Immunization with fibronectin binding protein from Staphylococcus aureus protects against experimental endocarditis in rats

Abstract

Rats were immunized with a fusion protein (gal-FnBP) encompassing beta-galactosidase and the domains of fibronectin binding protein from Staphylococcus aureus responsible for binding to fibronectin. Antibodies against gal-FnBP were shown to block the binding of S. aureus to immobilized fibronectin in vitro. Endocarditis in immunized and non-immunized control rats was induced by catheterization via the right carotid artery, resulting in damaged aortic heart valves which became covered by fibrinogen and fibronectin. The catheterized rats were then infected intravenously with 1 x 10(5) cells of S. aureus. The number of bacteria associated with aortic valves was determined 1 1/2 days after the challenge infection and a significant difference in bacterial numbers between immunized and non-immunized groups was then observed (p < 0.05).