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- Nilsdotter-Augustinsson, Åsa, 1962-, et al.
(författare)
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Adherence of Staphylococcus epidermidis to extracellular matrix proteins and effects of fibrinogen-bound bacteria on oxidase activity and apoptosis in neutrophils
- 2005
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 113:5, s. 361-373
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus epidermidis often causes foreign-body infections such as those associated with hip prostheses, but the underlying pathogenic mechanisms are not fully understood. We performed spectrophotometry to study the ability of S. epidermidis to bind to immobilised fibrinogen, fibronectin, vitronectin, and collagen. The strains were isolated from infected hip prostheses or from normal flora and the well-known protein-binding strain Staphylococcus aureus Cowan was used as positive control. We also analysed the interaction between neutrophils and a fibrinogen-bound prosthesis-derived strain of S. epidermidisby measuring chemiluminescence to determine the neutrophil oxidative response and binding of annexin V to indicate neutrophil apoptosis. We found that binding of S. epidermidis to extracellular matrix proteins varied under different growth conditions, and that prosthesis isolates adhered better to vitronectin than did strains from normal flora. The oxidative response caused by fibrinogen-bound S. epidermidis was not above the background level, which was in marked contrast to the distinct response induced by fibrinogen-associated S. aureus Cowan. Furthermore, fibrinogen-adhering S. epidermidis retarded neutrophil apoptosis. We conclude that surface-bound S. epidermidis induces only a weak inflammatory response, which in combination with the ability of the adherent bacteria to retard neutrophil apoptosis may contribute to low-grade inflammation and loosening of prostheses.
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| 2. |
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| 3. |
- Matussek, A, et al.
(författare)
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Infection of human endothelial cells with Staphylococcus aureus induces transcription of genes encoding an innate immunity response
- 2005
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 61:6, s. 536-544
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus aureus is a gram-positive bacterium frequently isolated from patients with bloodstream infections. Endothelial cells (EC) play an important role in host defence against bacteria, and recent reports have shown that infection of EC with S. aureus induces expression of cytokines and cell surface receptors involved in activating the innate immune response. The ability of S. aureus to invade nonphagocytic cells, including EC, has been documented. However, the knowledge of the role of EC in pathogenesis of S. aureus infection is still limited. In this study, we investigate the gene-expression program in human EC initiated by internalized 5. aureus, using microarray analysis. We found 156 genes that were differentially regulated at least threefold, using arrays representing 14,239 genes. Many of the up regulated genes code for proteins involved in innate immunity, such as cytokines, chemokines and cell adhesion proteins. Other upregulated genes encode proteins involved in antigen presentation, cell signalling and metabolism. Furthermore, intracellular bacteria survived for days without inducing EC death. © 2005 Blackwell Publishing Ltd.
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| 4. |
- Strindhall, J, et al.
(författare)
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Clinical isolates of Staphylococcus aureus vary in ability to stimulate cytokine expression in human endothelial cells
- 2005
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 61:1, s. 57-62
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Tidskriftsartikel (refereegranskat)abstract
- Human umbilical vein endothelial cells (HUVEC) were infected for 24 h with 18 well-characterized Staphylococcus aureus isolates, and the supernatants from infected HUVEC were analysed for interleukin (IL)-1β, tumour necrosis factor-alpha, IL-6, IL-8, IL-10, IL-12p70, growth-related oncogene (GRO)-α, granulocyte macrophage colony-stimulating factor (GM-CSF) and regulated upon activation, normal T cell expressed and secreted (RANTES) by immunoassay. All staphylococcal isolates induced the expression of IL-6, IL-8, GRO-α, GM-CSF and RANTES. The magnitude of cytokine expression varied between isolates. Staphylococcus aureus inducing high expression of one of these cytokines also showed simultaneous high expression of the other four, indicating a common mechanism for the ability of individual S. aureus to induce expression of these cytokines. No direct correlation between cytokine expression and adhesion of S. aureus to HUVEC was observed, indicating that bacterial properties besides adhesion contribute to the activation of HUVEC.
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