摘要目的 评估基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)技术直接检测肠杆菌科细菌产碳青霉烯酶效果.方法 收集2018年1月至5月苏州大学附属第二医院分离的21株对亚胺培南和(或)美罗培南敏感性下降的肠杆菌科菌株,包括11株肺炎克雷伯菌、3株产酸克雷伯菌、3株阴沟肠杆菌、4株大肠埃希菌.PCR检测21株菌株分别产A、B和D类碳青霉烯酶基因情况,同时将菌株与0.5 g/L美罗培南溶液孵育2 h后离心取上清进行MALDI-TOF MS检测,通过菌株水解药物所出现的特征性谱峰来快速判断菌株是否产碳青霉烯酶,并与PCR基因检测结果进行Kappa检验统计学比较.结果 PCR检测结果提示21株肠杆菌科细菌碳青霉烯酶基因检测均阳性,其中KPC阳性15株、GES阳性6株、NDM阳性2株、VIM阳性1株、GIM阳性4株、SIM阳性1株,同一菌株可产生一种或多种碳青霉烯酶基因.MALDI-TOF MS直接检测结果显示21株菌株与美罗培南孵育后,在质荷比199 m/z左右处均出现了一个特征性谱峰,为菌株产生碳青霉烯酶水解美罗培南药物所致,与PCR检测碳青霉烯酶基因结果高度一致.结论 本研究运用MALDI-TOF MS技术,可通过捕捉菌株水解碳青霉烯类药物所出现的特征性谱峰来直接检测碳青霉烯酶的产生.

abstractsObjective To evaluate the effect of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)on the detection of carbapenemase producing enterobacteriaceae. Methods A total of 21 carbapenem non-susceptible enterobacteriaceaeclinical strains were collectedfrom the Second Affiliated Hospital of Soochow University during January to May, 2018, including 11 strains of Klebsiella pneumonia, 3 strains of Klebsiella oxytoca, 3 strains of Enterobacter cloacae, and 4 strains of Escherichia coli. All the isolates were incubated with 0.5g/L meropenem solution for 2 hours. The supernatant was centrifuged and collected for MALDI-TOF MS detection. The characteristic peaks were captured to determin whether the strain was producing carbapenemase or not. And then, the results were compared with PCR results by Kappastatistical analysis. Results The PCR results showed that all the strains were positive for carbapenmase genes, among them 15 isolates were encoding KPC genes, 6 isolates encoding GES genes, 2 isolates encoding NDM genes, 1 isolate encoding VIM genes, 4 isolates encoding GIM and 1 isolate encoding SIM. And the strains could carry one or more carbapem-resistant determinants. MALDI-TOF MS showed that meropenem were hydrolyzed by 21 isolates and a characteristic drug hydrolysis peak appeared at 199 m/z, as a result of carbapenemase produced by enterobacteriaceae. The assay of MALDI-TOF MS was highly consistentwith PCR results. Conclusions The investigation showed that MALDI-TOF MS can directly detect the carbapenemase by capture the characteristic drug hydrolysis peak.