Zoonoses are infections and diseases that are transmissible between animals and humans. Infection can be acquired directly from animals, or through the ingestion of contaminated foodstuffs. The severity of these diseases in humans can vary from mild symptoms to life-threatening conditions. The zoonotic bacteria that are resistant to antimicrobials are of special concern since they might compromise the effective treatment of infections in humans. In order to follow the occurrence of antimicrobial resistance in zoonotic bacteria isolated from animals and food, information is collected and analysed from all European Union Member States.
In 2009, 25 Member States submitted information on the occurrence of antimicrobial resistance in zoonotic bacteria to the European Commission, the European Food Safety Authority and the European Centre for Disease Prevention and Control. In addition, three other European countries provided information. Assisted by its contractor, the Veterinary Laboratories Agency in the United Kingdom, the European Food Safety Authority and the European Centre for Disease Prevention and Control, analysed the data, the results of which are published in this European Union Summary Report. Information on antimicrobial resistance was reported regarding Salmonella and Campylobacter isolates from human cases, food and animals, whereas data on indicator Escherichia coli and indicator enterococci isolates derived only from animals and food. Data on antimicrobial resistance in isolates from human cases were mainly interpreted by using clinical breakpoints, while the quantitative data on antimicrobial resistance in isolates from food and animals were interpreted using harmonised epidemiological cut-off values defining the microbiologically resistant isolates.
In the European Union, the occurrence of resistance in Salmonella isolates from salmonellosis cases in humans was high for ampicillin, tetracyclines and moderate for sulphonamides, whereas resistance to the critically important antimicrobials for human medicine, cefotaxime (a third-generation cephalosporin) and ciprofloxacin (fluoroquinolones) was relatively low, although for ciprofloxacin reported resistance levels were higher in countries where epidemiological cut-off values were used. There was a high level of resistance to ampicillin, ciprofloxacin, nalidixic acid and tetracyclines among Campylobacter isolates from human cases, while relatively low resistance was recorded to the clinically most important antimicrobial, erythromycin.
Resistance to antimicrobials was commonly found in isolates of Salmonella, Campylobacter and indicator E. coli and enterococci from animals and food in the European Union.
The high proportions of Salmonella, Campylobacter and indicator E. coli isolates exhibiting resistance to ciprofloxacin are of concern. In food and animal isolates, the highest occurrence of resistance to ciprofloxacin was noted in Salmonella from fowl (Gallus gallus) and broiler meat, where 18 % to 22 % of the isolates were found resistant in the reporting Member States group. Among the indicator E. coli isolates, moderate to high levels of ciprofloxacin resistance was observed in isolates from Gallus gallus and pigs, at levels of 47 % and 12 %, respectively. Furthermore, high resistance to fluoroquinolones was commonly observed in Campylobacter isolates from Gallus gallus and broiler meat, as well as from pigs and cattle at levels of 33 % to 78 %.
Resistance to third-generation cephalosporins was observed in Salmonella and indicator Escherichia coli isolates from Gallus gallus, pigs, cattle and meat derived from broilers and pigs at very low or low levels varying from 0.4 % to 9 %. Resistance to erythromycin was detected in Campylobacter isolates from Gallus gallus, poultry meat and pigs at levels of 0.3 % to 35 %.
Among Salmonella isolates from meat and animals, resistance to tetracyclines, ampicillin and sulphonamides was reported at levels of 12 % to 60 % and it was higher in isolates from pigs and cattle compared to isolates from Gallus gallus. In contrast, resistance to ciprofloxacin and nalidixic acid was higher in Salmonella isolates from Gallus gallus and broiler meat.
In isolates of Campylobacter from meat and animals, resistance was commonly detected to ciprofloxacin, nalidixic acid and tetracyclines at levels of 33 % to 78 %, while much lower levels were reported to erythromycin and gentamicin.
For indicator E. coli from meat and animals, resistance to tetracyclines, ampicillin and sulphonamides was commonly reported at levels of 20 % to 64 %. In general, resistance levels were lowest among isolates from cattle in comparison to isolates from Gallus gallus and pigs. Resistance to ciprofloxacin and nalidixic acid was highest for isolates from Gallus gallus.
Among indicator enterococci, resistance to tetracyclines and erythromycin was common in isolates from Gallus gallus, pigs and cattle at levels of 22 % to 90 %, the level of resistance being lowest for isolates from cattle. Resistance to vancomycin continued to be detected, albeit at low to very low levels, at 0.2 % to 2 %, in enterococcal isolates from animals.