RobA-induced multiple antibiotic resistance largely depends on the activation of the AcrAB efflux

Microbiol Immunol. 1997;41(9):697-702. doi: 10.1111/j.1348-0421.1997.tb01913.x.


RobA is a member of the XylS/AraC subfamily of DNA binding proteins, and when overexpressed, it induces multiple antibiotic resistance in Escherichia coli. In this study, we introduced a multicopy robA plasmid (pMEP1) and its derivative into OmpF mutants and an AcrAB-deficient mutant. We found that a decrease in susceptibility to multiple antibiotics in these OmpF mutants when pMEP1 was introduced did not depend on OmpF porin expression. Interestingly, a delta ompF mutant (TK007) became more sensitive when pMEP1 was introduced. Moreover, no effect of RobA on the induction of multiple antibiotic resistance in an acrA1- mutant was observed. Therefore, we conclude that the multiple antibiotic resistance induced by the overexpression of RobA largely depends on the activation of the AcrAB efflux, as well as the activation of micF.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / physiology*
  • Biological Transport
  • Carrier Proteins / genetics
  • Carrier Proteins / physiology*
  • DNA-Binding Proteins / physiology*
  • Drug Resistance, Microbial / genetics*
  • Drug Resistance, Multiple / genetics*
  • Escherichia coli / drug effects
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism
  • Escherichia coli Proteins*
  • Gene Expression Regulation, Bacterial*
  • Lipoproteins / genetics
  • Lipoproteins / physiology*
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology*
  • Membrane Transport Proteins
  • Multidrug Resistance-Associated Proteins
  • Plasmids
  • Porins / genetics
  • Porins / metabolism*
  • RNA / genetics
  • RNA / physiology*
  • Recombinant Fusion Proteins / physiology
  • Transcription, Genetic


  • AcrA protein, E coli
  • AcrB protein, E coli
  • Bacterial Proteins
  • Carrier Proteins
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • Lipoproteins
  • Membrane Proteins
  • Membrane Transport Proteins
  • Multidrug Resistance-Associated Proteins
  • OmpF protein
  • Porins
  • Recombinant Fusion Proteins
  • Rob protein, E coli
  • RNA