Phenol-Soluble Modulin-Mediated Aggregation of Community-Associated Methicillin-Resistant Staphylococcus Aureus in
Deok-Ryeong Kim1, Yeonhee Lee2, Hyeon-Kyeong Kim2
1Department of Neurosurgery, Nowon Eulji Medical Center, Eulji University, Seoul 01830, Korea.
Abstract:
Phenol-soluble modulins (PSMs) are major determinants of Staphylococcus aureus virulence and their increased production in community-associated methicillin-resistant S. aureus (CA-MRSA) likely contributes to the enhanced virulence of MRSA strains. Here, we analyzed the differences in bacterial cell aggregation according to PSM presence in the specific human cerebrospinal fluid (CSF) environment. CSF samples from the intraventricular or lumbar intrathecal area of each patient and tryptic soy broth media were mixed at a 1:1 ratio, inoculated with WT and PSM-deleted mutants (Δpsm) of the CA-MRSA strain, USA300 LAC, and incubated overnight. Cell aggregation images were acquired after culture and image analysis was performed. The cell aggregation ratio in WT samples differed significantly between the two sampling sites (intraventricular: 0.2% vs. lumbar intrathecal: 6.7%, p < 0.001). The cell aggregation ratio in Δpsm samples also differed significantly between the two sampling sites (intraventricular: 0.0% vs. lumbar intrathecal: 1.2%, p < 0.001). Division of the study cases into two groups according to the aggregated area ratio (WT/Δpsm; group A: ratio of ≥ 2, group B: ratio of < 2) showed that the median aggregation ratio value differed significantly between groups A and B (5.5 and 0, respectively, p < 0.001). The differences in CSF distribution and PSM presence within the specific CSF environment are significant factors affecting bacterial cell aggregation.
Insights
Phenol-soluble modulin (PSM) presence significantly impacts Staphylococcus aureus cell aggregation in cerebrospinal fluid (CSF). PSM deletion reduces aggregation, especially in the lumbar intrathecal space, highlighting PSM
Area of Science:
- Microbiology
- Infectious Diseases
- Bacterial Pathogenesis
Background:
- Phenol-soluble modulins (PSMs) are key virulence factors in Staphylococcus aureus.
- Increased PSM production in community-associated methicillin-resistant S. aureus (CA-MRSA) correlates with enhanced virulence.
- The role of PSMs in bacterial aggregation within the human cerebrospinal fluid (CSF) environment requires further investigation.
Purpose of the Study:
- To investigate the influence of PSM presence on Staphylococcus aureus cell aggregation within the human CSF.
- To compare bacterial aggregation patterns in different CSF compartments (intraventricular vs. lumbar intrathecal).
- To analyze the impact of PSM deletion on S. aureus aggregation in the CSF.
Main Methods:
- CSF samples from intraventricular and lumbar intrathecal areas were collected.
- Tryptic soy broth media was mixed 1:1 with CSF and inoculated with wild-type (WT) and PSM-deleted (Δpsm) CA-MRSA strains (USA300 LAC).
- Bacterial cell aggregation was quantified using image analysis after overnight incubation.
Main Results:
- Significant differences in bacterial cell aggregation were observed between intraventricular and lumbar intrathecal CSF environments for both WT and Δpsm strains.
- WT strains exhibited higher aggregation ratios (intraventricular: 0.2%, lumbar intrathecal: 6.7%) compared to Δpsm strains (intraventricular: 0.0%, lumbar intrathecal: 1.2%).
- The ratio of aggregation between WT and Δpsm strains (WT/Δpsm) was significantly higher in group A (ratio ≥ 2) compared to group B (ratio < 2), indicating a substantial role of PSMs.
Conclusions:
- PSM presence is a significant factor influencing Staphylococcus aureus cell aggregation in the CSF.
- The anatomical location within the CSF compartment (intraventricular vs. lumbar intrathecal) differentially affects bacterial aggregation.
- These findings suggest that PSMs contribute to S. aureus pathogenesis in the CNS by modulating bacterial aggregation within the CSF environment.
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