Cloning And Sequencing Of Virulence Genes Of Escherichia Coli Isolated From Cow Clinical Mastitis

To study the E.coli isolates from clinical mastitis in Ningxia region.120 strains were submitted to serological testing using somatic and virulence factors testing using polymerase chain reaction (PCR). colonization factor fimH, f17, f165, f41, f5, eae, cs31a and transport proteins trat were detected by PCR.Clinical mastitis milk was collected as a sample in Ningxia region from 2013 to 2014. E.coli isolates were tested by Biochemical tests,120 strains E. coli isolates were identified.120 strains were submitted to serological testing using somatic.120 strains were identified 71 E. coli serotypes,O8, O10, O15, O18, O22, O26, O53, O55, O68, O86, O91, O92, O93, O101, O107,O117, O126, O142 O148, O153, O158 were identified. Advantages serotype O158,O101, O126, O91, O15, O26, O107, accounting for 61.9% of stereotypes strains,49 unidentified serotypes.To test trat and seven kinds of colonization factor fimh, f17, f165, f41, f5, eae, cs31a testing. Experimental results show that 120 strains E. PCR results,trat gene isolation rate was 24.2%, fimH gene isolation was 85.8%, f17 gene isolation was 5%, f165 gene isolation was 3.3%, f41 gene was isolated was 0, f5 gene isolation rate was 0, eae gene isolation rate was 0, cs31a gene isolation rate was 0.Experimental results show that the intestinal infection and clinical mastitis isolates of E. coli serotypes, there are significant differences in virulence genes separation rate.In this study, clinical mastitis strains of E. coli (O158) as a template, synthetic primers fimH genes were cloned and sequenced. Sequence analysis showed that in the 714 bases fimh gene mutation from T to A, in the 717 bases A mutation of the base by G, the 807 bp mutation from G to A, the 831 base T to C.