The European Food Safety Authority (EFSA) collaborating with the European Centre of Disease Prevention and Control (ECDC) recently released the 2011 European Union Summary Report on antimicrobial resistance in zoonotic and indicator bacteria from humans, animals and food. The report highlights the continued resistance of Salmonella and Campylobacter (the two most common causes of food-borne infection in the European Union) to a range of antimicrobials.
Zoonoses are infections and diseases that are transmissible between animals and humans. Human illness can be acquired directly from animals, or through the ingestion of contaminated foodstuffs. The severity of illness can vary from mild symptoms to life-threatening conditions. Antimicrobials (e.g. antibiotics) are commonly used in veterinary and human medicine to target the bacteria responsible for the infection or disease and either kill the bacterial cells or inhibit their growth. However, the emergence of bacteria resistant to antimicrobials poses a serious risk to public health as they can compromise the effective treatment of infectious diseases in both animals and humans. The emergence of antimicrobial resistance has been linked to the over-use or mis-use of antimicrobials.
In order to monitor antimicrobial resistance in the European Union, data is collated from Member States. These data are analysed and an EU summary report on antimicrobial resistance is produced annually. In 2011, 26 Member States submitted information to the European Commission and the European Food Safety Authority, and 21 submitted information to the European Centre of Disease Prevention and Control. Antimicrobial resistance data was submitted for Salmonella and Campylobacter isolates from human cases, animals and food. Data were also submitted for Escherichia coli, enterococci and Staphylococcus aureus isolates from animals and food. A new feature of the 2011 report was the reporting of multi-drug resistance (i.e. resistance to at least three different antimicrobial classes) and co-resistance patterns (i.e. combined resistance to two specific critically important antimicrobials) to critically important antimicrobials for zoonotic bacteria isolated from both humans and animals. This article focuses on the antimicrobial findings for two zoonotic bacteria, i.e. Salmonella and Campylobacter.
Salmonella isolated from humans with salmonellosis (the illness caused by Salmonella) were highly resistant to ampicillin, tetracyclines and sulfonamides (between 20 % and 30 %); however, resistance was relatively low for ciprofloxacin (<10%) and cefotaxime (<1%), which are important antimicrobials for human medicine. Multi-drug resistance was high in some countries; however, there were low levels of co-resistance to ciprofloxacin and cefotaxime. Regarding food and food-producing animals, the highest resistance to ciprofloxacin was observed in Salmonella isolated from fowl, turkeys and the meat derived from broilers (chicken) (28.7 to 50.4%). Resistance to cefotaxime was observed in Salmonella isolated from fowl, turkeys and pigs and in the meat derived from broilers (chicken) and pigs, but at low or very low levels (0.4 % to 3.3 %). However, even low levels of resistance to this critically important antimicrobial are important, and increases in resistance to cefotaxime compared with 2010 data were observed in some Member States.
Campylobacter isolated from humans with campylobacteriosis (i.e. the disease caused by Campylobacter) were highly resistant to nalidixic acid, ciprofloxacin, ampicillin and tetracyclines (between 30 and 50%). However, relatively low resistance was recorded for erythromycin (3.5%). Ciprofloxacin and erythromycin are the two most important antimicrobials for the treatment of campylobacteriosis in humans. High levels of multi-drug resistance were observed in some countries; however, there were moderate to low levels of co-resistance to ciprofloxacin and erythromycin. Regarding food and food-producing animals high levels of resistance to ciprofloxacin was observed in Campylobacter isolates from fowl and broiler meat, as well as from pigs and cattle (levels ranging from 36 to 78%). The highest level of resistance to erythromycin was observed in Campylobacter isolates from pigs (24.5%).
In conclusion, the report highlights the continued resistance of Salmonella and Campylobacter (the two most common causes of food-borne infection in the European Union) to a range of antimicrobials. In both cases co-resistance to critically important antimicrobials was low. This indicates that treatment options are still available to treat infections caused by them. However, antimicrobial resistance is a serious threat to public health and to address it joint efforts must be undertaken by multidisciplinary stakeholders in the European Union.
For further information:
European Food Safety Authority. 2013. The European Union Summary Report on antimicrobial resistance in zoonotic and indicator bacteria from humans, animals and food in 2011. EFSA Journal, 11(5):3196
EUFIC Science Brief on the European Union Summary Report on antimicrobial resistance in zoonotic and indicator bacteria from humans, animals and food in 2010