Prevalence and persistence of antimicrobial resistance in broiler indicator bacteria.
This study explored the prevalence and persistence of acquired antimicrobial resistance in Escherichia coli and Enterococcus faecium from healthy broilers. In 32 broiler farms, cloacal samples were taken during two production rounds, with one production round in between. For 10 of the sampled flocks, samples from the carcasses at the slaughterhouse were also collected. For E. coli, high levels of resistance were found for ampicillin, nalidixic acid, streptomycin, tetracycline, and the combination of trimethoprim and sulfonamide. Over 58% of all the isolates showed resistance to four or more antimicrobial agents. Only 4.8% were fully susceptible for all 14 drugs tested. A remarkably high resistance rate (up to 41%) to ceftiofur was found. The enterococci were frequently resistant to macrolides, tetracycline, and the combination quinopristin/dalfopristin. Over 80% displayed acquired resistance to four or more antimicrobial agents, and 3.9% were fully susceptible for the eight agents tested. Resistance was found to persist over consecutive production rounds. There was a good correlation between results obtained with cloacal samples of the live animals and caecal content samples collected in the slaughterhouse for both E. coli and E. faecium. For E. coli but not for E. faecium, the resistance profile of neck skin isolates was different from that of cloacal isolates.
Persoons
Davy
D
Veterinary Epidemiology Unit, Department of Obstetrics, Reproduction, and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke 820, Belgium. davy.persoons@ugent.be
Dewulf
Jeroen
J
Smet
Annemieke
A
Herman
Lieve
L
Heyndrickx
Marc
M
Martel
An
A
Catry
Boudewijn
B
Butaye
Patrick
P
Haesebrouck
Freddy
F
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001715:Bird Diseases / Q000453:epidemiology / Q000382:microbiology; D002645:Chickens; D024901:Drug Resistance, Multiple, Bacterial; D016984:Enterococcus faecium / Q000187:drug effects* / Q000302:isolation & purification; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D005516:Food Microbiology; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D008826:Microbial Sensitivity Tests; D011202:Poultry Products / Q000382:microbiology; D015995:Prevalence
D000900:Anti-Bacterial Agents