key: cord-0758452-qq9ecrhk
authors: Ragnar Norrby, S.
title: Infectious disease emergencies: role of the infectious disease specialist
date: 2015-12-28
journal: Clin Microbiol Infect
DOI: 10.1111/j.1469-0691.2005.01082.x
sha: c37c63d58f5106920f6841e8e043ab00f11ccfe4
doc_id: 758452
cord_uid: qq9ecrhk

The importance of infections for public health has become obvious during the last decades. Examples are emerging infections such as HIV/AIDS and severe acute respiratory syndrome, deliberate release of microorganisms, such as the anthrax episode in the USA, the increasing problems with organisms resistant to antimicrobial treatment, such as methicillin-resistant Staphylococcus aureus, and the threat of a new influenza pandemic with a case fatality rate similar to that in the 1918 outbreak. An effective response to infectious disease emergencies requires careful planning and establishment of resources in advance. The medical specialties involved are clinical microbiology, clinical infectious diseases and epidemiology. Clinical microbiology should include bacteriology, virology and parasitology; the technical developments during the last 15 years have clearly erased most of the methodological differences between these branches of microbiology. New techniques such as new generations of Polymerase Chain Reaction (PCR), rapid methods for nucleic acid sequence analyses and microarrays have enabled more rapid identification of organisms and provide powerful tools in the epidemiological analysis of an outbreak. The infectious disease specialists are necessary for rapid and adequate clinical diagnoses, optimal use of antimicrobial agents and provision of facilities for containment of patients who may spread the infections. The need for isolation units became acute when many countries prepared themselves for a possible severe acute respiratory syndrome outbreak in Europe. With few exceptions, Europe still lacks epidemiological field forces, and it has been embarrassing to be obliged to call upon the Centers for Disease Control for European outbreaks. Hopefully, this will be corrected with the creation of the European Centre for Disease Prevention and Control (ECDC).

Infectious diseases (IDs) have plagued humankind during its entire existence. With some notable exceptions, e.g., tuberculosis and HIV infections, IDs are acute and short-lasting. They afflict humans of all ages but are more common in children, the elderly and individuals who are immunocompromised, a group that is increasing rapidly, however with improved access to modern treatment of malignancies and the possibility of organ transplants.

Although patients with infections are seen by all physicians, who therefore need basic knowledge of how to diagnose and treat them, ID specialists are needed for optimal handling of many of these conditions, especially when dealing with emerging or re-emerging infections or major outbreaks of IDs. This overview will deal with some of the roles of an ID specialist, especially when society is faced with a major epidemic or increasing frequencies of infections caused by organisms resistant to antimicrobial drugs.

The training of an ID specialist should provide detailed knowledge of the clinical presentations of common IDs. This normally requires basic training in internal medicine for 2-3 years, to which should be added training at an ID unit or department. In addition, the specialist should have enough experience in clinical microbiology to know which samples should be taken for rapid and adequate aetiological diagnosis of an infection and also how to interpret the reports from the laboratories. While in most countries the ID specialist has internal medicine as a basis, there are other systems:

• In some countries, e.g., Sweden, the requirement for training in internal medicine is reduced to approximately 1 year, with a longer period at an ID unit, and the specialty is an independent one. The lack of formal internal medicine training is to some extent compensated for by the fact that, in Sweden, ID departments normally care for patients with respiratory tract infections, hepatitis, pyelonephritis or surgical infections. • Similar to the situation in the USA, some countries, e.g., Finland, have chosen to make ID a subspecialty of either internal medicine or paediatrics. It is notable that in many countries infections are included in general paediatrics and are not considered to require special training. • In the UK, a new curriculum for training of specialists in 'infection' has recently been introduced. Under this programme, the physicians receive approximately 3 years of training in each of the specialties: internal medicine, clinical IDs and clinical microbiology. Although the training period is longer than normal, it provides an optimal basis for an ID specialist. The ID specialty is today recognised in most European countries, notable exceptions being Austria, Belgium and Spain. In most countries the ID physicians serve as consultants and have relatively few, if any, beds of their own. However, in some countries, e.g., Sweden, there are relatively high numbers of beds in ID departments. Advantages of the latter system are that the capacity for effective isolation of contagious patients is increased and that the staff members have special training in preventing the spread of infections.

In 1972 the US Surgeon General is claimed to have said, 'The book of infectious diseases can now ultimately be closed.' Obviously, that statement was not justified. Since then the world has seen the emergence of several important infections. Examples are acquired immunodeficiency syndrome, hantavirus cardiopulmonary syndrome and severe acute respiratory syndrome (SARS). In addition, the rapid development of new microbiological techniques has made it possible to identify the aetiology of many important infections, such as those caused by Legionella pneumophila, Helicobacter pylori, several new viruses causing infectious hepatitis, and viruses causing haemorrhagic fevers. In many cases these discoveries have led to the development of effective treatments.

The ID specialist has several important roles in the management of emerging infections. First, and perhaps most important, is the recognition of a disease pattern and ⁄ or an epidemiological pattern outside the normal, i.e., the recognition of an epidemic. The earlier this is done, the easier it will be to contain an outbreak. An excellent example is the SARS epidemic. The first wave of some 300 patients with severe respiratory tract infections in the Guangdong province was noted as an accumulation of cases of atypical pneumonia. It was dismissed by local authorities and the World Health Organization (WHO) as not being a new influenza outbreak and not having any connections with avian influenza. However, only days after the worldwide dissemination from the index case at Hotel Metropole in Hong Kong, it became obvious, through observation by physicians in Hong Kong and Hanoi, that this was a completely new ID outbreak, which required extraordinary actions. Rapid recognition of the SARS outbreak also made it possible to contain the infection despite the fact that it had spread worldwide at an early stage.

In situations such as the SARS epidemic, the ID specialist has, or should have, clearly defined roles:

• Recognise the fact that a new epidemic has emerged. This is facilitated by regular ID consultancies at intensive care units and emergency rooms. • Initiate cooperation with clinical microbiologists to achieve optimal sampling to identify the aetiological agent. This may require access to special laboratory facilities, such as P3 and P4 laboratories. The latter are available in only a few countries, and samples may have to be sent to laboratories abroad. • Decide (or advise) on isolation of patients and hygienic measures to avoid transmission of the infection. This should be done in close cooperation with cross-infection control specialists. • Advise public health authorities on measures to be taken to limit the extent and consequences of an epidemic. • Assist public health authorities in communications with news media and the general public.

It is obvious that ID specialists cannot and should not operate as solitary individuals or groups of specialists. Optimal handling of outbreaks requires building of networks within healthcare and public health agencies. Key actors at the local level, in addition to the ID specialists, are the clinical microbiologists, hospital hygiene specialists, epidemiologists and public health organisations. When an epidemic results in large numbers of patients requiring hospital care, the local hospital authorities will have an important role to play. On the national level, most countries have infection control agencies, which, as early as possible, should be informed about suspected outbreaks. Internationally, the European Union network for surveillance of IDs should be contacted, as should the WHO. These contacts should be made through the national infection control agency. On a European level, it is likely that in the future the coordinating role within Europe will be taken over by the European Centre for Disease Prevention and Control.

A major reason why the Surgeon General was wrong was that he had not foreseen the problem of antimicrobial resistance. Today, such resistance is creating problems with handling a broad range of infections. In most countries, antibiotic resistance is very common in staphylococci, enterococci, pneumococci, enterobacters and non-fermenting Gram-negative species such as Pseudomonas spp. and Acinetobacter spp. In Mycobacterium tuberculosis, resistance to one of the main agents (rifampicin and isoniazid) is common and the frequency of multiresistant strains is increasing. Resistance is also creating clinical problems in viral infections. This is most pronounced for anti-retroviral drugs, and primary resistance, i.e., resistance to one or more anti-HIV drugs at the time of acquisition of the infection, is not uncommon. In parasitology, resistance to anti-malarial drugs is an increasing problem, which has led to a recommendation to use combination therapy for prophylaxis and treatment, something that is often not affordable in developing countries.

Adding to the problems of antimicrobial resistance is the fact that the development of new drugs for treatment of infections caused by resistant organisms is slowing down. At present, only five new antibiotics are in clinical development, and none of them will increase the possibilities of treating infections caused by multiresistant Gramnegative bacteria [1] .

The ID specialist has several important roles in combating antibiotic resistance. By education of colleagues and the general public, improper use of antibiotics should be avoided or reduced. It seems clear that in most countries there is a marked overuse of antibiotics [2] . Proper sampling from patients with infections should facilitate identification of resistant organisms. When infections caused by resistant organisms occur in a hospital setting, the ID specialists, together with the hospital hygiene specialists, should initiate necessary measures to avoid dissemination. In this respect, it is important to remember that more and more elderly people with serious conditions are cared for outside of hospitals, in nursing homes or even in their own homes. It is not unusual for these patients to harbour resistant bacteria as a result of more or less indiscriminate use of antibiotics. Again, the best way to reduce the consequences of such resistance is to increase the sampling for microbiological investigations, so that, when such a patient is hospitalised, adequate isolation and hygienic measures can be taken.

The ID specialty should be seen as an essential component in modern healthcare. The money used to create an effective ID service is well-invested, since ID specialists will decrease the risk of dissemination of infections within hospitals and within society. Also, by optimising antibiotic treatment, in terms of choice of drugs, dosages and treatment times, these specialists can contribute to a reduction in the incidence of antimicrobial resistance, the consumption of such medicines and the risk of nosocomial infections caused by resistant bacteria.

To be optimally efficient, the ID specialist must work in close cooperation with clinical microbiologists and hospital hygiene specialists. When outbreaks occur, cooperation with public health organisations is also necessary, as well as with national infection control agencies and with international organisations such as the European Centre for Disease Prevention and Control and the WHO.

Lack of development of new antimicrobial drugs: a potential serious threat to public health

Variation in antibiotic use in the European Union