Tioconazole exerts anti-TB activity by destroying cell integrity

The increasing prevalence of drug-resistant tuberculosis (TB), coupled with the lengthy and toxic nature of conventional treatments and the complicating factor of Human Immunodeficiency Virus (HIV) co-infection, underscores the urgent need for the development of effective anti-TB drugs and robust stockpiles to combat this global health crisis. In this study, the anti-tubercular activity and potential antibacterial mechanisms of tioconazole were investigated. Tioconazole exhibited remarkable antibacterial activity against Mtb H37Ra and H37Rv, with minimum inhibitory concentrations (MICs) of 4 μg/mL and 1 μg/mL respectively. While cholesterol or palmitic acid was utilized as a solo carbon source, its MIC against Mtb H37Ra decreased to 2 μg/mL. Mtb H37Ra CYP121 conditional mutant was more sensitive to tioconazole in comparison with Mtb H37Ra in the presence of the pristinamycin (0.1 μg/mL and 0.001 μg/mL). Further experiments demonstrated that treatment with 0.5 × MIC of tioconazole (2 μg/mL) for five days resulted in the formation of invagination and bulge on the surfaces of Mtb cells. Concurrently, intracellular ATP levels decreased by nearly 50 %, likely due to the inhibition of lipid metabolism by tioconazole, which compromises the integrity of the cell wall and cell membrane. Taken together, these findings suggest that tioconazole may serve as a novel anti-TB agent, exerting anti-TB activities by disrupting the structural integrity of the pathogen's cells.