Physiological characterisation of the efflux pump system of antibiotic-susceptible and multidrug-resistant Enterobacter aerogenes

A. Martins, G. Spengler, M. Martins, L. Rodrigues, M. Viveiros, A. Davin-Regli, J. Chevalier, I. Couto, J. M. Pagès, L. Amaral

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Enterobacter aerogenes predominates amongst Enterobacteriaceae species that are increasingly reported as producers of extended-spectrum β-lactamases. Although this mechanism of resistance to β-lactams is important, other mechanisms bestowing a multidrug-resistant (MDR) phenotype in this species are now well documented. Amongst these mechanisms is the overexpression of efflux pumps that extrude structurally unrelated antibiotics prior to their reaching their targets. Interestingly, although knowledge of the genetic background behind efflux pumps is rapidly advancing, few studies assess the physiological nature of the overall efflux pump system of this, or for that matter any other, bacterium. The study reported here evaluates physiologically the efflux pump system of an E. aerogenes ATCC reference as well as two strains whose MDR phenotypes are mediated by overexpressed efflux pumps. The activities of the efflux pumps in these strains are modulated by pH and glucose, although the effects of the latter are essentially restricted to pH 8, suggesting the presence of two general efflux pump systems, i.e. proton-motive force-dependent and ABC transporter types, respectively.

Original languageEnglish
Pages (from-to)313-318
Number of pages6
JournalInternational Journal of Antimicrobial Agents
Volume36
Issue number4
DOIs
Publication statusPublished - Oct 2010

Keywords

  • Automated ethidium bromide method
  • Efflux pump overexpression
  • Enterobacter aerogenes
  • Modulation by glucose
  • Modulation by pH
  • Multidrug resistance

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases
  • Pharmacology (medical)

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