碳青霉烯酶抑制剂增强试验检测肠杆菌目细菌碳青霉烯酶表型的临床应用

The inhibitor enhanced carbapenem inactivation method for the detection of metallo-p-lactamases and class A KPC carbapenemases in Enterobacteriaceae

目的:评估碳青霉烯酶抑制剂增强试验检测肠杆菌目细菌碳青霉烯酶表型的临床应用价值。方法:收集六安市人民医院2020-2021年分离自临床标本的耐碳青霉烯、非重复肠杆菌目细菌共227株。采用碳青霉烯酶抑制剂增强试验检测菌株携带的碳青霉烯酶,并以PCR试验扩增常见5种碳青霉烯酶基因为金标准,评估碳青霉烯酶抑制剂增强试验对CRE菌株A类和B类碳青霉烯酶的检测价值。结果:碳青霉烯酶抑制剂增强试验结果显示,产A类酶菌株有167株,产B类酶菌株有53株,5株肺炎克雷伯菌和1株产气肠杆菌未检出A类或B类酶。与PCR方法比较,碳青霉烯酶抑制剂增强试验检测单独产A类酶的灵敏度为100.0%(164/164),特异度为95.2%(60/63),对于单独产B类酶的检测,灵敏度和特异度均为100.0%,两种检测方法之间一致性高。结论:碳青霉烯酶抑制剂增强试验操作简便、结果易判读,适合临床微生物实验室普遍应用。

Objective:Evaluation of inhibitor enhanced carbapenem inactivation method detection of metallo-para-lactamases and class A KPC carbapenemases in clinical isolates of carbapenemase-resistant Enterobacteriaceae(CRE).Methods:Two hundred and twenty seven clinical strains of CRE clinical samples were collected from Lu′an People′s Hospital from 2020 to 2021.The type of carbapenemase was detected by the disk diffusion test for Imipenem(IPN)combined with 2 different inhibitors(phenylboronic acid and EDTA).The PCR amplification of drug-resistant genes was set as the gold standard to evaluate the simple phenotypic method.Results:Two hundred and twenty-seven CRE strains were amplified by PCR,in which 218 strains were confirmed to produce carbapenemase,including 164 strains producing KPC,53 strains producing metallo-β-lactamases.The sensitivity and specificity of the KPC phenotype detected by IPN combined with phenylboronic acid synergy test were 100.0%and 95.2%,respectively.The sensitivity and specificity of the IPN combined with the EDTA synergy test to detect MBL phenotype were both 100.0%.Conclusions:The simple phenotypic method has the high sensitivity and specificity for the detection of KPC and MBL carbapenemase,which is easy to operate and interpret,which is worth to be popularized and applied in various experiments.