This family consists of the N-terminal region of the prokaryoticfibronectin-binding protein. Fibronectin binding is consideredto be an important virulence factor in streptococcal infections.Fibronectin is a dimeric glycoprotein that is present in asoluble form in plasma and extracellular fluids; it is alsopresent in a fibrillar form on cell surfaces. Both the solubleand cellular forms of fibronectin may be incorporated into theextracellular tissue matrix. While fibronectin has criticalroles in eukaryotic cellular processes, such as adhesion,migration and differentiation, it is also a substrate for theattachment of bacteria. The binding of pathogenic Streptococcuspyogenes and Staphylococcus aureus to epithelial cells viafibronectin facilitates their internalisation and systemicspread within the host [1].