Abstract
Antibacterial resistance poses a severe threat to public health; an anticipated 14-fold increase in multidrug-resistant (MDR) bacterial infections is expected to occur by 2050. Contrary to antibiotics, combination therapies are the standard of care for antiviral and anticancer treatments, as synergistic drug-drug interactions can decrease dosage and resistance development. In this study, we investigated combination treatments of a novel succinate dehydrogenase inhibitor (promysalin) with specific inhibitors of metabolism and efflux alongside a panel of clinically approved antibiotics in synergy studies. Through these investigations, we determined that promysalin can work synergistically with vancomycin and antagonistically with aminoglycosides and a glyoxylate shunt pathway inhibitor at subinhibitory concentrations; however, these cooperative effects do not reduce minimum inhibitory concentrations. The variability of these results underscores the complexity of targeting metabolism for combination therapies in antibiotic development.