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Adherence of Staphylococcus aureus to cultures of human peritoneal mesothelial cells
G Glancey1, J S Cameron, C Ogg
1Renal Unit, Guy's Hospital, London, UK.
Abstract:
Strains of Staphylococcus aureus, isolated from the effluent of patients with peritonitis on CAPD (continuous ambulatory peritoneal dialysis), adhered well to both cultured human mesothelial cells and to fibronectin, but not to laminin or gelatin. Mesothelial cells grown in medium M199 exhibited more surface fibronectin compared to cells grown in MEM-Dval and demonstrated higher levels of S. aureus adherence. Soluble fibronectin concentrations up to 10 micrograms/ml increased the adherence of S. aureus to cultured mesothelial cells. The dose-response curve was consistent with the binding of fibronectin to a saturable receptor of apparent dissociation constant (KD) = 1.7 x 10(-10) M. This corresponds closely to the KD (2 x 10(-10) M) of the staphylococcal fibronectin-binding protein. S. aureus adherence was increased following the preincubation of mesothelial cell monolayers with interleukin-1 and was maximal after 6 h preincubation. Treating mesothelial cells with interferon-gamma for 48-72 h reduced the adherence of S. aureus.
Insights
Staphylococcus aureus readily adheres to human mesothelial cells, primarily through fibronectin interactions. This bacterial adherence is influenced by cell culture conditions and inflammatory mediators like interleukin-1 and interferon-gamma.
Area of Science:
- Microbiology
- Cell Biology
- Biochemistry
Background:
- Staphylococcus aureus is a common cause of peritonitis in patients undergoing continuous ambulatory peritoneal dialysis (CAPD).
- Understanding the mechanisms of bacterial adherence to the peritoneal lining is crucial for preventing and treating CAPD-related infections.
Purpose of the Study:
- To investigate the adherence of Staphylococcus aureus strains to human mesothelial cells.
- To identify host cell surface molecules and inflammatory mediators involved in Staphylococcus aureus adherence.
Main Methods:
- Adherence assays using cultured human mesothelial cells and various extracellular matrix proteins (fibronectin, laminin, gelatin).
- Assessment of bacterial adherence under different cell culture media conditions (M199 vs. MEM-Dval).
- Evaluation of the effect of soluble fibronectin, interleukin-1, and interferon-gamma on bacterial adherence.
Main Results:
- Staphylococcus aureus demonstrated significant adherence to cultured human mesothelial cells and fibronectin, but not laminin or gelatin.
- Mesothelial cells cultured in M199 showed higher fibronectin expression and increased S. aureus adherence compared to those in MEM-Dval.
- Soluble fibronectin enhanced S. aureus adherence in a saturable manner, suggesting a specific receptor interaction (KD ≈ 1.7 x 10(-10) M).
- Interleukin-1 preincubation increased S. aureus adherence, while interferon-gamma treatment reduced it.
Conclusions:
- Fibronectin is a key mediator for Staphylococcus aureus adherence to human mesothelial cells in CAPD peritonitis.
- The interaction involves a saturable staphylococcal fibronectin-binding protein.
- Modulation of mesothelial cell surface properties by inflammatory cytokines influences bacterial adherence.