MAST D73C组合纸片法检测肠杆菌科细菌碳青霉烯酶

目的使用MAST D73C组合纸片法检测儿童碳青霉烯类耐药肠杆菌科细菌(CRE)菌株中碳青霉烯酶及其分型,为临床提供一种简便快速的碳青霉烯酶检测方法。方法MAST D73C组合纸片法和PCR基因检测确认240株儿童临床分离CRE菌株碳青霉烯酶基因,并用统计学方法分析MAST D73C检测碳青霉烯酶的灵敏度和特异度。结果233株CRE碳青霉烯酶基因表达阳性,blaNDM、blaOXA-232、blaKPC-2和blaIMP检出率分别为40.00%、28.75%、23.33%和4.17%,另有2株同时携带2种碳青霉烯酶基因。MAST D73C组合纸片对MβL酶、OXA-48酶和KPC酶的检出率分别为48.48%(112/231)、27.27%(63/231)和8.66%(20/231),另有36株(15.58%)细菌抑菌圈结果无法解释。与PCR方法相比,MAST D73C检测MβL酶的灵敏度和特异度分别为99.06%和94.40%;检测OXA-48酶的灵敏度和特异度为81.16%和95.68%;检测KPC酶的灵敏度和特异度为33.93%和99.43%,但采用法罗培南耐药判断该菌为产KPC型碳青霉烯酶的补充标准后,灵敏度提高至87.50%,并且检测其他酶型的灵敏度和特异度不变,与PCR结果相比总符合率为90.91%(210/231)。结论儿童分离CRE菌株主要检出NDM-1酶和OXA-232酶,MAST D73C组合纸片法补充解释标准后可以简便、快速、准确地检测碳青霉烯酶,并可将其分型。

MASTDISCS combi Carba plus disc system D73C,a method for identifying carbapenemase phenotypes among Enterobacteriaceae

Objective To describe a simple and accurate method,MASTDISCS■combi Carba plus disc system D73C,for identifying carbapenemase phenotypes in the carbapenem-resistant Enterobacteriaceae(CRE)strains isolated from children.Methods MASTDISCS■D73C and polymerase chain reaction(PCR)were used for analysis of carbapenemase phenotypes and genotypes in 240 non-duplicate carbapenem-resistant Enterobacteriaceae strains.The sensitivity and specificity of MASTDISCS■D73C in detection of carbapenemases were evaluated by statsitical analysis.Results Carbapenemases were expressed in 233 strains.The prevalence of blaNDM,blaOXA-232,blaKPC-2,and blaIMP was 40.00%,28.75%,23.33%,and 4.17%,respectively.Two strains were positive simultaneously for 2 carbapenemase genes.Metallo-β-lactamase,OXA-48,and KPC carbapenemases were identified by MASTDISCS■D73C in 48.48%,27.27%,and 8.66%of the strains.Equivocal result was generated in 36(15.58%)strains.The sensitivity and specificity of MASTDISCS■D73C were 99.06%and 94.40%in identifying metallo-β-lactamase;81.16%and 95.68%in detecting OXA-48 carbapenemase;33.93%and 99.43%in identifying KPC carbapenemase.When KPCproducers were counted according to faropenem breakpoints,the sensitivity of MASTDISCS■D73C increased to 87.50%in detection of KPC carbapenemase,but its sensitivity and specificity remained stable for other carbapenemases.Conclusions NDM-1 and OXA-232 were the most prevalent carbapenemases in the CRE strains isolated from children.MASTDISCS■combi Carba plus disc system D73C is a simple,quick,and accurate method for discriminating the types of carbapenemase produced by CRE strains when faropenem breakpoints are considered to judge KPC-producers.