key: cord-0694368-ey9vbppj authors: Wendt, Constanze; Kampf, Birgit title: Evidence-based spectrum of antimicrobial activity for disinfection of bronchoscopes date: 2008-10-31 journal: Journal of Hospital Infection DOI: 10.1016/s0195-6701(08)60014-6 sha: 3a2ebe61bc67b4f57b6af20d70a3636ee22e5337 doc_id: 694368 cord_uid: ey9vbppj Summary Processing of bronchoscopes after a physical examination has to eliminate all micro-organisms that could have contaminated the endoscope and that may harm the following patient. The aim of this analysis is to define those micro-organisms that may contaminate the bronchoscope during the examination and that may cause disease in other patients. Methods Research of literature and analysis of laboratory data. Results During the passage of the respiratory tract the bronchoscope will be contaminated by the physiological flora of oral cavity, nasopharynx, trachea, bronchi, and pulmonary tissues. Whilst the oral cavity, the nasopharynx and the pharynx are the habitat for a great variety of bacteria the lower respiratory tract is virtually free of micro-organisms. However, in ventilated patients trachea and bronchi can become colonized as the result of bypassing the cleansing effect of the ciliated epithelium. In addition all agents that can cause bronchitis or pneumonia in immunocompromised or otherwise healthy individuals are potential contaminants of bronchoscopes. These microorganisms include bacteria, mycobacteria, yeasts and moulds, enveloped and non-enveloped viruses and rarely parasites. The bronchoscopic procedure can result in epithelial injury with subsequent bleeding. Therefore, all blood-borne pathogens, e.g. HIV or HBV are also potential contaminants of the bronchoscope. There are several reports of transmission of micro-organisms due to incomplete or faulty cleaning and disinfection procedures of bronchoscopes. These incidents include nearly all classes of micro-organisms but not parasites or viruses. However, the incubation period of viruses can be long and the association between bronchoscopy and infection may be obscure. Endospore forming micro-organisms and parasites are not part of the normal flora of the respiratory tract and may rarely cause disease, usually only in severely immunocompromised patients, but transmission of such organisms by bronchoscopy has never been reported. Conclusion The antimicrobial activity of the disinfection process, including chemical disinfectants for endoscopes has to include bacteria, fungi and viruses. Sporicidal activity may be only warranted in specific patient populations, i.e. after bronchoscopy of suspected anthrax patients or before examination of severely immunocompromised patients. Bronchoscopy is performed as a diagnostic procedure, i.e. to inspect trachea and bronchi and/or to obtain tissue or secretion samples, or as a therapeutic procedure to remove foreign bodies, to perform laser photocoagulation, electrocauterization, laser resection, or stent insertion. Thus patients undergoing bronchoscopy are frequently immunocompromised and often suffer from infection. Reports of increasing dissemination of multiresistant organisms and increasing numbers of health care associated infections caused concern for infections that are associated with medical procedures. In Germany this discussion reached its highpoint when an infection control specialist pointed out that he would not undergo any endoscopic examination himself due to the risk of an infection. 1 Faced with these challenges reassurance is sought that the reprocessing of bronchoscopes is safe. On the other hand endoscopes are highly sophisticated medical instruments that are difficult to decontaminate. Thus sterilisation procedures like steam sterilisation can be hardly performed without damage to the instrument. Processing of bronchoscopes after a physical examination has to eliminate all micro-organisms that could have contaminated the endoscope and that may cause harm to the next patient. The aim of this analysis was to define those microorganisms that may contaminate bronchoscopes during the examination and that may cause disease in subsequent patients. The data of a microbiological laboratory that serves a 1,400 bed tertiary care university hospital were analysed for species and frequency of bacterial organisms isolated from the respiratory and pulmonary tract. We analyzed 120 mouth wash solutions, 4,300 throat swabs, 6,420 tracheal secretions and 1,250 bronchial alveolar lavages collected between January 2006 and October 2007. The ten most frequently isolated organisms were summarized as top 10 organisms. Furthermore a literature review was performed to analyse the potential of the cultivated microorganisms to cause disease in healthy or immunocompromised patients. In addition, standard manuals of microbiology and infectious diseases were reviewed to collect data on physiological flora and on organisms that are known to cause infections of the respiratory and pulmonary tract. Finally a Medline search using the key words "bronchoscope", "cross infection" and "pseudo outbreak" was performed to identify outbreaks and pseudo-outbreaks in which organisms had been associated with bronchoscopic procedures. During passage of the respiratory tract the bronchoscope will be contaminated by the normal flora of oral cavity, nasopharynx, trachea, bronchi, and pulmonary tissues. Whilst the oral cavity is the habitat for a great variety of bacteria, e.g. streptococci, lactobacilli, staphylococci, corynebacteria, and a great number of anaerobes, especially Bacteroides spp., the predominant species of the nasopharynx are nonhaemolytic and alpha-haemolytic streptococci and Neisseria spp. (Tables 1 4) . Sometimes potential pathogens such as Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae and Neisseria meningitidis colonize the pharynx. 2 Correspondingly, in clinical specimens of the upper respiratory tract collected in the Heidelberg University Hospitals alpha-haemolytic streptococci (65 78%) and Neisseria spp. (26 39%) were the most frequently isolated organisms. The lower respiratory tract is virtually free of micro-organisms. 2 However, in ventilated patients trachea and bronchi can become colonized as the result of bypassing the efficient cleansing effect of the ciliated epithelium. Candida albicans, coagulase-negative staphylococci (CNS), alpha-haemolytic streptococci and enterococci are frequently isolated from tracheal secretions of such patients. 2 This was also reflected in our laboratory results, with C. albicans (24 28%) and CNS (21 28%) being the most frequently isolated organisms. All micro-organisms that can cause infection of the mouth, the pharynx and the larynx, bronchitis or pneumonia in immunocompromised or otherwise healthy individuals are potential contaminants of bronchoscopes, e.g. bacteria, such as pneumococci, Pseudomonas spp. or Chlamydia spp.; mycobacteria; viruses, such as influenza virus or CMV; fungi, such as Aspergillus spp.; or parasites, such as Toxoplasma or Cryptosporidium (Tables 1 4) . 2 The bronchoscopic procedure can result in epithelial injury with subsequent bleeding. Therefore, all blood-borne pathogens, e.g. HIV, HCV or HBV are also potential contaminants of the bronchoscope. There are several reports of transmission or pseudo-outbreaks of micro-organisms due to incomplete or faulty cleaning and disinfection procedures of bronchoscopes. 3 63 These incidents include nearly all of the above mentioned classes of micro-organisms. Bacteria were responsible for 26 outbreaks or pseudo-outbreaks reported in the literature, 3 25 mycobacteria were discussed in 22 reports 26 57 and fungi in 6 reports. 58 63 Cross-infections due to parasites or viruses were not reported. However, the incubation period of viruses can be long and the association between bronchoscopy and infection may be obscure. Endospore-forming micro-organisms are not part of the normal flora of the respiratory tract and may rarely cause disease, e.g. pneumonia due to Bacillus cereus in severely immunocompromised patients or respiratory anthrax. No evidence for a transmission of Bacillus spp. by bronchoscopy has been reported so far. Table 5 summarizes the risk of contamination of bronchoscopes compared to the risk of infection due to different organisms and the actual occurrence of cross-infection or pseudo-outbreaks due to the micro-organisms. Bacteria are the most common micro-organisms colonizing and infecting the respiratory tract in immunocompromised as well as in immunocompetent persons. Treatment of an increasing number of immunocompromised patients has led to an uncertainty in the classification of physiological flora, colonization or pathogenic colonization. This may be demonstrated by the tendency of standard text books to omit chapters on physiological flora, e.g. the Manual of Clinical Microbiology 6th edition's chapter 'Indigenous and Pathogenic Micro-organisms of Humans' had been considerably shortened in the 8th edition and has been deleted As has been demonstrated by several reported outbreaks, bacteria can cause cross-infections associated with bronchoscopes. Therefore it is beyond doubt that the decontamination process Table 3 Micro-organisms that are part of the normal flora, colonization flora or infectious agents in the respiratory tract: Trachea of bronchoscopes has to effectively eliminate bacteria. Infection or colonization with mycobacteria is rare compared to other bacteria. Therefore, mycobacteria should be less frequently contaminants of bronchoscopes, however, they can cause severe disease. The comparably high number of incidents of cross-transmissions or pseudooutbreaks due to mycobacteria demonstrates that there may exist difficulties in eliminating these micro-organisms from bronchoscopes. This can be particularly harmful in case of MDR-TB. In New York State in 1995 inadequate cleaning and disinfection of the bronchoscope after the procedure performed on a patient with MDR tuberculosis led to subsequent transmission of infection to one patient and active MDR-TB in another patient. 32 Apart from the patient's individual flora, water used for rinsing the bronchoscope during the decontamination procedure might be a source of contamination of bronchoscopes with mycobacteria as well. Contamination with Mycobacterium chelonae resulting from biofilms in washer disinfectors has been observed. 45, 56 The identification of acid fast bacteria resulted in isolation and antibiotic treatment of patients which might be regarded as unnecessary as M. chelonae rarely cause invasive disease. Thus, the decontamination procedure has to be not only effective against mycobacteria; secondary contamination with these organisms must be prevented as well. Yeasts and moulds cause infections predominantly in immunocompromised patients and only rarely in immunocompetent persons. However, bronchoscopy is performed frequently in even severely immunocompromised patients. As moulds exist ubiquitously in the environment and can contaminate the bronchoscope not only during examination but also during processing of the scope, the decontamination process has to include the elimination of yeasts and moulds. Viruses are common agents of respiratory infections and blood-borne pathogens can easily contaminate the bronchoscope during bronchoscopic procedures. On the other hand, we could not detect a reported incident of cross-transmission of viruses due to bronchoscopes. A publication bias seems to be unlikely, but some viral infections are very frequent and the source of infection may be manifold, e.g. influenza or RSV. For other viruses the incubation period can be long and the association between bronchoscopy and infection may be obscure, e.g. HCV or HIV. In spite of the lack of demonstrated transmissions due to bronchoscopy, the frequency and the outcome of the viral diseases necessitate the sufficient elimination of viruses during decontamination of bronchoscopes. Endospore-forming micro-organisms are not part of the normal flora of the respiratory tract and may rarely cause disease, e.g. pneumonia due to Bacillus cereus in severely immunocompromised patients or respiratory anthrax, but transmission of such organisms by bronchoscopy has never been reported. 65 67 There is a theoretical risk of transmission of Bacillus spp. but the rare occurrence of Bacillus spp. in the respiratory tract on one hand and the uncommon occurrence of disease on the other hand may not warrant the inclusion of procedures to eliminate spores in the routine decontamination of bronchoscopes. Parasites also occur infrequently in the respiratory tract and rarely cause disease, mostly in immunocompromised patients. As for Bacillus spp., transmission of parasites due to bronchoscopes has not been reported. Therefore, the necessity of special procedures to eliminate parasites is also questionable. In conclusion, the antimicrobial activity of disinfection procedures for bronchoscopes has to include bacteria and mycobacteria, fungi and viruses. Sporicidal activity and activity against parasites may be warranted only in special patient populations, e.g. after bronchoscopy of suspected anthrax patients or before examination of severely immunocompromised patients. Infektionsrisiko durch flexible Endoskope Pathogenic and indigenous micro-organisms of humans Absence of clinical pneumonia following bronchoscopy with contaminated and clean bronchofiberscopes Fiberoptic bronchoscope-related outbreak of infection with Pseudomonas Pseudomonas aeruginosa contamination of fiberoptic bronchoscopes Pseudo-outbreak of Pseudomonas aeruginosa in HIVinfected patients undergoing fiberoptic bronchoscopy Nosocomial infections and pseudoinfections from contaminated bronchoscopes: Two-year follow up using molecular markers Centers for Disease Control and Prevention (CDC). Bronchoscopy-related infections and pseudoinfections An outbreak of multidrugresistant Pseudomonas aeruginosa infection associated with contamination of bronchoscopes and an endoscope washer-disinfector Nosocomial transmission of imipenem-resistant Pseudomonas aeruginosa following bronchoscopy associated with improper connection to the Sterris system 1 processor Pseudomonas aeruginosa and Serratia marcescens contamination associated with a manufacturing defect in bronchoscopes An outbreak of Pseudomonas aeruginosa infections associated with flexible bronchoscopes Pseudo-outbreak of Pseudomonas aeruginosa and Serratia marcescens related to bronchoscopes Unusual implication of biopsy forceps in outbreaks of Pseudomonas aeruginosa infections and pseudo-infections related to bronchoscopy Nosocomial outbreak of Pseudomonas aeruginosa infections related to a flexible bronchoscope Outbreak of Serratia marcescens associated with the flexible fiberbronchoscope Unusual source of contamination of bronchoscopes An 'outbreak' of pulmonary pseudoinfection by Serratia marcescens An outbreak of Serratia marcescens traced to a contaminated bronchoscope Contamination of a fiberoptic bronchoscope with a Proteus species Outbreaks of contaminated broncho-alveolar lavage related to intrinsically defective bronchoscopes Pseudo-outbreak of Bacillus species: related to fiberoptic bronchoscopy Pseudooutbreak of Bacillus species: related to fiberoptic bronchoscopy A pseudo-outbreak of Methylobacterium mesophilica isolated from patients undergoing bronchoscopy Pseudoepidemic of Legionella pneumophila serogroup 6 associated with contaminated bronchoscopes Disinfecting endoscopes: how not to transmit Mycobacterium tuberculosis by bronchoscopy Transmission of tuberculosis by flexible fiberbrochoscopes Transmission von Mykobakterien durch das Fiberbronchoskop Bronchopulmonary cross-colonization and infection related to mycobacterial contamination of suction valves of bronchoscopes Contamination of bronchoscopes with Mycobacterium tuberculosis Transmission of Mycobacterium tuberculosis by a fiberoptic bronchoscope Transmission of a highly drug-resistant strain (Strain W1) of Mycobacterium tuberculosis. Community outbreak and nosocomial transmission via a contaminated bronchoscope Cluster of tuberculosis cases in North Carolina: Possible association with atomizer reuse Potential nosocomial exposure to Mycobacterium tuberculosis from a bronchoscope Molecular strain typing of M. tuberculosis isolates from a suspected outbreak involving a faulty bronchoscope A cluster of Mycobacterium gordonae isolates from bronchoscopy specimens Mycobacterial cross-contamination of bronchoscopy specimes Contamination of flexible fiberoptic bronchoscopes A pseudoepidemic due to atypical mycobacteria in a hospital water supply Mycobacterium chelonei isolation from bronchoalveolar lavage fluid and its practical implications Cross contamination of bronchial washings Cross contamination of bronchial washings Acid-fast contamination of a bronchoscope washing machine Nosocomial infection and pseudoinfection from contaminated endoscopes and bronchoscopes Wisconsin and Missouri Contamination of flexible fiberoptic bronchoscopes with Mycobacterium chelonae linked to an automated bronchoscope disinfection machine Pseudoepidemic of nontuberculous mycobacteria due to a contaminated bronchoscope cleaning machine: report of an outbreak and review of the literature A nosocomial pseudo-outbreak of Mycobacterium xenopi due to a contaminated potable water supply: lessons in prevention Mycobacterial contamination of fiberoptic bronchoscopes Bronchoscopy-associated Mycobacterium xenopi pseudoinfections A pseudoepidemic of Mycobacterium chelonae: Contamination of a bronchoscope and autocleaner Mycobacterium abscessus pseudoinfection traced to an automated endoscope washer: utility of epidemiologic and laboratory investigation A pseudoepidemic of Mycobacterium chelonae infection caused by contamination of a fiberoptic bronchoscope suction channel Eradication of contaminating Mycobacterium chelonae from bronchofibrescopes and an automated bronchoscope disinfection machine A pseudo-outbreak of Mycobacterium chelonae infections related to bronchoscopy Mycobacterium chelonae isolated from rinse water within an endoscope washer-disinfector Pseudo-outbreak of Mycobacterium chelonae and Mycobacterium mesophilicum caused by contamination of an automated endoscopy washer Pseudoepidemic from Mycobacterium gordonae due to a contaminated automatic bronchoscope washing machine A pseudoepidemic of pulmonary fungal infections related to fiberoptic bronchoscopy Pseudoepidemic of Rhodotorula rubra in patients undergoing fiberoptic bronchoscopy Rhodotorula rubra contamination in fiberotic bronchoscopy Pseudo-outbreak of blastomycosis associated with contaminated bronchoscopes A pseudoepidemic of Rhodotorula rubra: A marker for microbial contamination of the bronchoscope A pseudooutbreak of Aureobasidium species lower respiratory tract infections caused by reuse of single-use stopcocks during bronchoscopy Indigenous and pathogenic micro-organisms of humans Bacillus cereus pneumonia in a patient with acute lymphoblastic leukemia Fatal pneumonia among metalworkers due to inhalation exposure to Bacillus cereus containing Bacillus anthracis toxin genes Fatal inhalational anthrax with unknown source of exposure in a 61-yearold woman in New York City