Mykobakterielle Erkrankungen
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MALDI-TOF Protocol for M. tuberculosis Identification Improved MALDI-TOF MS Identification of Mycobacterium tuberculosis by Use of a Cell Disruption Protocol

Bacanelli GM*, Araujo FR, Verbisck NV

Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) has been used for the identification of Mycobacterium spp. due to its speed, reliability, cost-effectiveness and high efficiency. However, the cell wall of mycobacteria is rich in lipids which makes it difficult to obtain proteins for analysis by MALDI-TOF MS. In this study, two protein extraction protocols were compared: The MycoEx, recommended by the MALDI-TOF instrument manufacturer Bruker Daltonics and the MycoLyser protocol described here in, which used the MagNA Lyser instrument for cellular rupture. Protein extraction with the two protocols was performed using the virulent strain M. tuberculosis H37Rv (NCBI NC_000962) and the results compared. The MycoLyser protocol allowed enhanced Biotyper identification of M. tuberculosis since the scores obtained with this protocol were mostly ˃1,800. The identification accuracy was 38.8% (A), 44.5% (B), 16.7% (C) for MycoLyser and 0% (A), 16.7% (B), 83.3% (C) for MycoEx. In view of these results, it is evident that the new MycoLyser protocol for mycobacterial protein extraction allows improvement of the MALDI-TOF MS method efficacy for M. tuberculosis identification.