一株致病性临床型乳房炎源粪肠球菌SL22的分离与鉴定  

Isolation and Identifi cation of a Pathogenic Enterococcus faecalis Stain SL22

作　　者：常军帅 党瑞莹 杨盛源 屈勇刚[1,2] 梁晏 李娜[1] 张小玉 CHANG Junshuai;DANG Ruiying;YANG Shengyuan;QU Yonggang;LIANG Yan;LI Na;ZHANG Xiaoyu(College of Animal Science and Technology,Shihezi University,Shihezi 832003,China;Key Laboratory of Control and Prevention of Animal Disease,Xinjiang Production&Construction Corps,Shihezi 832003,China)

机构地区：[1]石河子大学动物科技学院,石河子832003 [2]动物疾病防控兵团重点实验室,石河子832003

出　　处：《中国动物传染病学报》2023年第6期35-44,共10页Chinese Journal of Animal Infectious Diseases

基　　金：动物疾病防控兵团重点实验室开放课题(2020BTDJ03);八师石河子市促进科技成果转化引导计划(2019ZH05);石河子大学成果转化与技术推广计划(CGZH201908)。

摘　　要：为了解北疆某规模化奶牛场临床型乳房炎源粪肠球菌的耐药与毒力情况,采集了47份临床型乳房炎乳样进行细菌分离,通过生化鉴定及16S rRNA对粪肠球菌进行鉴定,进行了药敏试验及33种耐药基因检测,了解其耐药情况;通过小鼠LD50、病变观察及6种毒力基因检测,了解其致病性。分离鉴定出了1株粪肠球菌,命名为SL22;遗传进化树构建中,与粪肠球菌菌株MD48、MD60(GenBank登录号分别为MW5784.17.1、MW5784.16.1)同源性为92.00%;在哥伦比亚血平板上具有溶血现象,为α溶血;在耐药情况检测中,SL22对青霉素G、杆菌肽耐药,对万古霉素等药物敏感,含有4种耐药基因(qnrD、floR、aac(6’)-lb-cr、int I 1);在毒力测定中,SL22对小鼠的LD50约为1.6×10^(9)CFU/只,死亡小鼠肝脏、小肠出血明显,且含有4种毒力基因(gelE、cylA、ace、efaA)。本试验为奶牛乳房粪肠球菌感染的防治提供了参考。To understand drug resistance and virulence of Enterococcusfaecalis,47 milk samples were collected from dairy cows with clinical mastitis on a farm in northern Xinjiang for bacterial isolation.The bacterial isolates were identified based on biochemical reactions and 16S rRNA sequencing and also tested for their drug susceptibility and presence of 33 drug resistance genes.As a result,one strain of E.faecalis was isolated and identified,named SL22.The genetic evolutionary analysis showed that the strain SL22 shared 92.00%homology with the reference strains MD48 and MD60(GenBank access number:MW5784.17.1 and MW5784.16.1).In addition,the strain SL22 hadαhemolysis on Colombian blood tablets.The drug resistance testing showed that the strain SL22 was resistant to penicillin bacterium G and bacterium peptide and susceptible to vancomycin and other drugs as it contained four drug resistant genes(qnrD,9floR,aac(6')-lb-crandintI1).Additionally,the strain SL22 was virulent to mice with LD50 of about 1.6×10^(9) CFU.The strain SL22 had 4 toxicity genes(gelE,cylA,aceandefaA)and caused obvious hemorrhage in livers and small intestines of the infected mice.These results provided a reference for the prevention and treatment ofE.faecalisinfection in the breast of cows.

关 键 词：粪肠球菌 耐药性 毒力基因 乳房炎 

分 类 号：S852.61[农业科学—基础兽医学]