纸片协同试验用于肠杆菌科细菌碳青霉烯酶检测的价值

Evaluation of disk synergy test for detection of carbapenemase-producing Enterobacteriaceae

目的评估纸片协同试验检测产碳青霉烯酶肠杆菌科细菌(CPE)的应用价值。方法收集2015年1月至2018年12月瑞安市人民医院75株可疑产碳青霉烯酶非重复肠杆菌科细菌和10株非CPE。通过使用美罗培南(MEM)联合多种抑制剂[包括苯基硼酸(PBA)、氯唑西林、乙二胺四乙酸钠(EDTA)和替莫西林]的纸片扩散法等试验检测菌株产碳青霉烯酶的类型。以PCR扩增相关耐药基因为金标准,评估纸片协同试验对CPE的检测价值。结果75株可疑CPE经PCR扩增,66株确证产碳青霉烯酶(其中产KPC 46株、产NDM-118株、产IMP 1株、产VIM 1株,无产OXA-48基因型),6株产超广谱β-内酰胺酶(ESBLs),3株未检测出基因;MEM联合PBA和氯唑西林协同试验检测KPC表型的灵敏度为100.0%,特异度为93.1%;MEM联合EDTA协同试验检测MBL表型的灵敏度和特异度均达到100.0%。10株非CPE均未检测出碳青霉烯酶耐药基因,且纸片协同试验均阴性。结论该表型检测方法对检测KPC、MBL类碳青霉烯酶有较高的灵敏度和特异度,并且操作简便、成本低,适合在临床微生物学实验室、医院感染管理科及疾病预防控制中心等单位普及应用。

Objective To evaluate the application of disk synergy test in detection of carbapenemase-producing Enterobacteriaceae(CPE).Methods Seventy-five clinical strains of suspected carbapenemase-producing non-repetitive Enterobacteriaceae and 10 strains of non-CPE were collected from Ruian People's Hospital from January 2015 to December 2018.The type of carbapenemase was detected by the disk diffusion test for meropenem(MEM)combined with various kinds of inhibitors,including phenylboronic acid(PBA),cloxacillin,EDTA and temocillin.The PCR amplification of drug-resistant genes was set as the gold standard to evaluate the detection performance of disk synergy test for CPE.Results Seventy five suspected CPE strains were amplified by PCR,of which 66 strains were confirmed to produce carbapenemase,including 46 strains producing KPC,18 strains producing NDM-1,1 strain producing IMP,1 strain producing VIM,and no strain producing OXA-48,6 strains were confirmed to produce ESBLs.The genes were not detected in 3 strains.The sensitivity and specificity of the KPC phenotype detected by MEMcombined with PBA and Cloxacillin synergy test were 100.0%and 93.1%respectively.The sensitivity and specificity of the MEM combined with the EDTA synergy test to detect MBL phenotype were both 100.0%.The carbapenemase resistance genes were not detected by disk synergy test in 10 non-CPE strains.Conclusion The disk synergy test has high sensitivity and specificity for the detection of KPC and MBL carbapenemase,and it is easy to operate and low in cost,which is worth to be popularized and applied in various settings.