N3 subdomain in a domain of fibronectin-binding protein B isotype I is an independent risk determinant predictive for biofilm formation of Staphylococcus aureus clinical isolates

Fibronectin-binding proteins (FnBP), FnBPA and FnBPB, are purported to be involved in biofilm formation of Staphylococcus aureus. This study was performed to find which of three consecutive N subdomains of the A domain in the FnBP is the key domain in FnBP. A total of 465 clinical isolates of S. aureus were examined for the biofilm forming capacity and the presence of N subdomains of FnBP. In the biofilm-positive strains, N2 and N3 subdomains of FnBPA, and N1 and N3 subdomains of FnBPB were significantly more prevalent. Multivariate logistic regression analysis of 246 biofilm-positive and 123 biofilm-negative strains identified only the FnBPB-N3 subdomain as an independent risk determinant predictive for biofilm-positive strains of S. aureus (Odds ratio [OR], 13.174; P