目的　了解重庆市区及近郊家禽家畜中O15 7大肠杆菌的存在和致病力情况以及对人群可能存在的威胁。方法　采集重庆近郊 5个区养殖场动物粪便和环境标本共 5 70份检测O15 7大肠杆菌 ,对分离菌株问的流行病学关系及菌株的致病力情况进行了探讨。结果　分离出 17株O15 7大肠杆菌 ,其中有 3株无动力O15 7:NM ,总分离率2 89%。通过质粒图谱和限制性酶切图谱分析发现 2株菌有流行病学相关性 ,属同一克隆株。通过溶血因子检测、小鼠毒力实验、Vero细胞毒实验及PCR毒力基因检测 ,发现多数大肠杆菌O15 7不含志贺毒素基因、不产志贺毒素 ,但却携带eae和hly基因 ,同时有溶血活性并均能致实验小鼠死亡。 结论　重庆市区的养殖场动物携带有O15 7大肠杆菌 ,并造成了环境的污染 ,污染细菌有不同程度的致病力 ,表明本地区已存在O15 7大肠杆菌感染的威胁 Objective To understand the existence and virulence of O157 Escherichia coli in poultry and livestock in downtown Chongqing and its suburbs, as well as possible threats to the population. Methods A total of 570 laboratory tests of E. coli O157 were collected from farm animal faeces and environmental samples from 5 farms in the suburbs of Chongqing. The epidemiological relationships among isolates and pathogenicity of the strains were also discussed. As a result, 17 strains of O15 7 Escherichia coli were isolated, of which 3 had no power O15 7: NM, with a total separation rate of 2 89%. Two isolates were found to be epidemiologically related to the same clone by plasmid map and restriction analysis. Through hemolysis test, mouse virulence test, Vero cytotoxic test and PCR virulence gene test, it was found that most E. coli O15 7 did not contain Shiga toxin gene and did not produce Shiga toxin, but it carried eae and hly genes simultaneously Hemolytic activity and can cause experimental mice to die. Conclusion The farm animals in Chongqing carry O15 7 Escherichia coli and cause environmental pollution. The contaminated bacteria have varying degrees of pathogenicity, indicating that there is a threat of E. coli infection O15 7 in this area