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Mouse skin passage of Streptococcus pyogenes results in increased streptokinase expression and activity

Myrna S Rezcallah1, Michael D P Boyle2, Darren D Sledjeski3

  • 1Department of Microbiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.

Microbiology (Reading, England)
|February 10, 2004
PubMed

Insights

Streptococcus pyogenes uses streptokinase (ska) to invade skin. More invasive strains show higher ska gene expression and lower SpeB protease activity, which degrades streptokinase.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Infectious Diseases

Background:

  • Streptococcus pyogenes causes skin infections.
  • The plasminogen activator streptokinase (ska) is implicated in S. pyogenes skin invasion.
  • A more invasive M1 serotype variant was identified.

Purpose of the Study:

  • Compare ska gene and protein levels in wild-type and invasive S. pyogenes M1 isolates.
  • Investigate the role of SpeB in streptokinase regulation.

Main Methods:

  • Quantitative analysis of ska gene message and protein.
  • Assay of plasminogen activator activity.
  • In vitro degradation assays of streptokinase by SpeB.

Main Results:

  • Invasive M1 isolates exhibited increased plasminogen activator activity.
  • This was linked to higher ska gene expression.
  • Invasive isolates showed decreased speB gene expression.
  • SpeB efficiently degraded streptokinase in vitro.

Conclusions:

  • Increased ska expression and reduced SpeB activity contribute to enhanced S. pyogenes invasiveness.
  • SpeB protease activity is a key regulator of streptokinase during infection.

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