Beyond bacilli: integrating the microbiome into the TB research agenda.

Tuberculosis (TB) remains a leading infectious killer, with growing evidence that the human microbiome-particularly in the gut and lungs-shapes susceptibility, progression, and treatment outcomes. Over the past decade, studies have reported that TB-associated dysbiosis, which is more common in the gut than in the lung, is often marked by the loss of short-chain fatty acid-producing taxa and the expansion of opportunistic microbes. However, findings are frequently confounded by diet, antibiotic exposure, comorbidities, geography, and methodological variability. Most research has relied on compositional profiling, offering limited insight into functional mechanisms. This narrative review synthesizes recent evidence, emphasizing the need to integrate multiomics approaches-metagenomics, metatranscriptomics, and metabolomics-and experimental validation to uncover causal links between microbiome alterations and TB pathogenesis or therapy response. We discuss potential clinical applications, including microbiome-based diagnostics (such as stool-based microbial or metabolite signatures for TB risk stratification), prognostic indicators (such as gut microbiome recovery predicting immune normalization during therapy), and adjunctive interventions (including microbiome-derived products to reduce drug-induced liver injury or fecal microbiota transplantation, which has been shown to be safe in people with HIV on stable ART) to mitigate drug toxicity or enhance immune recovery. Key priorities include methodological standardization, confounder control, mechanistic studies, and the inclusion of high-burden settings. By moving beyond descriptive surveys toward functional, translational research, integrating insights from different microbiome methods into TB prevention, diagnosis, and treatment could redefine the clinical research agenda and open new avenues for precision medicine in this global disease.