目的 分析北京市通州区腹泻就诊患者中肠致病性大肠埃希菌(EPEC)分离株的特征。 方法 eaeA基因聚合酶链反应(PCR)扩增阳性的菌株,进行系统生化鉴定、EPEC诊断血清分型、bfpA基因PCR扩增以及脉冲场凝胶电泳(PFGE)分析。 结果 20株成年人腹泻患者EPEC分离株中,仅1株鉴定为O126血清群;4株儿童腹泻患者分离株中,仅1株鉴定为O26血清群。儿童与成年人腹泻患者EPEC分离株bfpA基因均为阴性。23株EPEC菌株的PFGE带型呈高度多态性,聚类图显示与患者年龄及性别无明显相关。 结论 北京市通州区腹泻患者EPEC分离株以非典型为主,单纯通过血清群来诊断EPEC的方法,将会造成极大的漏诊。
Objective To understand the characteristics of enteropathogenic Escherichia coli (EPEC) isolated from diarrheal patients in Tongzhou district, Beijing. Methods The strains which were eaeA gene positive in PCR amplification were selected to conduct biochemical identification, serotyping, bfpA PCR amplification and pulsed field gel electrophoresis (PFGE) analysis. Results Only 1 isolate was identified as O126 serogroup from 20 EPEC strains isolated from adult diarrheal patients. Only 1 isolate was identified as O26 serogroup from 4 EPEC strains isolated from diarrheal children. The bfpA genes were negative in all EPEC isolates from children and adults. The PFGE patterns of 23 isolates showed high polymorphism and no obvious relation with age and gender was indicated in the phylogenic tree. Conclusion The EPEC strains isolated from patients in Tongzhou district were mainly atypical EPEC. Detection of EPEC only based on serum group would result in many misdiagnosis.