title: Essential oils from Moroccan plants as potential chemosensitisers restoring antibiotic activity in resistant Gram-negative bacteria.
abstract: Bacterial drug resistance is a worrying public health problem. Antibiotic efflux is a major non-specific resistance mechanism used by bacteria, and efflux pumps are involved in the low-level susceptibility of various important Gram-negative pathogens. Use of molecules that can block bacterial pumps is an attractive strategy, but several studies report only partial efficacy owing to limits of these molecules (stability, selectivity, bioavailability, toxicity, etc.). The objective of this study was to search for natural sources of molecules able to inhibit efflux pump systems of resistant Gram-negative bacteria (Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Salmonella enterica serotype Typhimurium and Pseudomonas aeruginosa). The results indicate that the studied essential oils exhibit interesting activity against the tested bacteria. This activity was significantly enhanced in the presence of an efflux pump inhibitor such as phenylalanine arginyl β-naphthylamide (PAβN). The role of lipopolysaccharide (LPS) structure in the effect of essential oils was also reported in Salmonella LPS deep-rough mutants. In addition, essential oils of Thymus maroccanus and Thymus broussonetii, used at a low concentration (a fraction of the minimum inhibitory concentration), are able to significantly increase chloramphenicol susceptibility of several resistant isolates. These results demonstrate that these essential oils can alter efflux pump activity and may be attractive candidates to develop new drugs for chemosensitising multidrug-resistant strains to clinically used antibiotics.
authors.affiliation: UMR-MD1, Facultés de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France.
authors.forename: Mariam
authors.initials: M
authors.lastname: Fadli
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Chevalier
authors.forename: Asmaa
authors.initials: A
authors.lastname: Saad
authors.forename: Nour-Eddine
authors.initials: NE
authors.lastname: Mezrioui
authors.forename: Lahcen
authors.initials: L
authors.lastname: Hassani
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Pages
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D002701:Chloramphenicol / Q000378:metabolism / Q000494:pharmacology; D055808:Drug Discovery; D024881:Drug Resistance, Bacterial / Q000187:drug effects* / Q000502:physiology; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000502:physiology; D021902:Enterobacter aerogenes / Q000187:drug effects / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000378:metabolism; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000378:metabolism; D019686:Lamiaceae; D008070:Lipopolysaccharides / Q000235:genetics; D008826:Microbial Sensitivity Tests; D009018:Morocco; D009281:Naphthalenes / Q000494:pharmacology; D009822:Oils, Volatile / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D008517:Phytotherapy; D035261:Plant Components, Aerial; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D008070:Lipopolysaccharides; D009281:Naphthalenes; D009822:Oils, Volatile; C072587:2-naphthylamide; D002701:Chloramphenicol