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Testing the Role of Multicopy Plasmids in the Evolution of Antibiotic Resistance
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First report of mefA and msrA/msrB multidrug efflux pumps associated with blaTEM-1 β-lactamase in Enterococcus

Chedly Chouchani1, Allaaeddin El Salabi, Rim Marrakchi

  • 1Université de Carthage, Institut Supérieur des Sciences et Technologies de l'Environnement de Borj-Cedria, Technopôle de Borj-Cedria, BP-1003, Hammam-Lif 2050, Tunisia. chdoula77@yahoo.fr

International Journal of Infectious Diseases : IJID : Official Publication of the International Society for Infectious Diseases
|December 6, 2011
PubMed
Abstract

Insights

This study identified TEM-1 beta-lactamase and mefA/msrA/msrB efflux pumps as resistance mechanisms in clinical Enterococcus faecalis isolates. This is the first report of these two mechanisms co-existing in E. faecalis strains.

Area of Science:

  • Microbiology
  • Antimicrobial Resistance
  • Molecular Biology

Background:

  • Enterococcus faecalis exhibits significant intrinsic resistance to various antimicrobial agents.
  • Understanding resistance mechanisms is crucial for effective treatment strategies.

Purpose of the Study:

  • To identify ampicillin- and erythromycin-resistant clinical isolates of E. faecalis.
  • To elucidate the specific resistance mechanisms employed by these isolates.

Main Methods:

  • Phenotypic identification and susceptibility testing using the Phoenix automated system.
  • PCR amplification and sequencing for beta-lactamase detection.
  • Colony blotting and protein sequencing to identify multidrug efflux pumps.

Main Results:

  • All E. faecalis isolates demonstrated high resistance to erythromycin and ampicillin (MIC >16 μg/ml).
  • TEM-1 beta-lactamase production was confirmed via PCR and sequencing.
  • The mefA and msrA/msrB efflux pumps were identified as contributing to multidrug resistance.

Conclusions:

  • The study identified TEM-1 beta-lactamase and mefA/msrA/msrB efflux pumps as key resistance mechanisms in E. faecalis.
  • This is the first documented instance of the co-existence of these two resistance mechanisms in E. faecalis strains.
  • These findings highlight the evolving resistance landscape of E. faecalis.

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