The mycobacterial ATP burst is a lysis artifact and serves as an assay for drug-induced cell wall damage

Abstract

Antibiotics targeting the mycobacterial cell wall are a cornerstone of tuberculosis treatment. Understanding how these drugs facilitate bacterial killing has important implications for identifying novel therapeutic targets and optimizing drug combinations. Previous studies on mycobacteria using the BacTiter-Glo luminescence assay have reported increased ATP levels after treatment with cell wall inhibitors such as isoniazid, a phenomenon referred to as an ATP burst. This phenomenon has been proposed to contribute to drug-induced killing. In this study, we demonstrate that the ATP burst is not a biological response but rather an experimental artifact resulting from enhanced cell lysis induced by cell wall-targeting drugs. The addition of a bead-beating lysis step prior to luminescence measurement abolishes the ATP burst, enabling a more reliable assessment of intracellular ATP levels with this assay. Our findings thus establish a direct link between the ATP burst and the canonical mechanism of action of cell wall inhibitors. We further demonstrate the utility of this approach as a functional readout for identifying compounds that disrupt the mycobacterial cell wall and for screening synergistic or antagonistic interactions with known cell wall-targeting agents. Together, our results elucidate the mechanistic basis of the ATP burst and provide a valuable tool for antimycobacterial drug discovery and development.