THE MAIN EFFLUX SYSTEMS IN ESCHERICHIA COLI AND THEIR ROLE IN ANTIMICROBIAL RESISTANCE, A NARRATIVE REVIEW

Abstract

Antimicrobial resistance represents one of the greatest challenges to global public health, with Escherichia coli being one of the main pathogens associated with community- and hospital-acquired infections. Among the various mechanisms involved in bacterial resistance, efflux systems stand out due to their ability to extrude a wide range of toxic compounds, including antibiotics from different classes, thereby reducing the intracellular concentration of these agents and compromising their therapeutic efficacy. In E. coli, multiple efflux systems belonging to different families have been well characterized, with particular emphasis on the RND (Resistance-Nodulation-Division) family, especially the AcrAB-TolC system. This narrative review aims to discuss, in an integrated manner, the main efflux systems described in E. coli, their structural and functional characteristics, regulatory mechanisms, transported substrates, and their relevance in the context of antimicrobial resistance, as well as to address therapeutic strategies aimed at inhibiting these systems.