Evaluation of Matrix-Assisted Laser Desorption Ionization−Time of Flight Mass Spectrometry for Identification of Mycobacterium abscessus Subspecies According to Whole-Genome Sequencing

This study was undertaken to evaluate the utility of matrix-assisted laser desorption ionization–time of flight mass spectrometry with the Vitek MS Plus system for identifyingMycobacterium abscessus subspecies in order to facilitate more rapid and appropriate therapy. A total of 175 clinicalM. abscessus strains were identified by whole-genome sequencing analysis: 139Mycobacterium abscessus subsp.abscessus and 36Mycobacterium abscessus subsp.massiliense . The research-use-only (RUO) Saramis Knowledge Base database v.4.12 was modified accordingly by adding 40M. abscessus subsp.abscessus and 19M. abscessus subsp.massiliense reference spectra to construct subspecies SuperSpectra. A blind test, used to validate the remaining 116 isolates, yielded 99.1% (n = 115) reliability and only 0.9% (n = 1) error for subspecies identification. Among the two subspecies SuperSpectra, two specific peaks were found forM. abscessus subsp.abscessus and four specific peaks were found forM. abscessus subsp.massiliense . Our study is the first to report differential peaks 3,354.4m /z and 6,711.1m /z , which were specific forM. abscessus subsp.massiliense . Our research demonstrates the capacity of the Vitek MS RUO Saramis Knowledge Base database to identifyM. abscessus at the subspecies level. Moreover, it validates the potential ease and accuracy with which it can be incorporated into the IVD system for the identification ofM. abscessus subspecies.