Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Agassiz, British Columbia, Canada V0M 1A0.
Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, British Columbia, Canada V0H 1Z0.
J Food Prot. 2014 Jan;77(1):40-9. doi: 10.4315/0362-028.JFP-13-251.
The objective of this study was to analyze the antibiotic resistance phenotype and genotype of Salmonella isolated from broiler production facilities. A total of 193 Salmonella isolates recovered from commercial farms in British Columbia, Canada, were evaluated. Susceptibility to antibiotics was determined with the Sensititre system. Virulence and antibiotic resistance genes were detected by PCR assay. Genetic diversity was determined by pulse-field gel electrophoresis (PFGE) typing. Seventeen serovars of Salmonella were identified. The most prevalent Salmonella serovars were Kentucky (29.0% of isolates), Typhimurium (23.8%), Enteritidis (13.5%), and Hadar (11.9%); serovars Heidelberg, Brandenburg, and Thompson were identified in 7.7, 4.1, and 3.6% of isolates, respectively. More than 43% of the isolates were simultaneously resistant to ampicillin, amoxicillin-clavulanic acid, ceftiofur, cefoxitim, and ceftriaxone. This β-lactam resistance pattern was observed in 33 (58.9%) of the Salmonella Kentucky isolates; 2 of these isolates were also resistant to chloramphenicol, streptomycin, sulfisoxazole, and tetracycline. Genes associated with resistance to aminoglycosides (aadA1, aadA2, and strA), β-lactams (blaCMY-2, blaSHV, and blaTEM), tetracycline (tetA and tetB), and sulfonamide (sul1) were detected among corresponding resistant isolates. The invasin gene (invA) and the Salmonella plasmid virulence gene (spvC) were found in 97.9 and 25.9% of the isolates, respectively, with 33 (71.7%) of the 46 Salmonella Typhimurium isolates and 17 (65.4%) of the 26 Salmonella Enteritidis isolates carrying both invA and spvC. PGFE typing revealed that the antibiotic-resistant serovars were genetically diverse. These data confirm that broiler chickens can be colonized by genetically diverse antibiotic-resistant Salmonella isolates harboring virulence determinants. The presence of such strains is highly relevant to food safety and public health.
本研究旨在分析从肉鸡生产设施中分离出的沙门氏菌的抗生素耐药表型和基因型。从加拿大不列颠哥伦比亚省的商业农场中回收了 193 株沙门氏菌分离株进行评估。使用 Sensititre 系统测定抗生素敏感性。通过 PCR 检测毒力和抗生素耐药基因。通过脉冲场凝胶电泳 (PFGE) 分型确定遗传多样性。鉴定出 17 种沙门氏菌血清型。最常见的沙门氏菌血清型是肯塔基州（29.0%的分离株）、鼠伤寒血清型（23.8%）、肠炎血清型（13.5%）和哈达尔血清型（11.9%）；分别在 7.7%、4.1%和 3.6%的分离株中鉴定出海德堡、勃兰登堡和汤普森血清型。超过 43%的分离株同时对氨苄西林、阿莫西林-克拉维酸、头孢噻呋、头孢西丁和头孢曲松耐药。这种β-内酰胺耐药模式在 33 株（58.9%）沙门氏菌肯塔基州分离株中观察到；其中 2 株分离株还对氯霉素、链霉素、磺胺甲恶唑和四环素耐药。在相应的耐药分离株中检测到与氨基糖苷类（aadA1、aadA2 和 strA）、β-内酰胺类（blaCMY-2、blaSHV 和 blaTEM）、四环素类（tetA 和 tetB）和磺胺类（sul1）耐药相关的基因。在 97.9%和 25.9%的分离株中分别检测到侵袭素基因（invA）和沙门氏菌质粒毒力基因（spvC），46 株鼠伤寒沙门氏菌分离株中有 33 株（71.7%）和 26 株肠炎沙门氏菌分离株中有 17 株（65.4%）携带 invA 和 spvC。PGFE 分型显示，抗生素耐药血清型具有遗传多样性。这些数据证实，肉鸡可定植具有毒力决定因素的遗传多样性的抗生素耐药沙门氏菌分离株。这种菌株的存在与食品安全和公共卫生密切相关。
