【摘要】 目的评估碳青霉烯类失活法(carbapenem inactivation method,CIM)和改良碳青霉烯类失活法(modified carbapenem inactivation method,mCIM)对肠杆菌科细菌碳青霉烯酶表型筛选的能力。方法选取110株碳青霉烯类耐药肠杆菌科细菌及25株碳青霉烯类敏感肠杆菌科细菌,分别进行CIM和mCIM表型筛选试验,采用PCR法检测KPC-2、NDM-1、IMP-4、VIM-1、OXA-48耐药基因,结果进行统计学分析。结果 110株碳青霉烯类耐药肠杆菌科细菌中,有99株耐药基因检测阳性,包括77株KPC-2型、15株NDM-1型、2株同时携带KPC-2和NDM-1型、4株IMP-4型和1株VIM-1型。未检出OXA-48型基因。25株碳青霉烯类敏感菌株基因检测均为阴性。CIM试验敏感度为87.9%,特异度为94.4%;mCIM试验敏感度为95.0%,特异度为91.7%。为了比较抑菌环直径大小对实验结果的影响,将CIM试验阴性菌株分为2组,耐药基因阳性组抑菌圈直径明显低于基因阴性组,差异有统计学意义(P<0.01)。结论通过对试验步骤及结果判读标准的优化,mCIM试验不仅保留了成本低、操作简单、敏感度高、特异度好等优点,其碳青霉烯酶筛选能力也得到明显提升,是一种经济高效的表型筛选方法。更多还原

【Abstract】 Objective To evaluate the screening capacity of carbapenem inactivation method(CIM)and modified carbapenem inactivation method(mCIM)for phenotypic carbapenemase activity in Enterobacteriaceae bacteria.Methods A total of 110 isolates of carbapenem-resistant Enterobacteriaceae and 25 isolates of carbapenem-sensitive Enterobacteriaceae were selected,and carbapenemase activity were determined by the CIM and mCIM,respectively.Meanwhile,the carbapenemase genes such as KPC-2,NDM-1,IMP-4,VIM-1 and OXA-48 were detected by PCR.The examination results were analyzed statistically.Results Of the 110 carbapenemresistant Enterobacteriaceae strains,99 strains were positive detected by PCR,including 77 strains for KPC-2,15 strains for NDM-1,2 strains for both KPC-2 and NDM-1,4 strains for IMP-4,and 1 strain for VIM-1.The strain carring OXA-48 gene was not detected.Twenty-five carbapenem-sensitive strains were all negative.For CIM,the sensitivity is 87.9% and the specificity is 94.4%.For mCIM,the sensitivity is 95.0%and the specificity is 91.7%.In order to compare the effects of the diameter of bacteriostasis ring on the experimental results,the CIM negative strains were divided into two groups,carbapenem-resistant gene positive group and carbapenem-resistant gene negative group.The bacteriostasis diameter of the carbapenemresistant gene positive group was significantly lower than that of the gene negative group,and the difference was statistically significant(P<0.01).Conclusion After the optimization of the experimental procedure and the interpretation criteria of the results,the mCIM not only retained the advantages of low cost,simple operation,high sensitivity and good specificity,but the screening ability of carbapenemases had also been significantly improved.mCIM should be a convenient,cost-saving and efficient phenotypic screening method.更多还原