Rapid identification of M. abscessus and M. massiliense by MALDI-TOF mass spectrometry with a comparison to sequencing methods and antimicrobial susceptibility patterns.

Aim: Development of the matrix-assisted laser desorption ionization-TOF (MALDI-TOF) mass spectrometry method to rapidly identify Mycobacteria abscessus and Mycobacteria massiliense from M. abscessus complex in clinical microbiology laboratories.

Materials & Methods: Of 128 M. abscessus complex clinical isolates, sequence analysis identified 64 as M. massiliense and 64 as M. abscessus. MALDI-TOF mass spectrometry with clustering analysis created a model to differentiate these two species. Multilocus sequence typing was used to confirm our model.

Results: Using a model containing five signals, 100% species recognition was achieved for 50 strains of each species. The sequence type (ST) cluster of M. abscessus was distinct from the cluster of M. massiliense. ST1 was prevalent (59%) among M. abscessus isolates, and ST117 was common (41%) among M. massiliense isolates.

Conclusion: Molecular methods are more costly and time-consuming and may not be available in the clinical microbial laboratory. Subsequently, MALDI-TOF analysis could be a rapid identification method in the future.