新疆奶牛乳源大肠杆菌毒力相关基因eaeA的克隆及序列分析

摘要

This study was carried out to collect the milk samples from the cattle doubted about suffering from recessive mastisis of 5 dairy cattle farms around Urumqi city and to seperate,purify and determine 34 strains milk Escherichia coli. According to the 16S rRNA and eaeA sequences published by GenBank.two pairs of specific primers were designed by Oligo 6. 0. 10 aureus were amplified by PCR,the positive rate is 29. 4％ (10/34). The positive samples were analyzed by sequence comparison The sequence homology rate is above 65％ when compared with the sequences published on GenBank,the homology for FJ609802 strain was 75％. The positive samples were determined by serum O simultaneity, and it was found that although there were eaeA positive samples in other serum types,there were high gene eaeA positive rate in O21 serum type strain%从采自新疆乌鲁木齐市周边的5个奶牛场疑患隐性乳腺炎奶牛乳样,分离、纯化、鉴定出34株牛乳源大肠杆菌.根据GenBank发表的大肠杆菌16SrRNA序列和eaeA基因序列,用Oligo 6.0软件分别设计两对特异性引物,对分离菌株进行复检,并利用聚合酶链式反应(PCR)对eaeA基因进行扩增,结果10株为阳性,阳性率为29.4%(10/34).将阳性样品进序列分析,结果与已发表的序列同源率为65%以上.与FJ609802株同源性较高,同源性75%.将阳性菌株用大肠埃希氏菌O抗原定型血清标定,以O21血清型的菌株eaeA基因阳性率较高.