Identification of virulence determinants for endocarditis in Streptococcus sanguinis by signature-tagged mutagenesis.

Streptococcus sanguinis is a gram-positive, facultative anaerobe and a normal inhabitant of the human oral cavity. It is also one of the most common agents of infective endocarditis, a serious endovascular infection. To identify virulence factors for infective endocarditis, signature-tagged mutagenesis (STM) was applied to the SK36 strain of S.

Demonstration of the involvement of outer surface protein E coiled coil structural domains and higher order structural elements in the binding of infection-induced antibody and the complement-regulatory protein, factor H.

Factor H (fH) is an important regulator of the alternative complement cascade. Several human pathogens have been shown to bind fH to their surface, a process that facilitates immune evasion or cell to cell interaction. Among the pathogens that bind fH are some Borrelia species associated with Lyme disease and relapsing fever.