Anti-Mycobacterium avium complex activity of clarithromycin, rifampin, rifabutin, and ethambutol in combination with adenosine 5′-triphosphate

We previously reported that adenosine 5 '-triphosphate (ATP) inhibited the growth of various bacteria, including mycobacteria, Staphylococcus, and Pseudomonas, without damaging bacterial surface structures. Notably, ATP's antibacterial activity was found to be attributable to its iron-chelating ability. ATP exhibited combined effects with some antimicrobials against Mycobacterium intracellulare and methicillin-resistant S. aureus, suggesting its usefulness as an adjunctive drug in the chemotherapy against certain intractable infections. In this study, we examined detailed profiles of the anti-Mycobacterium avium complex (MAC) activity of some antimicrobial agents, including clarithromycin (CIA), rifampin (RIF), rifabutin (RBT), and ethambutol (EMB), in combination with ATP. It was found that the anti-MAC activity of CLA + RIF, CIA + RBT, and CIA + EMB was markedly potentiated in a strain-dependent manner. In this case, the onset of the regrowth of antimicrobial agent-treated mycobacteria during cultivation was significantly delayed in the presence of ATP, indicating the usefulness of ATP as an adjunctive drug in chemotherapy against MAC infections. (C) 2017 Elsevier Inc. All rights reserved.