Bactericidal mode of action of bedaquiline

J Antimicrob Chemother. 2015 Jul;70(7):2028-37. doi: 10.1093/jac/dkv054. Epub 2015 Mar 8.


Objectives: It is not fully understood why inhibiting ATP synthesis in Mycobacterium species leads to death in non-replicating cells. We investigated the bactericidal mode of action of the anti-tubercular F1Fo-ATP synthase inhibitor bedaquiline (Sirturo™) in order to further understand the lethality of ATP synthase inhibition.

Methods: Mycobacterium smegmatis strains were used for all the experiments. Growth and survival during a bedaquiline challenge were performed in multiple media types. A time-course microarray was performed during initial bedaquiline challenge in minimal medium. Oxygen consumption and proton-motive force measurements were performed on whole cells and inverted membrane vesicles, respectively.

Results: A killing of 3 log10 cfu/mL was achieved 4-fold more quickly in minimal medium (a glycerol carbon source) versus rich medium (LB with Tween 80) during bedaquiline challenge. Assessing the accelerated killing condition, we identified a transcriptional remodelling of metabolism that was consistent with respiratory dysfunction but inconsistent with ATP depletion. In glycerol-energized cell suspensions, bedaquiline caused an immediate 2.3-fold increase in oxygen consumption. Bedaquiline collapsed the transmembrane pH gradient, but not the membrane potential, in a dose-dependent manner. Both these effects were dependent on binding to the F1Fo-ATP synthase.

Conclusions: Challenge with bedaquiline results in an electroneutral uncoupling of respiration-driven ATP synthesis. This may be a determinant of the bactericidal effects of bedaquiline, while ATP depletion may be a determinant of its delayed onset of killing. We propose that bedaquiline binds to and perturbs the a-c subunit interface of the Fo, leading to futile proton cycling, which is known to be lethal to mycobacteria.

Keywords: F1Fo-ATP synthase; R207910; TMC207; antimycobacterial agents; mycobacteria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antitubercular Agents / pharmacology*
  • Culture Media / chemistry
  • Diarylquinolines / pharmacology*
  • Gene Expression Profiling
  • Humans
  • Microarray Analysis
  • Microbial Viability / drug effects*
  • Microbiological Techniques
  • Mycobacterium smegmatis / drug effects*
  • Mycobacterium smegmatis / physiology*
  • Uncoupling Agents / pharmacology*


  • Antitubercular Agents
  • Culture Media
  • Diarylquinolines
  • Uncoupling Agents
  • bedaquiline