Mutations in drug resistance associated genes and the genetic diversity of mycobacterium tuberculosis in Bagamoyo district, Tanzania

The burden of drug-resistant tuberculosis globally underlines the need to improve knowledge on drug resistance profiles, genetic diversity, dominant strains and transmission patterns in the community. This study screened for mutations in drug resistance associated genes and determined the genetic diversity of M. tuberculosis (M. TB) isolates from Bagamoyo, Tanzania. The iSEQ Comparative sequence analysis and iPLEX SNP genotyping were performed. A total of 119 isolates were analyzed by full gene-length screening for mutations in katG, inhA, OxyR-aphC, rpoB, rpsL, rrs, embB, pncA, gyrA genes. On the other hand, 92 isolates were genotyped at 74 SNP positions. The majority (64%) of the mutations detected were nonsynonymous. Drug resistance-associated mutations were observed in 3 isolates harboring the katG 315 Ser->Thr (AGC-ACC) mutations. This observation predicts the emergence of drug resistance in the study area if proper TB management will not be maintained. On the other hand, study results indicate a high genetic diversity of M. TB in Bagamoyo with three predominant haplotypes coined BAG6, BAG9 and BAG 16. Similarly, results indicate four major SNP clusters in the study area. SNP clusters and haplotypes identified in this study may be useful for surveillance and monitoring the transmission of disease in the study area. In conclusion, further studies are recommended to gain better insights into TB epidemiology in the study area.