Bacterial multidrug resistance efflux pump (MDR efflux pump) (MDR efflux pump)

Bacterial multidrug resistance (MDR) efflux pumps are integral membrane proteins that actively extrude a broad spectrum of antibiotics, biocides, and metabolic byproducts from the bacterial cell (StatPearls, 2023). These systems are categorized into five major families—Resistance-Nodulation-Division (RND), Major Facilitator Superfamily (MFS), ATP-Binding Cassette (ABC), Small Multidrug Resistance (SMR), and Multidrug and Toxic Compound Extrusion (MATE)—distinguished by their structural organization and energy source (Nature Reviews Microbiology, 2015). By maintaining intracellular drug concentrations below lethal thresholds, these pumps serve as a cornerstone of both intrinsic and acquired antimicrobial resistance in pathogens like Pseudomonas aeruginosa and Staphylococcus aureus (PubMed, PMC7016768). Beyond drug resistance, they play critical roles in bacterial physiology, including the secretion of virulence factors and the regulation of quorum sensing molecules (Microbiology and Molecular Biology Reviews, 2009). Therapeutic strategies focusing on efflux pump inhibitors (EPIs) aim to block these transporters, thereby restoring the potency of conventional antibiotics and reducing the emergence of resistant strains (Journal of Medicinal Chemistry, 2020). However, the development of clinical EPIs remains challenging due to potential cross-reactivity with human transporters and the need for high potency without host toxicity (Frontiers in Microbiology, 2018).

Other names

Bacterial efflux systemMultidrug efflux transporterXenobiotic efflux pumpAntimicrobial resistance pumpEfflux protein

Efflux pump inhibitors (EPIs) function by competitively binding to the substrate-binding pocket, disrupting the energy source (proton motive force or ATP hydrolysis) required for transport, or interfering with the assembly of the multi-protein pump complex (Antibiotics, 2021; PubMed, 25611286).