Infectious diseases caused by bacteria remain a leading cause of death worldwide. Many of the antibiotics developed to combat bacterial infections have been rendered almost impotent due to the rapid evolution and spread of antibiotic resistance. A common and major resistance mechanism - the efflux system - enables bacteria to extrude structurally diverse antimicrobials, facilitating survival in toxic environments. The pumps also have important physiological functions, play major roles in bacterial pathogenesis, and are distributed widely across diverse bacterial species. In addition, a single...