M. tuberculosis clinical isolates distribution
A total of 78 M. tuberculosis clinical isolates of several tribal populations among 11 places were studied, samples obtained so far from Phase I study. Madhya Pradesh, Chhattisgarh, Jharkhand, A&N Island, Manipur, Nagaland, Tripura, Rajasthan, Telangana, Andhra Pradesh, and Odisha were the sampling sites. Out of 11 sampling sites, 30 M. tuberculosis cultures were from Madhya Pradesh and Chhattisgarh. Whereas 9 M. tuberculosis cultures were from A&N island (Harminder bay at Hut bay), comprises 3 Beijing strains and the respective tribal group was Nicobarese. The remaining 10 Beijing strains were reported in Madhya Pradesh, Jharkhand, Manipur, Nagaland, and Tripura respectively (Figure. 1a). The respective tribal population in Madhya Pradesh were Bheel, Kol, Baiga, Kokru, Korku, Gond, Bhil, Bhilala, Bhoomiya, Barela, Rathore, Barelapa, Rathiya, Shariya, and Bhiala. Similarly, the remaining predominant Chattisgarh site comprises the following tribes namely; Bhaina, Bhena, Gond, Binjwal, Charwaha, Cherwa, Chirwa, Khairwar, Sawara, Nagesiya, and Urao (Figure. 1b).
Lineage Dissemination
According to the lineage dissemination of the classification, the strain types were categorized into lineages 1 to 7 (L1 to L7). Based on this system of heterogeneous grouping, the distribution of strains belonging to lineages 1 to 4 were seen prevalent in Madhya Pradesh with more of L1 (n = 10), while L3 (n = 7) ranked next with one each of L4 and L2. In Odhisa, the predominant type was found to be L1 (n = 8). In A&N island L1 (n = 5) predominate followed by L2 (n = 3). In Chhattisgarh L3 lineage lead (n = 5) followed by L1 (n = 3). Whereas, the Northeast states comprising Manipur, Nagaland, and Tripura; overall exhibited L2 (n = 8) strain type followed by L3 (n = 6). Statistical analysis displayed non-significant findings between the different states and lineages (Figure. 2)
Gender wise distribution and Cluster examination
Almost 50 (64%) were isolated from men and 28 (26%) were women. The Male TB percentage exceeds the female case among the small sample size. Almost 16 different spoligotype patterns were identified in clinical isolates (n = 78) by the spoligotyping technique. Strains with the same spoligotype were considered as a cluster in the study. These 78 isolates were observed to belong to 8 clusters, ranging from 2–20 isolates per cluster, while 25 were found to be unique. Out of these 8 clusters, cluster 1 and cluster 8 were found to be MDR-TB Beijing strains, and cluster 3 was found to be mono resistant CAS1India strain from Madhya Pradesh (Table. 1) (Figure. 3a, 3b). The major spoligotype families observed belonged to Beijing, CAS1_DELHI, EAI3_IND, and EAI5 family of M. tuberculosis strains (n = 58, 74%), followed by Central Asian strain CAS2 (n = 2, 2.9%), EAI1_SOM (n = 3, 4.3%), and other strains viz; EAI3, EAI6_BGD1, LAM3, LAM6, LAM9, T1, T2, U are present solitary strains and cumulatively contribute 13% (Table. 2).
Drug Susceptibility testing
The drug susceptibility tests for INH and RMP were carried out for all the 78 clinical isolates. Results exhibited 15.4% (n = 12) of clinical isolates showing resistance to INH or RMP + INH, which are first-line anti-TB drugs. The results of our DST tests identified resistance to INH (mono drug) in 3.8% isolates and multidrug resistance in 11.5% of cases. While 2.6% MDR strain was recorded among the M. tuberculosis isolates from women subjects, 9% M. tuberculosis isolates from men were found to be MDR (Table. 3).
Mutation of rpoB, KatG and inhA
According to the LPA assay, 3 types of mutations were found in the rpoB gene among five different tribes. MUT3 (S531L) were found in TRI062 and TRI346, whereas 2 tribal clinical isolates (TRI326, TRI345) showed MUT1 (D516V) and MUT2 were seen in TRI339. Likewise, the katG gene exhibited a different mutation; MUT2 (S315T2) in TRI053 whereas other clinical samples showed similar mutations.