泛耐药鲍曼不动杆菌新疆分离株氨基糖苷类药物耐药机制研究

Drug-resistant mechanism of aminoglycosides in a group of pan-drug resistant Acinetobacter baumannii isolatedfrom Xinjiang

目的:探讨一组分离自新疆的泛耐药鲍曼不动杆菌对氨基糖苷类药物的耐药机制。方法:收集患者标本中分离的泛耐药鲍曼不动杆菌共20株,用聚合酶链反应(PCR)的方法分析5种氨基糖苷类修饰酶基因、2种16SrRNA甲基化酶基因和外排泵蛋白AdeB编码基因adeB。结果:本组20株泛耐药鲍曼不动杆菌检出aac(3)-Ⅰ、aac(6’)-Ⅰb、ant(3")-Ⅰ、aph(3’)-Ⅰ等4种氨基糖苷类修饰酶基因和armA 16SrRNA甲基化酶基因以及adeB外排泵基因,阳性基因共分为6种阳性模式。主要的阳性模式为(aac(3)-Ⅰ+aac(6’)-Ⅰb+ant(3")-Ⅰ+aph(3’)-Ⅰ+armA+adeB)六种基因阳性11株,占55%;(aac(3)-Ⅰ+aac(6’)-Ⅰb+ant(3")-Ⅰ+aph(3’)-Ⅰ+adeB)五种基因阳性4株,占20%;未检出ant(2")-Ⅰ及rmtB基因。结论:产修饰酶和产靶位甲基化酶以及AdeABC外排泵系统是导致本组菌株对氨基糖苷类药物耐药的主要原因。

Objective：To investigate the drug-resistant mechanism of aminoglycosides in a group of pan-drug resistant Acinetobacter baumannii isolated from Xinjiang.Methods：Twenty strains of pan-drug resistant Acinetobacter baumannii isolated from patients＇ samples were collected.Five aminoglycoside modifying enzyme genes,two 16 SrRNA methylase genes and drug efflux gene adeB were analyzed by PCR.Results：Four aminoglycoside modifying enzyme genes including aac（3）- Ⅰ,aac（6＇）- Ⅰb,ant（3＂）- Ⅰand aph（3＇）-Ⅰ,16 SrRNA methylase gene armA and drug efflux gene adeB were found in 20 strains of Acinetobacter baumannii.The positive genes were divided into 6positive modes.There were 6positive genes including aac（3）-Ⅰ,aac（6＇）-Ⅰb,ant（3）-Ⅰ,aph（3＇）-Ⅰ,armA and adeB in 11strains（55%）,and five genes including aac（3）-Ⅰ,aac（6＇）-Ⅰb,ant（3）-Ⅰ,aph（3＇）-Ⅰand adeB in 4strains.The ant（2＂）- Ⅰ and rmtB genes were not found.Conclusion：In this group of Acinetobacter baumannii,the producing aminoglycoside modifying enzyme gene,16 SrRNA methylase gene and drug efflux gene may play a key role in drug resistance to aminoglycosides.