肠杆菌科细菌产碳青霉烯酶的主要类型和流行病学分析

目的：了解对碳青霉烯类抗生素耐药的肠杆菌科细菌（CRE）中碳青霉烯酶的主要类型及流行情况。方法收集上海瑞金医院2011年5月至2013年6月对亚胺培南或美罗培南药敏纸片抑菌圈直径≤22 mm的CRE共114株，采用PCR方法扩增常见的碳青霉烯酶基因（blaKPC 、blaIMP 、blaOXA‐48、blaVIM 、blaNDM ）并对PCR扩增产物进行测序；所有菌株均进行了质粒接合试验；采用脉冲场凝胶电泳（PFGE）对KPC‐2检测阳性的肺炎克雷伯菌进行同源性分析。结果114株CRE以肺炎克雷伯菌、大肠埃希菌和肠杆菌属细菌为主，其中98株产碳青霉烯酶，以K PC‐2酶为主要类型（78／98）、其次为IM P‐4酶（15／98）， IMP‐8酶（2／98），1株肺炎克雷伯菌同时携带有 blaKPC‐2和 blaIMP‐4基因，还发现4株产 NDM‐1酶的菌株，未见OXA‐48酶及VIM酶阳性菌株。21株（21．4％，21／98）CRE菌株转移接合试验成功。PFGE结果显示49株 blaKPC‐2阳性肺炎克雷伯菌共分为12个型，其中34株属于同一谱型（type A ）。CRE菌株主要分离自ICU ，共39株，其次为普外科14株，血液科11株，呼吸科9株，其余科室共41株。结论本次分离的肠杆菌科细菌所产碳青霉烯酶的基因型以blaKPC‐2为主，其次为blaIMP‐4，并发现4株blaNDM‐1阳性CRE菌株，产KPC‐2酶的肺炎克雷伯菌在外科ICU、呼吸科及胸外科等科室间存在克隆株的流行传播，应采取及时有效的防控措施。

Prevalence and genotypes of carbapenemase-producing Enterobacteriaceae

Objective To investigate the prevalence and main genotypes of carbapenemases in carbepenem‐resistant Enterobacteriaceae （CRE） .Methods A total of 114 strains of CRE were isolated in Shanghai Ruijin Hospital from May 2011 to June 2013 .The diameter of inhibition zone of imipemen or meropenem for these strains was not larger than 22 mm .PCR method was used to screen for the main carbapenemase genes （blaKPC ,blaIMP ,blaVIM ,blaOXA‐48 and blaNDM ） with previously described primers followed by nucleotide sequencing analysis . Conjugation experiments were performed to examine the transferability of plasmids .Pulsed‐field gel electrophoresis （PFGE） was used to show the relatedness of KPC‐2‐producing Enterobacteriaceae .Results Most of the 114 isolates were K lebsiella pneumoniae and Escherichia coli .Of the 114 isolates ,98 was positive for carbapenemases ,specifically ,78 blaKPC‐2‐positive ,15 blaIMP‐4‐positive ,2 blaIMP‐8‐positive ,1 positive for both blaKPC‐2 and blaIMP‐4 and 4 blaNDM‐1‐positive .None of the strains was positive for blaOXA‐48 or blaVIM .About 21 .4% （21/98） of the isolates were conjugated successfully .The 49 blaKPC‐2‐positive K .pneumoniae isolates were grouped into 12 types according to PFGE patterns .Majority （34/49） of these isolates belonged to the same type A .Conclusions BlaKPC‐2 was the primary epidemic genotype of Enterobacteriaceae in Ruijin Hospital ,followed by blaIMP‐4 .NDM‐1 carbapenemase was produced in 4＆amp;nbsp;strains of CRE . Meanwhile , clonal spread of KPC‐2‐producing K . pneumoniae was observed in some departments of our hospital , such as surgical ICU , respiratory medicine and thoracic surgery . Appropriate measures should be taken timely and effectively to prevent the in‐hospital spread of resistant genes .