临床分离碳青霉烯类耐药鲍曼不动杆菌常见耐药基因检测及同源性分析

Detection of resistant gene and its homological analysis of clinical isolated Acinetobacter baumannii resistant to carbapenem

目的了解天津市南开医院临床分离碳青霉烯类耐药鲍曼不动杆菌(CRAB)的流行特征、耐药机制及基因同源性,为CRAB感染的防治提供依据。方法收集38株临床非重复分离的CRAB,进行碳青霉烯酶和金属β-内酰胺酶表型筛选,分析其耐药性、流行特征、耐药机制及基因同源性。结果 38株临床分离的CRAB主要来自痰液标本,ICU分离菌株数最高;米诺环素和替加环素未出现耐药株;碳青霉烯酶表型检测有33株阳性菌株,阳性率为86.8%;未检出产金属β-内酰胺酶菌株;38株CRAB均携带bla_(OXA-23)和bla_(OXA-51)基因,未检出bla_(OXA-24)、bla_(OXA-58)、bla_(KPC)、bla_(GES)、bla_(IMP)、bla_(GIM)、bla_(VIM)和bla_(NDM-1)基因,插入序列ISAba1检测均阳性,ISAba125扩增阳性2株,均未检出插入序列ISAba4;ERIC2-PCR基因分型提示为同一来源克隆株。结论本院分离的CRAB为同一克隆株,且都携带耐药基因bla_(OXA-23)和bla_(OXA-51)及插入序列ISAba1,提示存在克隆传播。

Objective To investigate the epidemic characteristics,resistance mechanisms and genetic homology in clinical isolates of carbapenem resistant Acinetobacter baumannii（ CRAB）,so as to provide evidence for controlling hospital infections.Methods 38 CRAB were isolated from clinical specimens. Carbapenemase phenotype identification and metalloenzyme beta-lactamase（ MBLs） screen were performed with the CRAB,and the drug resistance,epidemic characteristics,drug resistance mechanism and gene homology were analyzed. Results The 38 isolates of CRAB were mainly from sputum specimens,the highest isolation rate of isolates was from ICU. Minocycline and tigecycline has not yet appeared resistant strains. 33 positive strains were detected in carbapenemases phenotypic tests,and the positive rate was 86. 8%. Strains producing MBLs were not detected. All of CRAB strains were carrying bla_（OXA- 23）,bla_（OXA- 51） and ISAba1,2 of which were amplified ISAba125 positive,and the others were not detected. The result of ERIC2- PCR showed that they might derive from the same clone. Conclusion All the CRAB isolates belong to the same clone and carry the same bla_（OXA- 23）,bla_（OXA- 51） and ISAba1,indicating that there was clone spread among CRAB isolates.