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This Article Free via Open Access: OA OA Free Full Text Full Text (PDF) OA All Versions of this Article: mic.0.032078-0v1 155/11/3572    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Google Scholar Articles by Jakubovics, N. S. Articles by Jenkinson, H. F. PubMed PubMed Citation Articles by Jakubovics, N. S. Articles by Jenkinson, H. F. Agricola Articles by Jakubovics, N. S. Articles by Jenkinson, H. F.

Multiple adhesin proteins on the cell surface of Streptococcus gordonii are involved in adhesion to human fibronectin

¹ School of Dental Sciences, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4BW, UK
² Department of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, UK

Adhesion of bacterial cells to fibronectin (FN) is thought to be a pivotal step in the pathogenesis of invasive infectious diseases. Viridans group streptococci such as Streptococcus gordonii are considered commensal members of the oral microflora, but are important pathogens in infective endocarditis. S. gordonii expresses a battery of cell-surface adhesins that act alone or in concert to bind host receptors. Here, we employed molecular genetic approaches to determine the relative contributions of five known S. gordonii surface proteins to adherence to human FN. Binding levels to FN by isogenic mutants lacking Hsa glycoprotein were reduced by 70 %, while mutants lacking CshA and CshB fibrillar proteins showed approximately 30 % reduced binding. By contrast, disruption of antigen I/II adhesin genes sspA and sspB in a wild-type background did not result in reduced FN binding. Enzymic removal of sialic acids from FN led to reduced S. gordonii DL1 adhesion (>50 %), but did not affect binding by the hsa mutant, indicating that Hsa interacts with sialic acid moieties on FN. Conversely, desialylation of FN did not affect adherence levels of Lactococcus lactis cells expressing SspA or SspB polypeptides. Complementation of the hsa mutant partially restored adhesion to FN. A model is proposed for FN binding by S. gordonii in which Hsa and CshA/CshB are primary adhesins, and SspA or SspB play secondary roles. Understanding the basis of oral streptococcal interactions with FN will provide a foundation for development of new strategies to control infective endocarditis.

Correspondence
Nicholas S. Jakubovics
nick.jakubovics{at}newcastle.ac.uk