Antibiotic and antimicrobial resistance

Based on data collected by the European Antimicrobial Resistance Surveillance Network (EARS-Net) and the former EARSS, the present study describes the trends in antimicrobial susceptibility patterns and occurrence of invasive infections caused by Escherichia coli and Staphylococcus aureus in the period from 2002 to 2009. Antimicrobial susceptibility results from 198 laboratories in 22 European countries reporting continuously on these two microorganisms during the entire study period were included in the analysis. The number of bloodstream infections caused by E. coli increased remarkably by 71% during the study period, while bloodstream infections caused by S. aureus increased by 34%. At the same time, an alarming increase of antimicrobial resistance in E. coli was observed, whereas for S. aureus the proportion of meticillin resistant isolates decreased. The observed trend suggests an increasing burden of disease caused by E. coli. The reduction in the proportion of meticillin-resistant S. aureus and the lesser increase in S. aureus infections, compared with E. coli, may reflect the success of infection control measures at hospital level in several European countries.

The emergence and global spread of carbapenemase-producing Enterobacteriaceae is of great concern to health services worldwide. These bacteria are often resistant to all beta-lactam antibiotics and frequently co-resistant to most other antibiotics, leaving very few treatment options. The epidemiology is compounded by the diversity of carbapenem-hydrolysing enzymes and the ability of their genes to spread between different bacterial species. Difficulties are also encountered by laboratories when trying to detect carbapenemase production during routine diagnostic procedures due to an often heterogeneous expression of resistance. Some of the resistance genes are associated with successful clonal lineages which have a selective advantage in those hospitals where antimicrobial use is high and opportunities for transmission exist; others are more often associated with transmissible plasmids. A genetically distinct strain of Klebsiella pneumoniae sequence type (ST) 258 harbouring the K. pneumoniae carbapenemases (KPC) has been causing epidemics of national and international proportions. It follows the pathways of patient referrals, causing hospital outbreaks along the way. Simultaneously, diverse strains harbouring New Delhi metallo-beta-lactamase (NDM-1) are repeatedly being imported into Europe, commonly via patients with prior medical exposure in the Indian subcontinent. Since the nature and scale of carbapenem-non-susceptible Entrobacteriaceae as a threat to hospital patients in Europe remains unclear, a consultation of experts from 31 countries set out to identify the gaps in diagnostic and response capacity, to index the magnitude of carbapenem-non-susceptibility across Europe using a novel five-level staging system, and to provide elements of a strategy to combat this public health issue in a concerted manner.

A total of 2,662 samples, collected from March to September 2009 in Switzerland, were tested for the presence of meticillin-resistant Staphylococcus aureus (MRSA). The collection comprised nasal swabs from 148 pig farmers, 133 veterinarians, 179 slaughterhouse employees, 800 pigs, 300 calves, 400 cattle, 100 pooled neck skin swabs from chicken carcasses, and 460 food samples of animal origin. Moreover, 142 S. aureus strains, isolated from bovine mastitis milk, were included in the study. Twenty samples (<1%; four veterinarians, 10 pigs, three calves, one young bull, and two mastitis milk samples) tested positive for MRSA. Genotyping of the MRSA strains was performed by multilocus sequence typing, spa- and SCCmec-typing, and revealed ST398 (n=18), ST8 (n=1), ST 1 (n=1), spa types t011 (n=7), t034 (n=11), t064 (n=1), t127 (n=1), and SCCmec types IV (n=4) and V (n=16). The 20 MRSA strains were subjected to antibiotic susceptibility testing and pulsed-field gel electrophoresis using the restriction enzyme EagI. Supplementary PCR reactions were performed to investigate the presence of Panton-Valentine leukocidin and staphylococcal enterotoxins A to D.

Antibiotic resistance and nosocomial infections have recently been recognised as a growing threat in Latvian hospitals. We used a modified point prevalence study design to gain accurate information on the antibiotic prescription pattern and the prevalence of nosocomial infections in different hospital departments. A given department was observed on a given day in a given month (May) five years in a row. All antibiotic treatments, dose and route of administration were recorded, in addition to demographic data. The most commonly used antibiotic groups were first generation cephalosporins (35.6-38.9%), broad-spectrum penicillins (17.5-23.0%), fluoroquinolones (8.4-14.5%) and aminoglycosides (7.7-12.6%). Cefazolin was the most commonly used antibiotic. Antibiotics were predominantly used intravenously. The proportion of oral administration varied from 15.1% to 21.8%. A large proportion (13.3%) of the antibiotics was administered without clear reason. The crude prevalence rate of infection treated with antibiotics was 19.3%. The average prevalence of nosocomial infections was found to be 3.6%. These prevalence studies provided an opportunity to compare hospitals and outline variations and problem areas. They indicated the main problems in antibiotic prescription: large interhospital variations in the choice of an antibiotic for the most common infections, frequent antibiotic use without clear reason, and predominant intravenous administration.

A Belgian Antibiotic Policy Coordination Committee (BAPCOC) was officially established in 1999 by Royal Decree. The overall objective of BAPCOC is to promote judicious use of antibiotics in humans and animals and to promote infection control and hospital hygiene, with the overall aim to reduce antibiotic resistance. BAPCOC fostered strong and interdisciplinary public health, scientific and political leadership, which led to many evidence-based interventions such as multimedia campaigns to promote the prudent use of antibiotics in the community, national campaigns to promote hand hygiene in hospitals, publication of clinical practice guidelines, staffing and technical support for establishment of antibiotic management teams in all Belgian hospitals, surveillance programmes on antibiotic use and resistance in humans and animals and the promotion of research. These activities and interventions resulted in a measurable decrease in antibiotic use and resistance in the community and hospitals.

The overall aim of Strama (The Swedish Strategic Programme Against Antibiotic Resistance) is to preserve the effectiveness of antibiotics in humans and animals. Strama is organised at two levels: a network of independent local multidisciplinary groups in each county that provide prescribers with feedback on antibiotic use and resistance and implement guidelines; and a national executive working group funded by the government. To gain an insight into antibiotic use, Strama has conducted several large diagnosis-prescribing surveys in primary care, in the hospital settings and in nursing homes. National antibiotic susceptibility data for Sweden and mandatory notification show that in recent years the proportion of Streptococcus pneumoniae with decreased sensitivity to penicillin V has stabilised (around 6 %), but the number of notified cases of meticillin-resistant Staphylococcus aureus (MRSA) has increased and ESBL-producing Enterobacteraceae have turned into an endemic situation. Still, Sweden is among the countries with the lowest rates of MRSA (<1 %), S. pneumoniae can still be treated with penicillin V and the rate of Escherichia coli-producing ESBLs is below 5 %. Strama´s activities have contributed to a steady decrease in antibiotic use from the mid 1990s until 2004 (when total use slowly started to increase again) without measurable negative consequences. Regular collaboration with national and regional news media has been one of the key strategies.

For the past seven years (1999 to 2006), the European Antimicrobial Resistance Surveillance System (EARSS) has collected antimicrobial susceptibility test results of invasive isolates in humans of seven bacterial species that serve as indicators for the development of antimicrobial resistance in Europe.