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Updated: Aug 31, 2025
Genotyping of Staphylococcus aureus by Ribosomal Spacer PCR RS-PCR
Published on: November 4, 2016
Genotypes of Staphylococcus aureus Clinical Isolates Are Associated with Phenol-Soluble Modulin (PSM) Production
Harshad Lade1, Sung Hee Chung1, Yeonhee Lee2
1Department of Laboratory Medicine, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul 05355, Korea.
Abstract:
Phenol-soluble modulins (PSMs) are important S. aureus virulence factors that cause cytolysis, mast cell degranulation, and stimulate inflammatory responses. In this study, PSM production by S. aureus clinical isolates was measured by liquid chromatography/mass spectrometry (LC-MS) and correlated with staphylococcal protein A (spa) type and staphylococcal cassette chromosome mec (SCCmec) type. Of 106 S. aureus clinical isolates, 50 (47.2%) corresponded to methicillin-susceptible S. aureus (MSSA) and 56 (52.8%) to methicillin-resistant S. aureus (MRSA). LC-MS analysis revealed no significant difference in average PSMα3, PSMα4, PSMβ2, and δ-toxin production between MSSA and MRSA isolates, but PSMα1, PSMα2, and PSMβ1 production were higher in MSSA than MRSA. This study demonstrated that average PSMα1-α4, PSMβ1-β2, and δ-toxin production by SCCmec type II strains was significantly lower than the IV, IVA, and V strains. Most of the SCCmec type II strains (n = 17/25; 68.0%) did not produce δ-toxin, suggesting a dysfunctional Agr system. The spa type t111 (except one strain) and t2460 (except one strain producing PSM α1-α4) did not produce PSMα1-α4 and δ-toxin, while average PSM production was higher among the t126 and t1784 strains. This study showed that the genotype of S. aureus, specifically the spa and SCCmec types, is important in characterizing the production of PSMs.
Insights
Staphylococcal cassette chromosome mec (SCCmec) and staphylococcal protein A (spa) types influence phenol-soluble modulin (PSM) production in Staphylococcus aureus. Genotype, not methicillin resistance, is key to understanding PSM virulence factor expression.
Area of Science:
- Microbiology
- Molecular Biology
- Immunology
Background:
- Phenol-soluble modulins (PSMs) are critical virulence factors of Staphylococcus aureus, mediating cytolysis, mast cell degranulation, and inflammation.
- Understanding the factors influencing PSM production is essential for developing targeted therapeutic strategies against S. aureus infections.
Purpose of the Study:
- To investigate the correlation between PSM production levels and specific genotypic profiles (SCCmec and spa types) in clinical isolates of S. aureus.
- To compare PSM production between methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) isolates.
Main Methods:
- Quantification of PSM peptides (PSMα1-α4, PSMβ1-β2, and δ-toxin) using liquid chromatography/mass spectrometry (LC-MS).
- Classification of 106 S. aureus clinical isolates based on SCCmec and spa typing.
- Statistical analysis to correlate PSM production with MSSA/MRSA status, SCCmec types, and spa types.
Main Results:
- No significant difference in average PSMα3, PSMα4, PSMβ2, and δ-toxin production between MSSA and MRSA; however, PSMα1, PSMα2, and PSMβ1 were higher in MSSA.
- Significantly lower PSMα1-α4, PSMβ1-β2, and δ-toxin production in SCCmec type II strains compared to types IV, IVA, and V.
- Specific spa types (t111, t2460) showed reduced or absent production of PSMα1-α4 and δ-toxin, while t126 and t1784 exhibited higher average PSM production.
Conclusions:
- S. aureus genotype, specifically SCCmec and spa types, significantly impacts the production of PSMs.
- PSM production patterns are more strongly associated with genotypic characteristics than with methicillin resistance status (MSSA vs. MRSA).
- The observed differences in PSM production suggest distinct virulence profiles among different S. aureus genotypes, potentially influencing clinical outcomes.
