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Development and Assessment of Intracellular Infection Models for Staphylococcus aureus
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MsrR contributes to cell surface characteristics and virulence in Staphylococcus aureus

Judith Hübscher1, Nadine McCallum, Costi D Sifri

  • 1Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland.

FEMS Microbiology Letters
|May 23, 2009
PubMed

Insights

The protein MsrR in Staphylococcus aureus is crucial for maintaining cell envelope integrity and pathogenicity. Deleting msrR impacts cell structure and reduces virulence, suggesting MsrR has structural roles.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Bacterial Pathogenesis

Background:

  • MsrR is a cell envelope-associated protein in Staphylococcus aureus, implicated in methicillin resistance.
  • It belongs to the LytR-CpsA-Psr family of proteins.

Purpose of the Study:

  • To investigate the function of MsrR in Staphylococcus aureus.
  • To determine the role of MsrR in cell envelope maintenance, structure, and pathogenicity.

Main Methods:

  • Deletion mutagenesis to create an msrR mutant.
  • Analysis of cell morphology, envelope properties, and cell wall composition.
  • Transcriptome analysis using microarrays.
  • Virulence assays including nematode killing and rat experimental endocarditis.

Main Results:

  • Deletion of msrR resulted in increased cell size, aggregation, and altered envelope properties.
  • The mutant showed reduced cell surface hydrophobicity, diminished colony spreading, and increased susceptibility to Congo red.
  • Reduced cell wall phosphorus content suggested a decrease in wall teichoic acids.
  • Microarray analysis indicated minor transcriptional changes, supporting a structural role for MsrR.
  • Virulence was significantly decreased in both nematode-killing and rat endocarditis models.

Conclusions:

  • MsrR plays a significant role in Staphylococcus aureus cell envelope maintenance and cell separation.
  • MsrR contributes to the pathogenicity of Staphylococcus aureus.
  • MsrR likely functions structurally rather than as a global transcriptional regulator.

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