奶牛乳腺炎源大肠杆菌中耶尔森菌强毒力岛相关基因的检测及序列分析  

Detection of High Pathogenicity Islands in Escherichia coli Isolated from Clinical and Subclinical Bovine Mastitis in Some Areas of China

作　　者：徐继英[1] 杨志强[2] 陈化琦[2] 刘俊林[1] 邢娟[3] 李建喜[2] 李宏胜[2] 

机构地区：[1]西北民族大学生命科学与工程学院,兰州730000 [2]中国农业科学院兰州畜牧与兽药研究所,兰州730050 [3]中国农业科学院兰州兽医研究所,兰州730000

出　　处：《中国农业科学》2012年第6期1199-1205,共7页Scientia Agricultura Sinica

基　　金：中央级公益性科研院所基本科研业务费专项资金项目(BRF070304);甘肃省自然科学基金项目(3ZS061-A25-072)

摘　　要：【目的】研究奶牛乳腺炎源大肠杆菌中耶尔森菌HPI携带情况及其与O血清型的关系,并对部分菌株的相关基因序列进行分析。【方法】从中国北京、内蒙古、甘肃、四川、重庆、云南、贵州等7个省市部分地区1 260份临床型和隐性奶牛乳腺炎奶样中分离得到190株大肠杆菌,对分离菌株进行耶尔森菌强毒力岛核心区irp2基因、fyuA基因及HPI毒力岛在大肠杆菌染色体中插入位置的鉴定,分析HPI毒力岛的携带情况及其与分离菌株O血清型之间的关系。【结果】190株大肠杆菌分离株中,irp2基因阳性率为26.31%(50/190),fyuA基因阳性率为18.94%(36/190)。50株HPI+分离株中检出asn_tRNA_intB基因32株,阳性率为64%(32/50)。本试验克隆的irp2基因(273 bp)、fyuA基因(1 071 bp)、asn_tRNA_intB基因(1 512 bp)均与已发表序列高度同源,同源性分别在97.1%、98.2%、97.2%以上,且其HPI毒力岛大多位于大肠杆菌染色体的asn_tRNA位点上。【结论】耶尔森菌HPI在奶牛乳腺炎源大肠杆菌中广泛流行分布,但也存在差异,而不同血清型菌株携带HPI的倾向性可能只与特定的血清型有一定的关系。【Objective】The objective of the experiment is to investigate the present distribution of high pathogenicity island（HPI） in E.coli isolated from cows with clinical and subclinical mastitis in China.【Method】Milk samples from 1 260 cows with clinical and subclinical mastitis in different farms and areas were used to screen Gram-negative bacteria by MacConkey agar.One hundred and ninety E.coli isolates was further identified from the Gram-negative bacteria by microbiological tests.Total DNA extraction from E.coli was used to detect HPI genes by PCR.【Result】The PCR results showed that 50 out of 190 isolates carried the irp2 gene,36 isolates were positive for fyuA gene and 32 for intB genes.Sequence analysis of randomly selected PCR products showed that homology of genes irp2,fyuA,and asn_tRNA_intB were above 97.1%,98.2%,and 97.2% identical to the published sequences.HPI＋ isolates were associated with fyuA（72%） and asn_tRNA locus（64%）.【Conclusion】 Yersinia HPI was widely distributed in the E.coli isolates from cows with clinical and subclinical mastitis in China.The prevalence of HPI is associated with special serotypes in E.coli from cows with clinical and subclinical mastitis.

关 键 词：奶牛乳腺炎 大肠杆菌 HPI毒力岛 O血清型 

分 类 号：S858.23[农业科学—临床兽医学]