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Loss-of-Function Mutations in epaR Confer Resistance to ϕNPV1 Infection in Enterococcus faecalis OG1RF

Khang Ho1, Wenwen Huo1, Savannah Pas1

  • 1Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas, USA.

Antimicrobial Agents and Chemotherapy
|August 15, 2018
PubMed

Insights

Phage resistance in Enterococcus faecalis can arise from mutations in the epaR gene, which prevents phage adsorption. This resistance comes with increased susceptibility to other antibiotics and stresses.

Area of Science:

  • Microbiology
  • Bacteriology
  • Phage Therapy

Background:

  • Enterococcus faecalis is an opportunistic pathogen with increasing antibiotic resistance.
  • Bacteriophages (phages) are being explored as an alternative to antibiotics for treating enterococcal infections.
  • Mechanisms of phage resistance in E. faecalis are not well understood.

Purpose of the Study:

  • To identify genetic factors conferring resistance to phage NPV1 (ϕNPV1) in E. faecalis.
  • To investigate the phenotypic consequences of phage resistance in E. faecalis.

Main Methods:

  • Generating spontaneous phage-resistant mutants of E. faecalis OG1RF.
  • Identifying mutations conferring resistance using genetic analysis.
  • Assessing phage adsorption efficiency.
  • Evaluating susceptibility to daptomycin and osmotic stress.

Main Results:

  • Loss-of-function mutations in the epaR gene conferred resistance to ϕNPV1.
  • epaR mutations blocked phage adsorption, likely due to modification or loss of an extracellular polymer.
  • Phage-resistant epaR mutants showed increased susceptibility to daptomycin and osmotic stress.

Conclusions:

  • The epaR gene is a key determinant of ϕNPV1 resistance in E. faecalis.
  • Acquisition of phage resistance in E. faecalis can incur fitness costs, including increased susceptibility to antibiotics and stress.
  • Understanding phage resistance mechanisms is crucial for developing effective phage therapy strategies.
Keywords:
Enterococcusbacteriophagedaptomycin

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