title: Porin alteration and active efflux: two in vivo drug resistance strategies used by Enterobacter aerogenes.
abstract: Enterobacter aerogenes is among the five most frequently isolated nosocomial pathogens in France, and this bacterium also shows increasing multidrug resistance. In this study, various E. aerogenes strains isolated from hospital units were characterized for their outer-membrane proteins, antibiotic susceptibilities (inhibition diameters and MICs) and resistance mechanisms associated with modification of envelope permeability (porin alteration and active efflux). Diminished outer-membrane permeability due to porin alterations was found in conjunction with the expression of an enzymic barrier in resistant isolates. Interestingly, changes in the functional expression of porins appeared to play a special role in susceptibility to cefepime. An active efflux to quinolones was also identified. Simultaneous changes in envelope permeability, i.e. a porin deficiency (in) and an efflux mechanism (out), were clearly evident in two clinical strains.
authors.affiliation: Enveloppe Bacerienne, Antibiotiques et Colonization,CJF 96-06 INSERM and EA 2197, Facultt! de MCdecine, 27 Boulevard Jean Moulin,13385 Marseille Cedex 05,France.
authors.forename: Monique
authors.initials: M
authors.lastname: Mallea
authors.affiliation: Enveloppe Bacerienne, Antibiotiques et Colonization,CJF 96-06 INSERM and EA 2197, Facultt! de MCdecine, 27 Boulevard Jean Moulin,13385 Marseille Cedex 05,France.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Chevalier
authors.affiliation: Enveloppe Bacerienne, Antibiotiques et Colonization,CJF 96-06 INSERM and EA 2197, Facultt! de MCdecine, 27 Boulevard Jean Moulin,13385 Marseille Cedex 05,France.
authors.forename: Charleric
authors.initials: C
authors.lastname: Bornet
authors.affiliation: Enveloppe Bacerienne, Antibiotiques et Colonization,CJF 96-06 INSERM and EA 2197, Facultt! de MCdecine, 27 Boulevard Jean Moulin,13385 Marseille Cedex 05,France.
authors.forename: Annie
authors.initials: A
authors.lastname: Eyraud
authors.affiliation: Enveloppe Bacerienne, Antibiotiques et Colonization,CJF 96-06 INSERM and EA 2197, Facultt! de MCdecine, 27 Boulevard Jean Moulin,13385 Marseille Cedex 05,France.
authors.forename: Anne
authors.initials: A
authors.lastname: Davin-Regli
authors.forename: Claude
authors.initials: C
authors.lastname: Bollet
authors.affiliation: Enveloppe Bacerienne, Antibiotiques et Colonization,CJF 96-06 INSERM and EA 2197, Facultt! de MCdecine, 27 Boulevard Jean Moulin,13385 Marseille Cedex 05,France.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Pages
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism* / Q000494:pharmacology*; D002463:Cell Membrane Permeability; D004352:Drug Resistance, Microbial; D018432:Drug Resistance, Multiple; D004754:Enterobacter / Q000187:drug effects* / Q000201:enzymology / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D018272:Porins / Q000032:analysis / Q000378:metabolism*; D015363:Quinolones / Q000378:metabolism / Q000494:pharmacology; D001618:beta-Lactamases / Q000378:metabolism; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D018272:Porins; D015363:Quinolones; D047090:beta-Lactams; D001618:beta-Lactamases