Drug efflux pumps

Article By:

Poole, R. Keith Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada.

Last reviewed:2001

DOI:https://doi.org/10.1036/1097-8542.YB010540

Following the introduction of antibiotics into clinical usage in the 1940s, it soon became apparent that some bacteria were able to resist the killing action of the antibiotics. Bacteria resist or evade the toxic effects of antibiotics in a number of ways, one of which involves the energy-dependent efflux or pumping of antibiotics out of the bacterial cell. This mechanism was first identified in the early 1980s for tetracycline, and examples involving other antibiotics have since been reported. These original efflux pumps accommodated, and therefore provided resistance to, a single antibiotic or class of antibiotic. More recently, efflux pumps able to accommodate a variety of structurally unrelated antibiotics (and nonantibiotic molecules as well) have been described (Fig. 1). These pumps contribute significantly to the phenomenon of multiple antibiotic resistance in bacteria, a problem that severely complicates antibacterial chemotherapy. Multidrug efflux pumps are grouped into four families based upon amino acid sequence homology: the major facilitator superfamily (MFS), the ATP-binding cassette (ABC) family, the resistance-nodulation-division (RND) family, and the small multidrug resistance (SMR) protein family. Recently, a fifth family, referred to as the multidrug and toxic compound extrusion (MATE) family, has been identified.

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