title: Emergence of AmpC-producing Escherichia coli in the broiler production chain in a country with a low antimicrobial usage profile.
abstract: The aim of this study was to estimate the prevalence of cephalosporin-resistant Escherichia coli at the different levels of the Norwegian broiler production pyramid and identify the mechanisms responsible for the resistance phenotype. Samples from all levels of the broiler production pyramid and retail chicken meat (fillets) were included (n=649). The occurrence of cephalosporin-resistant E. coli at the different production levels ranged from 8 to 43%. All these isolates had an AmpC-phenotype, and the majority carried the blaCMY-2 gene. In addition, a few isolates with up-regulated chromosomal ampC were identified. The results show that Norway has a relatively high prevalence of cephalosporin-resistant E. coli in the broiler production chain in spite of a very low consumption of antimicrobial agents. Cephalosporins have not been used in the Norwegian broiler production, and it has been hypothesised that import of breeding animals and hatching eggs may be the source of these resistant bacteria. We demonstrate that these bacteria are disseminated in the production pyramid despite the lack of selection pressure from antimicrobial agents.
authors.affiliation: Norwegian Veterinary Institute, Pb 750 Sentrum, 0106 Oslo, Norway. Electronic address: solveig.mo@vetinst.no.
authors.forename: Solveig Sølverød
authors.initials: SS
authors.lastname: Mo
authors.affiliation: Norwegian Veterinary Institute, Pb 750 Sentrum, 0106 Oslo, Norway.
authors.forename: Madelaine
authors.initials: M
authors.lastname: Norström
authors.affiliation: Norwegian Veterinary Institute, Pb 750 Sentrum, 0106 Oslo, Norway.
authors.forename: Jannice Schau
authors.initials: JS
authors.lastname: Slettemeås
authors.affiliation: Nortura SA, Pb 33, 1891 Rakkestad, Norway.
authors.forename: Atle
authors.initials: A
authors.lastname: Løvland
authors.affiliation: Norwegian Veterinary Institute, Pb 750 Sentrum, 0106 Oslo, Norway.
authors.forename: Anne Margrete
authors.initials: AM
authors.lastname: Urdahl
authors.affiliation: Norwegian Veterinary Institute, Pb 750 Sentrum, 0106 Oslo, Norway.
authors.forename: Marianne
authors.initials: M
authors.lastname: Sunde
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002511:Cephalosporins / Q000494:pharmacology* / Q000627:therapeutic use; D002645:Chickens; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000662:veterinary*; D005511:Food Handling / Q000379:methods; D008460:Meat / Q000382:microbiology*; D009664:Norway / Q000453:epidemiology; D011201:Poultry Diseases / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D015995:Prevalence; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002511:Cephalosporins; C048795:AmpC beta-lactamases; D001618:beta-Lactamases
keywords: AmpC; Broiler; E. coli; ESBL