MALDI-TOF MS在鲍曼不动杆菌同源性分析中的临床应用评估

Clinical application of MALDI-TOF MS for homology analysis of Acinetobacter baumannii

摘要:

目的 评估基质辅助激光解析电离飞行质谱(MALDI-TOF MS)分析鲍曼不动杆菌(AB)同源性的临床应用价值。 方法 剔除同一患者或环境多次送检标本中的重复菌株, 收集某三甲综合医院2020年5月—2021年2月神经内科重症监护病房(ICU)住院患者痰标本及环境标本分离的46株AB, 使用VITEK-MS质谱仪检测菌株, 应用SARAMIS Premium软件进行聚类分析, 并采用多位点序列分型(MLST)的方法进行验证。 结果 通过MALDI-TOF MS和MLST聚类分析和比较, 46株AB中, 39株为MALDI-TOF MS的MS-a型, 其中, 22株为MLST的MT-A簇, 包括ST208型3株, ST540型3株, ST195型8株, ST369型5株, 以及ST136、ST436、ST1893型各1株; 16株为MT-B簇, 包括ST381型4株、ST469型11株和ST938型1株; 1株为MT-C簇(ST1821);MS-b型1株为ST381;MS-c型2株为ST369;MS-d型1株为ST195;MS-e型2株分别为ST540、ST369;MS-f型1株为STN1。 结论 作为AB同源性分析工具, MALDI-TOF MS具有一定的局限性, 其菌株同源性分析结果与MLST结果一致性低, 分辨特异性低, 不可取代MLST技术。

Abstract:

Objective To evaluate the clinical application value of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) in analyzing the homology of Acinetobacter baumannii (AB). Methods After excluding repetitive strains from multiple specimens of the same patient or environment, a total of 46 AB strains isolated from patients' sputum and environmental specimens of neurological intensive care unit (ICU) in a tertiary first-class general hospital from May 2020 to February 2021 were collected. Strains were detected by VITEK-MS mass spectrometer. Cluster analysis was performed by SARAMIS Premium software, and verified by multilocus sequence typing (MLST). Results Cluster analysis and comparison of MALDI-TOF MS and MLST found that among the 46 AB strains, 39 were the type MS-a of MALDI-TOF MS, of which 22 strains were the cluster MT-A of MLST, including ST208 (n=3), ST540 (n=3), ST195 (n=8), ST369 (n=5), ST136 (n=1), ST436 (n=1) and ST1893 (n=1); 16 strains were MT-B, including type ST381(n=4), type ST469 (n=11), and type ST938 (n=1); one strain was cluster MT-C (ST1821); one strain of type MS-b was ST381; two strains of type MS-c were ST369; one strain of type MS-d was ST195; two strains of type MS-e were ST540 and ST369, respectively; one strain of type MS-f was STN1. Conclusion As a homology analysis method, MALDI-TOF MS still has certain limitations such as low consistency with MLST results, low resolution and specificity, thus cannot replace MLST technology.