. the study showed that the may three-stage impinger proved successful in capturing h n rna. other studies have used larger static samplers to investigate airborne microbial concentration in operating theatres and recovery rooms, the aerial spread of mrsa in hospitals and residential environments, along with investigations undertaken in non-healthcare environments. , , , , , , determining the bioefficiency the most important aspect of bioaerosol sampling for the user to understand is bioefficiency. the bioefficiency of the sampling device is affected by the mechanical stress and desiccation experienced by the pathogen and will vary with the type of sampling device chosen, the sampling time, the type of pathogen under investigation and environmental conditions. , many studies have compared the effectiveness of various samplers but unless previous studies have examined the pathogen that you wish to investigate then such studies are of limited use in providing information on bioefficiency. e , , , , , it is therefore necessary to test the sampler/pathogen combination in a laboratory, preferably at a similar humidity to that which is expected in the field. this can be undertaken by spiking the sampler with a known concentration of the pathogen and then assessing the concentration collected. however, earlier studies used various other methods, such as using two samplers in tandem or parallel, to assess sampling efficiency. surrogate viruses may be used to limit the hazard when investigating high-risk pathogens, but it should be borne in mind that each pathogen responds uniquely to the conditions experienced. the time-interval during which the sampler will operate should also be replicated during laboratory testing in order to identify any operational issues or time-related loss of bioefficiency. during such bioefficiency tests, inherent variations in performance of the sampler may also become evident over different particle size ranges. with the limitations of different sampling devices being widely acknowledged and variation in collection efficiency between such devices being noted, establishing the bioefficiency of your chosen sampler against the target microbe in itself provides a valuable contribution to the field of bioaerosol sampling. , if the target microbe is unknown and a general assessment of bioaerosol particles present in an environment is sought, then the use of different types of sampling devices will mitigate the limitations of individual samplers, making a comprehensive study more likely. finally this is also a good opportunity to test the storage, enumeration and identification procedure, be that through cultivation and visual enumeration of the cfu, various pcr techniques, metagenomics, mass spectrometry, epifluorescence microscopy, matrix-assisted laser desorption/ionization mass spectrometry or other means. , , , , , , , these enumeration and identification methods, along with their advantages and limitations, have recently been discussed and are not repeated here; however, it should be noted that quantification of the pathogens captured by active samplers is normally expressed per cubic metre of air, which provides another reason to determine accurately the air flow rate of the device and the sampling time-period. , , , bioaerosol sampling out in the field the statistical analysis relating to bioaerosol sampling varies considerably depending on the nature of the study, and an investigator would do well to consult a statistician when designing any study. , , errors arising from bioaerosol sampling are typically threefold: random error of samples containing a finite number of discrete particles; errors due to non-uniformity of the bioaerosol distribution in the atmosphere; and errors due to sampling techniques. the sampling period will be influenced by factors that include the operational limitations of the sampling devices, such as the rate of evaporation of the collecting liquid, or the amount of time one has access to a site. however, even with such matters taken into consideration, the sampling timeperiods used by investigators varied widely, from as low as min to several hours. , the longer the sampling period the greater the volume of air being collected, thus the higher probability of capturing airborne pathogens, as long as the bioefficiency of the sampler does not deteriorate with time. when using samplers with differing flow rates concurrently, it may be preferable to calculate the sampling time of each device so that the volume of air captured is the same. if short sampling periods are most suited to the device being used, then repeating the sampling in triplicate should be considered. the overall length of the study may span from one day to a couple of years. new techniques such as lightinduced fluorescence (lif) methodologies are being implemented in real-time online biological particle sensors, enabling continuous on-site detection of bioaerosol counts. the height of the sampling device above floor level within an indoor environment is also important if the investigation is collecting samples from the breathing zone of patients. , if a more general bioaerosol sampling regime is undertaken, then sampling at different heights within a room and at several spatial locations will provide good sampling coverage. once the samples have been taken, they should be transported and stored in conditions that preserve their efficacy until cultivation and/or identification can be undertaken. having previously undertaken a bioefficiency study, the investigator is in a strong position to estimate with reasonable accuracy the concentration of the target bioaerosol in the sampled environment. combining this information with the genus of the captured microbe, the particle size range (informing on the penetration of the respiratory system), and the health effects on the human or animal population, conclusions can be made regarding bioaerosol concentration and health risk. presently there is no international consensus on the acceptable exposure limits of bioaerosol concentration, with a recent review drawing attention to this research deficit. a lack of bioaerosol studies targeting viruses and archea has also been identified, further limiting our understanding of the impact of airborne microbes on human health. several of the studies discussed in this review were based in bioaerosol-emitting facilities, such as wwtp and compost facilities, where the exposure to harmful microbes is a cause for concern for occupational safety reasons and for risk to health of the population in the surrounding area. in such cases the task for current research is to establish suitable doseeresponse relationships to enable health-based exposure limits for bioaerosols to be derived. such exposure limits would be designed to protect the general population from the ill effects of long-term exposure to bioaerosols. the situation for healthcare studies is quite different with a wide array of 'at risk' groups needing to be considered, making the derivation of health-based exposure limits challenging. the staff, patients or their visitors may be the source of the bioaerosol health risk, such as with sars virus, respiratory syncytial virus, influenza, measles, mumps, or rubella viruses. their stay in hospital may be brief and may not be contained to one ward, making it difficult to trace the source of an outbreak. the wider environment may also be a source of harmful bioaerosols, such as an increased risk of airborne aspergillus during construction activities or the risk of legionella bacteria in hvac (heating, ventilation, and air conditioning) or water systems. to gain a greater understanding of the transmission dynamics of certain airborne diseases and to increase hygiene standards through improved infection control, bioaerosol sampling studies have frequently focused on healthcare environments. bioaerosol sampling in operating theatres (ots) is motivated by the need to reduce the incidence of surgical-site infections. with the inclusion of high-efficiency particulate air (hepa) filters within ots, cleanroom technology standards have frequently been applied to these healthcare settings with the airborne particulate count being monitored. with the observations that bioaerosol sampling is time consuming, requires trained personnel and that results are not instantaneous, interest has grown in the correlation between microbiological and dust contamination, to the extent that it has been suggested that microbial sampling should be limited to epidemics, validation of protocols, or changes to the ot environment that may affect microbial content. further investigations have been unable to establish a relationship between dust particles and microbes in ots, although a relationship between the number of airborne microbes and human activity was confirmed. this relationship between increased airborne bacterial concentration and human activity is widely accepted. , approximately e % of human skin debris carries bacteria and skin shedding increases with physical activity, with millions of particles being shed per person each day. in addition to measuring the dust count using a light-scattering particle analyser, bioaerosol sampling was undertaken using both passive and active sampling. settle plates with a mm diameter were placed at strategic locations, m above floor level, throughout the ot and left exposed during surgical operations. the active sampling was undertaken using a single stage slip-type impactor operating at l/min for duration of min, with samples taken during operations. the study did observe an increased concentration of dust particles > mm during conventional surgery as opposed to scope procedures. an inverse relationship between dust and bacterial concentration was reported. as the ot door opened into the anaesthetic room, the turbulent airflow resulting from the pressure differential between the two rooms in effect removed dust from the ot. however, the bacterial concentration increased and it was proposed that this may be due to increased movement of the staff. this highlights the need for the investigator to be aware of airflow in and between areas under investigation, in addition to patterns of human activity. over a three-year sampling period, a study of surface and airborne microbial contamination was conducted in ots. both passive and active sampling was conducted during the commissioning of ots, during major renovations and surgical activities, as well as in adjacent corridors. passive sampling was undertaken using mm diameter settle plates using the / / scheme (explained in the section on 'passive sampling') with tryptic soy agar used for the total aerobic bacterial count, whereas sabouraud dextrose agar with chloramphenicol was used for fungal isolation. active sampling of airborne contamination was carried out using a duosas sampler (pbi international, milan, italy) operating at l/min. the study found a moderately strong correlation between the active and passive sampling methods, with the discrepancy between the two techniques being attributed to the relatively short sampling period and limited spatial collection zone of the active sampler compared with the longer exposure time of the settle plates. the investigation also concluded that bioaerosol sampling could be used for the evaluation of the ventilation and air conditioning system within the ot. comparing the results from sampling during different surgical procedures also had the potential to inform improved surgical hygiene practice. correlation between active and passive sampling was also described during a study comparing different ventilation regimes in ots. using a surface air system sampler (sas, international pbi, milan, italy) operating at l/min and settle plates, both with tryptic soy agar, the study showed that unidirectional airflows within ots did not guarantee low counts of airborne bacteria. the study also confirmed that an increased number of people and door openings in an ot influenced an increase in bacterial count. a year-long monitoring of airborne microbial contamination in ots and surrounding areas has also been studied using mixed effect models to assess the influence of air temperature, relative humidity, number of people in a space and different sampling locations on levels of co , suspended particulate matter, and airborne bacteria. bioaerosol sampling was undertaken using an andersen one-stage viable impactor (n ; andersen samplers, atlanta, ga, usa), with tryptic soy agar. the sampling period was min, with duplicate samples taken at a height of . e . m from floor level to represent the breathing zone of healthcare workers. in concurrence with a previous study, bacillus spp., micrococcus spp., and staphylococcus spp. bacteria were frequently found in the operating theatre area. the study found a positive correlation between airborne bacterial concentration and suspended particulate matter (pm and pm . ). a positive correlation was also found between the number of people in a room and co concentrations, but, when temperature, relative humidity and sampling location were accounted for, no significant correlation was found between the number of people and bacterial concentrations. one exception was the postoperative recovery room where there were a greater number of people, higher co levels, and higher concentrations of bacteria. caution should be exercised when investigating the relationship between the number of human occupants and the concentration of airborne microbes. although a correlation has been noted within one room of this investigation and in previous studies mentioned in this section, a study carried out in an environmental chamber suggested that outdoor air had a greater influence on the bioaerosol composition. airborne viral and bacterial concentrations were monitored in the outpatient area of a paediatric unit and in the paediatric emergency room twice a week for one year. the sampled air was filtered through a closed face, threepiece disposable, plastic cassette containing a . mm polytetrafluoroethylene filter and operating at l/min. the air within the outpatient area was sampled for h a day whereas the air in the emergency room was monitored during h periods. in both cases, the bioaerosol sampler was positioned in the breathing zone between . and . m above floor height. during the course of the study, filter samples were taken and airborne adenovirus and mycoplasma pneumoniae were detected in both monitored areas, with greatest prevalence found in the outpatient area. the negative control was the use of filters with no air flow passing though the sampling device. no adenovirus and m. pneumoniae was found on the negative controls. the study did, however, passive sampling e settle plates e consider using the : : scheme with mm plates e surface sampling e consider using membranes (e.g. nitrocellulose) as an alternative to contact plates on curved surfaces e surface and aerial contamination may have different sources e results from passive and active samplers should not be assumed comparable active sampling e impactors e collection on to agar plates e collection efficiency highly dependent on particle size (should be sieve-like in performance) e ideal as a particle size classifier e loss of bioefficiency: shear forces, desiccation, particle bounce, and deposition build-up e virtual impactors e collection into liquid, thus minimizing risk of desiccation e collection efficiency dependent on particle size e useful as particle concentrators e slit impactors e collection on to agar plates e loss of bioefficiency: shear forces, desiccation, particle bounce, and deposition build-up e records variation in bioaerosol concentration over a specified time-period e impingers e collection into liquid, thus minimizing risk of desiccation e loss of bioefficiency: shear forces, re-aerosolization, evaporation, adherence to device walls e collection efficiency dependent on particle size e cyclones (wetted) e collection into liquid, thus minimizing risk of desiccation e loss of bioefficiency: shear forces, liquid carryover, evaporation, adherence to device walls e may be used as pre-classifiers for particle size e collection efficiency dependent on particle size e vary considerably in size and airflow rate e filters e small, portable personal samplers e loss of bioefficiency: desiccation e collection efficiency dependent on particle size (sample head, foam, or cyclone being used as pre-selectors) in the laboratory e calibrate the flow rate of the active sampler e ensures the maximum collection efficiency e influences the size of particles collected e determine the bioefficiency of the sampler against the target pathogen e test in air conditions expected in the field (relative humidity and temperature) e spike sampler with known concentration of the target pathogen e each type of pathogen has a unique response to conditions experienced e surrogate viruses may be used in place of hazardous pathogens; however, response may differ from target pathogen e check that bioefficiency is maintained throughout planned sampling time e determine errors in numeration when sampling from a known, repeatable concentration of the target pathogen e ensure that the sampler exhaust is not a source of pathogen contamination to the environment e test the storage, enumeration, and identification procedure in the field e position of the inlet sampler e avoid strong airflows around the inlet of the sampler e if using an inlet nozzle, position horizontally e ensure that the sample position is beyond the range of droplet fallout from a source (e.g. coughing/vomiting patient) e aerial microbial concentration e expect non-uniformed concentration in the area studied (expect associated sampling errors) e consider taking samples at various locations in the area studied e note human/animal activity and number of humans/ animals present, as this may influence concentration of certain microbes e be aware of airflow patterns due to hvac (heating ventilation and air conditioning) and natural ventilation e note air quality: relative humidity, temperature (also consider co and particle dust count) e there may be seasonal variation in concentration of the target pathogen e active samplers: quantification of pathogens e expressed as enumeration per cubic meters of air e need to know the collection time and flow rate of the sampler notice evidence of seasonal variation in this taiwanese hospital, with airborne adenovirus peaking in the summer months, whereas m. pneumoniae detection rates increased in the autumn and winter. identifying peaks in bioaerosol contamination during certain months allows for ventilation rates in affected areas to be increased to reduce the risk to patient health. effective ventilation and controlled airflow patterns within wards alongside improvements in hygiene and operational procedures are arguably the strongest defence against high concentrations of airborne microbial contamination. , , , these hospital-based bioaerosol investigations highlight many of the issues facing the bioaerosol researcher. the methodologies applied differ between research teams. sampling devices vary with regards to their collection efficiency. concentrations of airborne pathogens are influenced by airflows within the hospital building and seasonal variation. the influence and correlation between human activity, air quality (humidity, temperature, co concentration) and dust particle count on bioaerosol concentration is uncertain, with contradictory results being presented. the transmission dynamics of some pathogens are not fully understood and an airborne component to transmission should not be overlooked. even with a good understanding of the concentrations of bioaerosols in an environment, the health-based exposure limits for a diverse group of patients and staff may not be known. yet such research can inform on appropriate ventilation rates to maintain good air quality, assess the bioaerosol risk to patients and staff, gain a greater understanding of the transmission dynamics of pathogens, and suggest improvements to hygiene procedures. amid all the uncertainties and difficulties of bioaerosol research, the goal remains to gain a greater understanding of airborne pathogens and to provide safe healthcare environments for our patients and staff. a summary of the key points in bioaerosol sampling is presented in box . a wide variety of bioaerosol samplers have been used to investigate airborne pathogens in healthcare facilities and other environments. we have described the underlying principles behind bioaerosol sampling devices along with benefits and disadvantages of various designs. examples of bioaerosol sampling have been given to point to best practice and to highlight the wide array of devices used and pathogens captured. due to the unique response of each variety of pathogen to environmental conditions and the stresses experienced in differing sampling devices, the investigator should commence studies by determining the bioefficiency of the chosen sampler and the pathogen under investigation within laboratory conditions. from such foundations, sampling for bioaerosol material in the complexity of the field holds greater certainty of successful capture of low-concentration airborne pathogens. avian influenza h n transmission in households, indonesia airborne transmission of influenza a/h n virus between ferrets influenza aerosols in uk hospitals during the h n ( ) pandemic e the risk of aerosol generation during medical procedures roles of sunlight and natural ventilation for controlling infection: historical and current perspectives a community-wide outbreak of legionnaires' disease linked to industrial cooling towers e how far can contaminated aerosols spread? the development of a bioaerosol sampler for the detection of enzymes in industry bioaerosol evaluation in indoor environments iso - : . cleanrooms and associated controlled environments e biocontamination control e part : general principles and methods aerosol technology environmental control of microbial contamination in the operating room the index of microbial air contamination operating theatre ventilation systems and microbial air contamination in total joint replacement surgery: results of the gisio-ischia study prospective survey of indoor fungal contamination in hospital during a period of building construction microbial air monitoring in operating theatres: experience at the university hospital of parma post-flood measurement of fungal bio-aerosol in a resourcelimited hospital: can the settle plate method be used? healthcare environments and spatial variability of healthcare associated infection risk: cross-sectional surveys comparative efficiency of nitrocellulose membranes versus rodac plates in microbial sampling on surfaces prediction of mold contamination from microbial volatile organic compound profiles using solid phase microextraction and gas chromatography/mass spectrometry physical and chemical properties of aerosols. london: blackie academic & professional investigation of inherent and latent internal losses in liquid-based bioaerosol samplers evaluation of sampling techniques for detection and quantification of airborne legionellae at biological aeration basins and shower rooms bioaerosol sampling with a wetted wall cyclone: cell culturability and dna integrity of escherichia coli bacteria metagenomic detection of viruses in aerosol samples from workers in animal slaughterhouses the impact of sampler selection on characterizing the indoor microbiome effect of sampling time on the collection efficiency of all-glass impingers long-term sampling of airborne bacteria and fungi into a nonevaporating liquid collection of airborne microorganism into liquid by bubbling through porous medium influence of storage on the fungal concentration determination of impinger and filter samples rapid quantification of bioaerosols containing l. pneumophila by coriolis Ò m air sampler and chemiluminescence antibody microarrays sampling port for real-time analysis of bioaerosol in whole body exposure system for animal aerosol model development reverse-flow centrifugal separators in parallel: performance and flow pattern the cyclone scrubber e a high efficiency wet separator the development of sampling methods for the assessment of indoor bioaerosols development of a biosensor for airborne proteases an improved wetted wall bioaerosol sampling cyclone a direct approach to the design of cyclones for aerosol-monitoring applications computational fluid dynamics (cfd) and empirical modelling of the performance of a number of cyclone samplers use of a culture-independent approach to characterize aerosolized bacteria near an open-freestall dairy operation correlation between olea europaea and parietaria judaica pollen counts and quantification of their major allergens ole e and par j -par j field evaluation of a personal, bioaerosol cyclone sampler wetted wall cyclones for bioaerosol sampling chamber evaluation of a personal, bioaerosol cyclone sampler development of a personal bioaerosol sampler based on a conical cyclone with recirculating liquid film new sampler for the collection, sizing, and enumeration of viable airborne particles positive-hole correction of multiple-jet impactors for collecting viable microorganisms inertial samplers: biological perspectives an alternative approach for the correction of bioaerosol data collected with multiple jet impactors effect of physical and biological parameters on enumeration of bioaerosols by portable microbial impactors enhancing bioaerosol sampling by andersen impactors using mineral-oil-spread agar plate reduction and characterization of bioaerosols in a wastewater treatment station via ventilation critical working tasks and determinants of exposure to bioaerosols and mvoc at composting facilities aerosol measurement: principle, techniques and applications review of bioaerosols in indoor environment with special reference to sampling, analysis and control mechanisms prediction of mold contamination from microbial volatile organic compound profiles using head space gas chromatography/mass spectrometry effects of condensational growth on culturability of airborne bacteria: implications for sampling and control of bioaerosols comparison of two biological aerosol sampling methods differences in detection frequency as a bioaerosol data criterion for evaluating suspect fungal contamination comparative performance of impactor air samplers for quantification of fungal contamination a comparison of the efficiencies of a portable biostage impactor and a reuter centrifugal sampler (rcs) high flow for measuring airborne bacteria and fungi concentrations exposure to airborne noroviruses and other bioaerosol components at a wastewater treatment plant in denmark use of gelatin filter and biosampler in detecting airborne h n nucleotides, bacteria and allergens charge levels and gram (ae) fractions of environmental bacterial aerosols collection of airborne microorganisms by a new electrostatic precipitator design and development of an electrostatic sampler for bioaerosols with high concentration rate influence of secondary flows on the collection efficiency of a cylindrical electrostatic precipitator development and evaluation of a novel bioaerosol amplification unit (bau) for improved viral aerosol collection the efficient method for simultaneous monitoring of the culturable as well as nonculturable airborne microorganisms airborne enteric coliphages and bacteria in sewage treatment plants microorganisms in bioaerosol emissions from wastewater treatment plants during summer at a mediterranean site reducing bioaerosol dispersion from wastewater treatment and its land application: a review and analysis relationship between airborne detection of influenza a virus and the number of infected pigs the potential for community exposures to pathogens from an urban dairy food animal transport: a potential source of community exposures to health hazards from industrial farming (cafos) bioaerosols from municipal and animal wastes: background and contemporary issues airborne bacteria and carcass contamination in slaughterhouses distribution and identification of culturable airborne microorganisms in a swiss milk processing facility human occupancy as a source of indoor airborne bacteria / )-b-d-glucan, fungi, and dust mite allergens in flood-affected homes of new orleans evaluation of respiratory symptoms and their possible association with residential indoor bioaerosol concentrations and other environmental influences / )-b-d glucan, and endotoxin from flood-affected materials collected in new orleans homes characterization of seasonal indoor and outdoor bioaerosols in the arid environment of el paso. texas isolation of staphylococcus aureus and antibiotic-resistant staphylococcus aureus from residential indoor bioaerosols indoor and outdoor bioaerosol levels at recreation facilities, elementary schools, and homes sampling for indoor fungi autocorrelation and variability of indoor air quality measurements environmental assessment of aerosols, bioaerosols, and airborne endotoxins in a machining plant bioaerosol concentrations in noncompliant, compliant, and intervention homes in the midwest exposure to culturable airborne bioaerosols during noodle manufacturing in central taiwan workplace exposure to bioaerosols in pet shops, pet clinics, and flower gardens characterizations and relationships between outdoor and indoor bioaerosols in an office building bioaerosol emissions from open window composting facilities: emission characterisation and dispersion modelling improvements presence of legionella and free-living amoebae in composts and bioaerosols from composting facilities spatial variations in airborne microorganism and endotoxin concentrations at green waste composting facilities evaluating the quality of bioaerosol risk assessments for composting facilities in england and wales particle size distribution of airborne aspergillus fumigatus spores emitted from compost using membrane filtration sorting and recycling of domestic waste. review of occupational health problems and their possible causes ambient influenza and avian influenza virus during dust storm days and background days. environ personal sampler for monitoring of viable viruses; modelling of outdoor sampling conditions culturable airborne fungi in outdoor environments in beijing evaluation of four bioaerosol samplers in the outdoor environment london plane tree bioaerosol exposure and allergic sensitization in the adaptation of existing personal inhalable aerosol samplers for bioaerosol sampling performance characteristics of the button personal inhalable aerosol sampler health effects among workers in sewage treatment plants work related symptoms among sewage workers: a nationwide survey in sweden characterization of bioaerosols from dairy barns: reconstructing the puzzle of occupational respiratory diseases by using molecular approaches effectiveness of surgical masks against influenza bioaerosols microbial diversity in bioaerosol samples causing odts compared to reference bioaerosol samples as measured using illumina sequencing and maldi-tof effect of sampling time and air humidity on the bioefficiency of filter samplers for bioaerosol collection air quality monitoring of the post-operative recovery room and locations surrounding operating theatres in a medical centre in taiwan surveillance of airborne adenovirus and mycoplasma pneumoniae in a hospital paediatric department indoor air quality varies with ventilation types and working areas in hospitals collection efficiencies of aerosol samplers for virus-containing aerosols air and surface contamination patterns of meticillin-resistant staphylococcus aureus on eight acute hospital wards change in environmental bacterial flora in a new hospital building comparison of the collecting efficiency of microbiological air samplers a slit sampler for collecting and counting air-borne bacteria methods for sampling of airborne viruses the performance of the biotest rcs centrifugal air sampler airborne viable, non-viable, and allergenic fungi in a rural agricultural area of india: a -year study at five outdoor sampling stations on-line monitoring of airborne bioaerosols released from a composting/green waste site ventilation and transport; bioaerosols in healthcare environments non-culturable bioaerosols in indoor settings: impact on health and molecular approaches for detection evaluation of exposureeresponse relationships for health effects of microbial bioaerosols e a systematic review environmental controls in operating theatres risk factors for particulate and microbial contamination of air in operating theatres reduction of skin bacteria in theatre air with comfortable, non-woven disposable clothing for operating-theatre staff behaviours and rituals in the operating theatre chamber bioaerosol study: outdoor air and human occupants as sources of indoor airborne microbes the control by ventilation of airborne bacterial transfer between hospital patients, and its assessment by means of a particle tracer: ii. ventilation in subdivided isolation units detection of viruses in used ventilation filters from two large public buildings none declared. none. key: cord- -gtb ictv authors: polkinghorne, a.; branley, j. title: evidence for decontamination of single-use filtering facepiece respirators date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: gtb ictv single-use filtering face respirators (ffrs) are critical pieces of personal protective equipment for healthcare workers treating patients with suspected upper respiratory tract pathogens. experiences during pandemics in the s, as well as the ongoing covid- pandemic caused by the sars- -cov , have highlighted concerns over the pressures that sustained respiratory virus pandemics may have on supplies of ffrs globally. decontamination of ffrs has been posited as one solution to support the re-use of ffrs with a growing body of literature over the last + years beginning to examine both the efficacy of disinfection of contaminated ffrs but also the impact of the decontamination process on the ffr’s performance. physical and chemical methods of decontamination have been tested for treatment of ffrs with ultraviolet germicidal irradiation, sterilization by steam, ethylene oxide and vaporous hydrogen peroxide, demonstrating the most promising results thus far. many of these methods utilize existing equipment that may already be available in hospitals and could be re-purposed for ffr decontamination. importantly, some methods may also be replicated on household equipment, broadening the utility of ffr decontamination across a range of healthcare settings. utilizing techniques to experimentally contaminate ffrs with a range of microorganisms, most decontamination methods appear to reduce the risk of the mask as a source of infection to the wearer and others to negligible levels. the performance of the filter, especially the efficiency of particle penetration following treatment, varied greatly depending on the processing method as well as the model of the filter itself, however. urgent regulatory body-supported research is required to endorse the routine decontamination of ffrs. in emergency settings, these methods should nevertheless be carefully considered as one strategy to address potential shortfalls in supplies of ffrs for healthcare workers. filtering face piece respirators (ffr) are standard and critical personal protection devices designed to protect health-care workers (hcws) required to undertake airborne precautions in treating patients with suspected respiratory pathogens . protection is facilitated by a close fit and filtration of > % of very small ( . micron) test particles from the inhaled air of the wearer , . as per the national institute for occupational safety and health (niosh) guidelines, the service life of a n ffr is not specified, however, its use should be limited by assessments of damage, soiling or an increase in breathing resistance . as such, n respirators are typically considered to be 'single-use', involving a single donning and doffing by a hcw prior to being discarded appropriately. previous outbreaks of respiratory viruses such as the sars outbreak influenza pandemic , have highlighted the risks of shortages of ffrs at the hospital level, leading to potential for significant rates of infection amongst hcws . in preparation for future pandemics that might likely lead to similar shortages, countries continue to stockpile medical devices such as n respirators with at least one study suggesting that public health agencies would need to significantly increase the stocks of respirators and other masks available to meet scenarios where - % of a population becomes affected . as an alternative to stockpiling of respirators, hcws may also choose to 'extend the use' of ffrs and/or 'reuse' masks, involving donning and doffing of masks multiple times. some recommendations exist for extended or limited reuse of ffrs during pandemics for certain types of respiratory viruses but not others . one of the principle concerns with abandoning disposal of respiratory masks is the potential for the masks to become contaminated with fluids, etc. that may affect respirator performance as well as the potential for the masks to act as reservoirs of infectious microorganisms. the latter is of concern with quantitative pcr (qpcr) screening of n ffrs worn by hcws exposed to patients during an influenza season found to be contaminated with influenza virus. while the risk of reaerosolisation of viable viral particles from contaminated ffrs has been assessed as low , virus-contaminated n ffrs may also act as a source of hand contamination . decontamination of masks to facilitate safe re-use has been postulated as one, albeit controversial , solution with a number of studies over the last years investigating the effectiveness of different decontamination methods on the performance of the treated ffr in protecting the hcw and/or removing the potential of the ffr to act as a fomite [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] . it has been suggested that for n ffr decontamination to be considered successful, the method must remove the presence of the infectious agent, not harm the user and not compromise the function of the respirator itself . the global spread of the sars-cov- virus, the cause of a pneumonia-like illness referred to as covid- , has placed critical demands on the supply of respirators and other medical supplies. as in previous pandemics , the use of n respirators alongside other airborne precautions appears to be the cornerstone of effective infection control schemes to protect hcws treating seriously ill individuals. for example, . % ( / ) of staff who did not wear n respirators, nor performed frequent disinfection by handwashing, became infected with sars-cov- virus compared to their colleagues who wore n respirators and followed frequent disinfection protocols ( . %; / ) over the same time period, despite the fact that the latter group worked in much higher risk areas. highlighting the significant potential for mask decontamination to meet the critical need for n ffrs during the current covid- outbreak, niosh is encouraging studies to assess the performance of decontaminated n ffrs . in this rapid review, we summarise previous and current research into the methods for decontamination and subsequent assessment of n respirators for contamination and/or filter performance. considerations in recommending the limited reuse of ffr for hcws have also been thoroughly discussed previously . together, this information should serve as a resource to advance research into the role of ffr reuse in emergency situations. relevant english language published literature on frr decontamination was identified by searching of the medline bibliographic database (https://pubmed.ncbi.nlm.nih.gov/). studies into ffr decontamination have focussed on two parameters, including (i) changes to the performance of the filter and/or (ii) the reduction in microbial burden following the decontamination procedure. respirator performance is primarily focussed on filtration efficiency with nisoh certification requiring a filtration efficiency of ≥ % or ≤ % penetration against challenges from a dispersed nacl aerosol in laboratory conditions . a number of decontamination studies have investigated the impact of decontamination on filtration efficiency , , , . in addition to penetration efficiency, additional criteria that have been investigated less frequently include filter air flow resistance, fit testing, and the stability of the physical components (e.g. straps, nose bridge) of the mask, over concerns that that decontamination may lead to physical damage of the ffr. in terms of the efficacy of ffr decontamination to control the microbial burden, the most relevant method has involved experimental inoculation of the masks with influenza virus prior to decontamination , , followed by viral recovery using culture and/or qpcr quantification of viral loads on extracted ffr material. as an alternative to influenza virus, experimental inoculation with ms viral coliphage has also been used in studies of ffr contamination and decontamination , , , [ ] [ ] [ ] . bacteria, including staphylococcus aureus and the spores of bacillus subtilis have also been loaded onto ffrs to assess decontamination efficacy. the following section outlines the published literature investigating different methods for decontamination of ffrs. the key findings of these studies, divided by the method utilised for decontamination, are summarised in table . while the majority of studies have investigated the use of existing methods and equipment that are typically used and available for disinfection within a health setting, a number of novel decontamination methods have also been investigated and will be described including those studies that have investigated the use of common household equipment such as ovens , , , , microwaves , , , , and rice cookers . the results of steam mediated ffr decontamination studies suggest that this method is extremely promising, perhaps more than any of the methods reported in this review. sterilisation by steam is widely used in health care settings as it is a non-toxic, cost-effective and rapid method for microbial destruction . microbial destruction is achieved by direct contact with steam, which leads to the irreversible coagulation and denaturation of microbial proteins . a variety of methods have been investigated to achieve steam sterilisation of ffrs, including common health setting equipment (e.g. autoclaves) as well as makeshift methods using microwaves, ovens etc. for the latter approaches, steam generation is typically achieved by the introduction of vessels containing water, with the exposed faces of the ffr positioned above the vessel to allow steam to be distributed across the ffr surface . microwave steam bags, designed for the disinfection of equipment for feeding infants, have also been investigated for the decontamination of individual ffrs . decontamination of ffrs experimentally contaminated with either influenza virus or its substitute, bacteriophage ms , reveal consistently successful and significant reductions in viral loads , , . steam sterilisation of ffrs has also shown to be % effective in killing b. subtilis spores on ffrs . filter performance does not appear to be significantly impacted either with autoclave, oven and microwave-based methods demonstrated to have no significant effect on ffr particle filtration , , , including after several cycles of exposure to steam decontamination . ffr fit does not appear to be affected as well . moist heat with a relative humidity of between - % has also be assessed for ffr decontamination , . oven-generated moist heat was found to reduce influenza viral loads on most models of ffrs to below detectable limits , without a significant impact on the mean penetraton of % nacl aerosols at a -nm particle size . dry heat is a useful method for sterilisation of materials that might be damaged by moist heat, however, it is more time consuming since heat penetration and microbial destructions rates are slower . several studies have investigated the impact of dry heat on microbial burden and/or the performance of the ffr post-treatment with researchers finding differing results depending on the device used to generate dry heat. a study by lin et al. found that dry heating of experimentally contaminated ffrs in a traditional electric rice cooker for only three minutes ( - °c; no water added) achieved > % b. subtilis spore destruction. this method does also not appear to impact on the penetration of particles or the pressure drop through the treated mask . the use of other methods for dry heat decontamination of ffrs are less promising. microwave oven derived heat decontamination for only two minutes was found to melt ffr components to the point that they were considerable unwearable . the metal nosebands of ffrs may also cause arcing, during exposure to microwaves. poor results were also found with dry oven baking for hr at temperatures ranging from - °c, with various models tested found to have filter aerosol penetrations > % following treatment . ultraviolet germicidal irradiation (uvgi) has been one of the most heavily investigated of the methods for ffr decontamination. uvgi utilises ultraviolet light to kill viruses from the energy contained within the electromagnetic short-waves ( nm) . uv irradiation has been shown to be an effective method for inactivation of sars-cov virus . experimental studies have found that uvgi, deployed at different doses, is effective (i.e. ≥ log reduction) in neutralising influenza or ms virus inoculated onto the surfaces of ffrs , , . vo et al. found that decontamination efficacy was time-dependent, with a ≥ log reduction observed only after hr uvgi exposure. effective decontamination time could be shortened to min by significantly increasing the uvgi dosage, however . when the filter performance of uvgi-treated ffrs was tested, differences in the mean penetration test results using a % nacl aerosol were found to be not significant , , . changes to flow resistance were similarly unaffected. at higher doses (e.g. j/cm ), however, uvgi was noted to significantly deteriorate the layers of respirator material while also weakening the breaking strength of the ffr straps . it was noted that visible deterioration alternatively could be used as an indicator on the number of uvgi cycles an individual ffr could be limited to . in terms of the practical application of uvgi, many health care organisations already have uvgi systems that could be repurposed for ffr decontamination if required, with staff training potentially required to limit uvgi expose to eyes and skin. gaseous phase chemicals are routinely used in health-care settings to sterilise medical products that are not suitable for treatment by steam sterilisation , with a number also tested for their use in decontamination of ffrs (table ) . vaporised hydrogen peroxide (vhp) is a vapour form of hydrogen peroxide (h o ), used as a low-temperature sterilant in health-care settings . vhp decontamination does not appear to affect ffr particle penetration and filter airflow resistance after single or multiple cycles of treatment . a single vhp vapor cycle was found to reduce (> log) the infectious dose of spiked bacteriophage to levels below the infectious dose required for most respiratory viruses . ethylene oxide (eto) is a colourless gas that causes alkylation of proteins, impeding normal metabolism and replication in cells . eto sterilisation is a relatively slow procedure, requiring treatment and then extensive aeration post-treatment. assessment of filter performance following eto decontamination suggests that filter aerosol penetration, as well as appearance and filter airflow resistance are unaffected in treated filters . furthermore, changes in filter penetration following three cycles of treatment were < % . several studies have investigated the efficacy of ffr decontamination using physical cleaning or submersion.in liquid chemicals. bleach has been shown to have strong bactericidal and virucidal activity when used to decontaminate experimentally inoculated ffrs , , however, the effect on filter performance appears to be variable with a decrease in ffr particle filtration noted for certain ffr models tested , , . as an alternative, physical removal with bleach wipes has also been tested on ffrs contaminated with mucin and viable s. aureus, revealing significant microbial attenuation and little or no impact on particle penetration performance . cleaning with other wipes were also investigated in this study, with inert wipes (no antimicrobial activity) showing moderate cleaning efficacy while benzalkonium-embedded wipes produced similar results to the bleach cleaning wipes. physical degradation and changes to ffr particle penetration were negligible , although results varied depending on the models tested. immersion in liquid hydrogen peroxide was also found to not impact on filter performance . although disinfection was not tested, it could be predicted that it would be effective given that this chemical has strong germicidal activity . immersion in alcohol (ethanol & isopropanol) were found to have small impact on ffr particle filtration in a recent study . an obvious concern associated with the use of chemical methods is related to the potential for harmful chemical residues to remain on the ffr after decontamination, providing the potential for respiratory and/or skin irritation for the wearer. this fear was confirmed by a study from salter et al. revealing that residual chemicals could be detected on ffrs following treatment with a variety of gaseous and liquid decontaminants. for the majority of chemicals measured, it was concluded that the amount of chemical detected would be below the permissible exposure limit of the wearer. a noticeable odour was also detected that some wearers may be unable to tolerate, an observation that was also made in a previous study examining bleach decontamination of ffrs . in terms of safety, one noticeable exception was the use of eto, a toxic carcinogen , with harmful carcinogenic and mutagenic residues detected on the ffrs post-treatment . the ongoing covid- pandemic has placed significant pressures on the availability of critical hcw ppe such as ffrs for front-line staff required to implement airborne precautions. the ability to stockpile sufficient ffrs to endure a -week influenza pandemic in the usa was previously identified as a cause of significant concern health care officials and this concern has now come to reality during the covid- pandemic . while adopting extended wear is one potential solution to address this ffr shortage , this review has highlighted the growing body of literature providing evidence that ffrs can be biologically decontaminated for reuse. the impact that decontamination has on filter particle penetration is less compelling, with much still unknown about how these processes will affect other aspects of ffr performance such as fit and seal. of the methods that have been investigated to date, decontamination by steam, uvgi and hpv hold the most potential as solutions that can be employed using existing health care facility infrastructure. in the case of steam, this method has the potential to be used by hcws outside of the healthcare setting, where required, by co-opting household equipment (e.g. microwaves, ovens, rice cookers) to assist with steam generation. these methods appear to be very effective at biological decontamination of ffrs contaminated with bacteria and viruses, addressing one of the primary concerns over the re-use of ffrs, namely that contaminated masks may become a fomite for infection of the hcw or susceptible patients. in terms of ffr performance, ffr particle penetration, perhaps the most important aspect to the function of an ffr, also appears to be unaffected after treatment with these methods, suggesting that decontaminated ffrs will provide some level of protection from aerosolised infectious particles, certainly more so than not wearing an ffr at all. evidence for the use of rice cookers and other household implements for ffr decontamination also highlights the potential for other non-conventional methods that may be available to support the reuse of ffrs. one unexplored option involves the use of solar disinfection, an unconventional method that relies on the use of energy from the sun to obtain sufficiently high temperatures to inactive or destroy microorganisms . this method has been successfully used to decontaminate water containing rna viruses at high temperatures and may represent a free solution available for hcws to perform decontamination of their own personal protective equipment. the decision over which method to employ for decontamination of ffrs will almost certainly need to take into consideration the throughput capacity of the chosen method, the time required for decontamination, including the period of time required after treatment for the ffr to be worn safely, particularly for chemical methods for decontamination such as eto and vhp. the number of cycles with which an individual ffr can be recycled also needs to be carefully considered. while multiple cycles (e.g. three) of ffr decontamination did not appear to impact ffr function more than a single cycle for most methods investigated, factors such as the way the masks are stacked and the relative level of exposure to processing conditions have been suggested to influence the 'survival' of ffrs after decontamination . in the case of uvgi, the dosage also needs to be carefully planned with higher levels of uvgi dosage having a measurable deleterious effect on the respirator material than lower doses . in worst case scenarios, it has been suggested that the physical degradation of the respirator material could be used as a visual cue to determine when a treated ffr should be discarded . there are three other important issues that need to be considered, however, when considering the relative risk and benefit of ffr decontamination: • ffr integrity and performance following decontamination appears to be modelspecific. hundreds of models of ffr are currently approved for use by hcws around the world. as highlighted by mills et al. , ffr models vary greatly in their design including the ffr shape, material composition, and other features such as pleats and flaps with many of these design features potentially effecting the efficacy of biological contamination as well as the physical degradation of the ffr. for example, in the latter study, uvgi decontamination efficiency was noted to be potentially affected by shadowing created by the presence of ridges in the mask . physical damage to the mask as filter performance also appears to vary between models when treated by the same method . these model-specific differences pose significant challenges to regulators considering general recommendations over the use of mask decontamination and re-use, with none of the studies described providing sufficient replicated data to support the use of any one method for all models available. in the absence of this information, when implementing any of the decontamination methods described in this review, care needs to be taken to ensure that (a) the methods are repeated exactly as described in the published studies; and (b) the ffr models being treated are similar to, it not identical, to those tested in the study. • the impact of decontamination processes on other ffr performance factors other than particle penetration have yet to be fully explored. while particle penetration should be the most important factor to measure ffr penetration, more information is required about other factors such as filter air flow resistance, fit testing, the stability of physical components such as straps, as well as the impact of contamination on filter comfort and donning ease need to be studied in detail . a number of studies have included these ffr performance factors in their analyses , , , however, most only examine filter penetration. • willingness of hcws and administrators to adopt ffr decontamination and reuse. the most obvious concern arising from any discussion of filter decontamination is that the methods investigated all involve 'off-use' of government-regulated single use equipment. manufacturers of ffrs recommend that masks should be disposed of after a single use and that interference (e.g. cleaning) will disqualify the devices from use as filtering devices. approval by regulators for mask decontamination might also been seen as acknowledgement that administrators have failed to provide appropriate amounts of ppe to hcws. conversely, a recent survey by nemeth et al. showed that hcws hold significant concerns about the availability of ffrs during a highmortality pandemic event and that use of decontamination methods to support reuse of ffrs was seen favourably, as long as government agencies would provide approval to support their use. extensive training in ffr decontamination by hcws would need to be implemented after the development of standard operating procedures for this infection control procedure . an obvious limitation of this rapid review is that information was biased towards englishlanguage research articles published in scientific journals listed in the medline bibliographic database. other information on ffr decontamination may be available (e.g. 'grey' literature) and could be reviewed as part of a more systematic and comprehensive review on this topic at a later date. resource shortages through excessive demand and supply chain limitations have led to the need to consider reusing items normally regarded as single use. the lessons learned from this crisis may lead to a greater appreciation of the need for conservation of life-saving protective equipment. necessity is indeed the mother of invention, and we may learn that using less is beneficial in the developed as well as the developing world. rice cooker - % bactericidal to bacillus subtilis spores no significant differences in ffr particle filtration - microwave < % decrease in ffr particle penetration after three decontamination cycles - -> log tcid reduction in spiked influenza viral load no significant decrease in ffr particle filtration > log tcid reduction in spiked influenza viral load no significant decrease in ffr particle filtration > . % ms virus challenge decontamination efficiency oven / incubator < % decrease in ffr particle penetration after three decontamination cycles - -> log tcid reduction in spiked influenza viral load no significant decrease in ffr particle filtration > log tcid reduction in spiked influenza viral load rice cooker - % bactericidal to b. subtilis spores autoclave - % bactericidal to b. subtilis spores no significant decrease in ffr particle filtration - physical -irradiation uv-c < % decrease in ffr particle penetration after three decontamination cycles - no significant decrease in ffr particle filtration > log tcid reduction in spiked influenza viral load small decrease (< . %) in ffr particle filtration - no significant decrease in ffr particle filtration; measurable chlorine off-gassing - ethanol ( - %) - % bactericidal to b. subtilis spores decrease in ffr particle filtration - isopropanol ( %) decrease in ffr particle filtration - liquid hydrogen peroxide < % decrease in ffr particle penetration after three decontamination cycles - benzalkonium chloride wipes < % decrease in ffr particle penetration -> . % reduction in inoculated staphylococcus aureus inert wipes < % decrease in ffr particle penetration - % reduction in inoculated s. aureus bleach wipes < % decrease in ffr particle penetration > . % reduction in inoculated s. aureus ethylene oxide no significant decrease in ffr particle filtration - < % decrease in ffr particle penetration after three decontamination cycles - vaporised hydrogen peroxide / hydrogen peroxide gas plasma no significant decrease in ffr particle filtration - < % decrease in ffr particle penetration after three decontamination cycles - -> log reduction in spiked bacteriophage viral load > % decrease in ffr particle penetration after three decontamination cycles - considerations for recommending extended use and limited reuse of filtering facepiece respirators in health care settings guide to the selection and use of particulate respirators. centre for disease control and prevention hung ls the sars epidemic in hong kong: what lessons have we learned? evaluation of respiratory protection programs and practices in california hospitals during the - h n influenza pandemic potential demand for respirators and surgical masks during a hypothetical influenza pandemic in the united states shaffer re reaerosolization of ms bacteriophage from an n filtering facepiece respirator by simulated coughing transfer of bacteriophage ms and fluorescein from n filtering facepiece respirators to hands: measuring fomite potential wiwanitkit v face mask decontamination and reuse: is it ok? shaffer re evaluation of five decontamination methods for filtering facepiece respirators lin wy filter quality of electret masks in filtering . - nm aerosol particles: effects of five decontamination methods relative survival of bacillus subtilis spores loaded on filtering facepiece respirators after five decontamination methods shaffer re evaluation of multipe ( -cycle) decontamination processing for filtering facepiece respirators wander jd cleaning of filtering facepiece respirators contaminated with mucin and staphylococcus aureus a pandemic influenza preparedness study: use of energetic methods to decontaminate filtering facepiece respirators contaminated with h n aerosols and droplets hinrichs sh effectiveness of three decontamination treatments against influenza virus applied to filtering facepiece respirators ultraviolet germicidal irradiation of influenza-contaminated n filtering facepiece respirators shaffer re evaluation of microwave steam bags for the decontamination of filtering facepiece respirators effects of ultraviolet germicidal irradiation (uvgi) on n respirator filtration performance and structural integrity development of a test system to evaluate procedures for decontamination of respirators containing viral droplets reuseability of facemasks during an influenza pandemic epidemiology, pathogenesis, and control of covid- transmission of pandemic influenza a (h n ) virus among healthcare personnel-southern california respirator assessments to support the covid- response. . . niosh. determination of particulate filter efficiency level for n series filters against solid particulates for non-powered, air-purifying respirators standard testing procedure (stp) shaffer re evaluation of the survivability of ms viral aerosols deposited on filtering face piece respirator samples incorporating antimicrobial technologies pandemic influenza a (h n ) virus (ph n ) in surface survival studies on n filtering facepiece respirators wander j method for contamination of filtering facepiece respirators by deposition of ms viral aerosols impact of three biological decontamination methods on filtering facepiece respirator fit, odor, comfort, and donning ease infection control: the role of disinfection and sterilization taylor dr inactivation of the coronavirus that induces severe acute respiratory syndrome, sars-cov terminal sterilization of medical devices using vaporized hydrogen peroxide: a review of current methods and emerging opportunities hydrogen peroxide vapor sterilization of n respirators for reuse wander jd analysis of residual chemicals on filtering facepiece respirators after decontamination the problem of drinking water access: a review of disinfection technologies with an emphasis on solar treatment methods solar disinfection of viruses in polyethylene terephthalate bottles preparing for an influenza pandemic: hospital acceptance study of filtering facepiece respirator decontamination using ultraviolet germicidal irradiation disinfection of reusable elastomeric respirators by health care workers: a feasibility study and development of standard operating procedure we thank ethan polkinghorne for assistance in identifying and reviewing relevant literature and prof lyn gilbert for helpful discussions. key: cord- -z u d ec authors: shears, p. title: poverty and infection in the developing world: healthcare-related infections and infection control in the tropics date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: z u d ec in many hospitals serving the poorest communities of africa and other parts of the developing world, infection control activities are limited by poor infrastructure, overcrowding, inadequate hygiene and water supply, poorly functioning laboratory services and a shortage of trained staff. hospital transmission of communicable diseases, a high prevalence of human immunodeficiency virus and multidrug-resistant tuberculosis, lack of resources for isolation and disinfection, and widespread antimicrobial resistance create major risks for healthcare-related infections. few data exist on the prevalence or impact of these infections in such environments. there is a need for interventions to reduce the burden of healthcare-related infections in the tropics and to set up effective surveillance programmes to determine their impact. both the global (g ) international development summit of and the united nations millennium development goals (mdgs) have committed major resources to alleviating poverty and poor health in the developing world over the next decade. targeting resources specifically to infection control in low-resource settings must be a part of this effort, if the wider aims of the mdgs to improve healthcare are to be achieved. summary in many hospitals serving the poorest communities of africa and other parts of the developing world, infection control activities are limited by poor infrastructure, overcrowding, inadequate hygiene and water supply, poorly functioning laboratory services and a shortage of trained staff. hospital transmission of communicable diseases, a high prevalence of human immunodeficiency virus and multidrug-resistant tuberculosis, lack of resources for isolation and disinfection, and widespread antimicrobial resistance create major risks for healthcare-related infections. few data exist on the prevalence or impact of these infections in such environments. there is a need for interventions to reduce the burden of healthcare-related infections in the tropics and to set up effective surveillance programmes to determine their impact. both the global (g ) international development summit of and the united nations millennium development goals (mdgs) have committed major resources to alleviating poverty and poor health in the developing world over the next decade. targeting resources specifically to infection control in lowresource settings must be a part of this effort, if the wider aims of the mdgs to improve healthcare are to be achieved. ª the hospital infection society. published by elsevier ltd. all rights reserved. 'the widening gap between the developed countries and the poorest communities of the developing world has become a central issue of our time.' this is not a quote from the global (g ) international development summit of , or from international awareness events such as the live aid and live concerts e it is the opening sentence of the pearson report of , a commission set up by the world bank to investigate why, after a decade of 'development', little impact had been achieved for the poorest communities of the tropics. , in , the alma ata conference of the world health organization (who) stated as its aim 'health for all by '. a visit to a village affected by human immunodeficiency virus (hiv) and malaria in tropical africa, to a shanty town in south asia with inadequate water and sanitation ( figure ), or to a displaced community in southern somalia suffering from cholera, dysentery and rift valley fever, suggest that these aims are yet to be fulfilled. many medical journals are currently devoting part of their current issues to the themes of poverty and infection in the developing world, in recognition of the commitments made by the g summit and the united nations (un) millenium development goals (mdgs) to improve maternal healthcare, reduce childhood mortality and the impact of human immunodeficiency virus (hiv)/ acquired immunodeficiency syndrome (aids), malaria and other communicable diseases. if g and the un mdgs are to be catalysts for change, it will be necessary to look beyond international conferences and mission statements and to concentrate on specific objectives that can be implemented in resource-poor settings. from the viewpoint of hospital infection control, the concern is how hospital and healthcarerelated infections affect poorer communities of the developing world, and what can be done to begin to make a contribution to reducing the associated morbidity and mortality. a visit to a sub-saharan african country, where i had been looking at laboratory services and hospital infection control, left two particular memories. the first is the overwhelming disadvantages faced by health workers surrounded by hiv/aids, multidrug-resistant tuberculosis, overcrowding and lack of resources for the most basic of hygiene activities. the second is the impossibility of knowing the magnitude of hospital-related infections and optimum treatment strategies without effective laboratory services. these comments would certainly have been equally appropriate or years ago. might be a turning point? with the current emphasis of governments and un agencies to focus again on poverty and health, there is an opportunity to move healthcare-related infections, and the support required in terms of laboratory development, education, hospital infrastructure, and appropriate professional training, into a focused agenda, rather than the 'cinderella' position that has until now been the case. the ebola virus outbreak in southern sudan in was a vivid reminder of the potential magnitude of hospital-acquired infection in tropical africa. on august , a student from nzara presented to the local district hospital at maridi in equatoria province, southern sudan, suffering from a severe febrile disease. he died a week later. over the next week, a nurse, a cleaner, and a hospital messenger became unwell, and then further medical and auxiliary staff. by the time a ministry of health/who team arrived in maridi approximately six weeks after the first case, one of the two doctors in the hospital had been infected and died, all six of the medical assistants had been infected and five had died, and twenty student nurses had died. further spread and deaths occurred until the impact of basic infection control strategies, involving gloves, gowns and masks for healthcare workers, and hygienic measures in dealing with body fluids and the deceased, brought the outbreak to an end. while the maridi ebola outbreak was an extreme case, it emphasised that the priorities for healthcare-associated infection control in the tropics, particularly away from tertiary or university hospitals in capital cities, cannot be a simple translation of expertise from the west. while limited systematic data exist on the overall patterns and prevalence of infection, experience from the field, and a review of available literature, indicate that the following are the major groups of infection control areas: since the outbreaks in sudan and zaire (now democratic republic of the congo, drc), nosocomial transmission of ebola virus has been reported in drc (kikwit), uganda, and probable cases in gabon and sudan. nosocomial transmission of other viral haemorrhagic fevers has included lassa fever in nigeria, and marburg haemorrhagic fever in angola. e prevention of transmission is difficult in resource-limited settings, with no total protective clothing or isolation facilities available. specific guidelines for control in district hospitals have been drawn up by who, and these cover issues including patient isolation, locally produced protective clothing, waste disposal, disinfectants, and community education. early diagnosis of the first cases, often in the community or peripheral health centres, is the mainstay of ensuring that preventive measures are initiated in a timely fashion and that transmission is kept to a minimum. if severe acute respiratory syndrome, pandemic influenza or h n avian flu were to become pathogens in these underresourced tropical areas, the pattern of the ebola outbreaks could be repeated. in any hospital infection control programme in much of africa, and large parts of asia and latin america, prevention of the spread of hiv, between patients, from patients to health workers, and from health workers to patients, is a priority. largely due to the un and who global aids programme, there is considerable literature and guidance available. at the level of the individual, poorly resourced hospital with limited reuseable equipment and disinfectants, hiv is a major concern for all health workers and local health education and support programmes have been shown to be effective. with the rise in hiv, there has been an increasing prevalence of tuberculosis, both in hiv-affected patients but also in the wider community, and in many areas an increasing prevalence of multidrug-resistant tuberculosis (mdrtb). this poses a risk for nosocomial transmission between patients, but particularly for health workers who will have direct contact, often with undiagnosed cases, and with less than adequate protective clothing. there are likely to be few rural hospitals in africa with a supply of pfr masks. the strict barrier precautions described by uk and centers for disease control and prevention (cdc) guidelines are unlikely to be practicable and workers dealing with these issues daily have developed more appropriate strategies. nosocomial spread of other communicable disease where hospital hygiene is limited, and wards are crowded, the risk of transmission of communicable disease is high. the source may be an inadequately isolated index case, relatives who are staying in the hospital to provide food and general care for patients, or contaminated food or water in the hospital. although from observation such transmission must occur, few such episodes have been recorded. nosocomial outbreaks of cholera have been published from tanzania and mozambique and these reports suggest that outbreaks of other faecal-oral infections, particularly shigellosis, typhoid and hepatitis a and e, must also occur. , other reported hospital communicable disease outbreaks have included measles and non-typhoidal salmonellae. , for communicable diseases in the tropics, the boundary between hospital and community infection is blurred. among relatives camping within the hospital compound, there may be a case of undiagnosed tuberculosis? is the infected person part of the community or part of the hospital? this distinction between public health and healthcare-related infection is particularly complex in the setting of refugee camps. , direct hospital acquired infections studies of surgical and other hospital-related infections have been published from several countries in africa, including kenya, nigeria, tanzania, ethiopia and burkina faso. e these studies show a similar pattern of pathogens that are seen globally; staphylococci, enterobacteriaceae and pseudomonas spp., with high levels of antimicrobial resistance and a high and somewhat arbitrary use of antimicrobials. the studies are necessarily selective e only those hospitals in which there is a functioning microbiology laboratory, and which have sufficient staff, can undertake such work. in addition, with limited laboratory facilities, only the more easily culturable bacteria may be isolated and the results may give only a partial picture of the true prevalence and antimicrobial resistance patterns of pathogens. in situations where more sophisticated microbiological studies have been undertaken in two particular non-western environments e the tsunami area of south east asia and repatriated combatants from afghanistan e unusual and multiply resistant isolates have been found. , occurrence of multi-resistant bacterial pathogens a common theme in all published studies of hospital infections in the tropics is the high prevalence of antimicrobial-resistant bacterial pathogens. this raises one of the major areas of concern. in terms of hygiene facilities, crowding and laboratory support, many hospitals in the tropics are like those of the 'pre-penicillin era', yet within them are the multi-resistant bacteria of the twenty-first century. data in many areas are limited or non-existent, but, where surveys have been done, meticillin-resistant staphylococcus aureus and extended-spectrum b-lactamase-producing and other multi-resistant gram-negative bacteria have been shown to be widely disseminated. e the problem is compounded as antimicrobials, including quinolones and third-generation cephalosporins, are available without prescription, many areas have no laboratory facilities to provide accurate susceptibility data, and, despite several past attempts, there are no functioning international resistance surveillance programmes. , hospital infrastructure and facilities the 'catalogue of disadvantage' for a rural district hospital in africa demonstrates the commitment of local staff in providing even the most basic services (figure ). the catalogue includes: poor building infrastructure, inadequate water supply, electricity for perhaps only a few hours a day, overcrowded wards with patients lying on the floor as well as on beds, lack of resources for cleaning the environment, beds or equipment, often an absence of soap, and remoteness from regional centres or the capital city. maridi, the hospital of the ebola outbreak in southern sudan, is km from khartoum, with a road link not possible for three months in the rainy season. this situation is compounded by civil strife in the democratic republic of congo, southern somalia or darfur, for example, where hospitals may have influxes of patients with both infected injuries and communicable diseases. , as patients with communicable diseases are admitted from crowded refugee camps, they may become the index cases for further spread within the hospital if infection control facilities are overstretched (figure ). there is no director of infection prevention and control in an african rural district hospital. nor is there usually a dedicated infection control nurse, almost certainly not a clinical microbiologist, and rarely clinicians with sufficient time to work with the laboratory staff. there have been developments in training personnel specifically to work in infection control in larger hospitals, those supported in some way by outside agencies, and in teaching hospitals in larger cities. most published work on training for infection control has been from south africa, with an understandable emphasis on hiv transmission, but many hospitals will have developed local, basic policies. the requirements to improve hospital infection control in the tropics have been considered in a number of valuable papers. e the key areas that have been identified include the following: e setting up national and regional infection control networks. many of these will only occur when there are the resources for major economic change and that is why it is necessary to consider poverty reduction, institutional as well as individual, rather than to focus on improving infection control as simply a 'health' or 'medical' problem. whether g or the mdgs for can achieve this poverty reduction remains to be seen. past experience of the pearson commission and health for all by suggests that targets alone, without addressing the fundamental causes of poverty or ill health, need to be handled with care. in the mean time, what can be done to assist the improvement of infection control in resource-poor settings? local health workers themselves are the most likely to achieve progress. the resources for hiv infection control that are part of the global aids programme represent one means for local improvement. the main who strategy to improve infection control internationally is the global patient safety challenge. this has involved many meetings and recommendations, but whether these will have a significant impact in resource-poor, tropical settings has yet to be seen. however, the initiative may give support to policy-makers in giving a priority to infection control. certainly, links that have been established between hospitals in the uk and individual hospitals in africa can provide muchneeded resources, can share expertise and provide training opportunities. the existence of the internet has in many ways revolutionised the ability of even remote hospitals to acquire information, to download who or cdc guidelines, to communicate with distant colleagues, and in some situations to be part of a telemedicine network. such initiatives include the raft network in francophone africa (réseau en afrique francophone pour la télémédicine) and the who health initiative for access to research information (hinari) programme. , if the aim of an internetlinked computer in every village in africa or asia or latin america, or at least in hospitals in those areas is to be achieved, there are practical issues of connectivity and band width that have to be faced. providing laptop computers without adequate connectivity and support will not be productive. efficient internet links will enable very real possibilities of support between hospitals in the uk and rural tropical hospitals. the absence of effective laboratory services at district hospital level is a major impediment to the long-term control of hospital-associated infections. unless the causative pathogens can be identified, and where appropriate the antimicrobial susceptibilities determined, there is a considerable risk that multiply resistant bacteria will become the dominant pathogens, with few antimicrobials available for treatment. within the mdgs, no specific mention is made of infection control or laboratories; without these, we cannot achieve the three specific health goals of: (i) improving maternal health, (ii) reducing child mortality and (iii) tackling aids, malaria and other communicable diseases. healthcare-associated infections have been near the top of the political agenda in the uk, resulting in increased funding and commitment for change. for the developing world the same priority is required if the aims of g and the mdgs are to be approached. the g and global health: what now? what next? partners in development: report of the commission on international development achieving the millennium development goals report of a who/international study team ebola outbreak in kikwit, democratic republic of the congo: discovery and control measures outbreak of ebola hemorrhagic fever uganda review of cases of lassa fever in nigeria: the high price of poor medical practice lessons from nosocomial haemorrhagic fever outbreaks centers for disease control and prevention and world health organisation. infection control for viral haemorrhagic fevers in the african health care setting the joint united nations programme on hiv/aids. project update self reported infection control practices and perceptions of hiv/aids risk amongst emergency department nurses in botswana tuberculosis infection among health care workers in kampala, uganda practical and affordable measures for the protection of health care workers from tuberculosis in low income countries hospital outbreaks of cholera transmitted through close person to person contact a hospital outbreak of cholera in maputo nosocomial outbreaks e a potential threat to the elimination of measles? nosocomial outbreak of neonatal salmonella enteritidis in a rural hospital in northern tanzania epidemiological assessment of health and nutrition of ethiopian refugees in emergency camps in sudan communicable diseases in complex emergencies: impact and challenges nosocomial infections at kenyatta national hospital intensive care unit in aerobic bacterial nosocomial infections in paediatric surgical patients at a tertiary health institution in lagos risk factors for surgical site infections in a tanzanian hospital: a challenge for the traditional national nosocomial infections surveillance system index wound infection in tikur anbessa hospital surgical department survey of nosocomial infection prevalence on the surgery department of the central national hospital of ouagadougou rare bacteria species found in wounds of tsunami patients. gram negative bacteria from patients seeking medical advice in stockholm after the tsunami catastrophe multidrug resistant acinetobacter extremity infections in soldiers first report of mrsa from hospitalised patients in sudan staphylococcus aureus bacteraemia in the dakar fann university hospital nasal carriage of meticillin resistant staphylococcus aureus among health care personnel in abidjan (cote d'ivoire) extended spectrum beta lactamases among gram negative bacteria of nosocomial origin from an intensive care unit of a tertiary health facility in tanzania occurrence of extended spectrum beta lactamase enzymes in clinical isolates of klebsiella species from harar region, eastern ethiopia surveillance of antimicrobial resistance at a tertiary hospital in tanzania surveillance of antimicrobial resistance: the whonet programme burden of injury during the complex emergency in northern uganda the disease profile of poverty: morbidity and mortality in northern uganda in the context of war, population displacement and hiv-aids south african health service must strengthen infection control measures infection control in africa south of the sahara nosocomial infections in developing countries: cost effective control and prevention risk of nosocomial infection in tropical africa countdown to : will the millenium development goal for child survival be met? clean care is safer care'; the global patient safety challenge the raft network: years of distance continuing medical education and teleconsultations over the internet in french speaking africa who's health internetwork access to research initiative (hinari) access to electronic health knowledge in five african countries: a descriptive study none declared. none. key: cord- -k qzb authors: shalhoub, s.; abdraboh, s.; palma, r.; alsharif, h.; assiri, n. title: mers-cov in a healthcare worker in jeddah, saudi arabia: an index case investigation date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: k qzb in september , a confirmed case of middle east respiratory syndrome (mers) was diagnosed in a healthcare worker in jeddah, saudi arabia. given the absence of confirmed mers cases in jeddah at the time, an epidemiological index case investigation took place. the investigation identified a probable source of an index case who had been in hospital in jordan in august while there was an ongoing mers outbreak and who then subsequently sought medical care in jeddah. since the discovery of the middle east respiratory syndrome coronavirus (mers-cov) in , saudi arabia has faced several mers outbreaks in both hospitals and communities. e the most recent outbreak has been in riyadh. on september th, , a laboratory-confirmed mers case was diagnosed in a tertiary care hospital in jeddah. this report describes the index case investigation that took place. king fahad armed forces hospital is a -bed tertiary care hospital that serves military personnel, their families, and other community members in the western region of saudi arabia. there are beds in the emergency department (ed) where admitted medical patients sometimes have extended stays due to bed limitations in the medical ward. patients nursed by patient a (a nurse) were identified using ed records and those who remained in hospital were screened for mers-cov. diagnosis of mers was confirmed in the same centre where the investigation took place using a reverse transcriptionepolymerase chain reaction (pcr) diagnostic kit (mers-coronavirus emc orf a and sa upstream e-gene, light mix modular assays; roche, mannheim, germany). results were obtained within e h. patient a was a -year-old nurse, with no significant medical history, who worked in the ed of a tertiary care hospital. she travelled back from a -day-long vacation in the philippines on august th, , and worked three ed shifts on august th, st, and september st. patient a exhibited fever and dry cough on september th. she sought medical advice in the ed, she was initially given antipyretics, and she was thought to have a transient viral upper respiratory tract infection. chest x-ray initially revealed no infiltrates. she was later referred to an internal medicine clinic on september th and was discharged home on antipyretic medications. she was admitted to the hospital on september th with fever and epistaxis. her laboratory investigations revealed a reduced white blood cell count of .  /l and platelet counts of  /l, and she was therefore admitted with a provisional diagnosis of dengue fever. chest radiography revealed lobar infiltrates, and, due to a working diagnosis of viral pneumonia, she was placed in a negative pressure isolation room in ed. two nasopharyngeal swab (np) samples taken for mers-cov reverse transcriptionepolymerase chain reaction (rtepcr) were negative. a subsequent sputum sample obtained on september th tested positive for mers-cov. due to lack of vacant beds in the medical unit, initially patient a remained in the ed in a neutral room for h, and was later transferred to a negative pressure isolation room. once the mers-cov diagnosis was confirmed, patient a was moved to a negative pressure isolation room in the intensive care unit (icu). both rooms in the ed were terminally disinfected. infection control measures were taken as follows: all patients present in ed on the day of patient a's diagnosis were screened for mers-cov using lower respiratory tract samples or np samples using rtepcr. contacts of patient a were divided between close contacts (defined as unprotected exposure within a . m distance for > min) or non-close contacts through personal interviews by infection control practitioners. fifteen nurses (including one room-mate and two flat mates) and five physicians were deemed to be close contacts. all were asymptomatic and screening np samples were negative for mers-cov. they were monitored for symptoms for days from the last day of unprotected exposure. the patients nursed by patient a prior to the onset of her illness on august th, st, and september st were identified as follows: two patients in icu on mechanical ventilators, one patient in main icu on mechanical ventilator, three patients in ed [one in c bay, one in b bay (patient b) on a mechanical ventilator and one in code room ] (figure ), three deceased patients (all deceased patients had been taken for burial), one patient in medical ward ii, and five discharged patients. the discharged patients were contacted; three tested negative and the remaining two had no symptoms and remained well for days after the last day of exposure. two tracheal aspirate samples from the ventilated patients and two sputum samples from non-ventilated patients were tested for mers-cov rtepcr. initial np samples taken from patient b on september th and th tested negative for mers-cov. a tracheal aspirate sample obtained on september th tested positive for mers-cov. patient b was a -year-old woman, with a background of diabetes mellitus and right lower limb ischaemia. she was admitted on august th with shortness of breath and right foot gangrene. the patient had travelled to amman, jordan for femoralepopliteal artery bypass surgery on august th due to right lower limb ischaemia. on admission, the patient required oxygen l/min through nasal prongs. examination findings included a conscious patient with a temperature of . c, infected right groin wound and a right gangrenous foot. respiratory tract examination revealed coarse crackles at lung bases. screening for mers-cov on september nd through rtepcr using np swab was negative and the patient was not producing any sputum. her fever resolved on september th following treatment with broad-spectrum antibiotics for the infected groin wound and a urinary tract infection. however, due to respiratory failure and increased oxygen requirements she required endotracheal intubation and mechanical ventilation on september th. a tracheal aspirate sample obtained after intubation tested mers-cov rtepcr positive on september th. case b was initially admitted for three days to the critical care area (code room) in the ed. she was then moved to the holding bay for three days and finally to b bay (figure ). names and medical record numbers of patients who had been admitted to these areas on the same days were collected. of those, remained in the hospital and were screened for mers-cov using a minimum of two samples including tracheal aspirates, sputum, or, if neither unavailable, np swabs. patients who had fever, cough, leucopenia, hypo-oxygenation or infiltrates on chest x-ray were considered highly suspected mers-cov cases and were therefore moved to negative pressure isolation rooms while screening was undertaken. highly suspected mers-cov cases were kept in negative pressure isolation rooms until there were three negative respiratory samples from three consecutive days. a total of patients were screened. a patient who died an hour after confirmation of the mers-cov diagnosis in patient b was screened for mers-cov using a tracheal aspirate sample, and tested negative, before the body was released for burial. patients who had been discharged were contacted and symptoms elicited. screening for mers-cov with rtepcr was done at least once if symptoms were absent, and more frequently in the presence of symptoms. as of october th, , a total of contacts had been screened for mers-cov rtepcr, of whom were close contacts of case b (i.e. exposure for > min at a distance of < . m), including five nurses, four physicians, and two respiratory therapists. all screened contacts were negative. patient a had not worn personal protective equipment when nursing for patient b because at the time of admission to ed, patient b was not suspected of having mers-cov infection. however, patient a reported complying with good hand hygiene practice. patient a recovered with no complications. she resumed working in the ed two weeks after recovery. patient b was transferred to a designated hospital to manage confirmed mers cases and was then transferred back to the primary hospital after being cleared for mers-cov. she was kept in isolation until clearance of mers-cov was confirmed. however, the patient later died due to complications related to her underlying illnesses. transmission of respiratory viral infections across countries has been described in several reports. , there have been no recent mers-cov cases reported in the philippines; it was assumed that the nurse had contracted the infection from one of the patients she attended to during her shifts between august th and september st. based on that assumption, an index case investigation was carried out. the systematic screening of contacts to confirmed mers cases is in line with saudi arabian ministry of health recommendations. the city of amman had been experiencing a nosocomial outbreak of mers-cov where patient b was admitted for the femoralepopliteal bypass. she had no history of travelling to any other city in saudi arabia that had been dealing with mers-cov cases. the patient's diagnosis was probably delayed due to an initial negative mers-cov np swab sample, which was obtained because the patient had no cough and was unable to produce sputum. following admission and negative np result, infection control precautions were lifted because the patient's main complaint was an infected gangrenous foot with minimal respiratory symptoms and oxygen requirements. however, had the link between recent hospitalization of the patient in jordan and the mers-cov outbreak in jordan been noticed, more than one sample would have been obtained prior to lifting isolation precautions. moreover, patients who are highly suspected to have mers-cov infections are screened at least twice from sputum or tracheal aspirate samples, or, if unavailable, three times from np samples due to previously reported reduced sensitivity of np samples compared with lower respiratory tract samples. , it was only after intubation that tracheal aspirate samples were obtained, testing positive for mers-cov. case b was cared for by a number of health professionals and it remains unclear why only one nurse became infected with mers-cov. case a was in contact with case b during a h shift on august th, and performed standard nursing care that included inserting a peripheral intravenous access, taking vital signs, accompanying the patient to the radiology department and inserting a urinary catheter. case a was a smoker but had no known medical comorbidities. in conclusion, although transmission of mers-cov from saudi arabia to other countries has been reported before, this article describes the importation of mers-cov from a neighbouring country. we have highlighted the importance of detailed history-taking, especially an epidemiological history. moreover, maintaining a high index of suspicion to ensure the correct identification of all suspected cases and the strict employment of infection control measures remain crucial in preventing spread of mers-cov. isolation of a novel coronavirus from a man with pneumonia in saudi arabia hospital outbreak of middle east respiratory syndrome coronavirus mers-cov outbreak in jeddah e a link to health care facilities ministry of health. command and control center. press releases. statistics. available at infection prevention and control guidelines for middle east respiratory syndrome coronavirus (mers-cov) infection preliminary epidemiological assessment of mers-cov outbreak in south korea first cases of middle east respiratory syndrome coronavirus (mers-cov) infections in france, investigations and implications for the prevention of human-to-human transmission saudi arabia, jordan, who. archive number: . . october . : : . international society for infectious diseases ifn-alpha a or ifn-beta a in combination with ribavirin to treat middle east respiratory syndrome coronavirus pneumonia: a retrospective study respiratory tract samples, viral load, and genome fraction yield in patients with middle east respiratory syndrome the authors would like to thank d. abu al saod, s. fallatah, and a. jamal for their excellent technical assistance with processing and running the samples. none declared. none. key: cord- - oextxkm authors: feng tan, l.i. title: preventing the transmission of covid- amongst healthcare workers date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: oextxkm nan to date, no healthcare worker has contracted covid- in a singapore healthcare institution. however, healthcare workers including non-clinical staff have contracted covid- in the community and from overseas travel . whilst some had continued working for a short period prior to diagnosis, thus far there have been no cases of healthcare worker-to-patient covid-sars which was predominantly transmitted nosocomially in singapore , covid- is predominantly acquired in the community. this presents a different challenge to preventing covid- infection in healthcare workers. in singapore, we have put in place strict staff management policies that have progressed as the infection continues its spread worldwide. all staff with travel to affected regions are placed on a -day compulsory leave of absence with overseas travel strongly discouraged as the infection has now spread across the globe. twice daily temperature screening and reporting are carried out on all clinical and nonclinical staff. all staff with respiratory symptoms are not allowed to come to work and placed on mandatory -day medical leave or longer till symptoms completely resolve . separation of teams into those who care for covid- patients and those who do not as well as designated clean and covid- contact areas are carried out in order to minimise exposure risk to staff and patients. whilst some countries have achieved some initial control of the spread of covid- through various measures, a second wave of infections is already being seen from imported cases as covid- spreads throughout the world . it appears covid- may be here for the long haul and countries need to continue to exercise heightened vigilance and adapt strategies to continue to contain the virus and especially to prevent its spread within the hospital and amongst healthcare staff. none. funding sources reasons for healthcare workers becoming infected with novel coronavirus disease (covid- ) in china beyond the assistance: additional exposure situations to covid- for healthcare workers report on current pneumonia epidemic situation in the city (in chinese) sars in singapore--key lessons from an epidemic key: cord- -kngf qpe authors: chan, kwok-hung; sridhar, siddharth; zhang, ricky ruiqi; chu, hin; fung, agnes yim-fong; chan, gabriella; chan, jasper fuk-woo; to, kelvin kai-wang; hung, ivan fan-ngai; cheng, vincent chi-chung; yuen, kwok-yung title: factors affecting stability and infectivity of sars-cov- date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: kngf qpe background: in late , a novel human coronavirus, sars-cov- , emerged in wuhan, china. this virus has caused a global pandemic involving more than countries. sars-cov- is highly adapted to humans and readily transmits from person-to-person. aim: the aim of this study was to investigate the infectivity of sars-cov- under various environmental factors, disinfectants and different ph conditions. the efficacy of a variety of laboratory virus inactivation methods and home disinfectants against sars-cov- were investigated. methods: the residual virus in dried form or in solution was titrated on vero e cell line at day , , , , and after incubation at different temperatures. the viability of virus was determined after treatment with different disinfectants and ph solutions at room temperature ( ∼ (o)c). findings: sars-cov- was able to retain viability for - days in dried form or days in solution at room temperature. sars-cov- could be detected under a wide range of ph conditions from ph to ph for several days and to days in stool at room temperature but lost logs of infectivity. a variety of commonly used disinfectants and laboratory inactivation procedures were found to reduce viral viability effectively. conclusion: this study demonstrates the stability of sars-cov- on environmental surfaces and raises the possibility of faecal-oral transmission. commonly used fixatives, nucleic acid extraction methods and heat inactivation were found to significantly reduce viral infectivity that could ensure hospital and laboratory safety during the covid- pandemic. ten µl of virus (sars-cov- , . tcid /ml; sars-cov- , tcid /ml) was placed on a glass slide within a shell vial, kept at room temperature ( ~ o c and relative humidity of %) and allowed to dry according to our previous study with slight modifications ( ). one hundred microliters of mem were used to re-suspend the virus for , , , , and days after viral transport medium with different ph from to using m and m hcl or n and n naoh were prepared as described ( ). one hundred microliters of sars-cov- with . tcid /ml was added into each bottles of . ml vtm and incubated at room temperature ( - o c). all the tests were done in triplicates. the viability of virus was tested on day , day and day . on each testing day, the ph of the vtm bottles were neutralized to ph and viral titre was measured using the tcid assay ( ). an untreated virus stock solution as the viral load for the positive control was included. thirty microlitres of sars-cov- ( . tcid /ml) and µl of various disinfectants were mixed and incubated at room temperature (table ) thirty microlitres of sars-cov- ( . tcid /ml) and µl of fbs were mixed and incubated at °c for min. then, the residual infectivity of the virus was determined by tcid assay as described above. the test was set up in triplicates. when sars-cov- was added in vtm with ph ranging from to , the virus remained viable up to days but lost between . and . logs of infectivity from ph to ph and up to ~ days in ph and ph ( table ) . the virus lost infectivity within day at ph extremes (ph ~ and ph ~ ). the virus lost . logs of infectivity in stool over a -day period. laboratory or domestic disinfectants, including two commonly used as a lysis buffer for nucleic acid extraction, were tested for their effects on sars-cov- on vero e (table ) . due to the cytotoxicity of certain disinfectants, detection limit of inactivation had been found all tests were neutralized before testing and was set up in triplicates. negative ( . ± . ) negative ( . ± . ) nd untreated virus stock solution as the viral load for the positive control all tests were neutralized before testing and conducted in triplicates key: cord- -ocrhgoba authors: chen, v.; long, k.; woodburn, e.v. title: when weighing universal precautions, filtration efficiency is not universal date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: ocrhgoba nan interest in homemade face masks for personal use and hospital donation has surged in the past month due to ppe shortages and updated cdc guidelines for public use. though existing studies show low filtration efficiency of certain homemade mask materials [ ] , this does not diminish the potential usefulness of homemade masks in combating the covid- pandemic. most existing studies investigate masks made of cotton, but there are many promising materials that have not been formally tested, ranging from medical textiles like surgical wrap to consumer goods like non-woven polypropylene shopping bags. these materials have piqued interest in engineering communities due to their similarity to existing mask textiles. because many of the properties that contribute to an effective mask, such as diffusion characteristics and electrostatic forces, are not routinely measured in alternative materials, particulate filtration efficiency (pfe) testing is necessary to determine which are most suitable for constructing masks. recently, a widely circulated story claimed that sterilization wrap, which boasts a filtration efficiency of %, could be used to make masks more effective than n s. this innovation was publicized in the media before it was noted that the % efficiency of the surgical wrap refers to a measure called the bacterial filtration efficiency (bfe), and thus could not be meaningfully compared with n masks that are tested on their ability to remove much smaller particles. this confusion stems, in part, from the variety of metrics that the fda accepts to prove filtration efficiency. the most common metric comes from a testing procedure developed by niosh, where uncharged nacl particles . microns in diameter are sent through the test filter at a rate of l/min. this method uses smaller particles and a higher flow rate than what is typically encountered in medical settings, therefore giving a conservative estimate of filtration efficiency [ ] . other fda-recognized filtration tests measure pfe, bfe, and viral filtration efficiency (vfe) using transmission of . micron polystyrene latex particles, s. aureus or e. coli, and the phix virus, respectively [ ] . because each method uses different sized particles to test filtration, the significance of different metrics varies greatly and meaningful conclusions cannot be drawn by comparing, say, a standalone bfe to an n efficiency. understanding the distinction between various filtration metrics is crucial for physicians and other decision-makers so they can accurately interpret study results on alternative mask materials and translate them into much-needed recommendations for their communities. testing the efficacy of homemade masks: would they protect in an influenza pandemic a comparison of facemask and respirator filtration test methods surgical masks-premarket notification [ (k)] submissions. guidance for industry and fda key: cord- -wowihqea authors: tang, j.w.; eames, i.; li, y.; taha, y.a.; wilson, p.; bellingan, g.; ward, k.n.; breuer, j. title: door-opening motion can potentially lead to a transient breakdown in negative-pressure isolation conditions: the importance of vorticity and buoyancy airflows date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: wowihqea a patient with severe chickenpox was admitted to a negative-pressure isolation room. he remained sedated, intubated and mechanically ventilated throughout his admission. he was managed only by nurses immune to chickenpox. a non-immune male nurse occasionally handed equipment through the doorway, without entering the room. ten days later, he also developed chickenpox. sequencing of viruses from the patient and nurse showed the same rare genotype, indicating nosocomial transmission. an experimental model demonstrated that, despite negative pressure, opening the door could have resulted in transport of infectious air out of the isolation room, leading to a breakdown in isolation conditions. door-opening motion can potentially lead to a transient breakdown in negative-pressure isolation conditions: the importance of vorticity and buoyancy airflows introduction this paper describes a case of hospital-acquired chickenpox in a medical intensive care unit (icu), despite negative-pressure isolation. it suggests a possible route of aerosol transmission using a -year-old caucasian man was admitted to the icu with a four-day history of severe haemorrhagic chickenpox with pneumonitis. the patient was nursed using respiratory isolation measures in a negative-pressure single room. he remained sedated, intubated and mechanically ventilated throughout his stay. all respiratory care was performed using a closed-suction system with no recorded breaks in his closed-airway system. to keep the patient warm, a bair hugger blanket was used. only staff with a history of chickenpox were allowed to enter the room. despite full icu support and intravenous aciclovir - mg/kg every h, the patient died of multi-organ failure. ten days after admission of the patient, a male icu nurse developed chickenpox. this nurse gave no other history of contact with chickenpox. he was known to be seronegative for varicella zoster virus (vzv) and had therefore not been allocated to this patient's care. however, the nurse did admit that several times a day he would spend up to min handing equipment through the door to colleagues attending this patient inside the isolation room. during this activity, the nurse wore no personal protective equipment (i.e. no gloves, mask or apron). the doorway of the patient's isolation room was approximately m from the patient's bed. the patient's room was at a negative pressure of approximately pa (pascals), and underwent eight total air changes/h. the hinged door opened into the isolation room. vesicle swabs were taken from the skin of the patient and the nurse during the time of their chickenpox rash. deoxyribonucleic acid (dna) from vesicle swabs was extracted using qiamp w dna mini kit (qiagen ltd, crowley, uk) according to the manufacturer's instructions. viruses were genotyped using single nucleotide polymorphism (snp) and r published methods. initially, a total of snps were used to determine the genotype (a-c). then a dna fragment, comprising vzv r variable region, was amplified and directly sequenced in a geneamp polymerase chain reaction machine. viral dna sequences were analysed using bioedit v . . and chromas software. to test the hypothesis of airborne transmission experimentally, a water tank was built with food dye to simulate infectious aerosols in an isolation room. this tank was constructed to simulate the flow of air across a full-size doorway, with an inward-opening door, by using water to simulate air in a scaled-down model using the principle of reynolds number equivalence, where water can be used to simulate air (the reynolds number is a dimensionless number equal to the ratio of inertial to viscous forces where fluids, i.e. gases or liquids, are in motion). the motions of the door and food shows how the dye has moved (long arrow) when the door (short arrow) has stopped opening (tz . s). transport of the dye into the adjacent room is shown in (c) (tz . s). dye were captured on video camera with a time scale (figure ). vzv was cultured from both the patient's and the nurse's vesicular fluid. no other pathogens were identified. typing of viruses from both sources showed vzv genotype a (centers for disease control and prevention m type). the r variable region length and pattern of nucleotide repeats were identical in the two isolates. from analysis of the video footage of the model water tank (figure ) , it can be seen that after the door was opened to about [ figure genotype a is found in fewer than % of strains circulating in the uk. the r region comprises variable numbers of nucleotide repeats and is highly polymorphic. these r sequences in the patient and the nurse were identical. these results therefore indicate nosocomial transmission of vzv from the patient to the nurse. the simple water tank and food dye model shows that movement of air from opening the door could have resulted in the exposure of the susceptible nurse to airborne vzv from the patient in the isolation room ( figure ). although the negativepressure system inside the isolation room would have acted to reduce the movement of infectious air from inside to outside across the open doorway, the negative-pressure gradient may have been transiently reversed if the door-opening motion was too rapid. such behaviour of airflows across open doorways has been well described, and depends on the temperature and density of the air, the velocity of door opening, and the angle to which the door is opened. based on these principles, figure showing a three-dimensional view of possible airflow trajectories induced by the movement of the door opening into a hypothetical isolation room. the red (dark) face represents a person entering the room, through the doorway, who may be exposed to infectious air. (c) same view from inside the room as illustrated in (b), but this time showing the possible airflow trajectories taking into account the temperature and density differences between cooler air outside (in the corridor) and warmer air inside a hypothetical isolation room. at the doorway itself, differences in air temperature and density with height are marked by the faces: red (dark) face, head height; blue (light) face, just above the floor. inside (red, dark arrows) circulating around the open door are present. thus, a person (represented by the red dark face) walking into this area of air circulation would be exposed to and may inhale infectious air emerging from the isolation room. the negative-pressure gradient may also have been transiently reversed if the temperature gradient across the doorway was too steep. figure (c) shows that if a temperature gradient existed between the warm air inside the room and the cooler air outside, this would have created a 'two-way buoyancy flow'. this would have encouraged the warm air to rise as it flowed out of the room (red, dark arrows), while cool air from the corridor flowed in at floor level (blue, light arrows). this potentially increased the exposure of the nurse to infected room air (as shown by the red, dark arrows) leaving the room at head level (as shown by the red, dark face). in this case report, the hinged door opened into the patient's isolation room, which was at a negative pressure of approximately pa. although previous guidelines of the centers for disease control and prevention required a minimum of . pa of negative pressure, this requirement has been replaced by the american institute of architects' guidelines that recommend a minimum of . pa of negative pressure. in the uk, a recent recommendation by the national health service estates agency has adopted a slightly different approach. instead of a negative pressure in the isolation room, the outside corridor pressure will be at a positive pressure of pa. this will have a similar aerosol containment effect but it is likely to be more effective at this higher pressure difference. aerosolized vzv dna has been detected in the environment around patients with varicella and shingles, and the nosocomial transmission of vzv via aerosol is well established. , therefore, there is a distinct possibility that despite the negative pressure inside the room, transmission of vzv may have occurred via infectious aerosol as the nurse stood at the door. in summary, we report a case of nosocomial transmission of vzv to a nurse that may have occurred via aerosol transmission, despite negative-pressure isolation of the infected patient. other infectious agents, such as severe acute respiratory syndrome and tuberculosis, are also transmitted by aerosol and may pose a similar risk. sliding rather than hinged doors (with an airlocklike arrangement) or an anteroom at the entrance would reduce airflow perturbation caused by staff entering the isolation room through the door. this cross-infection incident should not be taken as a warning that all existing negative-pressure rooms will inevitably fail. however, care should be taken in reducing adverse airflow and bidirectional flow through a doorway when the door is open. thus, this case report recommends that susceptible personnel should not stand at the entrances of isolation rooms containing patients with respiratory infections since, despite negative pressure, nosocomial transmission via an airborne route may still be possible. investigation of varicella-zoster virus variation by heteroduplex mobility assay an introduction to fluid dynamics combining door swing pumping with density driven flow guidelines for preventing the transmission of mycobacterium tuberculosis in health-care facilities new ventilation guidelines for healthcare facilities health building note (hbn) . in-patient accommodation: options for choice. supplement . isolation facilities in acute settings. uk: national health service estates airborne transmission of chickenpox in a hospital detection of varicella-zoster dna in air samples from hospital rooms evidence of airborne transmission of the severe acute respiratory syndrome virus cough-generated aerosols of mycobacterium tuberculosis: a new method to study infectiousness our special thanks to the icu staff nurse for his permission and co-operation in the writing of this report. key: cord- -a qbiyd authors: bae, suyeon title: the ways in which healthcare interior environments are associated with perception of safety from infectious diseases and coping behaviours date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: a qbiyd background: global pandemic outbreaks often have people fear. healthcare personnel (hcp), especially those fighting the pathogens at the front lines, encounter a higher risk of being infected, while they treat patients. in addition, a variety of environmental fomites in hospitals, which may contain infectious agents, can post a high risk of getting infectious diseases. aim: making hcp feel safe from infectious diseases is critical to delivering the best healthcare practice. therefore, this study aims provide a better understanding of hcp’s hh behaviours and perceptions of infectious diseases from psychological perspectives. method: observations measured different environmental features at three different departments and questionnaires asked hcp’s perception of safety from infectious diseases and coping behaviors (e.g., avoidance and disinfection). findings: this study has implications for potential interventions that enough hh stations at convenient locations would increase hh compliance rate from psychological perspectives, perception of safety from infectious diseases. in response to the current research gap in psychological aspects associated with hh, this study also presents hcp’s coping behaviours (e.g., avoidance and disinfection) would be predicted by their perceived contamination likelihoods and their perceived vulnerability enhanced the associations. conclusions: nonetheless, due to several limitations, those findings should be carefully interpreted and further studies must be conducted with more solid academic rigor. continuous outbreaks of infectious diseases, from severe acute respiratory syndrome to explore how interior environments are associated with hcp's perception of safety from infectious diseases and coping behaviours, a mixed-method design consisting of observations and questionnaires was applied. in the observations, data were collected regarding environmental features, such as hh stations, sharing medical equipment (sme), and traffic volume. the questionnaires were conducted to measure participants' perception of safety from infectious diseases and their behaviours. the observations were conducted to examine the interior environmental features (i.e., the number of hh stations, the number of sme, and traffic volume) in the three departments. each department was observed for one and a half hours at five randomly selected days and times. before the initial observation, the numbers of hh stations and sme were counted. the hh stations included form/gel-type sanitizers and sinks with a hand-soap. the examples counted for the sme are a computer, mouse, keyboard, phone, thermometer, blood pressure equipment, etc. therefore, a hh ratio for each department was calculated by dividing the total number of hh stations by the average number of hcp at each department, and an sme ratio for each department was calculated by dividing the total number of smes by the average number of hcp. additionally, the numbers of people who occupied the space were counted at the beginning and table summarizes the environmental features for each department. icu had a relatively medium hh ratio and a low sme ratio, but it had a high traffic volume. er had high hh and sme ratios but a low traffic volume, while op had a low hh ratio but a high sme ratio and traffic volume. paper questionnaires were distributed and a total of hcp completed the questionnaires throughout the three departments (icu = , er = , and op = ). table summarizes the participants' demographic information. the participants were asked to report the degree of their perceptions of safety from infectious diseases at work (α = . ) and perceived vulnerability on the -likert scale (strongly disagree to strongly agree), the likelihoods of a physical object being contaminated and causing infection (α = . ) on the - scale (not at all to extremely likely), their behaviours (α = . ) on the -likerts scale (never to always), and hh compliance rates among the hcps themselves. for the hh compliance rates, all three departments reported higher compliance rates for their own rates compared to their colleagues' rates. insert table to explore how the participants at the three different departments differently reported their perception and behaviours, anova analyses were conducted. subsequently, mann-whitney u tests were used to examine the statistical differences in the self-reported hh compliance rates between two groups (i.e., the participants who perceived the hindrance of hh stations' quantity and location and the participants who did not perceive the hindrance). finally, regression analyses were conducted to find any associations between perceived contamination likelihoods and coping behaviours and the role of perceived vulnerability on the associations. to analyse data, ibm spss version (armonk, new york) was used. this study was approved by the institutional review board of [a university to be named]. all participants were included in the study after provided written informed consent. all data were analysed and presented anonymously. the participants across the three departments felt safe from infectious diseases at their workplace (see table ). to be specific, they perceived safety from infectious diseases because of the supportive conditions of physical environments (e.g., easily cleanable furniture materials and fomites), sufficient and accessible hh stations, and their hh protocol compliance. the participants reported high hh compliance rates for themselves and their colleagues (see table ). when they were asked about the reasons for poor hh adherence or any barriers against appropriate hh compliance, the most frequent reason was "not thinking about it/forgetfulness" ( %) followed by "skin irritation and dryness" ( %), "too busy/insufficient time" ( %), and "inconvenient location/shortage of hh stations" ( %) (see figure ). anova analyses showed that the participants at three departments differently selected the reasons for poor hh adherence. specifically, more than % of the participants at op reported that inconvenient locations and shortage of hh stations can hinder their hh compliance, while approximately % of the participants at icu and er reported it as the reason for poor hh adherence. in contrast, roughly % of the participants at icu and er identified that priority of patient care would hinder the hh compliance, whereas the significantly fewer participants at op selected it as a barrier against good hh adherence. to understand the association between the hh compliance rate and hh stations, mann- whitney u tests were conducted because the shapiro-wilk test indicated the non-normality of the data distribution (see table ). the results implied that the participants, who perceived the inconveniently located and insufficient hh stations as the barrier against good compliance, reported statistically significant lower hh compliance rate (m = . ) than the hh compliance rate among the participants, who did not perceive the hh stations' locations and quantity as the barrier (m = . ). the participants were asked to indicate a likelihood that eight objects would be contaminated and that touching the objects would cause infection (see table ). the participants perceived that all of the objects had higher likelihoods being contaminated than causing infection. table when the participants were asked about their responding behaviours to the eight objects which might be contaminated and cause infection, their coping behaviours (e.g., disinfecting hands and avoiding touching the objects) were different depending on the objects (see table ). to be specific, the participants at all three departments more frequently washed/disinfected their hands after using the toilet, touching medical equipment and the objects in restrooms (e.g., insert table additional regression analyses (models , , and ) included the perceived vulnerability of the participants to infectious diseases to examine its moderating effects on the associations in models , , and . the results demonstrated the perceived vulnerability to infectious diseases, as a moderator, strengthened the associations between three objects' contamination likelihoods and coping behaviours by explaining more variance through the increased values of adjusted r . because of a sufficient number and accessible hh stations (see table ). this result might be because the er had a higher hh ratio but a lower traffic volume than the icu and op (see table ). previous literature has also investigated the perception of safety from infectious diseases and hh compliance. pediatric residents indicated their concern about getting infectious themselves as well as infecting their loved ones could motivate them to adhere to a proper hh [ ]. one qualitative research also found that nurses believed that hh protected them from infectious diseases as a protective behaviour [ ] . another study showed that beliefs about consequence were the most compelling facilitator of hh among hcp [ ] . even more, a control belief, where nurses believed they possessed or had access to hh resources to adhere to the hh recommendation, had a strong association with their adherence intentions, which also led to a higher hh compliance rate [ ] . in addition, a previous study explored hcp's perception of design factors in hospitals and found the participants ranked the factors associated with safety higher than aesthetics [ ] . the study also showed that they perceived provision for hh as an in conclusion, hcp's concern, salient beliefs about hh outcomes, and preference on safety features including provision for hh can explain that hcp might perceive a higher degree of safety from infectious diseases if ample hh stations are located appropriately. in light of our findings, this paper further explored the association between interior environments and hh compliance. more than % of the participants thought not enough and inconveniently located hh stations would hinder appropriate hh compliance (see figure ). furthermore, more participants working at the op (above %), where the hh ratio was the lowest, perceived the inconveniently located and insufficient hh stations as the barrier than the participants working at the icu and er, where the hh ratios are higher. in addition, the participants, who thought inconvenient locations of and not enough number of hh stations, reported a statistically lower hh compliance rate, compared to the participants who did not perceive the spatial barrier (see table ). what is highlighting from this study is that the perception of barriers affects a self- third, hh compliance and the coping behaviours are self-reported values. whether or not the actual hh compliance rates were increased with convenient locations and sufficient numbers of hh stations is still questionable. also, the participants could report a higher hh compliance ratios and their coping behaviours reflect the reality is unproven. hence, future studies should enhance the reliabilities of the hh compliance and coping behaviours. . ** . ** adjusted r . ** . ** note. *** p < . , ** p < . , * p < . . m: mean, sd: standard deviation. , report on the burden of endemic health care-associated note. *** p < . , ** p < . , * p < . . m: mean, sd: standard deviation. key: cord- -v fjh authors: carducci, a.; verani, m.; lombardi, r.; casini, b.; privitera, g. title: environmental survey to assess viral contamination of air and surfaces in hospital settings date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: v fjh the presence of pathogenic viruses in healthcare settings represents a serious risk for both staff and patients. direct viral detection in the environment poses significant technical problems and the indirect indicators currently in use suffer from serious limitations. the aim of this study was to monitor surfaces and air in hospital settings to reveal the presence of hepatitis c virus, human adenovirus, norovirus, human rotavirus and torque teno virus by nucleic acid assays, in parallel with measurements of total bacterial count and haemoglobin presence. in total, surface and air samples were collected. bacterial contamination was very low (< cfu/cm( )) on surfaces, whereas the ‘medium’ detected value in air was cfu/m( ). overall, ( . %) surface samples tested positive for viral nucleic acids: one for norovirus, one for human adenovirus and ( . %) for torque teno virus (ttv). only this latter virus was directly detected in air samples ( . %). haemoglobin was found on two surfaces. no relationship was found between viral, biochemical or bacterial indicators. the data obtained confirm the difficulty of assessing viral contamination using bacterial indicators. the frequent detection of ttv suggests its possible use as an indicator for general viral contamination of the environment. the risk of viral diseases in healthcare settings has important implications for both patients and staff. there are innumerable agents, routes of transmission, procedures and conditions that can cause infections in people attending units such as transfusion centres, laboratories, haemodialysis, infectious disease clinics, intensive care, and surgery, not to mention during clinical waste collection. bloodborne viruses (human immunodeficiency virus, hepatitis b virus and hepatitis c virus) are the most widely studied with regard to transmission in healthcare settings, and although epidemiological studies indicate accidents as the primary cause of exposure, there is a hypothetical although not proven possibility of viral transmission via droplets and surfaces. , 'airborne' viruses, such as influenza virus, respiratory syncytial virus, adenovirus, rhinovirus, coronavirus, measles, rubella and mumps viruses and parvovirus b , are easily spread by 'droplets' that can be inhaled directly or settle on surfaces. moreover, viral agents transmitted via the faecaleoral route, such as rotavirus, human adenovirus and and norovirus, are frequently associated with healthcare setting infections spread by air, hand and surface contamination. to assess and control the risk of infection in healthcare settings, environmental microbial contamination monitoring can represent an invaluable tool for determining the means of transmission, testing the efficacy of preventive measures, conducting periodic checks of hygiene levels, and alerting staff to the need for preventive measures and ensuring their compliance. however, such monitoring is generally limited to bacterial indicators (mainly total bacterial count) and specific studies on pathogenic agents have rarely taken viruses into account. , the biological characteristics, resistance markers, epidemiology and ecology of viral agents are quite different from bacteria, hence the microbial indicators commonly used for environmental monitoring cannot truly represent viral contamination. this has been well documented with regard to water contamination, although, so far, data on healthcare settings remain few. thus, the aim of the present study was to assess viral contamination on hospital surfaces and in the air using biomolecular tests by contemporaneously testing for the presence of different viral agents. the viruses chosen are considered representative of nosocomial infections commonly transmitted through various routes: hepatitis c virus for the bloodborne route; norovirus and human rotavirus for faecaleoral transmission; and human adenovirus for the respiratory route. apart from these agents of nosocomial infections, we also considered the torque teno virus (ttv), which, although not clearly associated with any specific disease, is widespread among the healthy population, irrespective of age, sex and any risk factors, reaching a prevalence of %. since ttv dna has been found in peripheral blood mononuclear cells, liver, faeces, urine, saliva, cord blood, amniotic fluid, breast milk, semen, cervical secretions and sewage, it may be regarded as a possible indicator of general viral contamination. along with viral detection tests, surfaces and aerosols were also monitored for viable bacterial count (vbc). although this parameter is not strictly associated with contamination, it is generally used to assess hygienic conditions in healthcare settings and the effectiveness of cleaning and disinfection procedures. for this reason, it was chosen as a comparison with the data on viral presence. other specific bacteria were also sought, but were found to be wholly absent from surfaces. in addition, their presence and mean counts in air were so variable that no hypotheses could be made over any association with viruses. finally, haemoglobin (hb) determinations were also made. these are commonly used in forensic settings to reveal bloodborne contamination of surfaces, but have also been applied to healthcare settings. the study was carried out over two years during the following periods: january to august, and january to july, in the following units of pisa university hospital ( beds): sterilisation centre, dental clinic, burn unit, paediatrics, haematology, bronchial endoscopy, general surgery, paediatric oncohaematology, endocrinology, heart surgery, intensive care, neurology, neurological surgery, intensive cardiac care, ophthalmology, and psychiatry. in total surface and aerosol samples were collected. the sampling points were chosen to reflect the potential for contamination from healthcare procedures. sampling was performed during working hours or shortly thereafter. samples were analysed for: À both surface and air samples: hepatitis c virus (hcv), norovirus genogroups i and ii (nov ggi and nov ggii), human rotavirus (hrv), human adenovirus (hadv), torque teno virus (ttv) and viable bacterial count (vbc); À only surface samples: haemoglobin (hb). four adjacent cm squares were delineated by a polypropylene mask and sampled. for the detection of the rna viruses (hcv, nov ggi, nov ggii, hrv), one square area was eluted with cotton swabs soaked in ml of % beef extract at ph . the eluate was then neutralised with n hcl and viral nucleic acids extracted using qiaamp rna mini kit (qiagen, hilden, germany). the rna recovery efficiency of the technique has been estimated at % in a previous study, which also indicated a detection limit of about genomic copies. the dna viruses (ttv and hadv) were detected using a commercial kit (dna iq system, promega italia, milan, italy) designed for forensic use and modified for the detection of virus on surfaces. a previous study with artificially contaminated samples indicated an approximate dna recovery efficiency of % and a detection limit of around genomic copies. in this preliminary study, for the method set up we included negative controls to confirm the absence of ttv on swabs, sterile surfaces and equipments. for bacteriological analyses, the third adjacent surface delineated by the polypropylene mask was eluted by cotton swabs soaked in a . % w/v nacl solution. swabs were then incubated in ml of nutrient broth for min at c. the whole solution was then seeded by inclusion on to plates containing plate count agar and incubated for h at c. finally, the fourth square was sampled for haemoglobin detection, using a commercial kit (oc hemocard, alfabiotech, pomezia, italy) used for blood detection in faeces and modified for environmental samples. air samples were collected with an impactor sampler (microflow, aquaria, italy). for virus detection, l of air were sampled on rodac plates containing tryptone soy agar (tsa). the agar was then eluted in % beef extract at ph , and viral rna and dna were respectively extracted using a qiaamp rna mini kit and a qiaamp dna mini kit (qiagen, hilden, germany). in this case, the recovery efficiency has been estimated at . % for viable virus with cell cultures and the detection limit was about .  pfu. for bacterial counts, l were sampled using an impactor sampler (microflow), with rodac plates containing plate count agar (pca). the plates were then incubated for h at c. all bacterial and viral counts were normalised to a volume of m . the nucleic acids extracted from samples were analysed according to published protocols of nested (rt)epcr to detect and distinguish the target viruses: the primers, virus genome regions and reaction conditions are reported in table i . e for each sample series, negative and positive specific rna or dna controls were used. for the rna viruses (hcv, nov ggi, nov ggii, hrv), a reverse transcription reaction was performed before the nested pcr: the extracted rna was mixed with buffer containing mm kcl, mm mgcl , mm trisehcl at ph . , mm ddt (promega italia, milan, italy), dntps, mulv reverse transcriptase (promega italia, milan, italy) and the specific reverse primer for the virus target. they were then incubated under the conditions specified in table i . for the first stage of the nested pcr, the obtained cdna was mixed with reaction buffer containing mm kcl, . % triton x- , mm trisehcl at ph . , mg/ml bsa, mgcl , dntps, u of taq polymerase (promega italia, milan, italy) and specific target virus pcr primers. the samples were then incubated for amplification according to the specific protocol reported in table i . in the second stage of the nested pcr, amplicons from the first step were mixed with primers and incubated according to the specific protocols reported in table i. for the dna viruses (hadv, ttv), in the first stage of the nested pcr the extracted dna was mixed with reaction buffer containing mm kcl, . % triton x- , mm trisehcl at ph . , mg/ml bsa, mgcl , dntps, u of taq polymerase, and specific primers. the mix was incubated according to amplification protocols (table i ). in the second reaction, the amplicons from the first stage were amplified with the specific primers. for each virus, the pcr products were detected under uv light after horizontal electrophoresis in % agarose gel. positive pcr products were purified using the qiaquick pcr purification kit (qiagen, hilden, germany) and confirmed by sequencing with an abi prism dna sequencer (applied biosystems by life technologies corporation, california, usa). the results were genotyped through the 'basic local alignment search tool' (blast). sequence analyses were carried out using the national center for biotechnology information genebank. the results of the environmental surface analyses are reported in figure . the vbcs were consistently very low (< cfu/cm ), probably due to frequent disinfection procedures in use. nevertheless, haemoglobin was found in two samples from the dental clinic, and samples ( . %) tested positive for viral nucleic acids: one ( . %) for hadv dna, one ( . %) for nov rna, both from sites in the general surgery unit, and ( . %) for ttv dna, from the sterilisation centre ( ), paediatrics ( ), haematology ( ), bronchial endoscopy ( ), endocrinology ( ), cardiac care ( ), neurology ( ), ophthalmology ( ) and psychiatry ( ) ( table ii) . sequencing of positive samples revealed that the hadv belonged to type , nov to the ggii, and ttv to genogroups i and iii, with a higher percentage ( %) for genogroup iii (figure ). air samples (figure ) yielded an average vbc value of cfu/ m (sd ae ), corresponding to a 'medium' contamination level according to the european commission ( ) (< cfu/m ). at eight ( . %) sampling points, however, the load was 'very low', corresponding to cfu/m for a sterile room (no. ) and below the detection limit for the other seven points. these last sampling points were located in a corridor (no. ), an operating room (no. ) and a further five sterile rooms, where the air is filtered by high efficiency particulate air (hepa) filters (nos. , , , , ). of the viruses, only ttv dna was detected in air samples. six of the positive samples demonstrated medium-level bacterial contamination and four, very low level. of these latter air samples, three came from the six above-mentioned sterile rooms (nos. , , ). the genome sequencing of the positive pcr samples confirmed positive results for ttv belonging to genogroups i and iii (figure ). due to the inherent difficulty in finding a correlation between environmental contamination and cases of infection, microbiological monitoring of the environment in healthcare settings is generally considered of limited utility. it is more often associated with safety control rather than risk assessment. although this is particularly true for viruses, where detection on surfaces and in air is very difficult, the low reliability of bacterial counts as indicators of viral contamination, suggests studying alternative parameters for assessing virological safety. in the present study, monitoring revealed the presence of viral nucleic acid in out of field samples; adenovirus dna and norovirus rna were found only once each and only on surfaces. ttv was detected frequently, with positive findings in . % of surface samples and . % of air samples, indicating environmental contamination consistent with the high prevalence of ttv carriage. furthermore, the detected strains belonged to the genogroups most widespread in the general population. this study is the first in which ttv has been sought and detected in a hospital setting, hence no comparisons with other studies are possible. the finding of different ratios of positive samples in different hospital units indicates that some areas may be more prone to viral contamination than others. the highest rates of positive results for surfaces were found in the sterilisation centre and bronchoscopy unit, and in the haematology units for air samples. the parallel monitoring for viruses and two indicators (vbc and haemoglobin) failed to reveal any associations; on surfaces where vbc was consistently . cfu/cm , ttv dna was more frequently detected than other viruses or haemoglobin. no differences in vbc were observed between virus-positive and -negative samples in air samples. although biomolecular methods for virus detection do not enable infectivity assessment, positive results indicate previous viral contamination. accordingly, such an interpretation seems compatible with the present findings. since ttv is non-cultivable, environmental longevity has been assessed only through dna persistence. on surfaces where effective disinfection procedures have been applied (as confirmed by a very low bacterial load), detected ttv could have been inactivated, and its presence indicative only of previous contamination. moreover, although the antibacterial action of the disinfectant used ( e ppm of chlorine) has been clearly established as per guidelines for hospital surfaces ( log reduction), no such data are available for its effect on viruses. this is the case for virion inactivation and degradation of nucleic acids, so that any possible effects on pcr reaction are unknown. in the air, which is not routinely disinfected (as indicated by the mean bacterial counts), ttv could presumably remain viable and possibly lead to airborne transmission. where the air is filtered, as in sterile rooms, the presence of ttv dna could indicate that air filters fail to retain the virus. however, the actual significance of its presence cannot be clearly understood without an evaluation of virus viability. some experimental data (not shown) on ttv dna persistence on artificially contaminated surfaces following different disinfection procedures have shown that after h treatment with . ppm chlorine, . % of the initial genome copies were still present. virus infectivity remained indeterminable because ttv cannot be cultured. the same test, conducted in parallel with hadv (culturable) revealed the persistence of . % of genome copies and . % viable virus. these data suggest the possible survival of infective ttv on surfaces, though to a lesser extent than suggested by its nucleic acid stability. in conclusion, although total bacterial count revealed only a lowto-medium degree of contamination of the hospital environment, viral dna was found to be widespread, both on disinfected surfaces and in filtered air. since the spread of viral infections in healthcare settings is still an unresolved, and possibly underestimated issue, greater and more 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cross-over study evaluation of contamination by blood aerosols produced during various healthcare procedures detection and potential indicators of the presence of hepatitis c virus on surfaces in hospital settings a new potential indicator of virological contamination of surfaces detection of coliphages and enteroviruses in sewage and aerosol from an activated sludge wastewater treatment plant three step isolation methods for sensitive detection of enteroviruses, rotoviruses, hepatitis a virus, and small round structured viruses in water samples detection of hepatitis c viral sequences in blood donations by "nested" polymerase chain reactions and prediction of infectivity detection of hepatitis c virus-rna by polymerase chain reaction in dental surgeries detection of adenoviruses in stool from healthy persons and patients with diarrhea by two-step polymerase chain reaction detection of adenoviruses and enteroviruses in polluted waters by nested pcr amplification marked genomic heterogeneity and frequent mixed infection of tt virus demonstrated by pcr with primers from coding and noncoding regions guidelines for environmental infection control in health care facilities relationship between total plasma load of torquetenovirus (ttv) and ttv genogroups carried chemical disinfectants and antiseptics. basic bactericidal activity. test method and requirements none declared. this work was supported by research projects of the italian national institute of occupational safety and prevention. key: cord- -emdj vj authors: kampf, günter; brüggemann, yannick; kaba, hani e.j.; steinmann, joerg; pfaender, stephanie; scheithauer, simone; steinmann, eike title: potential sources, modes of transmission and effectiveness of prevention measures against sars-cov- date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: emdj vj during the current sars-cov- pandemic new studies are emerging daily providing novel information about sources, transmission risks and possible prevention measures. in this review, we aimed to comprehensively summarize the current evidence on possible sources for sars-cov- , including evaluation of transmission risks and effectiveness of applied prevention measures. next to symptomatic patients, asymptomatic or pre-symptomatic carriers are a possible source with respiratory secretions as the most likely cause for viral transmission. air and inanimate surfaces may be sources; however, viral rna has been inconsistently detected. similarly, even though sars-cov- rna has been detected on or in personnel protective equipment, blood, urine, eyes, the gastrointestinal tract and pets, these sources are currently thought to play a negligible role for transmission. finally, various prevention measures such as hand washing, hand disinfection, face masks, gloves, surface disinfection or physical distancing for the healthcare setting and public are analysed for their expected protective effect. the end of the infectious period. in fact, real-time reverse transcriptase pcr results remained positive - days after the loss of transmissibility [ ] . for sars coronavirus, viral rna was detectable in the respiratory secretions and stools of some patients after onset of illness for more than month, but live virus could not be detected by culture after week [ ] . the inability to differentiate between infective and non-infective (dead or antibody-neutralised) viruses therefore remains a major limitation of nucleic acid detection methods. despite this limitation, given the difficulties in culturing infectious virus from clinical specimens during a pandemic, using viral rna load as a surrogate remains plausible for generating careful clinical hypotheses. the association between viral load and clinical outcome including severity of symptoms is still poorly characterized although the majority of studies reported an association between higher viral loads and more severe symptoms [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] . transmission dynamics of sars-cov- are heterogeneously [ ] . numerous individual infection clusters in particular in asia with variable size have been reported [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] . originating from a single travel-associated primary case from china, the first documented chain of multiple human-to-human transmissions of sars-cov- outside of asia allowed a detailed study of transmission events and identified several factors (e.g. cumulative face-toface contact, direct contact with secretions or body fluids of a patient, personal protective equipment) to classify contacts as low or high risk [ ] . furthermore, factors such as immune suppression, increased disease severity and viral load, asymptomatic individuals, the practice of seeking care at multiple healthcare facilities, frequent inter-hospital transfer, large numbers of contacts and prolonged duration of exposure facilitate transmission [ ] . household transmission is also common [ ] . superspreading is regarded as a normal feature of disease spread and has also been described with sars-cov- [ , ] . importantly, a recent study observed that transmission clusters occurred in many, predominantly indoor settings and most clusters involved fewer than cases, with the exceptions being in healthcare (hospitals and elderly care), large religious gatherings, food processing plants, schools, shopping, and large co-habiting settings (worker dormitories, prisons and ships) [ ] . given the predominately mild, non-specific symptoms, infectiousness before symptom onset the successful containment of covid- relies on stringent and urgent surveillance and infection-control measures. based on the definition of the who a confirmed case is a person with laboratory confirmation (detection of viral genomic material) of sars-cov- , irrespective of clinical signs and symptoms [ ] . asymptomatic coronavirus infections have been described before [ ] and might together with pre-symptomatic spread form a potential source of covid- infections acquired in a social or nosocomial context [ , [ ] [ ] [ ] [ ] [ ] [ ] . in february , a total of , confirmed cases were reported for china with a proportion of . % of asymptomatic cases [ ] . data from the first of april based on more rigorous testing of contact persons suggest in a small cohort of new cases a proportion of % as asymptomatic cases [ ] . irrespective of the frequency of asymptomatic carriers, they are considered to be important for the transmission of the disease [ ] . various studies reported sars-cov- infections, originating from asymptomatic carriers during close contacts such as household contacts or residents of a long-term care skilled nursing facility [ , [ ] [ ] [ ] [ ] [ ] . importantly, several studies have reported that viral rna loads in pre-symptomatic, asymptomatic and symptomatic patients do not differ significantly [ ] [ ] [ ] . others have reported no transmission from contacts (patients, family members, hospital staff) to asymptomatic carriers and concluded that the infectivity of some asymptomatic carriers may be weak [ ] . as summarized in table i , the proportions of asymptomatic sars-cov- cases at the time point of testing have been determined for different cohorts of patients. in hospitalized patients it was described to range be between . % and . % [ ] [ ] [ ] [ ] . in a long-term care facility, it was quite high with . % [ ] . in family clusters it was found between % and . % [ , ] . in children in china the proportion was . % [ ] . among japanese nationals evacuated from wuhan by chartered flights it was . % in contrast to german nationals with . % [ , ] . on board of a cruise ship asymptomatic carriers were detected in . % of the cases. the delay-adjusted asymptomatic proportion, however, was only . % [ ] . in iceland, a proportion of . % of the general population ( out of inhabitants) were investigated. overall, of them ( , %) were positive with a proportion of % asymptomatic carriers. among inhabitants with a high risk for infection the proportion of asymptomatic cases was only % [ ] . overall, asymptomatic sars-cov- infections seem to account for up to % of sars-cov- infections in selected cohorts, suggesting a significant factor for the rapid progression of the covid- pandemic [ , , ] . for comparison, the prevalence of asymptomatic influenza virus carriage (total absence of symptoms) ranged from . % to . % and subclinical cases (illness that did not meet the criteria for acute respiratory or influenza-like illness) between . % to . % [ ] . with mers a proportion of . % of cases was asymptomatic [ ] . follow-up examinations, however, indicate that the majority of initially tested asymptomatic cases ( . % - %) develop moderate but detectable clinical symptoms over time and therefore should be considered as pre-symptomatic. only in a small group of patients, no symptoms or radiological findings became apparent, but were described as potentially infectious for up to d (table ii) [ ] . of note, patients with negative pcr result prior to discharge may also become transient asymptomatic carriers again. one patient, for example, was retested positive for sars-cov- during the weeks quarantine after discharge [ ] . two healthcare workers (hcws) were also tested (throat swab) after discharge (covid- ) and were weakly positive in of samples and positive in of samples (case sampled over d), and weakly positive in of samples and positive in of samples (case sampled over d) [ ] . however, these results have to be interpreted with caution as currently applied pcr methods can lead to fluctuating results in weakly positive samples due to detection limits of the assays. indeed, a single case was described with low viral rna loads or negative rt-qpcr results, despite a sars-cov- infection confirmed by the presence of anti-sars-cov- specific antibodies [ ] . importantly, a systematic meta-analysis of different cohort studies observed that asymptomatic patients with covid- seems to correlate with young age and social activity [ , ] . in particular, future studies aiming to understand the contribution of young aged patients such as children to asymptomatic transmission of sars-cov- should be prioritised [ ] . in summary, the prevalence of asymptomatic sars-cov- infection and duration of pre-symptomatic infection are not well understood, as asymptomatic individuals are not routinely tested. studies on the immune response of asymptomatic carriers are lacking, which could contribute to a better characterization of the protective factors under natural conditions [ ] . several sources have been described that could possibly be involved in sars-cov- transmission based on the detection of viral rna. these include the respiratory tract, air contamination, the gastrointestinal tract, eyes, inanimate surfaces, personnel protective equipment, pets, and rather less likely blood and the urinary tract. sars-cov- has been frequently associated with droplet-based transmission [ , ] . likewise, person-to-person transmission has been assumed for sars-cov- very early [ ] . importantly, a more efficient transmission of sars-cov- compared to sars-cov- has been suggested, due to active pharyngeal viral shedding while symptoms are still mild and typical of upper respiratory tract infection [ ] . table iii summarizes the frequency and magnitude of sars-cov- viral rna loads in respiratory tract samples obtained from covid- patients. the viral rna load with sars-cov- can be as high as . log cpm (table iii) . it seems to be particularly high in the early and progressive stage of disease [ ] or two days before and one day after symptom onset [ ] . however, in some cases rna could still be found up to days after the first positive test with negative results in-between [ , ] . influenza a virus rna has even been released for up to d with negative results in-between although infectious virus was only detected for d after symptom onset [ ] . age was also associated with high viral rna load [ ] . most studies observed decreased viral rna loads over time [ , ] . one study shows that sars-cov- was detected by culture in out of clinical samples (nasopharyngeal swab) from covid- patients [ ] . the viral rna load detected in the asymptomatic patient was similar to that in the symptomatic patients, which suggests the transmission potential of asymptomatic or minimally symptomatic patients [ ] . it is important to differentiate between detection of rna and the isolation of infectious virus in cell culture. pcr for rna of sars-cov- does not distinguish between infectious virus and non-infectious nucleic acid. thus, interpretation of duration of viral shedding and infection potential should be based on viable virus from cell culture and needs to be carefully evaluated when solely based on pcr results. j o u r n a l p r e -p r o o f a strict distinction between droplet versus airborne transmission routes for infections is not possible [ ] . virus transmission via droplets and aerosols enables many viruses to spread efficiently between humans [ ] . airborne transmission is defined as the transmission of infection by expelled particles of comparatively small in size and which can remain suspended in air for long periods of time [ ] . the world health organization uses a particle diameter of ߤm to delineate between airborne (≤ ߤm) and droplet (> ߤm) transmission [ ] . transmission of infectious diseases by the airborne route is dependent on the interplay of several factors, including particle size (i.e., particle diameter) and the extent of desiccation [ ] . particle desiccation is a critical variable and depending on environmental factors as even large, moisture laden droplet particles desiccate rapidly [ ] . for example, wells showed that particles begin desiccating immediately in a rapid fashion upon air expulsion: particles up to ߤm can desiccate completely within approximately . seconds [ ] . rapid desiccation is a concern since the smaller and lighter the infectious particle, the longer it will potentially remain airborne. hence, even when infectious agents are expelled from the respiratory tract in a matrix of mucus and other secretions, causing large, heavy particles, rapid desiccation can lengthen the time they remain airborne (the dried residuals of these large aerosols, termed droplet nuclei, are typically . - ߤm in diameter) [ ] . of further concern, very large aerosol particles may initially fall out of the air only to become airborne again once they have desiccated [ ] . one of the challenges facing practitioners, particularly in an enclosed building, is that even large-sized droplets can remain suspended in air for long periods. the reason is that droplets settle out of air onto a surface at a velocity dictated by their mass [ ] . if the upward velocity of the air in which they circulate exceeds this velocity, they remain airborne. hence, droplet aerosols up to ߤm diameter have been shown to remain suspended in air for prolonged periods when the velocity of air moving throughout a room exceeds the terminal settling velocity of the particle [ ] . respiratory virus shedding can occur via sneezing, coughing or talking. sneezing distributes approximately , particles (droplets or airborne microorganisms) per sneeze, coughing approximately particles per cough, and talking approximately particles per words [ ] . using highly sensitive laser light scattering observations a recent study describes that loud speech can emit thousands of oral fluid droplets per second [ ] , indicating that normal speaking may also contribute to virus transmission in stagnant air. most of the , large droplet particles caused by a single sneeze will desiccate immediately into small, infectious droplet nuclei, with % of the particles being smaller than ߤm [ ] . the transmission of infectious diseases via airborne or droplet routes may further also depend on the frequency of the initiating activity. a single sneeze may produce more total infectious particles, while overall coughing may potentially be a more effective route of airborne transmission (e.g. during infection with coxsackievirus a) [ ] . coronavirus-infected humans coughed on average times over min during exhaled breath collection [ ] . given that dry cough is also a common symptom of covid- patients [ ] , it may therefore contribute to potential airborne transmission of this pathogen. in this context, airborne transmission has been considered to be possible in a cluster of infections in a restaurant with air conditioning [ ] . few studies are available to evaluate the role of air for transmission of sars-cov- , most of them obtained in hospitals with covid- patients. from the data shown in table iv viral copies were only detected in large air volumes of l with a larger proportion on icu ( % detection rate) compared to general wards ( . % detection rate). in smaller volumes such as l, , l or . m no virus was detected. even directly in front of a covid- patient it was not possible to detect the sars-cov- rna in the air [ ] . the viral rna loads of the first confirmed case were . × copies per ml in the pooled nasopharyngeal and throat swabs and . × copies per ml in saliva on the day of air sampling [ ] . the air samples of l were collected at a distance of cm at the level of patient's chin while the patient performed different manoeuvres (i.e., normal breathing, deep breathing, speaking " , , " continuously, and coughing continuously) while putting on and putting off the surgical mask were all undetectable for sars-cov- rna [ ] . nosocomial transmission of sars-cov- by an airborne route has been described to be very unlikely [ ] . nonetheless, sars-cov- can remain infectious in air for h measured in a goldberg drum with a decline of viral load from . log to . log per litre of air [ ] . in a subset of study participants with a symptomatic seasonal coronavirus infection but without any coughing during the min exhaled breath collection no coronavirus rna was detected in respiratory droplets or aerosols [ ] . other aspects influencing droplet or airborne transmission are temperature and humidity because they correlate with the spread of and deaths associated with covid- [ ] [ ] [ ] . in china, the number of confirmed cases increased with higher temperature and higher humidity in most of the provinces [ , ] . covid- lethality significantly worsened ( times on average) with environmental temperatures between °c and °c and relative humidity between % and % [ ] . biktasheva et al., however, described that the covid- mortality correlates with low air humidity, probably caused by a lower resistivity of dry or very dry mucous membranes [ ] . huang et al. described that % of all covid- cases are found in places with an air temperature between °c and °c [ ] . in brazil a °c increase in temperature has been associated with a decrease in confirmed cases of % [ ] . in wuhan and xiaogan temperature was the only meteorological parameter constantly but inversely correlated with covid- incidence [ ] . at low temperature and low humidity, droplets tend to remain suspended in air [ ] . high relative humidity will increase the droplet sizes due to the hygroscopic growth effect, which increases the deposition fractions on both humans and the ground [ ] . overall, a seasonal pattern of covid- is very likely. sars-cov- aerosolized from infected patients and deposited on surfaces could remain infectious outdoors for considerable time during the winter in many temperate-zone cities, with continued risk for re-aerosolization and human infection [ ] . conversely, sars-cov- should be inactivated in the environment relatively fast during summer in many populous cities of the world, indicating that sunlight should have a role in the occurrence, spread rate, and duration of coronavirus pandemics [ ] . simulated sunlight has been described to rapidly inactive sars-cov- [ , ] . indoor transmission of sars-cov- is much more likely compared to outdoor transmission [ ] . in a closed seafood market, the risk of a costumer to acquire sars-cov- infection via the aerosol route after h exposure in the market with one infected shopkeeper was about . × − . the risk rapidly decreased outside the market due to the dilution by ambient air j o u r n a l p r e -p r o o f and became below − at m away from the exit [ ] . outdoor, these virus particles are very strongly diluted by the open air [ ] . some patients displayed diarrhoea at the beginning or during the course of infection suggesting that sars-cov- may also affect the gastrointestinal tract. viral rna was detected in a proportion between . % and % in covid- patients with up to . log viral copies per g (table v) . one study including patients with of them reporting gastrointestinal manifestations ( %) reported diarrhea as the most common symptom ( %), followed by abdominal pain ( %), dyspepsia ( %), and nausea ( %) [ ] . analysing two groups of overall patients, none of the stool samples resulted in successful virus isolation in cell culture, irrespective of viral rna concentration [ , ] . in contrast, one study described the successful isolation of virus by cell culture from out of patients [ ] . of note, another study showed higher viral rna loads in fecal samples of mildly symptomatic or asymptomatic children compared to nasopharyngeal swabs [ ] . these results indicate the possibility of fecal-oral transmission or fecal-respiratory transmission through aerosolized feces. furthermore, the presence of sars-cov- rna in bile juice was reported from one patient and speculated that rna in fecal specimens may partly originate from bile juice [ ] . finally, a recent study suggested that detectable sars-cov- rna in the digestive tract could be a potential warning indicator of severe disease [ ] , however further evidence will be needed. transmission of sars-cov- through the ocular surface was considered to be possible [ ] . conjunctivitis has been reported in a patient in the middle phase of covid- , the conjunctival swab specimens remained positive for sars-cov- on and days after onset and were negative on day [ ] . another study showed among covid- patients that the virus was detected in tears and conjunctival secretions only in the one patient with conjunctivitis [ ] . furthermore, in another group of covid- patients two of them were identified with positive findings for sars-cov- in their conjunctival as well as nasopharyngeal specimens, a total of patients had ocular manifestations consistent with conjunctivitis, including conjunctival hyperemia, chemosis, epiphora, or increased secretions [ ] . in addition, no virus was detected on the conjunctiva in other covid- patients [ ] . one patient was described with persistent conjunctivitis with viral rna detection until day after symptom onset and confirmation of infectious virus in the first rna-positive ocular sample [ ] . even though the virus can be detected rarely in the conjunctival sac at very low levels [ , ] , there is no evidence that it can replicate locally [ ] . that is why the conjunctiva were considered not to be the preferred gateway into the respiratory tract [ ] . a study analysed human post-mortem eyes for the expression of ace (the receptor for sars-cov- ) and tmprss . in all samples the expression of ace and tmprss was detected in the conjunctiva, limbus, and cornea, with especially prominent staining in the superficial conjunctival and corneal epithelial surface [ ] . in contrast, another study from germany found no relevant conjunctival expression of the ace receptor on mrna and protein levels [ ] . in summary, the detailed pathophysiology of ocular transmission of sars-cov- remains not completely understood [ ] and both the presence of viral particles in tears and conjunctiva, and the potential for conjunctival transmission remains controversial [ ] . in conclusion, spread of covid- from ocular secretions cannot be ruled out but seems to be very unlikely. indirect transmission of covid- has been assumed to be possible via fomites although direct evidence is currently not available [ ] . in hospitals some data were collected to describe the frequency of detection of sars-cov- rna on inanimate surfaces in the immediate patient surrounding. the detection rate was variable on icu surfaces ( % - %), in isolation rooms ( . - %) and on general wards ( % - %). the mean virus concentration per swab were . - . log on icus and . - . log on general wards. a positive correlation between patient viral rna load and positivity rate of surface samples was described [ ] . however, on cleaned and disinfected surfaces viral rna could mostly not be detected (table vi) . detection of viral rna on the floor is indicative for sedimentation of contaminated droplets. surfaces outside the covid- patient room were also investigated. on icu the virus was rarely detected as "weak positive" on the floor and on door knobs in buffer rooms, dressing rooms and a nurse station ( of samples; . %) [ ] . on the general ward the virus was rarely detected on the patient floor ( samples; one "weak positive" result on the computer mouse or keyboard) and never detected on doorknobs and the floor in buffer rooms and dressing rooms ( samples) [ ] . viral rna could be detected even d after discharge of covid- on surfaces of pagers and in drawers of the isolation wards. the relevance of finding, however, is not clear because it is not known if infectious virus was present at that time [ ] . in a microbiology laboratory the detection rate on surfaces was . %. in the domestic environment of sars-cov- carriers the detection rate on surfaces was overall low ( % - . %; table vi) . it has to be mentioned that in most studies only pcr was performed for rna. but detection of viral rna on surfaces does not provide any information about viral infectivity or viability [ ] . new findings from a covid- cohort in gangelt, germany, and with cases in italy provide data on the detection of infectious sars-cov- on surfaces. although viral rna was detected in . % of surface samples in households of confirmed covid- -cases and on . % of sampled surfaces around covid- -cases in italy, infectious sars-cov- was not found in any sample [ , ] . similar findings were described with sars-cov and influenza-virus. in canada, a total of samples from inanimate surfaces were taken in a sars-hospital. viral sars-cov rna was present in . % of samples, but none of the samples revealed infectious virus [ ] . in thailand and taiwan rna of sars-cov was detected on . % of surface samples in a sars-hospital or in a sars-ward; in none of the samples infectious sars-cov was found [ ] . similar data were reported from households with proven h n influenza virus infections in children. viral rna was detected on . % of inanimate surfaces but virus could never be cultured [ ] . in cell culture studies, sars-cov- has been described to remain infectious on stainless steel and plastic for - d, on glass and banknote for d, on wood for d, all with a decrease of viral infectivity with time [ , ] . in the close surrounding of covid- patients in hospitals sars-cov- rna is detected more frequently compared to surfaces outside the patient rooms but samples were so far consistently negative for infectious virus. if infectious sars-cov- may be detected in a relevant amount on various surfaces in the public when only a short exposure to potentially infected, may be even asymptomatic people exists, is currently unknown but very unlikely. surfaces in air planes or trains in coughing or sneezing distance for potentially infected long-distance travellers may theoretically have a higher risk for contamination. the rna of sars-cov- has so far mainly been found on ppe used by healthcare workers on icu ( % - %), mainly on shoes and gloves. in other settings ppe was only very rarely contaminated with sars-cov- (table vii) . all studies performed pcr assays for sars-cov- rna detection. blood sars-cov- rna has occasionally been detected in blood of covid- patients, i.e. in of patients on days , , and after onset of disease [ ] , in of covid- patients ( . %) [ ] , in of asymptomatic and symptomatic patients with sars-cov- infection [ ] , or in of samples ( . %) obtained from covid- patients [ ] . sars-cov- rna can very rarely (in of samples) be detected in plasma during routine screening of blood donors considered to be healthy population [ ] . detection of sars-cov- rna in blood is considered a strong indicator for further clinical severity [ ] . so far, no cases of transmission due to transfusion of blood products have been reported for sars-cov, mers-cov, and sars-cov- , and clinically ill patients are not considered as blood donors [ ] . therefore, no immediate risk can be derived for the transfusion system [ ] . based on the existing evidence, transmission of covid- by handling potentially contaminated blood products (laboratory technician) or by contact with blood e.g. from a wound to intact skin is very unlikely. sars-cov- rna has occasionally been detected in urine swabs from patients. in patients with confirmed sars-cov- infections one of the patients was positive for viral rna in urine [ ] . this observation is supported by observations among sars-cov- positive children with of them positive for viral rna in urine ( %) [ ] . importantly, infectious virus could be detected from urine in one covd- patient [ ] . however, other studies with a total of patients [ , , ] failed to detect sars-cov- rna in urine. these data indicate that urine might be a potential source of infection but further evidence is needed. there is evidence that the main entry receptor of sars-cov- , ace , is expressed in cells of the reproductive system [ , ] . however, one study with covid- patients in the acute ( patients) and recovery phase ( patients) failed to detect viral rna in semen [ ] , indicating a low probability of sexual transmission through semen. sars-cov- rna has temporarily been detected in breast milk samples in one study in one of two infected mothers with approximately viral copies per ml [ ] . similarly, the presence of viral rna was reported in breast milk of an actively breastfeeding mildly symptomatic covid- patient raising the possibility of a potential transmission from breast milk [ ] . so far, no evidence for transmission of the virus from pet animals to humans exists [ ] . however, shi et al. reported that ferrets and cats were highly susceptible to sars-cov- , while dogs had a low susceptibility and livestock including pigs, chickens, and ducks were not susceptible to the virus, under experimental conditions [ ] . one of cats (france) and two of cats (wuhan) of covid- patients has been described to have a sars-cov- infection with mild respiratory and digestive symptoms whereas all dogs (france) and of dogs (wuhan) were sars-cov- and serologically negative [ , ] . interestingly, viral transmission between cats has been observed [ ] . out of six naïve cats (three subadults and three juveniles), each exposed to a sars-cov- inoculated cat, transmission occurred in two cats (one cat of each age group). similar findings were reported by halfmann et al. [ ] . this indicates that cats, being common companion animals, might theoretically transmit the virus to other animals and humans. however, there is so far no clear evidence that cat-to-human transmission of sars-cov- can occur. several practices are recommended with the aim to limit further transmission of sars-cov- in clinical practice but also public settings. these include hand washing, hand disinfection, wearing of face masks and gloves, disinfection of surfaces and physical distance. based on an integrated theoretical and statistical analysis of the influence of individual variation in infectiousness on disease emergence it has been suggested that individual-specific control measures outperform population-wide measures [ ] . a hand soap solution ( : ) has been described to have some effect (≥ . log reduction of viral infectivity) against sars-cov- in min [ ] . for healthcare workers hand washing is only useful when hands are visibly soiled [ ] . although sars-cov- has never been detected on hands of the public population yet, it seems reasonable to assume that the hand contamination by droplets from others may take place in the public with an unknown viral load. apart from avoiding hand-face-contacts in general, hand washing is first choice for the decontamination of hands, especially after returning home from public places with many close contacts to potentially infected people. ethanol and iso-propanol inactivate sars-cov- at concentration between % and % (both v/v) in s [ ] . both who-recommended hand rubs based on % iso-propanol or % ethanol (both v/v) also inactivate sars-cov- in only s [ ] . similar results were obtained with a propanol-based hand rub against sars-cov [ ] . on clean hands use of an alcohol-based hand rub is first choice in healthcare for the decontamination of hands due to the better activity against nosocomial pathogens including bacteria and yeasts and a better dermal tolerance [ ] . it may also be useful for covid- patients, e.g. before leaving the patients room for examinations. in this situation it is reasonable to recommend a hand disinfection in order to reduce potential transmission by direct hand contacts. the routine use of alcohol-based hand rubs for the general population should be discouraged, since there are currently no clear indications when to use them. it may be useful if a contamination of hands with sars-cov- is likely and a hand washing facility is not available. otherwise the widespread use of alcohol-based hand rubs may even enhance the shortage of the products in patient care which should be avoided by all means [ ] . inadequate ppe including facemask at the beginning of the epidemic in china has resulted in infections and deaths among healthcare workers [ , ] . unprotected patient care with long and close contacts was also later a major risk for healthcare workers to acquire covid- [ ] . in covid- cases face masks can at least reduce the viral spread. in individuals with a symptomatic seasonal coronavirus infection a surgical face mask was able to reduce the proportion of viral rna detection in droplets from % to % and in aerosols from % to % during min exhaled breath collection suggesting a protective effect when worn by infected patients [ ] . in another study covid- patients coughed times in front of a petri dish ( cm distance) with a surgical mask, a cotton mask or without a mask. without a mask . log viral copies per ml were detected, with a surgical mask it was . , and with a cotton mask . log viral copies per ml [ ] . household transmission was more likely when the primary case and other household members did not wear a mask at home resulting in the possibility of unprotected transmission [ ] . data on a protective effect of face masks when only worn by healthy subjects in an endemic covid- setting are not available. despite these results it was shown in south korea that none of hcws with close contacts to a covid- patient developed symptoms or were pcr positive in the nasopharynx although they only wore a surgical mask for more than ten minutes during activities including aerosol-generating procedures such as intubation [ ] . in addition, one study could show that a days surgical mask partition between cages reduces the risk of noncontact transmission between artificially infected and naïve golden syrian hamsters [ ] . importantly, a used face mask worn by a sars-cov- spreader will be contaminated. after only coughs all surgical or cotton face masks worn by covid- patients were contaminated on the outer surface whereas samples from the inner surface were mostly negative [ ] . chin et al. found that the virus can remain infectious or detectable for up to days on the outer layer of a surgical mask, on the inner layer for days [ ] . although the results are only based on three independent triplicates, this finding should have implications for the re-use of face masks in a shortage situation [ ] . wearing a face mask is recommended for healthcare workers in case of suspected or confirmed covid- patients [ , ] although it was described in hong kong that of hcws had unprotected exposure to confirmed covid- cases, none of these were infected [ ] . wearing a face mask may also be useful for hcws when mild respiratory symptoms occur because in the netherlands . % of such healthcare workers were positive for sars-cov- [ ] . even universal masking in hospitals by healthcare workers has been proposed although the expected effect was described as marginal [ ] . suspected and confirmed covid- cases should wear a face mask to prevent the spread of infectious droplets [ ] . so-called mass masking has been proposed as a considerable option [ , ] . many countries have recommended or legally ordered the use of fabric masks or face coverings for the general public. the who, however, acknowledged that the widespread use of masks by healthy people in the community setting is not yet supported by high quality or direct scientific evidence and that there are potential benefits and harms to consider [ ] . but in areas of known or suspected widespread community transmission and limited or no capacity to implement other containment measures, governments should encourage the general public to wear masks in specific situations and settings [ ] . some recent studies suggest that general face mask usage by the healthy population in the community reduces the risk of transmission [ , ] . but in order to evaluate only the effect of masks worn by healthy people in the community on the prevention of transmission in a country or region, some relevant variables with a proven impact on transmission should have been considered for the study period: the seasonal effect on the incidence (similar weather conditions), the main mode of transmission during the period of observation (mainly local clusters or mainly transmission in buildings or mainly transmission in the public), the total number of new cases in the observation period (mass masking in a region with new case per day may have a different effect compared to a region with . new cases per day) and the extent of community lockdown (the less people are in the public the less likely a protective effect of general masks can be expected). in an endemic population scenario without restrictions regarding physical distance and close or long face-to-face contacts it may indeed be useful, especially for the part of the population which has a high risk for a severe covid- infection. it is, however, a controversial debate among the scientific community if any additional protective effect by mass masking is expectable if a minimum distance between people is assured (e.g. m) and contacts are only of short duration. gloves can partially prevent the contamination of the hands with specific pathogens or all types of bioburden [ ] . however, at the same time wearing gloves is associated in hospitals with a lower compliance in hand hygiene [ , ] . use of gloves is recommended for hcws in specific patient care activities, e.g. when soiling of the hands is expected and when caring for covid- patients [ , ] . if there is any protective effect by wearing gloves by the general population in the public is speculative. one aspect is that wearing gloves may result in more awareness too reduce face hand contacts. and yet it seems reasonable not be encourage the general population to routinely wear gloves in the public. even if a hand contact yields a transient contamination with sars-cov- on the hands it does not make a difference if the virus is found on the bare or gloved hand; the essential preventive measure in this case is to avoid hand-face contacts and to wash hands when returning from the public. the resident hand flora is even able to provide some colonisation resistance in contrast to the glove [ ] . if wearing gloves by the general population has a similar effect on hand hygiene compliance as it has been described for healthcare workers wearing gloves in the public may even have the unwanted effect of less hand washing potentially increasing the risk of transmission via hands. some surface disinfectant agents have been described to inactivate sars-cov- in s such as ethanol and iso-propanol ( % - %, v/v) [ ] . in min household bleach ( : and : ) and . % benzalkonium chloride were also very effective against sars-cov- [ ] . limited data from surface samples in covid- settings support their efficacy [ , ] . in healthcare settings routine cleaning and disinfection of surfaces with which the patient is in contact is recommended [ ] . so far, no studies were reported to address if sars-cov- (viral rna or infectious virus) may be found on public inanimate surfaces. disinfection of surfaces in a household with chlorine-or ethanol-based products can reduce the risk of transmission when the primary case has diarrhoea [ ] . the frequent use of household disinfectants also results in a remarkable increase of exposures reported to us poison centers, especially via ingestion in the age group between and years [ ] . general disinfection of frequently touched surfaces in the public such as shopping carts or door handles is, however, unlikely to add any protective value because even in covid- wards inanimate surfaces were mainly contaminated in the permanent and immediate surrounding of symptomatic patients (detection of viral rna, not of infectious virus) and only rarely one room away [ ] suggesting that the risk to find sars-cov- on frequently touched surfaces in the public is low. future research will hopefully clarify the role of public inanimate surfaces for the spread of sars-cov- . close and long contacts are probably the main risk for transmission of sars-cov- from asymptomatic or symptomatic patients to healthy people as shown in clusters in families, a cruise ship, hospitals and nursing homes [ ] . the mode of transmission is very likely by droplets during coughing, sneezing or talking. the risk of long and close contacts is supported with experimental data obtained with syrian hamsters which were inoculated with viral copies in µl intranasally. h later each hamster was transferred to a new cage with one naïve hamster as close contact. sars-cov- was detected in nasal secretions, trachea and lung after days in all naïve contact hamsters [ ] . physical distancing is another option to slow down the spread of sars-cov- . early data from china suggests that quarantine, physical distancing, and isolation of infected populations can flatten the epidemic [ ] . so far, there are no "real-life" data which provide conclusive evidence regarding effectiveness of physical distancing interventions. however, in a simulation model the likelihood of sars-cov- human-to-human transmission in a singaporean population was predicted [ ] . they could demonstrate that the combined intervention, in which quarantine, school closure, and workplace distancing were implemented, was the most effective compared with the baseline scenario of no interventions, which reduced the estimated median number of covid- infections by . % when r was . , by . % when r was . , and by . % when r was . [ ] . nevertheless, an evaluation of the effect of physical distancing alone is currently not possible. maintaining a physical distance of at least m from other individuals is regarded as one of the most effective preventive measures by the who [ ] . günter kampf has received personal fees from dr. schumacher gmbh, germany, for presentation and consultation. yannick brueggemann, hani e. j. kaba, joerg steinmann, stephanie pfaender, simone scheithauer and eike steinmann have no conflicts of interest. 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equipment by sars-cov- during routine care of patients with mild covid- j o u r n a l p r e -p r o o f [ ] j o u r n a l p r e -p r o o f [ ] *no absolute numbers reported; **first survey; ***second survey two weeks later.j o u r n a l p r e -p r o o f j o u r n a l p r e -p r o o f j o u r n a l p r e -p r o o f samples significantly higher than for nasopharyngeal swab specimens cpm = copies per ml; cpg = copies per g; cps = copies per whole swab; pfu = plaque forming units. key: cord- -gxpia rs authors: lim, soo; yoon, ho il; song, kyoung-ho; kim, eu suk; kim, hong bin; fidsa title: face masks and containment of coronavirus disease (covid- ): experience from south korea date: - - journal: j hosp infect doi: . /j.jhin. . . sha: doc_id: cord_uid: gxpia rs nan a novel coronavirus (sars-cov- ) emerged in the city of wuhan, china in december and has now spread worldwide. since the end of february , the covid- spread to south korea and there was a rapid increase in covid- cases from the end of february to mid-march. fortunately, due to the efforts from both government and private sectors, the spread of the disease has been declining rapidly and only a few cases were reported in may. there are several reasons why covid- has been relatively well controlled in south korea. wearing a face mask in public seems to have been one of the major contributing factors. during the covid- pandemic, the use of face masks has been discouraged in several countries, particularly in europe. however, our government has strongly advised wearing a mask ( , ) from the beginning. hence, we felt it would be highly informative to share the experience of south korea from a public health perspective. in south korea, an aggressive "trace, test, and treat" program was put in place. the general public was advised to avoid large gatherings and crowded places, and to keep quarantine protocols, such as wearing a mask, washing hands, and social distancing. among these, wearing a mask is counted as one of the most effective preventive measures among general protocols. according to a recently published article, . % of koreans reported wearing a facial mask when they were outside ( ). in another international survey, the reported rate of wearing face masks among koreans was even higher ( %) and the highest among countries ( ). the increased awareness of particulate matter (pm) also needs to be mentioned. south korea has had the highest pm level among oecd countries ( ) . over the last few years, people in korea became more and more aware of the problem after government started to issue alerts. yellow dust (also called yellow sand or asian dust), a natural source of particulate matter(pm), originates from the deserts of mongolia and northern china, particularly in springtime, and has long been a public health issue after a formal warning in february, ( ) . the professional medical societies in south korea have warned about health hazards from impaired infant health to increased adult mortality rate, and people are advised to wear a facial mask when pm level is very high ( ) ( ) ( ) ( ) ( ) . this increasing public concern regarding pm has made wearing a face mask a matter of everyday life during epidemics of respiratory diseases in south korea. the acceptance of wearing face masks might be influenced by cultural differences. in european countries, wearing a face mask traditionally has been taken to indicate illness or bad intention. by contrast, it seems to be generally regarded as a sign of thoughtfulness and modesty in south korea. interestingly, young korean pop (kpop) singers made mask- wearing a fashion trend. so, wearing a mask is considered as a fashion item by young persons in many asian countries. although n respirators showed several advantages over medical masks in experimental conditions, several meta-analyses have concluded that there are insufficient data to support the superiority of n respirators over medical masks in protecting against transmissible respiratory pathogens including sars-cov- in clinical settings ( ) ( ) ( ) . a recently published article clearly showed the effectiveness of surgical face masks in reducing respiratory viral shedding ( ) to conclude, considering the relatively low incidences of severe cases or mortality and good control of covid- in several countries where self-quarantine principles are well established, wearing protective masks is an important strategy to stop the spread of respiratory viruses such as sars-cov- . among several ways that were helpful for south korea to combat this pandemic effectively, adhering to quarantine protocols such as wearing an appropriate mask in the proper way seems to have been vital. maintaining social distance at all times and washing hands thoroughly also must have played a critical role for controlling covid- . the authors have nothing to declare. psychological and behavioral responses in south korea during the early stages of coronavirus disease (covid- 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