多重耐药鲍曼不动杆菌碳青霉烯酶耐药基因和同源性分析

Analysis for genotype and homology of carbapenemase resistance in multi-drug resistant Acinetobacter baumannii

目的分析多重耐药鲍曼不动杆菌碳青霉烯酶耐药基因型和医院感染鲍曼不动杆菌同源性。方法收集四川省人民医院重症监护病房(ICU)分离的鲍曼不动杆菌复合群76株,用OXA-51基因扩增法鉴定。用Vitek 2 Compact全自动微生物分析系统进行药敏试验,同时用PCR技术分析其产碳青霉烯酶相关耐药基因类型,对其中确定为医院感染的19株鲍曼不动杆菌和5株物体表面的鲍曼不动杆菌用重复序列聚合酶链反应(Rep-PCR)的DiversiLab系统进行同源性分析。结果 76株菌株均显示多重耐药,全部检出携带OXA-51、OXA-23基因,未检出OXA-24、OXA-58、VIM、IMP-1、IMP-4、SIM、NDM-1耐药基因。DiversiLab系统将19株医院感染鲍曼不动杆菌和5株物体表面的鲍曼不动杆菌分为4个亲缘性不同的克隆组及9个亚克隆组。结论该院鲍曼不动杆菌多重耐药现象严重,OXA-23基因可能是其耐碳青霉烯类抗生素的主要原因。克隆组1为该院鲍曼不动杆菌医院感染的主要流行株。

Objective To analyze the genotype of carbapenemase-resistant genes in multi-drug resistant Acinetobacter baumannii（A.baumannii） and the homology of A.baumannii from nosocomial infection.Methods Seventy-six Acinetobacter spp.isolates which were collected from intensive care units（ICU） were identified by amplificating OXA-51 gene.The antimicrobial susceptibility test was performed by Vitek 2 Compact automatic analysis system.Carbapenem resistance-associated genotypes of all isolates were identified by polymerase chain reaction（PCR）.Homology among 19 strains of A.baumannii from nosocomial infection and 5 strains from surface of objects was analyzed by DNA-fingerprints-based DiversiLab system.Results All of 76 isolates of A.baumannii were found to carry OXA-51,OXA-23,but not OXA-24,OXA-58,VIM,IMP-1,IMP-4,SIM and NDM-1.The 19 isolates of A.baumannii from nosocomial infection and 5 strains from surface of objects were classified into 4 unrelated groups and 9 patterns by DiversiLab system.Conclusion The multi-drug resistant phenomenon of A.baumannii in the hospital studied was serious.The existence of OXA-23 gene may be the main reason of carbapenem-resistance of A.baumannii.Group 1 should be the major epidemic strains causing nosocomial infection of A.baumannii.