JAC Advance Access originally published online on February 20, 2009
Journal of Antimicrobial Chemotherapy 2009 63(4):733-744; doi:10.1093/jac/dkp012
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Original research |
A pan-European survey of antimicrobial susceptibility towards human-use antimicrobial drugs among zoonotic and commensal enteric bacteria isolated from healthy food-producing animals
1 EASSA Study Group, c/o CEESA, 1 Rue Defacqz, Brussels, Belgium 2 Bayer HealthCare, Animal Health GmbH Leverkusen, Germany 3 Bywater Consultancy, Clungunford, UK 4 CEVA Sante Animale, Libourne, France 5 Fort Dodge Animal Health, Louvain-la-Neuve, Belgium 6 Pfizer Animal Health, Sandwich, UK 7 Novartis Animal Health, Basel, Switzerland 8 European Animal Health Study Centre (CEESA), Brussels, Belgium 9 Elanco Animal Health, Basingstoke, UK 10 Alpharma Belgium BVBA, Antwerp, Belgium 11 Intervet Schering Plough Animal Health, Boxmeer, The Netherlands 12 Vetoquinol S. A., Lure, France 13 Charles River, Tranent, UK
Received 24 September 2008; returned 24 November 2008; revised 6 December 2008; accepted 6 January 2009
* Corresponding author. Tel: +49-2173-384475; Fax: +49-2173-382448; E-mail: anno.jong{at}bayerhealthcare.com
Objectives: The aim of the study was to study antimicrobial susceptibility in Escherichia coli, Salmonella, Campylobacter and Enterococcus recovered from chickens, pigs and cattle using uniform methodology.
Methods: Intestinal samples were taken at slaughter in five EU countries per host and bacteria isolated in national laboratories. MICs were determined in a central laboratory of key antimicrobials used in human medicine. Clinical resistance was based on CLSI breakpoints and decreased susceptibility on EFSA epidemiological cut-off values.
Results: Isolation rates from a total of 1500 samples were high for E. coli (n=1465), low for Salmonella (n=205) and intermediate for Campylobacter (n=785) and Enterococcus (n=718). Resistance prevalence varied among antibiotics, bacteria, hosts and countries. For E. coli and Salmonella, clinical resistance to newer compounds (cefepime, cefotaxime, ciprofloxacin) was absent or low, but a decreased susceptibility was apparent, particularly in chickens. Clinical resistance to older compounds (except colistin and gentamicin) was variable and higher. For Campylobacter jejuni from chickens, ciprofloxacin resistance was markedly higher than in isolates from cattle. Clinical resistance to erythromycin was absent for both hosts; decreased susceptibility very low. Similar trends were determined for Campylobacter coli, but C. jejuni was less resistant. None of the enterococcal strains was resistant to linezolid, but a few displayed resistance to ampicillin or vancomycin. Resistance prevalence to quinupristin/dalfopristin was clearly higher.
Conclusions: Antimicrobial resistance among enteric organisms in food animals varied among countries, particularly for older antimicrobials, but clinical resistance to essential compounds used to treat disease in humans was generally zero or low. In the absence of clinical resistance to newer compounds in E. coli and Salmonella, the apparent decreased susceptibility should be monitored carefully.
Keywords: antimicrobial resistance , E. coli , Salmonella , Campylobacter , enterococci , surveillance