title: Mechanisms of drug efflux and strategies to combat them: challenging the efflux pump of Gram-negative bacteria.
abstract: Chemoresistance presents a general health problem concerning the therapy of infectious disease and cancer. In this context, the worldwide dissemination of "multidrugresistant" (MDR) pathogens has severely reduced the efficacy of our antimicrobial weapons and dramatically increased the frequency of therapeutic failure. Because MDR bacterial infections involve the over-expression of efflux pumps that expel unrelated antibiotics before they can reach their targets, it is necessary to clearly define the molecular and genetic bases of the MDR mechanisms in order to combat these infectious diseases. This characterization of efflux pumps allows the definition of an original anti-resistance weapon, the efflux pump inhibitor (EPI). Several chemical families of EPIs have been now described and characterized. Among them several inhibitor compounds display an efficient activity and inhibit the major AcrAB-TolC and MexAB-OprM efflux systems which are the major efflux pumps responsible for MDR Gram negative clinical isolates. The use of these EPIs induces a significant reduction of resistance to one or more antibiotics to which these isolates were initially resistant. Hence, the EPI when used as an adjuvant to the given antibiotic, restores the activity of the antibiotic. The description of the responsible efflux mechanism at its structural and physiological level will make it possible to develop along intelligent lines an improved new generation of EPIs that can readily be added to the armamentarium of current and past "fallen by the wayside" antibiotic therapies.
authors.affiliation: UMR-MD-1, Transporteurs Membranaires, Chimiorésistance et Drug Design, Facultés de Médecine et de Pharmacie, Université de la Méditerranée, 27 Bd Jean Moulin, 13385 Marseille cedex 05, France. jean-marie.pages@univmed.fr
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Pagès
authors.forename: Leonard
authors.initials: L
authors.lastname: Amaral
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D001693:Biological Transport, Active / Q000187:drug effects / Q000502:physiology*; D002462:Cell Membrane / Q000187:drug effects; D024901:Drug Resistance, Multiple, Bacterial / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D010879:Piperazines / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D011804:Quinolines / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D010879:Piperazines; D010880:Piperidines; D011804:Quinolines