6.3.2. Antimicrobial resistance and healthcare-associated infections

 

Resistance to antibiotics is a large problem in the community, but even worse in healthcare settings. Hospitals, especially intensive care units often have their own resident bacterial flora, which are often highly resistant to those antibiotics that are commonly used locally. Although not all health care associated infections (HCAI) are caused by resistant bacteria, a very large and increasing proportion is, intertwining the two problems of antimicrobial resistance (AMR) and HCAI.

 

6.3.2.1. Antimicrobial resistance and antibiotic consumption

 

AMR is one of the most serious public health problems both at globally and European level. If the present rapid negative development is not halted, mankind will soon lose one of its most important weapons against infectious diseases.

 

Resistance has also evolved against bacterial, viral (e.g. HIV, influenza), parasitic (malaria) and fungal infections, making AMR the most serious of all communicable disease threats.

 

The bacterium that has received prime attention is methycillin-resistant Staphylococcus aureus (MRSA). A larger and larger proportion of all invasive S. aureus infections are caused by MRSA. Data on AMR show that in general the problem is somewhat lesser in Northern Europe (Scandinavia and the Netherlands), and more serious in the Southern and South-Eastern parts of the Union. Intra-country variation is also reported to be significant and deserves attention, in view of the general increase in MRSA, which occurs throughout Europe, and includes countries with high, medium, as well as low baseline figures (figure 6.1). However, two countries (Slovenia and France) have succeeded at significantly reducing the proportion of MRSA, thus demonstrating that this MRSA pandemic may not be irreversible.

 

Figure 6.1. Proportion of methicillin-resistant isolates over total S. aureus blood stream infections in selected EUGLOREH Countries.

 

For most other bacteria and virus under EU surveillance the overall trend is also very worrying. AMR is a particular concern when it comes to the global killer diseases TB, malaria, HIV and pneumococcal infections. AMR data are currently collected via several surveillance networks, whilst coverage across and within countries shows a lot of variation. Furthermore, there may be big regional differences within countries, which are not visible the way the data are presented. A prerequisite to be able to follow the trends of resistance patterns is that the methodology for sensitivity testing is the same in all laboratories and that it is reliable and quality assured.

 

For other bacteria under EU surveillance, such as the intestinal bacteria enterococci, E. coli, Klebsiella pneumoniae, Campylobacter, Salmonella and Pseudomonas aeruginosa, the overall trend is also worrying. For Streptococcus pneumoniae (pneumococcus), the most common bacterium causing respiratory tract infections and a major microbial cause of death in young children, the picture is more mixed, with decreasing penicillin-resistance in some highly endemic countries and increasing resistance to penicillin and other antibiotics elsewhere. Resistance is mainly confined to a few serogroups, all of which have been included in the recently introduced conjugated vaccines. This suggests that vaccination of young children would represent an effective additional means of controlling antibiotic-resistant pneumococci in Europe.

The emergence of strains resistant to the two most effective agents against TB, isoniazid and rifampicin, (multi-drug resistance, MDR), as well as to other second line antibiotics (extensive drug resistance, XDR), poses a serious challenge to TB control today. Multi-drug resistant TB (MDR-TB) was present in 15–20% of cases reported by the Baltic Republics (Estonia, Lithuania and Latvia), but ranged from 0–6% in the rest of the countries. MDR is more frequent in previously treated cases, and in foreigners, especially those originating from the former Soviet Union. The wider participation of countries in surveillance of drug resistance is needed to ensure a better monitoring of this public health concern.

 

Risk factors

 

A key factor in the development of AMR is the inappropriate utilization of antibiotics. Since their discovery, antibiotics have revolutionised the way we treat patients with bacterial infections and have significantly contributed to reducing death and morbidity from bacterial diseases. They are also absolutely essential for modern medicine. Common procedures such as transplants, chemotherapy for cancer, and even orthopaedic surgery could not be performed without the availability of potent antibiotics. Unfortunately, they have also been liable to inappropriate use, often unnecessarily prescribed for viral infections. Similarly, when diagnoses are not accurately made, more often than not broad-spectrum antibiotics, i.e. antibiotics that kill a large proportion of the normal bacterial flora and not only the disease-causing bacteria, are prescribed. These examples of the misuse of antibiotics promote the emergence and selection of resistant bacteria.

 

Data on antibiotic consumption are difficult to obtain and come from different sources. Yet in most countries it has been possible to differentiate antibiotic usage in hospitals and outpatient settings. It has been shown that the amount of antibiotic consumed per inhabitant varies three-fold between Member States, though it is difficult to understand why.

 

As for AMR, antimicrobial use shows a general gradient from low use in Northern Europe to higher use in Southern Europe; the highest user prescribing three times more antibiotics than the lowest. Additionally, there are marked differences in the type of antibiotics that are used. In the Nordic countries, a larger proportion of total use is still represented by older narrow-spectrum antibiotics, whilst newer broad-spectrum classes are seldom used on outpatients. This is the most likely reason for the low levels of resistance to the newer antibiotics classes in these countries. A consistent association between the level of use of specific antibiotic classes, and resistance to these classes has been reported.

 

Control tools and policies

 

Control tools include surveillance, and other specific measures for primary prevention.

 

Surveillance

 

AMR is a phenomenon that affects most, if not all, pathogens of importance to human health; therefore, the demands on effective surveillance systems are immense. The current EU surveillance networks are focused on a few key pathogens, but most pathogens are not covered and the system relies on voluntary reporting from a limited number of laboratories, sometimes disguising regional differences within countries. Ideally, surveillance of AMR should work on three levels:

·          following trends of resistance in major important pathogens;

·          detecting outbreaks and/or spread of different ‘problem bacteria’; and

·          spotting novel ‘super strains’ where each isolate requires immediate and forceful action.

Today, EU-level (and national) surveillance only covers the first of these three levels. Further developing surveillance of AMR is therefore a priority.

 

Primary prevention

 

Considering the mechanisms behind the emergence of AMR, the EU Health Council has provided recommendations to Member States to establish national strategies to contain AMR: use them in the correct way; and block the spread of resistant strains between people. There are many examples from across Europe of good practices and success stories.

 

6.3.2.2. Healthcare-associated infections

 

HCAI also referred to as nosocomial infections, are a huge public health problem in Europe. On the basis of recent surveys, the total number of patients acquiring a HCAI in the EU25 every year can be estimated at 3 000 000, and approximately 50 000 deaths occur every year as the consequence of the infection. Of 87 000 patients staying more than two days in an intensive care unit, 7.2% acquired pneumonia, and 3.1% acquired bloodstream infections.

 

The most frequent infections are urinary tract infections (28% of all HCAI), followed by respiratory tract infections (25%), surgical site infections (17%), bacteraemia (10%), and others (including diarrhoea, with the increasingly important Clostridium difficile). Other major nosocomial pathogens are methycillin-sensitive Staphylococcus aureus (Figure 6.1), Pseudomonas aeruginosa, enterobacteriaceae (E. Coli, Enterobacter, Klebsiella), Enterococci, fungi (Candida, Aspergillus), and Acinetobacter.

 

 

Control tools and policies

 

 

Approximately 20–30% of nosocomial infections are considered to be preventable by an intensive infection control programme that includes surveillance. National or regional surveillance is mostly performed in the context of a surveillance network of hospitals, whereby individual rates are compared to those of other participating hospitals and services as a measure of own performance using risk-adjusted infection rates. Since the latter requires the collection of risk factors and the involvement of clinicians, infection control staff and microbiologists, HCAI surveillance is labour-intensive and therefore targeted at specific high-risk populations (such as intensive care patients) or infection types (surgical site infections, bloodstream infections). Furthermore, several EU Member States still do not have a national surveillance network for nosocomial infections, since setting up such a programme usually involves important political decisions, specific legislation and a financial investment at both national and hospital levels in order to set up or reinforce infection control programmes with surveillance.