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

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。

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.