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

Abstract

Objectives: This multicenter study's aim was to assess the performance of two commercially available matrix-assisted laser desorption/ionization time of flight mass spectrometry 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 Bruker Biotyper with Mycobacterial Library v5.0.0 and bioMérieux VITEK MS with v3.0 database.

Results: Using the Bruker or bioMérieux systems, 92% and 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 Mycobacterium 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.

Keywords: Bruker Biotyper; Comparison; Identification; MALDI-TOF; Mass spectrometry; Nontuberculous mycobacteria; bioMérieux VITEK MS.

Figure 1

Chief limitations of the Bruker Biotyper system with RUO Mycobacteria Library v5.0.0 and the VITEK MS IVD system with v3.0 Knowledge Base, for the identification of nontuberculous mycobacteria. ^aThe Biotyper system was better able to differentiate among Mycobacterium fortuitum group members compared with the VITEK MS system.