Nontuberculous mycobacteria - clinical and laboratory diagnosis: experiences from a TB endemic country

Aim:To evaluate the performance of VITEK(R)MS with DNA sequencing for laboratory diagnosis of non-tuberculous mycobacteria (NTM) species in a resource-limited setting.Methods:16SrRNAsequencing and MALDI-TOF mass spectrometry (VITEK(R)MS) was performed at a tertiary-care hospital in India. MALDI-TOF results were confirmed by 16S rRNA sequencing. In addition, sequencing of the internal transcribed spacer region was performed on slowly growing NTM.Results:Commonest species isolated wereM. abscessus, M. intracellulare,M. avium, M. fortuitumandM. simiae.16S rRNAsequencing and MALDI-TOF results had agreement of 94.5% for rapidly growing and 77.5% for slowly growing NTM.Conclusion:There is good correlation between VITEK(R)MS and sequencing for rapidly growing NTM. For slowly growing species, sequencing would be required in a third isolates.