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

Abstract

ABSTRACT 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 identifying Mycobacterium abscessus subspecies in order to facilitate more rapid and appropriate therapy. A total of 175 clinical M. abscessus strains were identified by whole-genome sequencing analysis: 139 Mycobacterium abscessus subsp. abscessus and 36 Mycobacterium abscessus subsp. massiliense . The research-use-only (RUO) Saramis Knowledge Base database v.4.12 was modified accordingly by adding 40 M. abscessus subsp. abscessus and 19 M. 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 for M. abscessus subsp. abscessus and four specific peaks were found for M. abscessus subsp. massiliense . Our study is the first to report differential peaks 3,354.4 m / z and 6,711.1 m / z , which were specific for M. abscessus subsp. massiliense . Our research demonstrates the capacity of the Vitek MS RUO Saramis Knowledge Base database to identify M. 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 of M. abscessus subspecies.