耐碳青霉烯类肠杆菌科细菌耐药基因分型

Typing of drug resistance genes in carbapenem-resistant Enterobacteriaceae

目的分析天津市第三中心医院住院患者临床分离的耐碳青霉烯类肠杆菌科细菌(CRE)的菌株类型、耐药机制及耐药基因分型,为临床合理用药提供依据。方法收集医院2016年6月-2017年10月临床分离的CRE菌株23株。应用VITEK-2 Compact全自动微生物分析仪进行细菌鉴定和药敏试验;Carba NP试验检测产碳青霉烯酶类型;PCR技术进行耐药基因blaKPC、blaVIM、blaNDM、blaSME、blaIMP的检测。结果临床分离的23株CRE,肺炎克雷伯菌19株,大肠埃希菌4株;主要来自于尿液和痰标本;药敏结果显示23株CRE均对美罗培南、亚胺培南、厄他培南和头孢他啶耐药;对他唑巴坦的耐药率为95.7%(22/23);NP试验阳性率为73.9%;blaKPC、blaVIM、blaNDM、blaIMP基因阳性,检出率依次为52.2%、30.4%、4.3%、4.3%,未检出blaSME耐药基因。结论天津市第三中心医院患者检出的CRE中,耐药基因主要是blaKPC,其次是blaVIM,医院需对携带blaKPC、blaVIM基因的耐碳青霉烯类肠杆菌科细菌加强耐药检测,合理使用抗菌药物,并做好防护和消毒措施以防止医院感染和该类细菌的暴发流行。

OBJECTIVE To study the types of carbapenem-resistant Enterobacteriaceae(CRE)strains isolated from the hospitalized patients of Tianjin Third Central Hospital and observe the drug resistance mechanisms and genotypes of drug resistance genes so as to provide guidance for reasonable clinical use of antibiotics.METHODS Totally 23 strains of CRE were isolated from clinical specimens between Jun 2016 and Oct 2017.The strains were identified by using VITEK-2 Compact automatic microorganism analysis system,the drug susceptibility testing was performed,the types of carbapenemases produced by the strains were detected by means of Carba NP test,and the drug resistance genes blaKPC,blaVIM,blaNDM,blaSME and blaIMP were detected with the use of PCR.RESULTS Among the 23 clinical CRE isolates,there were 19 strains of Klebsiella pneumoniae and 4 strains of Escherichia coli;most of the strains were isolated from urine and sputum specimens.The result of drug susceptibility testing showed that all of the 23 strains of CRE were resistant to meropenem,imipenem,ertapenem and ceftazidime;the drug resistance rate to tazobactam was 95.7%(22/23);the positive rate of NP test was 73.9%;the positive rates of detection of blaKPC,blaVIM,blaNDM and blaIMP were 52.2%,30.4%,4.3%and 4.3%,respectively,while the drug resistance gene blaSME was not detected.CONCLUSION blaKPC is the predominant drug resistance gene in the CRE strains isolated from the patients of Tianjin Third Central Hospital,followed by blaVIM.It is necessary for the hospital to strengthen the surveillance of drug resistance of the CRE strains carrying with blaKPC and blaVIM genes,reasonably use antibiotics and take effective prevention and disinfection measures so as to prevent nosocomial infection as well as the outbreak and prevalence of CRE.