牦牛产志贺毒素大肠杆菌主要黏附因子相关基因的分子流行病学调查

Molecular Epidemiological Investigation of Genes Related with the Major Adhesion Factors in Shiga Toxin-producing Escherichia coli from Yak

为了解中国牦牛产志贺毒素的大肠杆菌(Shiga toxin-producing Escherichia coli,STEC)中主要黏附因子的流行情况,采用PCR方法对来自四川甘孜阿坝等地区健康牦牛的70株STEC的eae、saa、iha3种与黏附相关的毒力基因进行检测,并对部分含有相关黏附因子的阳性分离株的毒力基因进行了克隆及序列分析。结果显示,牦牛STEC中saa、iha的阳性率分别为71.42%(50/70)和78.57%(55/70),无eae基因序列(0/70),saa、iha的测序结果与GenBank上序列的同源性分别为100%和93%～99%。健康牦牛分离的STEC无LEE毒力岛编码eae,其他的一些与黏附相关的主要毒力基因saa、iha的携带率较高。

The assay was aimed to investigate the prevalence of the major adhension factors in Shiga toxin-producing Escherichia coli from Yak.By using the method of PCR to detect the adhension factors of eae,saa,iha genes in the 70 STEC isolates from the healthy Yak in Sichuan Ganzi,Aba and other places,some of the adhension genes were cloned and sequenced.The results showed that the carried rates of saa and iha genes were 71.42%（50/70） and 78.57%（55/70） respectively in 70 STEC strains from Yak,none of the STEC isolates carried the eae gene（0/70）,the homologies of saa and iha genes were 100% and 93% to 99% respectively with the reference sequences in GenBank.STEC isolates from the healthy Yak didn＇t have eae gene which was encoded by LEE virulence island,the carried rates of other adhension virulence genes saa,iha were higher.