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目的对我国人源与牛源的肠致病性大肠杆菌(Enteropathogenic Escherichia coli,EPEC)分离株进行脉冲场凝胶电泳(Pulsed-Field Gel Electrophoresis,PFGE)分析,了解我国EPEC分离株的分子流行病学特征并初步建立我国EPEC菌株的PFGE基础数据库。方法参照Pulse Net中非O157大肠杆菌的PFGE分型方法,对实验室保存的74株EPEC代表性菌株进行PFGE分型,并用Bio Numerics软件进行聚类分析。结果在Pulse Net推荐的参数条件下,菌株基因组限制性内切酶Xba I酶切片段分布均匀,条带易于识别。74株EPEC菌株共产生66种PFGE带型(EPEC0001-EPEC0066),其中5株典型EPEC(t EPEC)分为3种PFGE带型,69株非典型EPEC(a EPEC)分为63种带型。PFGE聚类分析显示人源菌株与牛源菌株虽各自存在一定程度的集中分布趋势,但二者也相互散在分布,人源菌株EP120与牛源菌株EP125聚类相似性达90%。结论我国EPEC分离株呈现高度多态性,分离自牛的菌株与分离自人的菌株在PFGE聚类中呈现一定的相互散在分布,提示牛作为EPEC的重要宿主,可能在人类感染EPEC中发挥一定作用。
Objective To investigate the molecular epidemiology of EPEC isolates in China by pulsed-field gel electrophoresis (PFGE) analysis of enteropathogenic Escherichia coli (EPEC) isolates from human and bovine origin in China. The characteristics and preliminary establishment of our country EPEC strain PFGE basic database. Methods PFGE typing of 74 strains of EPEC strains preserved in the laboratory was performed according to the method of PFGE typing of Pulse Net Central African O157 Escherichia coli. The data were analyzed by Bio Numerics software. Results Under the parameters recommended by Pulse Net, the fragments of Xba I restriction endonuclease were evenly distributed and the bands were easy to identify. A total of 66 PFGE bands (EPEC0001-EPEC0066) were generated from 74 strains of EPEC strains. Among them, 5 strains of classical EPEC (t EPEC) were divided into 3 PFGE bands and 69 strains of asexual EPEC (a EPEC) were divided into 63 bands. PFGE clustering analysis showed that there was a certain degree of concentration distribution trend between human and bovine source strains, but the two were also scattered with each other. The similarity between EP120 strain and EP125 cluster was 90%. Conclusion The EPEC isolates showed a high degree of polymorphism in China. The strains isolated from cattle and strains isolated from humans showed some scattered distribution in the PFGE cluster, suggesting that cattle as an important host of EPEC may play a certain role in human EPEC infection effect.