A potent phenylalkylamine disrupts mycobacterial membrane bioenergetics and augments bactericidal activity of bedaquiline.

Clinically efficacious combination therapies capable of impeding resistance are widely sought for the treatment of mycobacterial infections. Here, we described structural modifications of the phenylalkylamine scaffold of verapamil to give an analog with more than 10-fold greater growth inhibitory activity than verapamil against Mycobacterium tuberculosis, M. bovis BCG, and M. abscessus abscessus (Mab abscessus). The analog synergized with the F1Fo-ATP synthase inhibitor bedaquiline in checkerboard assays and augmented the bactericidal properties of bedaquiline against M. bovis BCG and Mab abscessus. Using live cell bioorthogonal imaging techniques, in vitro biochemical and genetic assays, the bactericidal activity of the analog is attributed to the perturbation of membrane bioenergetics and disruption of mycobacterial respiration. Overall, its promising activity profile, mode of action and synergistic interaction with bedaquiline support further exploration of the phenylalkylamine scaffold as a valued source of potential leads for antimycobacterial drug discovery.