title: Demonstration of intrinsic efflux activity of Escherichia coli K-12 AG100 by an automated ethidium bromide method.
abstract: Demonstration of efflux of ethidium bromide (EtBr) has been made for over 30 bacterial species, usually by showing enhanced efflux in multidrug-resistant strains that was then abolished by inactivating efflux pumps. Here we present a relatively simple automated method that employs EtBr as an efflux pump substrate for the demonstration of intrinsic efflux activity in Escherichia coli K-12 AG100. The method uses the Rotor-Gene 3000 instrument for real-time fluorometric measurement of EtBr accumulation under conditions that limit energy (absence of glucose, low temperature) and of EtBr extrusion under optimum conditions. The method can be used for screening compound libraries for efflux inhibiting capacity.
authors.affiliation: Unit of Mycobacteriology, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 96, Lisbon, Portugal.
authors.forename: Miguel
authors.initials: M
authors.lastname: Viveiros
authors.forename: Ana
authors.initials: A
authors.lastname: Martins
authors.forename: Laura
authors.initials: L
authors.lastname: Paixão
authors.forename: Liliana
authors.initials: L
authors.lastname: Rodrigues
authors.forename: Marta
authors.initials: M
authors.lastname: Martins
authors.forename: Isabel
authors.initials: I
authors.lastname: Couto
authors.forename: Eva
authors.initials: E
authors.lastname: Fähnrich
authors.forename: Winfried V
authors.initials: WV
authors.lastname: Kern
authors.forename: Leonard
authors.initials: L
authors.lastname: Amaral
mesh_terms: D001692:Biological Transport / Q000187:drug effects; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D048168:Escherichia coli K12 / Q000378:metabolism*; D004996:Ethidium / Q000378:metabolism*; D008828:Microbiological Techniques / Q000379:methods*
chemical_list: D004996:Ethidium