Comparison of Two Commercial Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) Systems for Identification of Nontuberculous Mycobacteria.

Objectives: This multi-center study’s aim was to assess the performance of two commercially-available matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems in identifying a challenge collection of clinically-relevant nontuberculous mycobacteria (NTM). Methods: NTM clinical isolates (N=244) belonging to 23 species/subspecies were identified by gene sequencing and analyzed using the Bruker Biotyper with Mycobacterial Library v5.0.0 and the bioMérieux VITEK MS with v3.0 database. Results: Using the Bruker or bioMérieux systems, 92% or 95% of NTM strains, respectively, were identified at least to the complex/group level; 62% and 57%, respectively, were identified to the highest taxonomic level. Differentiation between members of the M. abscessus, M. fortuitum, M. mucogenicum, M. avium, and M. terrae complexes/groups was problematic for both systems, as was identification of M. chelonae for the Bruker system. Conclusions: Both systems identified most NTM isolates to the group/complex level, and many to the highest taxonomic level. Performance was comparable