Identification of Probiotic Strains with Anti-Tuberculosis Activity and Their Characterization as Potential Therapeutic Agents

Tuberculosis (TB) remains a global health crisis, with the emergence of multidrugresistant strains necessitating the development of novel therapeutic strategies.Approximately one-fourth of the world's population, or 2 billion people, are infected with latent TB.The rise of multidrug-resistant (MDR), extensively drug-resistant (XDR), and totally drug-resistant (TDR) strains of Mycobacterium tuberculosis (M.tb) poses a significant threat, reducing the effectiveness of conventional treatments.The limitations of current antibiotic regimens underscore the urgent need for alternative approaches.This highlights the urgent need for new anti-tuberculosis drugs.Probiotics, known for their health benefits against various infections, may offer a promising alternative in combating antibiotic-resistant TB.This study aimed to identify novel probiotic strains with anti-tuberculosis potential.Seven probiotic strains were selected by screening with the GFP-TB in vitro model.Treatment with probiotic extracts significantly reduced the TB burden inside macrophage cells analyzed by confocal microscopy, ranging from 51% to 76%.The anti-tuberculosis efficacy of these candidate strains was further evaluated using CFU and resazurin assays, where treatment with probiotics resulted in up to a 1.25 log reduction of viable TB in the CFU assay.To ensure the probiotic strains were safe for therapeutic application, comprehensive safety assessments were conducted, including evaluations of cytotoxicity, antibiotic susceptibility test, hemolysis, bile salt deconjugation, and D-lactate assay.Following the safety confirmation, we investigated the underlying mechanisms by which these probiotic strains enhance immunity and facilitate the clearance of TB within macrophage cells in vitro.This involved assessing autophagy gene expression and nitrite reduction, which are established methods for studying anti-tuberculosis effects.The results of these mechanistic studies align with the CFU and confocal microscopy findings, indicating that at least three of the probiotic strains have the potential to mitigate tuberculosis infection significantly.This research provides a foundation for further exploration of these probiotic strains as potential biotherapeutics in tuberculosis treatment.However, further studies on toxicity, mechanism of action, and efficacy in animals, followed by clinical trials, are necessary.