Porin alteration and active efflux: two in vivo drug resistance strategies used by Enterobacter aerogenes.
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.
Mallea
Monique
M
Enveloppe Bacerienne, Antibiotiques et Colonization,CJF 96-06 INSERM and EA 2197, Facultt! de MCdecine, 27 Boulevard Jean Moulin,13385 Marseille Cedex 05,France.
Chevalier
Jacqueline
J
Enveloppe Bacerienne, Antibiotiques et Colonization,CJF 96-06 INSERM and EA 2197, Facultt! de MCdecine, 27 Boulevard Jean Moulin,13385 Marseille Cedex 05,France.
Bornet
Charleric
C
Enveloppe Bacerienne, Antibiotiques et Colonization,CJF 96-06 INSERM and EA 2197, Facultt! de MCdecine, 27 Boulevard Jean Moulin,13385 Marseille Cedex 05,France.
Eyraud
Annie
A
Enveloppe Bacerienne, Antibiotiques et Colonization,CJF 96-06 INSERM and EA 2197, Facultt! de MCdecine, 27 Boulevard Jean Moulin,13385 Marseille Cedex 05,France.
Davin-Regli
Anne
A
Enveloppe Bacerienne, Antibiotiques et Colonization,CJF 96-06 INSERM and EA 2197, Facultt! de MCdecine, 27 Boulevard Jean Moulin,13385 Marseille Cedex 05,France.
Bollet
Claude
C
Pages
Jean-Marie
JM
Enveloppe Bacerienne, Antibiotiques et Colonization,CJF 96-06 INSERM and EA 2197, Facultt! de MCdecine, 27 Boulevard Jean Moulin,13385 Marseille Cedex 05,France.
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
D000900:Anti-Bacterial Agents; D018272:Porins; D015363:Quinolones; D047090:beta-Lactams; D001618:beta-Lactamases