Automated quantitative drug susceptibility testing of non-tuberculous mycobacteria using MGIT 960/EpiCenter TB eXiST.

OBJECTIVES To assess the predictive value of in vitro drug susceptibility testing (DST) in slow-growing non-tuberculous mycobacteria (NTM), knowledge on quantitative levels of drug susceptibility should be available. The aim of this study was to investigate the suitability of the MGIT 960/TB eXiST system for quantitative DST of NTM. METHODS We have assessed quantitative levels of drug susceptibility for clinical isolates of Mycobacterium avium, Mycobacterium intracellulare and Mycobacterium kansasii by comparing radiometric Bactec 460TB-based DST with non-radiometric DST using MGIT 960/TB eXiST. RESULTS MGIT 960/TB eXiST gives results comparable to those of Bactec 460TB. CONCLUSIONS The MGIT 960/TB eXiST appears suitable for quantitative DST of NTM.