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Epidemiology of Clostridium perfringens and Clostridium difficile among Ontario broiler chicken flocks

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Title: Epidemiology of Clostridium perfringens and Clostridium difficile among Ontario broiler chicken flocks
Author: Kasab-Bachi, Hind
Department: Department of Population Medicine
Program: Population Medicine
Advisor: Guerin, Michele
Abstract: This thesis is an investigation of the epidemiology and antimicrobial susceptibility of C. perfringens and C. difficile, and the use of antimicrobials, among commercial broiler chicken flocks in Ontario. Data were obtained from the Enhanced Surveillance Project, a large-scale, cross-sectional study (July 2010 to January 2012). Caecal and colon/caecal swabs (5-pooled samples from 15 birds per flock) from 231 randomly selected flocks were collected and delivered to the laboratory for microbiological testing. Flock data were collected from producers using a questionnaire. Clostridium perfringens was frequently recovered from flocks. The netB gene was found in a moderate number of isolates and flocks. All of the C. perfringens isolates were classified as type A, except for one type E. Clostridium perfringens isolates had reduced susceptibility to ceftiofur, erythromycin, tylosin tartrate, clindamycin, oxytetracycline, tetracycline, and bacitracin. The most commonly used antimicrobials in the feed were polypeptides and ionophores. The most commonly used antimicrobials in the water were penicillins and sulfonamides. A small proportion of flocks received cephalosporins at the hatchery. Our study identified a number of factors associated with the presence of C. perfringens (and netB among C. perfringens positive flocks), and C. perfringens resistance to ceftiofur, tylosin, erythromycin, and clindamycin, oxytetracycline, tetracycline, and bacitracin. Factors included some feed mills, use of feed containing antimicrobials, feed problems, season, average duration of monitoring the flock per visit, and presence of a garbage bin at the barn entrance. Clostridium difficile was infrequently isolated from flocks. Genes encoding for toxin A and/or B, and ribotypes 001 and 014, were detected in isolates. Isolates had reduced susceptibility to ceftiofur, tylosin tartrate, erythromycin, penicillin, oxytetracycline, tetracycline, clindamycin, ampicillin, imipenem, and cefoxitin. Our study identified the baseline prevalence, genetic characteristics, and antimicrobial susceptibility of C. perfringens and C. difficile, and described the use of antimicrobials, among Ontario broiler chicken flocks. Our study also identified biosecurity, and management practices factors, including antimicrobials, significantly associated with the presence of C. perfringens (and netB), and with C. perfringens resistance to several antimicrobials. Our study findings can be used to inform future disease intervention studies.
URI: http://hdl.handle.net/10214/10434
Date: 2017-05


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