Molecular investigations applied to nontuberculous mycobacteria identification

Objective. Aim of this study was molecular identification in clinical specimens of NonTuberculous Mycobacteria (NTM) with commercial methods and automated sequencing. Materials and methods. Three thousand clinical specimens were analyzed for the isolation of Mycobacteria. Forty strains of NTM were previously analyzed with GenoType Mycobacteria CM/AS kit and then with partial 16S rDNA sequencing. Results. 38/40 NMT strains were identified with GenoType Mycobacteria CM/AS kit as: M. gordonae (15), M. intracellulare (8), M. xenopi (8), M. mucogenicum (2), M. kansasii (2), M. chelonae (1), M. avium (1), M. lentiflavum (1). Two unidentified strains were subjected to 16S rDNA sequencing and were identified as M. kumamotonense. Conclusions. Partial 16SrDNA sequencing is a valid assay to study NTM strains unidentified with commercial assays. This new approach, applied to clinical diagnostic, also permits the recognition of unusual strains or new species.