临床克雷伯菌属碳青霉烯酶三种检测方法的实验比较研究

Comparative Study on Three Detection Methods of Clinical Carbapenemase Producing Klebsiella

目的对聚合式酶链反应(polymerase chain reaction,PCR)、改良碳青霉烯酶灭活试验(modified carbapenem inactivation method,mCIM)+EDTA碳青霉烯酶灭活试验(EDTA-carbapenem inactivation method,eCIM)和GeneXpert三种方法检测碳青霉烯酶的性能进行了比较,为临床选择合适的检测方法提供依据。方法收集2019年1月~2021年5月临床分离的43株碳青霉烯类抗生素耐药及37株碳青霉烯类抗生素敏感克雷伯菌属菌株,用PCR法和GeneXpert试验检测碳青霉烯酶基因,mCIM+eCIM试验检测碳青霉烯酶。以PCR法为金标准,对三种试验方法检测结果进行比较。结果43株耐碳青霉烯克雷伯菌属经PCR扩增检测有40株携带碳青霉烯耐药基因,blaKPC 30株,blaNDM 8株,blaIMP 2株;37株碳青霉烯类敏感克雷伯菌属经PCR扩增均未检出碳青霉烯酶基因。与PCR法结果相比,mCIM+eCIM试验检测丝氨酸酶及金属酶表型结果敏感度和特异度均为100%,Kappa值为1;GeneXpert技术敏感度和特异度分别为94.9%,97.6%,Kappa值为0.925。结论mCIM+eCIM试验和GeneXpert与PCR结果一致程度强,但鉴于临床诊断的时效性,GeneXpert技术操作简单,耗时短,结果准确可信且易于判读,对于有条件的医院,可以用于临床微生物实验室常规开展。

Objective To provide a basis for clinical selection of appropriate detection methods of carbapenemases,compared the difference of three clinical methods,including polymerase chain reaction(PCR),modified carbapenem inactivation method(mCIM)+EDTA synergistic carbapenem inactivation method(eCIM)and GeneXpert,and evaluated their performance.Methods Collected 43 carbapenem antibiotic-resistant Klebsiella strains and 13 carbapenem antibiotic-sensitive Klebsiella strains were collected from January 2019 to May 2021.PCR and GeneXpert test were used to detect carbapenemase gene,and mCIM+eCIM test was used to detect carbapenemase.The PCR method was used as the gold standard to compare the detection results of the three test methods.Results 40 out of 43 carbapenem-resistant Klebsiella carried carbapenem resistance genes detected by PCR,including 30 blaKPC,8 blaNDM,and 2 blaIMP.None of the 37 carbapenem-sensitive Klebsiella strains detected the carbapenemase gene by PCR.The sensitivity and specificity of the serinase and metalloenzyme phenotypes detected by mCIM+eCIM test were 100%,and the Kappa value was 1.The sensitivity and specificity of GeneXpert technology were 94.9%and 97.6%,respectively,and the Kappa value was 0.925.Conclusion Both the mCIM+eCIM test and GeneXpert have a strong agreement with PCR results.Considering effectiveness,GeneXpert is simple to operate,easy to interpret,time-consuming,accurate,and reliable.It is suitable for routine development in clinical microbiology laboratories.