Bacterial cytological profiling identifies transmembrane anion transport as the mechanism of action for a urea-based antibiotic

There is a growing fear that bacteria are emerging that are resistant to most known antibiotics, which could lead to an increasing number of fatalities due to bacterial infections. There is therefore an urgent need for the development of novel antibacterial products, preferably with novel mode of actions for which there are no known resistance pathways. We have previously found serendipitously that a simple urea-based compound functions as a potent antibacterial agent. In this manuscript, we use bacterial cytological profiling (BCP) to determine its mechanism of action. BCP reveals that the urea is acting through a membrane-based pathway that is comparable to, but distinct from, the mechanism of cationophore calcimycin. Additional liposome-based assays suggest that the likely mechanism of action of this mono-urea is transmembrane anion transport. This finding highlights that synthetic anionophores could be used as potential antibiotics.