厄他培南不敏感大肠埃希菌耐药性及同源性分析

目的探讨临床分离大肠埃希菌对碳青霉烯类抗生素的耐药机制及流行情况，为临床用药和院内感染监控提供依据。方法收集2012年8月至2013年7月温州医科大学附属第二医院厄他培南不敏感的大肠埃希菌10株，采用VITEK Compact2全自动微生物分析仪检测18种常用抗菌药物的MIC值；改良Hodge试验检测碳青霉烯酶，PCR扩增包括碳青霉烯酶基因在内的多种B．内酰胺酶基因；应用脉冲场凝胶电泳（PFGE）分析菌株同源性。结果分离菌株来自不同病区无聚集现象，标本来源以尿液为主；菌株对广谱青霉素、三代、四代头孢菌素、氟喹诺酮类和酶抑制剂复合物耐药严重，对氨基糖苷类抗生素较为敏感；PCR扩增几乎所有菌株携带ESBL基因，只有一株除外，其中主要是blarsm和、blactx-mo3株blaNOM-1基因阳性，未检出其他碳青霉烯酶基因；脉冲场凝胶电泳分析表明，菌株之间没有克隆关系。结论该院分离10株大肠埃希菌对碳青霉烯类耐药主要是存在NDM-1金属酶联合ESBL，菌株间未发现克隆传播。

Analysis antibiotics resistance and homology in ertapenem non-sensitive Escherichia coli

Objective To characterize the mechanisms and prevalence in the clinical isolates of E. coli, and provide evidence for the using of clinical medicine and surveillance of nosocomial infections. Methods 10 isolated E. coli clinical isolates, which were non-sensitive to ertapenem, were collected from Aug. 2012 to July. 2013 at the Second Affiliated Hospital of Wenzhou Medical University, and were analyzed the minimum inhibitory concen- trations （MICs） of 18 antibiotics drugs by the VITEK~ Compact2. Modified Hodge test was assisted in screening the presence of carbapenemase. PCR was used to amplify the β-1actamase genes, including carbapenemase genes. To study the clonal relationships of isolates, molecular typing by PFGE was analyzed for organisms. Results Isolates from different wards without aggregation were mainly urine specimen. Clinical isolates showed highly resistance to broad-spectrum penicillin, third generation, fourth generation cephalosporins, fluoroquinolones and enzyme inhibitor complexes, relatively susceptibility to aminoglycoside. Almost all the strains except one carried ESBL genes, among which blarEraand blacTx_M were most prevalent, blaNDM_I was carryed by 3 of strains, and none of other carbapenemase genes were detected. Pulsed-field gel electrophoresis analysis demonstrated that there was no major clonal relationship among these isolates. Conclusion The presence of NDM-1 and ESBL can be regarded as the leading cause of carbapenem resistance in the 10 Escherichia coli strains ,which is unlikely to exist the clone spread among the strains.