Figure 1. Model for Efflux Pump Inhibitor Action in Mycobacterium tuberculosis (Mtb).
Efflux pump expression is induced in Mtb following macrophage residence, perhaps stimulated by macrophage antimicrobial peptides. With antimicrobial treatment alone, non-tolerant bacteria are killed, but tolerant bacteria survive and multiply within the macrophage. When antimicrobials are given in conjunction with an efflux pump inhibitor, the tolerant bacteria are killed along with non-tolerant bacteria. Note that in this simplified diagram there is no attempt to differentiate between mycobacterial residence in the cytoplasm versus the phagosome. Modified from (Adams et al. 2011)