AcrAB efflux pump plays a major role in the antibiotic resistance phenotype of Escherichia coli multiple-antibiotic-resistance (Mar) mutants.
Multiple-antibiotic-resistance (Mar) mutants of Escherichia coli are resistant to a wide variety of antibiotics, and increased active efflux is known to be responsible for the resistance to some drugs. The identity of the efflux system, however, has remained unknown. By constructing an isogenic set of E. coli K-12 strains, we showed that the marR1 mutation was incapable of increasing the resistance level in the absence of the AcrAB efflux system. This experiment identified the AcrAB system as the major pump responsible for making the Mar mutants resistant to many agents, including tetracycline, chloramphenicol, ampicillin, nalidixic acid, and rifampin.
Department of Molecular and Cell Biology, University of California, Berkeley 94720, USA.
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D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D002352:Carrier Proteins; D004352:Drug Resistance, Microbial / Q000235:genetics*; D018432:Drug Resistance, Multiple / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D029968:Escherichia coli Proteins; D008074:Lipoproteins / Q000235:genetics / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D026901:Membrane Transport Proteins; D008826:Microbial Sensitivity Tests; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009154:Mutation; D009876:Operon
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D008074:Lipoproteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; C083497:AcrA protein, E coli; C083496:AcrB protein, E coli