Bacterial efflux pump system (BEP)

Bacterial efflux pump systems are specialized membrane proteins that actively transport a wide variety of substrates, including antibiotics, biocides, and metabolic byproducts, from the interior of the cell to the external environment (StatPearls, 2023). These systems are categorized into several major families—such as the Resistance-Nodulation-Division (RND) and Major Facilitator Superfamily (MFS)—based on their structure, energy source, and substrate specificity (Nature Reviews Microbiology, 2018). They represent a primary mechanism of multidrug resistance (MDR) in both Gram-positive and Gram-negative bacteria, effectively lowering the intracellular concentration of antimicrobial agents to sub-lethal levels (Frontiers in Microbiology, 2018). Beyond drug resistance, these pumps are essential for bacterial physiology, playing roles in quorum sensing, virulence, and the maintenance of cellular homeostasis (PubMed, PMC4141120). Targeting these systems with efflux pump inhibitors (EPIs) is a strategic approach to restore the efficacy of existing antibiotics and combat the global rise of resistant pathogens (Antibiotics, 2020). However, the development of therapeutic EPIs is challenged by potential toxicity and the need for high specificity to avoid interfering with essential human transporters (PubMed, PMC6271414).

Other names

Multidrug efflux pumpBacterial multidrug resistance pumpEfflux transporterXenobiotic transporterAntimicrobial efflux pump

Efflux pump inhibitors (EPIs) function by competitively or non-competitively binding to the pump's substrate binding site, disrupting the energy source (such as the proton motive force or ATP hydrolysis), or interfering with the assembly of the multicomponent pump complex (e.g., blocking the outer membrane channel).