奶牛养殖场环境大肠杆菌的ERIC-PCR分型和系统进化分群

ERIC-PCR Genotyping and Phylogenetic Grouping of Escherichia coli from a Dairy Farm Environment

旨在了解奶牛养殖场环境中大肠杆菌流行情况及遗传多样性,探究不同样品分离菌株的遗传关系及系统进化分群情况,收集2017—2019年新疆某大型奶牛场养殖环境中的209份样品进行大肠杆菌分离和16S rRNA鉴定,对非重复菌株进行ERIC-PCR分型和系统进化分群试验。结果显示,共分离到338株大肠杆菌,分离率为67.46%。ERIC-PCR将其分为Ⅰ~ⅩⅣ共14型。Ⅳ(196株)型为优势型;其次为Ⅰ型(59株)、Ⅴ(31株)、Ⅹ(11株);剩余41株分布于其他10种型。除2株未分群外,其他被分为6个群,B1群(75.45%)分布最多,其次是A群(18.34%)、C群(2.96%)、D或E群(1.18%)、F群(0.30%)。综上表明,奶牛养殖场环境中大肠杆菌存在广泛的DNA多样性,且不同时间及来源菌株间存在较近的亲缘关系;系统进化分群以B1群为主。

To understand the prevalence and genetic diversity of Escherichia coli(E.coli)in the dairy farm environment and explore the genetic relationships of isolates from different samples,we conducted this experiment.In this study,E.coli was isolated from 209 samples which collected from a dairy farm environment in 2017-2019 and identified by 16S rRNA gene.The ERIC-PCR genotyping and phylogenetic grouping were performed respectively with non-duplicate E.coli.Three hundred and thirty-eight E.coli strains were isolated and the isolation rate was 67.46%.The E.coli was clustered into 14 types by ERIC-PCR genotyping.TypeⅣwas the dominant,including 196 strains,followed by typeⅠ(59 strains),typeⅤ(31 strains)and typeⅩ(11 strains).The remaining 41 strains were distributed in the other 10 types.The phylogenetic grouping results showed that 2 strains were not classified.The rest were classified into 6 types and the most strains were in group B1(75.45%).The proportion of group A,C,E,D and F were 18.34%,2.96%,1.18%,1.18%and 0.30%,respectively.E.coli had a wide range of DNA diversity in the dairy farm environment,and there was a close relationship between the strains from samples of different sources at different time.The phylogenetic grouping was mainly B1 group.