Non-tuberculosis mycobacterial infection among clinically suspected tuberculosis in eastern India (2019-2023)

Incidence of non-tuberculous mycobacterial (NTM) infections is on rise globally and poses significant diagnostic and treatment challenges for tuberculosis as most of them are resistant to anti-tubercular drugs. NTM susceptibility to drugs varies from species to species and there is no specific regimen for treatment. We conducted this study to understand the epidemiology of NTM infections in Odisha from 2019 to 2023.

All the samples referred from districts suspected for NTM infections were subjected to culture followed by species identification using line probe assay (Hain Lifesciences, details). Anti-mycobacterial susceptibility was determined by MIC breakpoints and the analysis was done as per the Clinical and laboratory Standard Institute (CLSI) M24S 2018 guidelines.

A total of 828 suspected NTM infection samples were included in the study. Non- tuberculous mycobacteria were found in 67 (8.1 %, 67/828) samples. The most prevalent non-tuberculous mycobacteria isolated was found to be M. intracellulare (32.8 %,22/67), followed by M. abscessus (22.3 %, 15/67), M. fortuitum (11.9 %,8/67), and M. scrofulaceum (8.9 %),6/67). Non tuberculosis mycobacterial disease was seen from most of the districts but it was more common in the coastal districts of Odisha like Khordha (29.8 %,20/67), Cuttack (11.9 %,8/67), Bhadrak (8.9 %,67), Kendrapada (7.4 %,5/67), Balasore (4.4 %, 3/67), Jajpur (4.4 %, 3/67), Puri (7.4 %,5/67). NTM was more prevalent in males (65.7 %) than females (34.3 %). The MIC breakpoints showed different sensitive and resistant patterns for NTM isolates. It was seen that M. mucogeniucum was sensitive to all the drugs tested, M. avium and M. abscessus isolates were resistant to most of the drugs and sensitive to few drugs like doxycycline, kanamycin and clarithromycin.

The increasing prevalence of NTM infections necessitates precise identification at the species level, coupled with drug susceptibility testing (DST), to guide targeted therapy. This approach is critical not only for optimizing patient outcomes but also for mitigating the emergence of antimicrobial resistance through inappropriate or empirical treatment strategies.