Multidrug efflux pumps and their inhibitors characterized by computational modeling

Antimicrobial resistance is a key public health concern of our era due to an ever-increasing number of drug-resistant pathogens, including several Gram-negative bacilli. The latter are endowed with a low permeable outer membrane and with numerous chromosomally encoded multidrug efflux pumps, which are not only ubiquitous but also nonspecific, thus recognizing a broad range of compounds. Efflux pumps are a major defense mechanism of these organisms against antimicrobials as they can significantly increase the levels of resistance by allowing time for the organisms to develop specific resistance mechanisms. One of the potential strategies to reinvigorate the efficacy of antimicrobials is by joint administration with efflux pump inhibitors, which either block the substrate binding and/or hinder any of the transport-dependent steps of the pumps. In this chapter, we provide an overview of multi-drug resistance efflux pumps, their inhibition strategies, and the important findings from the various computational simulation studies reported to date with respect to the rational design of inhibitors and on deciphering their mechanism of action.