Adhesion of Staphylococcus aureus to horny layer: role of fibrinogen

Staphylococcus aureus cells attach to and invade the epidermis more easily under conditions of abrasion or occlusion or in the presence of irritant dermatitis than when the epidermis is intact. This fact strongly suggests that exuded plasma components may play an important role in the adherence of S. aureus cells to the horny layer. S. aureus cells (Cowan 1 strain, Wood 46 strain, and the protein A-deficient mutant, C7 strain, which was isolated from the Cowan 1 strain) were epicutaneously inoculated on the backs of mice. Biopsy specimens were taken from the mice at 1 h, 3 h, and 6 h after inoculation and examined using immunoelectron microscopy. Gold particles for fibrinogen gathered in a time-dependent manner at the interfaces of S. aureus cells and horny material in the lesions inoculated with the Cowan 1 and C7 strains but not in the lesions inoculated with the Wood 46 strain. These results suggest that fibrinogen plays a role in the binding of S. aureus cells to the horny layer.