WIV-ISP's experiences in the use of MALDI-TOF for the identification of Mycobacteria and their drug resistance profiles

An Van den Bossche presented WIV-ISP's experiences in the use of Brüker’s Biotyper MALDI-TOF for the identification of Mycobacteria and their drug resistance profiles. By using an optimized extraction protocol, they successfully identified 88.14 % of 194 Mycobacterial strains at a species-level and 3.09 % at genus-level, using the Brüker Database v3.0. For organisms of the Mycobacterium tuberculosis complex, identifications were 100% correct, while the concordance with standard methods was a bit lower for Nontuberculous Mycobacteria, 88.03%. Five organisms were misidentified. A novel method of drug resistance testing was also presented, which uses semi-quantitative measurement of bacterial biomass by creating MALDI-TOF spectra in the presence of an internal standard.