Multidrug resistance pumps (MDR pumps) also known Multidrug efflux pumps are a type of

efflux pump In microbiology, efflux is the moving of a variety of different compounds out of cells, such as antibiotics, heavy metals, organic pollutants, plant-produced compounds, quorum sensing signals, bacterial metabolites and neurotransmitters. All micr ...

and

P-glycoprotein P-glycoprotein 1 (permeability glycoprotein, abbreviated as P-gp or Pgp) also known as multidrug resistance protein 1 (MDR1) or ATP-binding cassette sub-family B member 1 (ABCB1) or cluster of differentiation 243 (CD243) is an important protein ...

. MDR pumps in the

cell membrane The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment ( ...

extrudes many foreign substances out of the cells and some pumps can have a broad specificity. MDR pumps exist in animals, fungi, and bacteria and likely evolved as a defense mechanism against harmful substances. There are seven families of MDRs and are grouped by homology, energy source, and overall structure. There are five major classes of efflux pumps in bacteria: the ATP-binding cassette (ABC) superfamily, the resistance nodulation division (RND) superfamily, the major facilitator superfamily (MFS), the small multidrug resistance (SMR) superfamily, and the multidrug and toxic compound extrusion (MATE) family. There are also two minor classes: the proteobacterial antimicrobial compound efflux (PACE) family, and the p-aminobenzoyl-glutamate transporter (AbgT) family. The ABC superfamily uses ATP as an energy source for export while the rest of the efflux pumps use proton motive force. Between them, the efflux pump classes cover a wide range of substrate specificities and are involved in numerous cellular processes including cell-to-cell communication, biofilm formation, virulence, and impart cellular protection through extrusion of toxic metabolic byproducts, toxic compounds, and clinical antibiotics. Extrusion of compounds by efflux pumps is energy dependent. ABC transporters use ATP hydrolysis for efflux. The rest of the characterized pumps use proton motive force. The increased use in antibiotics has resulted in a concomitant increase in antibiotic resistant bacteria. Pathogenic bacterial and fungal species have developed MDR pumps which efflux out many antibiotics and antifugals, increasing the concentration needed for their effect. In bacteria, overexpression of some efflux pumps can result in decreased susceptibility to multiple antibiotics.

References

{{reflist Protein families Drug resistance