Identification of Significant Pathogenic Nontuberculous Mycobacteria Species from Presumptive TB Patients Using...

To date, the diagnosis of nontuberculous mycobacteria (NTM) disease primarily relies on clinical symptoms and radiological features. Our objective was to apply a sequence-based analysis method by using partial gene sequencing of heat shock protein 65 (hsp65) to identify NTM species.

A total of 32 stored isolates obtained from individuals suspected of having pulmonary NTM infection were subjected to solid Ogawa culture. Genomic DNA from each sample was extracted and used in a conventional polymerase chain reaction (PCR) targeting a specific region of hsp65 gene. Identified amplicons from the PCR were then subjected to targeted sequencing. Analysis of the obtained hsp65 sequence was performed using DNA Baser tool. The consensus sequences obtained were compared to references in the GenBank NCBI database to determine NTM species.

We identified several important NTM species which posses opportunistic characteristics. M. abscessus and M. chelonae are the most frequent NTM species identified in this study (40.63% and 18.75%, respectively). These two species have the potential to cause significant infections in human, ranging from opportunistic pulmonary infection to localized skin infection. Additionally, pathogenic NTM members of M. fortuitum group (MFG), M. avium, M. intracellulare, M. kansasii, and M. celatum were also found among all identified species.

Sequence-based analysis is a promising method for identifying species of NTM. The hsp65 gene has a high discriminatory power to identify opportunistic pathogen NTM species in specimens in Indonesia. Consequently, hsp65 partial gene sequencing is considerable as an alternative and reliable approach for NTM speciation.