MALDI-TOF MS在耐碳青霉烯类肺炎克雷伯菌同源性分析的应用研究

摘要：目的 探究基质辅助激光解析电离飞行时间质谱(matrix-assisted laser desorption/ionization-time of flight mass spectrometry, MALDI-TOF MS)分析耐碳青霉烯类肺炎克雷伯菌(carbapenem-resistant Klebsiella pneumoniae, CRKP)同源性在临 床中的应用价值。方法 收取某院2018年9月-2020年10月临床分离的肺炎克雷伯菌非重复菌株295株，经耐药表型筛选出 CRKP；利用MALDI-TOF MS采集CRKP的质谱图，分别运用SARAMIS软件中的相似性分型和identical masses分型进行同源性 分析；以脉冲场凝胶电泳(pulsed-field gel electrophoresis, PFGE)为参考标准，将CRKP分为高度、中度、低度同源性3组，评价 MALDI-TOF MS在分析CRKP同源性分析中的应用价值。结果 经耐药表型筛选出55株CRKP；3组同源性分析显示：高度同 源组中，应用SARAMIS软件自带的identical mass分型和相似性分型分析，大多identical mass集中分布(60%~80%)，相似性＞ 80%，与PFGE结果较为一致；中度同源组中，identical mass＞70%，相似性＞85%，显示菌株间高度集中，跟PFGE结果存在较 大的差异；低度同源组中，identical mass＜70%，相似性＜80%，与PFGE结果类似，能较好体现菌株间的差别。结论 MALDITOF MS自带的SARAMIS软件目前仅在高度同源和低度同源菌株中，可作为分析同源性的初筛方式。

Application research in homology analysis of carbapenem-resistant Klebsiella pneumoniae by MALDI-TOF MS

Abstract Objective To explore the clinical applicability of matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) in the analysis of carbapenem-resistant Klebsiella pneumoniae(CRKP). Methods A total of 295 Klebsiella pneumoniae non repetitive strains were collected from a hospital from September 2018 to October 2020, and CRKP was screened by drug resistance phenotype; the mass spectra of CRKP were collected by MALDI-TOF MS, the similarity and identity masses in SARAMIS software were used to analyze the homology; using pulsed field gel electrophoresis (PFGE) as reference standard, CRKP were divided into three groups: High, medium and low degree of homology, and MALDI-TOF MS was applied in CRKP homology analysis. Results 55 CRKP strains were screened by drug resistance phenotype; three groups of homology analysis showed that: In thehighly homologous group, most of them were distributed in a centralized manner (60%~80%) with similarity > 80%, which was consistent with PFGE results; in the moderate homology group, the identity mass value was more than 70%, and the similarity was more than 85%. It showed that the strains were highly concentrated, which was different from the results of PFGE; in the low degree homology group, the identity mass was less than 70%, and the similarity was less than 80%, which was similar to that of PFGE. Conclusion At present, the SARAMIS software provided by MALDI-TOF MS is only used in high homologous and low homologous strains, which can be used as the primary screening method for analyzing the