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Antibiotic resistance of enteric bacteria in commercial broiler chickens in the Fraser Valley, BC. Nancy de With, DVM MSc Veterinary Epidemiologist BC Ministry of Agriculture and Lands. Introduction. The use of antibiotics in poultry has been associated with increased AMR in enteric bacteria
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Antibiotic resistance of enteric bacteria in commercial broiler chickens in the Fraser Valley, BC Nancy de With, DVM MSc Veterinary Epidemiologist BC Ministry of Agriculture and Lands
Introduction • The use of antibiotics in poultry has been associated with increased AMR in enteric bacteria • Resistant bacteria (or genetic determinants of resistance) can be transmitted from animals to humans • Food chain • Environmental contamination
Study Objectives • To observe the pattern of AMR over time in enteric bacteria collected from freshly voided feces of commercial broiler chickens • To collect farm data regarding the feeding of poultry foods containing antimicrobials • To observe the pattern of AMR in isolates collected from broiler carcasses at slaughter
Enteric Bacteria Organisms of interest: • Escherichia coli • Salmonella spp. • Campylobacter spp. • Enterococcus spp.
Study • 11 commercial broiler barns on 9 farms • 9 medicated barns • 3 medicated feed regimes • 2 non-medicated barns • 5 visits • days 1, 14, 26, 37 (feces) • carcass swab at slaughter
Study • Samples collected Sept 2003 to Jan 2004 • Feces and carcass samples were pooled into 1 or 2 pools for each barn and visit • Standard lab procedures used to isolation and growth of each bacteria • 5 colonies of each bacteria were selected and used for AMR testing using the SensititreTM (Trek Diagnostic Systems Ltd.) • MIC values were obtained
Antibiotics: the NARMS plate Amikacin Amoxicillin/Clavulanic Acid Ampicillin Cefoxitin Ceftriaxone Ceftiofur Cephalothin Chloramphenicol Ciprofloxacin Gentamicin Kanamycin Nalidixic Acid Streptomycin Sulfamethoxazole Tetracycline Trimethoprim/Sulfamethoxazole
Results • A total of 475 E. coli, 370 Enterococcus, 40 Salmonella, and 8 Campylobacter isolates were recovered • E. coli and Enterococcus were found from all barns and all visits • Salmonella were found from 2 barns/farms • Campylobacter was found in one barn/farm
Poultry Feeds • 3 feed companies (Feed Mill A, B & C) supplied the 9 barns that received medicated feed • Feed Mill A and Feed Mill C supplied the 2 barns that received non-medicated feed
More on Medicated Feeds • Medicated feed was used in accordance with the CMIB (administered by CFIA) • Prevent necrotic enteritis (virginiamycin, bacitracin) • Prevent coccidiosis (narasin, nicarbazin, salinomycin, monensin) • Growth promotion (penicillin) • Stimulate appetite and maintain weight gain (oxytetracycline, bacitracin) • Nicarbazin has a 4-day withdrawal time and oxytetracycline has a 7-day withdrawal
Conclusions • Chicks came on to farms with more resistance than expected • Few identifiable trends • Management factors were not considered • Would like to look at source flocks
BC MAL S. Byrne E. Whitton J. Osei-Appiah D. Lightfoot L. Lindahl M. Wetzstein H. Hannah J. Waddington Others D. Léger C. Stephen S. Ritchie R. Reid-Smith Acknowledgments