Efflux pumps of Gram-negative bacteria in brief

Abstract

The development of multidrug resistance in Gram-negative bacteria is a major problem faced antimicrobial therapy and management of infectious diseases. Too many resistance mechanisms were developed since the antimicrobial agents were produced and actually used. The mechanisms involved in antimicrobial agents' resistance are, modifying enzymes, alteration of the target site of antimicrobials and prevention of antimicrobials accumulation inside the bacterial cells. The latest is accomplished by two mechanisms: alteration of outer membrane permeability and efflux pumps. Efflux pumps are either chromosomal or plasmid-encoded although chromosomal encoded efflux pumps are common in Gram-negative bacteria. Resistance nodulation division (RND) efflux pump superfamily are predominant in Gram-negative and involved in pathogenesis, virulence and stress response of bacteria as well as the well-known function, antimicrobial resistance. Moreover, efflux pumps may involve in antimicrobial resistance or they may increase the level of resistance by their overexpression and by synergy with other resistance mechanisms. Overexpression of efflux pumps encode by regulatory genes occurs near of far from operons of efflux pumps. The recent review article highlights the Gram-negative efflux pumps structure, function and substrate specificity in brief.