[Objective] To understand the contamination status and antimicrobial activity of Escherichia coli in retail meat sold in Guangzhou .[Method]We collected 310 meat samples including 253 retail pork and 57 chicken meat from markets and supermarkets in Guangzhou from July to August , 2011.E.coli strains were isolated and identified using the selective media .The susceptibilities of E.coli strains to 19 common antibiotics represented by the minimum inhibitory concentrations ( MIC ) were tested using the agar dilution method .[Result]Totally 213 E.coli strains were isolated from 310 meat samples with the detection frequency of 68.7%, including 117 pork isolates and 36 chicken meat isolates .More than 75.0%isolates were resistant to sulfamethoxazole/trimethoprim , streptomycin and tetracycline , 10.0%to 60.0%isolates were resistant to ampicillin , nalidixic acid , chloramphenicol , neomycin , florfenicol , fosfomycin, ciprofloxacin, apramycin, enrofloxacin, gentamicin and cefazolin, and the isolates were sen-sitive to cefoxitin , ceftriaxone , ceftazidime , colistin and amikacin with below 5.0% being resistant strains.Isolates from chicken meat showed significantly higher resistance to cefazolin , cefoxitin, ceftriax-one, ceftazidime and fosmycin compared to pork isolates ( P <0.01 ) .There were 82.2% multi-drug resistant strains of 213 E.coli strains.[Conclusion]Retail meat sold in Guangzhou were severely contami-nated by multi-drug resistant E.coli, and chicken meat isolates showed higher resistance compared to pork isolates .%【目的】了解广州市售肉类食品源大肠埃希菌的污染和耐药情况。【方法】自2011年7月至8月，从广州市各大农贸市场和超市采集市售肉类样品310份，其中猪肉253份，鸡肉57份。采用选择性培养基分离鉴定大肠埃希菌Escherichia coli，琼脂稀释法测定大肠埃希菌对19种抗菌药物的最小抑菌浓度（ MIC）。【结果】310份样品中共分离到213株大肠埃希菌，分离率为68.7％，其中猪肉源177株，鸡肉源36株。受试菌株对复方新诺明、链霉素和四环素的耐药率超过75.0％，对氨苄西林、萘啶酸、氯霉素、新霉素、氟苯尼考、磷霉素、环丙沙星、安普霉素、恩诺沙星、庆大霉素和头孢唑啉的耐药率为10.0％～60.0％，而对头孢西丁、头孢曲松、头孢他啶、黏菌素和阿米卡星表现较为敏感，耐药率小于5.0％。鸡肉源大肠埃希菌对头孢唑啉、头孢西丁、头孢曲松、头孢他啶和磷霉素的耐药率均高于猪肉源大肠埃希菌，差异极显著（ P＜0.01）。213株大肠埃希菌中82.2％为多重耐药菌。【结论】广州市售肉类食品存在较为严重的多重耐药大肠埃希菌污染，且鸡肉源大肠埃希菌耐药性较猪肉源大肠埃希菌严重。
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