Repurposing Penfluridol to combat mycobacteria via bioenergetic collapse

(Mtb) infections constitute a persistent and severe public health crisis worldwide. Standard anti-tuberculosis (anti-TB) therapies often fail to eradicate resistant strains, resulting in poor clinical outcomes and underscoring the demand for new treatment options. Drug repurposing offers a practical and time-efficient approach to accelerate the development of new anti-mycobacterial regimens. In this work, we evaluated the antimycobacterial potency of penfluridol (PL), a Food and Drug Administration (FDA)-approved antipsychotic drug, and explored its functional mechanism against mycobacteria. Our experimental data revealed that PL compromises mycobacterial membrane integrity and depletes the proton motive force (PMF), leading to disrupted energy metabolism and mycobacterial growth inhibition. PMF depletion disables energy-reliant efflux systems, facilitates intracellular PL accumulation, and further deteriorates membrane damage, creating a sustained bactericidal effect. Notably, continuous PL exposure rarely induces stable drug resistance. These observations suggest that PL can be repurposed for treating drug-resistant TB and confirm that targeting bacterial bioenergetics is an effective strategy to overcome clinical antimicrobial resistance. IMPORTANCE: Tuberculosis (TB) remains a major threat to global public health, and the widespread emergence of drug-resistant strains has substantially compromised the efficacy of existing anti-TB regimens. The scarcity of approved anti-TB drugs, combined with lengthy treatment regimens and frequent therapeutic failure, further exacerbates the global TB crisis, highlighting an urgent need for safe and effective alternative therapies. Drug repurposing serves as a time-saving and reliable strategy to accelerate anti-TB drug development. This study explores the antimycobacterial efficacy and unique working mechanism of the clinically approved agent penfluridol (PL). Our findings identify a feasible candidate for treating drug-resistant TB and provide a valuable bioenergetic-targeting strategy to combat bacterial antimicrobial resistance.