ICU病区多重耐药鲍曼不动杆菌的分子流行病学调查及耐药基因研究

Studies on molecular epidemiology and antibiotic resistance related genes of multi-resistant strains of Acinetobacter baumannii isolated from Intensive Care Units

目的了解重症监护室(ICU)病区多重耐药鲍曼不动杆菌(MDR-Aba)的流行趋势、同源性以及耐药机制,为临床用药提供参考并有效控制院内感染的发生。方法收集2008年6-12月沈阳军区总医院ICU病区住院患者临床分离出的耐碳青霉烯类鲍曼不动杆菌14株。采用K-B法检测其对β-内酰胺类、氨基糖苷类、氟喹喏酮类等14种抗菌药物的敏感性;行脉冲场凝胶电泳(PFGE),使用GelCompar 6.3软件进行聚类分析对MDR-Aba进行分型;采用PCR方法扩增部分耐药基因并进行测序比对。结果 14株菌株在体外对头孢菌素类、碳青霉烯类、氨基糖苷类、氟喹喏酮类12种抗生素均呈高水平耐药,大部分菌株对米诺环素敏感,部分菌株对头孢哌酮/舒巴坦敏感。PFGE聚类分析结果显示,14株MDR-Aba菌株均为同一基因型,来源相同,分为A1(10株)和A2(4株)两种亚型。PCR扩增结果显示,14株MDR-Aba菌株均携带blaOXA-23-like、blaOXA-51-like和IntⅠ基因。结论所收集的14株MDR-Aba菌株均属同一基因型,其耐药性可能与blaOXA-51-likeb、laOXA-23-like和IntⅠ等耐药基因关系密切。

Objective To study the epidemic trend,homology and the mechanism of drug resistance of Acinetobacter baumannii（MDR-Aba） in Intensive Care Units（ICU） of the hospital in which the authors served,so as to offer a reference for clinical treatment and efficient preveation of iatrogenic infection.Methods Fourteen consecutive MDR-Aba isolates were collected from ICU of General Hospital of Shenyang Command from June to Dec.2008.Drug sensitivity of these isolates to 14 antibiotic drugs,including β-lactam,aminoglycoside and fluoroquinolone,etc,was examined by K-B test.Pulsed-field gel electrophoresis（PFGE） was employed to detect the homology of Acinetobacter baumannii,and cluster analysis was carried out with GelCompar 6.3 software to group the isolated MDR-Aba.PCR was performed to amplify the genes related to drug resistance from these isolates,and the results were identified by sequencing.Results All the 14 isolates were highly resistant to cephalosporins,carbapenems,aminoglycoside and fluoroquinolone,while some of them retained susceptibility to cefoperazone/sulbactam,and most of the strains showed susceptibility to minocycline in vitro.All isolates belonged to a same PFGE pulsotype,which may be divided into 2 subtypes as Type A1（n=10） and Type A2（n=4）.OXA-23-like,OXA-51-like and Int I genes were detected by PCR in all isolates.Conclusion All MDR-Aba isolates collected basically belong to the same lineom.The mechanism of antibiotic resistance may be closely related to these genes such as OXA-23-like,OXA-51-like and Int I.