RESUMEN
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<0.001). We also attempted to delete each of the fnbA-N2 and -N3 and fnbB-N1 and -N3 from S. aureus strain 8325-4 and examined the biofilm forming capacity in the derivative mutants. In agreement with the results of the multivariate regression analysis, deletion of either the fnbA-N2 or -N3, or fnbB-N1 did not significantly diminish the capacity of strain 8325-4 to develop a biofilm, while deletion of the fnbB-N3 did. Therefore, it is suggested that the FnBPB-N3 subdomain of isotype I may be a key domain in FnBP which is responsible for the causing biofilm formation in S. aureus clinical isolates.
Asunto(s)
Adhesinas Bacterianas/metabolismo , Biopelículas , Dominios y Motivos de Interacción de Proteínas , Staphylococcus aureus/crecimiento & desarrollo , Staphylococcus aureus/metabolismo , Adhesinas Bacterianas/química , Adhesinas Bacterianas/genética , Orden Génico , Humanos , Isoformas de Proteínas , Staphylococcus aureus/genéticaRESUMEN
To find predictive genetic risk markers for strong biofilm producers of Staphylococcus aureus, we studied the relatedness of agr and SCCmec types and fnbB and IS256 genes to biofilm-forming ability in 465 clinical isolates. fnbB and SCCmec type III are candidates as genetic risk predictors for the strong biofilm producers.