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为了了解西藏地区牦牛源肠产毒性大肠杆菌毒力基因分布情况,本试验对西藏林芝、拉萨等不同地、市107株牦牛源大肠杆菌进行了大肠杆菌毒力基因的PCR检测和基因分型。结果显示,利用22对肠产毒性大肠杆菌毒力基因引物进行检测,只检出STp以及CS8基因;对所检测到的16株牦牛源肠产毒性大肠杆菌进行克隆测序,经系统发育分析发现牦牛源肠产毒性大肠杆菌菌株内同源性达到99.9%左右,与GenBank中所录其他菌株的同源性达到95%~100%。按照系统发育进化分型的方法,对16株大肠杆菌中有3株属于D群,其余均属于A群。结果表明,西藏牦牛源大肠杆菌中肠产毒性大肠杆菌基因确实存在,其毒力基因主要为STp以及CS8基因;西藏林芝、拉萨、山南和日喀则均有分布,那曲和阿里地区未检出,通过对小鼠的致病性试验,致死率为95%,说明致病性很强,应引起重视。
In order to understand the distribution of virulence genes of Yak originally producing enterotoxigenic E. coli in Tibet area, 107 strains of Yak origin Escherichia coli from different sites in Tibet such as Nyingchi and Lhasa were detected by PCR and genotyping of virulence genes of E. coli. The results showed that 22 strains of enterotoxigenic E. coli virulence genes were detected and only STp and CS8 genes were detected. The 16 yak-producing enterotoxigenic Escherichia coli strains that were detected were cloned and sequenced. The phylogenetic analysis showed that yak The homology of the enterotoxigenic E. coli reached 99.9%, which was 95% ~ 100% homologous with other strains recorded in GenBank. According to the method of phylogenetic evolutionary typing, 3 out of 16 E.coli belonged to D group, the rest belong to A group. The results showed that the Yak-producing Escherichia coli producing enterotoxigenic Escherichia coli gene existed in Tibet, and the virulence genes were mainly STp and CS8. There were distribution of Nyingchi, Lhasa, Shannan and Shigatse in Tibet, but not in Naqu and Ali regions Pathogenicity test in mice, the lethal rate was 95%, indicating a strong pathogenic, should pay attention.