摘要
Biofilm formation plays a major role in the pathogenesis of nosocomial infections caused by Staphylococcus epidermidis ( S.epidermidis ). It has been suggested that protein encoded by the fbe (fibrinogen binding protein) gene of S.epidermidis enhances bacterial adherence to medical devices and biofilm formation by binding to host fibrinogen (Fg). In this study, a 1.7 kb fbe gene fragment was amplified in 111 of 115 strains of S.epidermidis clinical isolates using PCR. Contrary to expectations, only 14 strains showed marginally increased adherence to Fg-coated polystyrene wells compared with BSA coated wells. Quantitative real-time PCR revealed no statistically significant difference in Fbe expression between Fg binding strains and Fg non-binding strains. Furthermore, in the presence of soluble Fg, S.epidermidis biofilm formation decreased in a dose-dependent manner. In contrast, the Staphylococcus aureus ( S.aureus ) strain Cowan Ⅰ and other 5 S.aureus clinical isolates showed a substantial increase in both adherence and biofilm formation in the presence of Fg. The results suggest that in S.epidermidis the fbe gene may not be associated with bacterial adherence and biofilm formation.
Biofilm formation plays a major role in the pathogenesis of nosocomial infections caused by Staphylococcus epidermidis ( S.epidermidis ). It has been suggested that protein encoded by the fbe (fibrinogen binding protein) gene of S.epidermidis enhances bacterial adherence to medical devices and biofilm formation by binding to host fibrinogen (Fg). In this study, a 1.7 kb fbe gene fragment was amplified in 111 of 115 strains of S.epidermidis clinical isolates using PCR. Contrary to expectations, only 14 strains showed marginally increased adherence to Fg-coated polystyrene wells compared with BSA coated wells. Quantitative real-time PCR revealed no statistically significant difference in Fbe expression between Fg binding strains and Fg non-binding strains. Furthermore, in the presence of soluble Fg, S.epidermidis biofilm formation decreased in a dose-dependent manner. In contrast, the Staphylococcus aureus ( S.aureus ) strain Cowan Ⅰ and other 5 S.aureus clinical isolates showed a substantial increase in both adherence and biofilm formation in the presence of Fg. The results suggest that in S.epidermidis the fbe gene may not be associated with bacterial adherence and biofilm formation.
基金
This work was supported by the Chinese National Science Foundation Grant (30170845)
National High Tech Research and Development Program of China (2001AA223011) and Fudan University Innovation Grant for Graduate Students
