›› 2010, Vol. 37 ›› Issue (3): 55-59.

• 生理生化 • 上一篇    下一篇

16S rRNA甲基化酶rmtB在猪肠道菌中的传播方式分析

陈琳1,2,张俊丰3,刘健华1,陈杖榴1,曾振灵1   

  1. (1.华南农业大学兽医学院 广东省兽药研制与安全评价重点实验室, 广州 510642;2.江苏畜牧兽医职业技术学院, 泰州 225300; 3.重庆市畜牧科学院, 荣昌 402460)
  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:2010-03-20 发布日期:2010-03-20

Transfer Mode of 16S rRNA Methylase rmtB in EnterobacteriaIsolates from Pig Farms

CHEN Lin1,2, ZHANG Jun-feng3, LIU Jian-hua1, CHEN Zhang-liu1, ZENG Zhen-ling1   

  1. (1.Guangdong Provincial Key Laboratory for Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; 2.Jiangsu Animal Science and Veterinary Medicine College, Taizhou 225300, China; 3.Chongqing Academy of Animal Science, Rongchang 402460, China)
  • Received:1900-01-01 Revised:1900-01-01 Online:2010-03-20 Published:2010-03-20

摘要: 为研究16S rRNA甲基化酶rmtB在猪肠道菌中的传播方式,用脉冲场凝胶电泳(PFGE)分别对来源于A、B猪场的48株rmtB阳性大肠埃希氏菌进行基因分型;用膜接合试验研究rmtB基因的水平传播方式;用微量稀释法对rmtB阳性菌及其接合子进行药敏试验。有45株rmtB阳性大肠埃希氏菌(45/48)能进行PFGE分型,可分为28种不同的PFGE基因型。其中来源于A猪场的20株菌可分为12种基因型,来源于B猪场的25株菌可分为16种基因型;46株rmtB阳性菌可以通过接合试验将rmtB基因及其介导的耐药性传递给受体菌E.coli C600和E.coli 488 Rifr,接合频率从4.6×10-13~3.0×10-6不等,接合子对卡那霉素、阿米卡星、妥布霉素、西梭米星、萘替米星、庆大霉素6种二脱氧链霉胺类抗生素均高度耐药(MIC≥512 μg/mL)。结果表明,rmtB基因位于接合性质粒上,该基因在两猪场的大肠埃希氏菌中既存在克隆传播,又存在水平传播,以水平传播为主。

关键词: 16S rRNA甲基化酶; rmtB; 质粒; 水平传播; 克隆传播

Abstract: To study the transfer mode of rmtB in Enterobacteria isolates from pig farms. Pulse field gel electrophoresis(PFGE) were carried out to study the genotyping of 48 rmtB-positive E.coli isolates from A and B pig farms. Conjugation experiments was carried out to study the horizontal transfer mode of rmtB genes by filter mating method. Broth microdilution method was applied to test susceptibility of rmtB-positive isolates and their transconjugants to antimicrobial agents. Among 48 rmtB-positive E.coli isolates, 45 strains were successfully typed by PFGE. Total of 28 different PFGE profiles were obtained, and 12 different PFGE profiles were obtained in 20 isolats from A pig farm, 16 different PFGE profiles were acquired in 25 isolats from B pig farm. All the rmtB genes located in 46 rmtB-positive isolates were easily transferred to recipients of E.coli C600 and E.coli 488 Rifr. Conjugative transfer frequencies varied from 4.6×10-13 to 3.0×10-6 cells per recipient cell. And all 46 transconjugants showed extraordinarily high-level resistance to 4,6-substituted deoxystreptamine (MICs>512 μg/mL). It concluded that the rmtB gene was located on a conjugative plasmid in E.coli. Both horizontal gene transfer and clonal expansion were responsible for the dissemination of rmtB gene and horizontal gene transfer was predominant in E.coli isolates from two pig farms.

Key words: 16S rRNA methylase; rmtB; plasmid; horizontal gene transfer; clonal expansion

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