宜昌地区临床分离耐碳青酶烯类鲍氏不动杆菌的分子流行病学特征

Molecular epidemiological characteristics of carbapenem resistant Acinetobacter baumannii isolates in Yichang

目的了解宜昌地区临床分离耐碳青酶烯类鲍氏不动杆菌(CRAB)的耐药性,研究CRAB的分子流行病学特征,为CRAB感染的预防治疗及分子流行病学研究提供实验依据。方法分析宜昌地区4所综合医院2013年10月-2014年10月临床分离的CRAB 30株,双纸片增效法(DDST)筛选金属β-内酰胺酶(MBLs),PCR扩增OXA-23、OXA-24、OXA-51、OXA-58、IMP-1、IMP-2、VIM-1、VIM-2型碳青霉烯酶基因,阳性进行测序分析。结果监测的17种药物中,除对多黏菌素全部敏感外,对头孢哌酮/舒巴坦和米诺环素耐药率为26.7%和63.3%,对其他抗菌药物耐药率均>80.0%;1株MBLs为阳性,28株扩增OXA-23阳性,30株扩增OXA-51阳性,1株VIM-2阳性,未检出OXA-24、OXA-58、IMP-1、IMP-2、VIM-1基因。结论宜昌地区临床分离CRAB耐药十分严重,产OXA-23、OXA-51型碳青霉烯酶是鲍氏不动杆菌对碳青酶烯类药物耐药的重要机制,同时产VIM-2型金属β-内酰胺酶也不容忽视。

OBJECTIVE To survey antibiotic resistance of clinical isolates of carbapenem resistanct Acinetobacter baumannii（CRAB）in Yichang,and investigate molecular epidemiological characteristics of CRAB,so as to provide experimental evidence for the prevention and molecular epidemiology of CRAB infection.METHODS A total of 30 strains of CRAB from 4general hospitals in Yichang from Oct.2013 to Oct.2014 were analyzed.Double-disk synergy test（DDST）was used to detect metallo-β-lactamase（MBLs）,PCR was used to amplify carbapenemase genes（including OXA-23,OXA-24,OXA-51,OXA-58,IMP-1,IMP-2,VIM-1and VIM-2）,and the positive products were sequenced.RESULTS Of the 17 antibiotics tested,all strains were sensitive to polymyxin,the resistant rates to cefoperazone/sulbactam,minocycline were 26.7 % and 63.3%,and to other antibiotics were more than80.0%.One strain of MBL phenotype was positive.Totally 28 strains amplified blaOXA-23 gene and one amplified blaVIM-2gene.All the 30 strains were positive for the amplification of the OXA-51 gene,and no strain was found which carried OXA-24,OXA-58,IMP-1,IMP-2,or VIM-1gene.CONCLUSION Multiple drug resistance is serious problems in Yichang.Production of OXA-23 and OXA-51 carbapenemases is an important mechanism of resistance to carbapenem antibiotics,and VIM-2carbapenemases also cannot be ignored.