Prevalence of fibronectin-binding protein (FnbA and FnbB) genes among clinical isolates of methicillin resistant Staphylococcus aureus

Abstract

One of the most important stages in the occurrence of infection caused by Staphylococcus aureus is able to adhere of the bacterium to the cells and the extracellular matrix. Among adhesins, two fibronectinbinding proteins, (FnbA and FnbB) have been proved significantly to contribute to tissue colonization in various pathological conditions and indwelling medical device related infections. The aims of this study were to detect fnbA and fnbB genes and relation to the fibronectin binding ability in clinical isolates of methicillin resistant Staphylococcus aureus (MRSA). Of the 62 MRSA clinical isolates collected from selected hospitals in Tehran, Iran, fibronectin binding ability was determined by microtiter tissue culture coated by fibronectin plates. All MRSA isolates were examined for determination the fnbA and fnbB genes by using PCR method. The prevalence of fnbA and fnbB in MRSA strains was 82.2 and 46.7% respectively. In 26 (42%) MRSA strains both fnbA and fnbB genes were positive. All fnbA+ or fnbB+ strains were found to be positive also to in vitro fibronectin binding activity, while the fnb-negative strains were found negative to the in vitro binding assay. The finding that, fibronectin-adhesins are present in the most of the MRSA clinical isolates encourages the development of strategies to specifically block the interaction of this bacterium with fibronectin by antagonist molecules.