血流感染大肠埃希菌耐药性分析

Drug resistance of Escherichia coli causing blood stream infections

目的了解血流感染中大肠埃希菌耐药性,为临床经验性用药提供依据。方法采用法国生物梅里埃公司的VITEK-2Compact全自动细菌鉴定仪鉴定细菌;按CLSI2010标准,用K-B琼脂扩散法进行药敏试验以及ESBLs确证试验;采用WHONET5.6分析软件进行统计。结果 2009-2011年血培养共检出病原菌4723株,前3位病原菌依次为凝固酶阴性葡萄球菌、大肠埃希菌、肺炎克雷伯菌,分别占47.2%、11.9%、9.5%;检出562株大肠埃希菌,其中产ESBLs大肠埃希菌314株,占55.9%;从住院患者中分离到大肠埃希菌453株,产ESBLs菌株245株占54.1%,常见科室为ICU、肝移植及肝胆胰中心、血液科,检出产ESBLs大肠埃希菌阳性率分别为63.3%、59.3%、58.7%;来自门急诊患者109株,其中产ESBLs共45株阳性率为41.3%;体外试验显示,2009-2011年,产ESBLs大肠埃希菌对亚胺培南的耐药率分别为0.6%、0.8%、0.9%,对阿米卡星分别为11.4%、6.7%、9.7%,对哌拉西林/他唑巴坦分别为7.2%、17.6%、4.3%,对头孢西丁分别为16.3%、17.6%、11.9%,对头孢他啶分别为16.3%、28.7%、19.1%;产ESBLs大肠埃希菌的耐药率均明显高于非产ESBLs大肠埃希菌。结论医院血流感染中产ESBLs大肠埃希菌比率较高,住院患者产ESBLs大肠埃希菌比率高于门诊患者;ESBLs尚未有效控制;3年间产ESBLs大肠埃希菌耐药谱变化不大,对亚胺培南耐药株数有上升趋势;阿米卡星、哌拉西林/他唑巴坦、头孢西丁、亚胺培南等抗菌药物具有良好的治疗效果。

OBJECTIVE To investigate the drug resistance of Escherichia coli causing blood stream infections so as to provide the basis for empirical medication in the hospital.METHODS The France Bio-Merieux company VITEK-2Compact automatic bacterial identification instrument was employed to identify the bacteria.According to the CLSI2010standard,the ESBLs confirmation experiment was performed by using K-B agar diffusion method,and WHONET5.6analysis software was used for statistics.RESULTS Of totally 4723strains of pathogens isolated from the blood during 2009-2011,the top three species were the coagulase-negative Staphylococcus,Escherichia coli,and Klebsiela pneumoniae,accounting for 46.8%,11.9%,and 9.5%,respectively.Of totally 562strains of E.coli,there were 314（55.87%）strains of ESBLs-producing E.coli;of totally 453strains of E.coli isolated from the hospitalized patients,there were 245（54.1%）strains of ESBLs-producing E.coli.The ICU,liver transplantation and hepatobiliary and pancreatic center,and hemology department were the most common departments where the ESBLs-producing strains were isolated,accounting for 63.3%,59.3%,and 58.7%,respectively.Of 109strains of E.coli isolated from the emergency outpatient department,there were 45（41.3%）strains of ESBLs-producing E.coli.The in vitro test indicated that the drug resistance of the ESBLsproducing E.coli to imipenem was 0.6%in 2009,0.8%in 2010,and 0.9%in 2011;the drug resistance rate to amikacin was 11.4%in 2009,6.7%in 2010,and 9.7%in 2011;the drug resistance rate to piperacillin/tazobactam was 7.2%in 2009,17.6%in 2010,and 4.3%in 2011;the drug resistance rate to cefoxitin was 16.3%in 2009,17.6%in 2010,and 11.9%in 2011;the drug resistance rate to ceftazidime was 16.3%in 2009,28.7%in 2010,and 19.1%in 2011;the drug resistance rate of the ESBLs-producing E.coli was significantly higher than that of the non-ESBLs-producing strains.CONCLUSIONThe detection rate of the ESBLs-producing E.coli causing blood stream infections is high,and the isolation rate of the ESBLs-producing E.coli isolated from the hospitalized patients is higher than that of the strains isolated from the outpatients.The ESBLs have not yet been effectively controlled;the drug resistance spectrum of the ESBLs-producing E.coli dose not change too much,and the strains resistant to imipenem are increased;amikacin,piperacillin / tazobactam,cefoxitin,and imipenem can achieve good therapeutic effect.