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Small colony variants of Staphylococcus aureus--review
1Department of Medical Microbiology, 2nd Medical Faculty, Charles University in Prague, Prague 5-Motol, Czech Republic. oto.melter@lfmotol.cuni.cz
Folia Microbiologica
|January 22, 2011
Summary
Small colony variants (SCVs) of Staphylococcus aureus are auxotrophic bacterial subpopulations that persist within host cells. Molecular methods are preferred for detecting these challenging-to-culture variants, especially in chronic infections.
Area of Science:
- Microbiology
- Bacterial Genetics
- Infectious Diseases
Background:
- Staphylococcus aureus can form small colony variants (SCVs), which are auxotrophic subpopulations with altered metabolism.
- SCVs exhibit reduced virulence but can persist intracellularly, posing diagnostic challenges.
- These variants are often associated with chronic infections and may evade standard laboratory detection methods.
Purpose of the Study:
- To highlight the characteristics and diagnostic difficulties of Staphylococcus aureus small colony variants (SCVs).
- To emphasize the importance of molecular methods for identifying SCVs in clinical settings.
- To discuss potential mechanisms of antibiotic resistance in SCVs.
Main Methods:
- Review of literature on Staphylococcus aureus SCVs.
- Discussion of diagnostic challenges and the utility of molecular techniques (16S rRNA sequencing, species-specific DNA targets).
- Analysis of potential resistance mechanisms in SCVs.
Main Results:
- SCVs are characterized by auxotrophic growth, depressed α-cytotoxin activity, and altered biochemical tests.
- SCVs can be overgrown by wild-type strains, complicating laboratory detection.
- Molecular methods are crucial for accurate identification of SCVs.
- Mutations in genes like thyA can confer resistance to certain antibiotics.
- Reduced ATP production may contribute to aminoglycoside resistance in SCVs.
Conclusions:
- Staphylococcus aureus SCVs represent a clinically significant challenge due to their persistence and diagnostic difficulty.
- Molecular detection methods are essential for identifying SCVs, particularly in patients with chronic infections.
- Understanding the genetic basis of SCV auxotrophy and resistance is critical for effective treatment strategies.
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