摘要
目的探索鸭源大肠杆菌对氨基糖苷类耐药及耐药传播的分子机制。方法用微量稀释法测定鸭源大肠杆菌对氨基糖苷类药物的耐药表型,用PCR和DNA测序方法检测多种氨基糖苷修饰酶基因和质粒介导的16S甲基化酶基因,通过质粒接合试验分析有关耐药基因和耐药性的质粒接合传递特点,并采用基因克隆方法研究rmtB的基因环境。结果 27株分离菌中,有23株、19株、19株和18株分别对安普霉素、庆大霉素、阿米卡星和新霉素耐药,耐药率分别为85.2%、70.4%、70.4%和66.7%。27株中的13株检测到rmtB基因,6株同时检测到rmtB和aac(3)-IV基因。质粒接合试验获得5株接合子,接合子对安普霉素、庆大霉素、阿米卡星和新霉素均高水平耐药(MIC≥128μg/ml),rmtB基因检测呈阳性反应。结论鸭源大肠杆菌氨基糖苷类药物耐药和交叉耐药十分严重,质粒介导的rmtB基因和质粒接合传递是其耐药及其传播扩散的重要机制。
The aim was to elucidate the molecular mechanisms of resistance of E. colt isolates from duck against amin- oglycosides and the dissemination mechanism of this resistance. Broth microdilution method was applied to investigate the drug- resistant phenotypes of E. colt isolates （n= 27） from ducks, and the aminoglycoside resistance genes including aminoglycoside- modifying enzyme genes and 16S rRNA methylase genes in these isolates were detected by PCR and sequencing. Through plas- mid conjugation, characteristics of resistance gene transfer were observed. The method of gene cloning was used to investigate the genetic environment of the rrntB gene. The results indicated that 23, 19, 19, and 18 of 27 isolates were resistant to apra- mycin, gentamicin, amikaein and neomycin, with resistance rates of 85.20/00, 70.4%, 70.4%, and 66.7%, respectively. The rrntB gene were detected in 13 of 27 E. colt isolates and both rmrB and aac（3）-IV genes were found in 6 strains. All five transconjugants were obtained and seriously resistant to apramycin, gentamicin, amikacin and neomycin （ MIC~ 128 t^g/mL） and positive for rrntB gene. Resistances to aminoglycoside antibiotics and cross-resistance in E. colt isolates from ducks were very serious. The rrntB gene was responsible for the resistance to aminoglycoside antibiotics in the tested strains and the hori zontal transfer of this resistance may mainly be mediated by plasmid conjugation.
出处
《中国人兽共患病学报》
CAS
CSCD
北大核心
2013年第2期138-141,147,共5页
Chinese Journal of Zoonoses
基金
国家自然科学基金项目(No.31072170)
河南省郑州市金水区科技攻关项目(No.金科201223)联合资助~~
关键词
鸭源大肠杆菌
氨基糖苷类耐药基因
质粒接合传递
传播扩散机制
Escherichia coli from duck
aminoglycoside resistance gene
plasmid conjugation transfer
disseminationmechanism
