Drug efflux pump

Drug efflux pumps are membrane transport proteins in bacteria that actively expel a wide variety of structurally diverse compounds, including antibiotics, toxins, detergents, heavy metals, and metabolites, from the cytoplasm or periplasm to the outside of the cell[2][3][5][7][8]. They are a major mechanism underlying multidrug resistance in pathogenic bacteria, often rendering antimicrobial therapies less effective[5][6][7]. These systems can have broad or narrow substrate selectivity and are classified into several superfamilies: major facilitator (MFS), small multidrug resistance (SMR), ATP-binding cassette (ABC) transporters, resistance-nodulation-division (RND), and multi-antimicrobial extrusion protein (MATE) families[6][7]. Efflux pumps function via either secondary active transport (using electrochemical gradients) or primary active transport (using ATP hydrolysis)[5][7]. As a collective mechanism ("drug efflux system"), the term does not refer to a single defined molecular entity but rather to a functionally and structurally diverse set of transporters[5]. Overexpression or mutation of efflux pumps is frequently observed in multidrug-resistant bacterial clinical isolates, and targeting efflux activity is a current focus for reversing antibiotic resistance[6][7][8]. Note: The query "Drug efflux system" is imprecise because it refers to a group of transporters with multiple molecular identities, rather than a single defined target. For structured drug development, refer to individual efflux pumps (e.g., AcrAB-TolC, NorA, Mdr1, etc.), since "Drug efflux system" as a target aggregates multiple, sometimes unrelated, molecular entities and mechanisms[5][6][7].

Other names

Multidrug efflux pumpEfflux pumpMultidrug efflux systemBacterial efflux systemMultidrug transporter

Active transport (energy-dependent extrusion); includes proton motive force-driven antiport (MFS, RND, SMR, MATE families) and ATP-dependent transport (ABC family).