title: Evaluation of antimicrobial resistance profiles of Salmonella isolates from broiler chickens at slaughter in Alberta, Canada.
abstract: Antimicrobial-resistant Salmonella species are threatening to become a serious public health problem. Therefore, surveillance and prudent use of antimicrobials is needed in both the agricultural and human health sectors. The aim of this study was to describe the antimicrobial susceptibility profiles of Salmonella isolates recovered from healthy broiler chickens at slaughter from November 2004 to April 2005. Salmonella isolates recovered from 36 broiler flocks in Alberta, Canada, were serotyped and tested for antimicrobial susceptibility against 15 antimicrobials. Of 272 Salmonella isolates tested, 64.0% were resistant to one or more antimicrobials, 10.0% were resistant to three or more antimicrobials, and 1.8% were resistant to five antimicrobials. All isolates were susceptible to amikacin, amoxicillin-clavulanic acid, ceftiofur, cefoxitin, ceftriaxone, ciprofloxacin, and nalidixic acid. The highest prevalence of resistance was to tetracycline (54.8%), followed by streptomycin (24.2%) and sulfisoxazole (8.4%). The most common multiantimicrobial resistance patterns were to streptomycin-tetracycline (24.3%), streptomycin-sulfisoxazole-tetracycline (6.6%), and ampicillin-streptomycin-sulfisoxazole-tetracycline (3.7%). The strongest associations were observed between resistance to kanamycin and tetracycline (odds ratio = 65.7, P = 0.001) and to ampicillin and sulfisoxazole (odds ratio = 62.9, P = 0.001). Salmonella Hadar and Salmonella Heidelberg were the two most common serovars accounting for 40.4 and 13.6% of the total isolates, respectively. Eighty-one percent and 12.7% of Salmonella Hadar isolates and 62.0 and 8.1% of Salmonella Heidelberg isolates were resistant to 1 or more and three or more antimicrobials, respectively. The flock level prevalence of resistance ranged from 5.6% for trimethoprim-sulfamethoxazole to 83.3% for tetracycline. This study provides baseline information on antimicrobial susceptibility of Salmonella isolates of broiler chickens at slaughter in Alberta that can serve as a benchmark for future research.
authors.affiliation: Food Safety and Animal Health Division, Alberta Agriculture and Rural Development, O.S. Longman Building, 6909-116 Street, Edmonton, Alberta, Canada T6H 4P2. chunu.mainali@gov.ab.ca.
authors.forename: C
authors.initials: C
authors.lastname: Mainali
authors.affiliation: Food Safety and Animal Health Division, Alberta Agriculture and Rural Development, O.S. Longman Building, 6909-116 Street, Edmonton, Alberta, Canada T6H 4P2.
authors.forename: M
authors.initials: M
authors.lastname: McFall
authors.affiliation: Food Safety and Animal Health Division, Alberta Agriculture and Rural Development, O.S. Longman Building, 6909-116 Street, Edmonton, Alberta, Canada T6H 4P2.
authors.forename: R
authors.initials: R
authors.lastname: King
authors.affiliation: Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, 160 Research Lane, Unit 103, Guelph, Ontario, Canada N1G 5B2.
authors.forename: R
authors.initials: R
authors.lastname: Irwin
mesh_terms: D000416:Alberta; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002645:Chickens; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004305:Dose-Response Relationship, Drug; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D005516:Food Microbiology; D006801:Humans; D008460:Meat / Q000382:microbiology; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D015995:Prevalence; D012475:Salmonella / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents