Efflux pumps, OprD porin, AmpC beta-lactamase, and multiresistance in Pseudomonas aeruginosa isolates from cystic fibrosis patients

Maria Tomas, Michel Doumith, Marina Warner, Jane F. Turton, Alejandro Beceiro, German Bou, David M. Livermore, Neil Woodford

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Expression of ampC, oprD, mexA, mexC, mexE, and mexX was studied in 25 Pseudomonas aeruginosa isolates from cystic fibrosis patients, including 14 isolates of the Liverpool epidemic strain. Overexpressed mexA or ampC and reduced oprD were associated with beta-lactam resistance. A specific combination of mexR, nalC, and nalD mutations occurred in 11 Liverpool strain isolates, including 7 with upregulated mexA.
Original languageEnglish
Pages (from-to)2219-2224
Number of pages6
JournalAntimicrobial Agents and Chemotherapy
Issue number5
Publication statusPublished - May 2010


  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • Cystic Fibrosis
  • Drug Resistance, Bacterial
  • Drug Resistance, Multiple
  • Electrophoresis, Gel, Pulsed-Field
  • Humans
  • Membrane Transport Proteins
  • Mutation
  • Porins
  • Pseudomonas Infections
  • Pseudomonas aeruginosa
  • Reverse Transcriptase Polymerase Chain Reaction
  • Up-Regulation
  • beta-Lactamases

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