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Staphylococcus aureus small-colony variants are adapted phenotypes for intracellular persistence
Lorena Tuchscherr1, Vanessa Heitmann, Muzaffar Hussain
1Institutes of Medical Microbiology, Center of Clinical Research, University Hospital of Münster, Münster, Germany.
The Journal of Infectious Diseases
|August 19, 2010
Summary
Staphylococcus aureus small-colony variants (SCVs) persist within host endothelial cells, evading immune responses. This intracellular survival strategy likely fuels chronic S. aureus infections and relapses.
Area of Science:
- Microbiology
- Infectious Diseases
- Cell Biology
Background:
- Staphylococcus aureus causes chronic endovascular infections with high relapse rates.
- Small-colony variants (SCVs) are linked to persistent, antibiotic-refractory S. aureus infections.
Purpose of the Study:
- To investigate the interaction of Staphylococcus aureus wild-type and SCV phenotypes with endothelial cells.
- To understand the role of SCVs in S. aureus persistence and host immune evasion.
Main Methods:
- Infection of endothelial cells with S. aureus wild-type and SCV strains.
- Microarray analysis to assess host gene expression changes.
- Monitoring of bacterial survival and host inflammatory response.
Main Results:
- Both wild-type and SCV S. aureus were invasive to endothelial cells.
- Wild-type S. aureus induced significant endothelial gene expression changes related to innate immunity.
- SCVs survived intracellularly at high numbers, with reduced induction of host inflammatory and cytotoxic responses.
Conclusions:
- S. aureus SCVs exhibit enhanced intracellular persistence within endothelial cells.
- Intracellular survival of SCVs represents a potential reservoir for chronic S. aureus infections.
- SCVs may employ host cell adaptation as a strategy to evade immune clearance.
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