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为了解河北省腹泻仔猪源产毒素性大肠杆菌肠毒素的流行分布情况,试验采用PCR方法以质粒DNA为模板对40株大肠杆菌进行肠毒素基因Sta和Stb的检测,并通过对其序列比对分析菌株之间的同源性。结果表明:在40株大肠杆菌中成功扩增出Sta基因36株,Stb基因23株,其中有19株同时携带2种肠毒素,占全部菌株的47.5%(19/40);单独携带肠毒素Sta基因的有17株,占肠毒素阳性菌株的42.5%(17/40)。Sta和Stb基因序列同源性分析显示,已测序的试验菌株之间的同源性在99.6%～100%之间。说明河北省致仔猪腹泻大肠杆菌流行株所携带的肠毒素主要是Sta+Stb及Sta,各地区流行菌株所携带的ST基因具有高度的同源性,具有相近的亲缘关系。
In order to understand the epidemiological distribution of toxin-producing enterotoxigenic enterotoxigenic Escherichia coli in diarrhea piglets in Hebei province, 40 strains of Escherichia coli were tested for Sta and Stb enterotoxins by PCR using plasmid DNA as a template. Strains were analyzed for homology. The results showed that 36 Sta genes and 23 Stb genes were successfully amplified in 40 Escherichia coli strains, of which 19 strains simultaneously carried 2 enterotoxins, accounting for 47.5% (19/40) of the total strains; Sta gene has 17 strains, accounting for 42.5% (17/40) of enterotoxin-positive strains. Homology analysis of Sta and Stb revealed that the homologies between sequenced strains ranged from 99.6% to 100%. Staphylococcal enterotoxigenic strains of Staphylococcus aureus are mainly Sta + Stb and Sta. The ST genes carried by the endemic strains in all regions have a high degree of homology and have similar genetic relationships.