Abstract
Emerging evidence suggests the link between pulmonary tuberculosis (PTB) and gut microbiota dysbiosis. This is the first study from the southern Indian population that characterized the gut microbiota of PTB patients using 16 S amplicon sequencing. The analysis revealed a significant reduction in gut microbial diversity among PTB patients, with particularly lower alpha diversity (Chao1 index, p ≤ 0.0001) than healthy controls (HC). This was further depleted during antitubercular therapy (ATT). Beta diversity indicated distinct clustering in all the groups (p < 0.05). Subgroup analyses showed that supplementation of probiotics with ATT improved microbial richness and diversity. However, broader shifts in composition were not observed. At the genus level, specific taxa were upregulated or downregulated in PTB patients compared to HC. Functional analysis showed a depletion in biosynthesis pathways in PTB patients. Short-term probiotic supplementation had a partial effect on microbial recovery but did not fully restore gut microbial diversity. These findings highlight persistent dysbiosis in PTB patients, even after ATT. Large-scale studies are needed to evaluate the role of microbiome-targeted therapies to address this dysbiosis.