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Quantitative Proteomics Analysis of Membrane Proteins in Enterococcus faecalis With Low-Level Linezolid-Resistance

Jia Yan1, Yun Xia1, Mi Yang1

  • 1Department of Clinical Laboratory, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.

Frontiers in Microbiology
|August 14, 2018
PubMed

Insights

Low-level linezolid resistance in Enterococcus faecalis is primarily mediated by the OptrA protein, potentially enhanced by biofilm formation. This study used quantitative proteomics to identify key resistance mechanisms and regulatory proteins.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Proteomics

Background:

  • Increasing global reports of low-level linezolid-resistant enterococci.
  • Mechanisms underlying this resistance remain poorly understood.
  • Previous transcriptome studies identified potential resistance genes in Enterococcus faecalis.

Purpose of the Study:

  • To investigate the proteomic changes associated with low-level linezolid resistance in Enterococcus faecalis.
  • To correlate proteomic findings with previous transcriptome data.
  • To elucidate the specific proteins and pathways involved in linezolid resistance.

Main Methods:

  • Quantitative proteomics analysis of membrane proteins.
  • Comparison of a resistant Enterococcus faecalis isolate (P10748) with two susceptible strains (3138 and ATCC 29212).
  • Identification of peptides and proteins using mass spectrometry with stringent statistical criteria (FDR 1%, P < 0.05).

Main Results:

  • Identified 1,170 proteins across all isolates.
  • Found 14 significantly up-regulated and 6 significantly down-regulated proteins in the resistant strain.
  • Results showed a positive correlation between proteomic and transcriptomic data.
  • Identified ATP-binding cassette protein OptrA as a primary mediator of resistance via ribosomal protection.
  • Suggested roles for enterococcal surface protein (Esp) and biofilm formation in resistance.
  • Identified potential regulators of optrA genetic transfer (Sea1, TraB, RepA, XRE family protein).

Conclusions:

  • Quantitative proteomics provides insights into linezolid resistance mechanisms in Enterococcus faecalis.
  • OptrA is the primary protein conferring low-level linezolid resistance through ribosomal protection.
  • Biofilm formation, potentially involving Esp, may also contribute to resistance.
  • Proteins regulating optrA transfer, such as Sea1, TraB, RepA, and XRE family proteins, are implicated.
Keywords:
Enterococcus faecalislinezolidlow-level resistancemembrane proteinsquantitative proteomics

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