Association Between Production of Fibrinolysin and Virulence of Staphylococcus hyicus in Relation to Exudative Epidermitis in Pigs

Abstract

Staphylococcus hyicus is the causative agent of exudative epidermitis (EE) in pigs, characterized by a generalized infection of the skin with greasy exudation and exfoliation (L’Ecuyer 1966). S. hyicus is a natural part of the skin flora of healthy pigs worldwide (Wegener 1992), and several different strains may simultaneously colonize the same pig (Wegener 1993a). Both virulent and avirulent strains can be present simultaneously on diseased piglets (Wegener et al 1993), and virulent strains can be isolated from healthy carriers (Devriese 1977, Park & Kang 1988). The pathogenesis of EE has only been studied in a limited number of studies, but EE most likely occurs as a consequence of skin trauma that exposes the dermis and facilitates establishment of virulent strains. The exact mechanism of infection is not known, but a number of potential virulence factors including capsule production, protein A, coagulase and catalase production has been suggested as potential virulence factors in the initial pathogenesis of EE (Wegener 1990). Amtsberg (1979) showed that virulent strains of S. hyicus produced an exotoxin that resulted in the separation of cells in the epidermis which caused exfoliative lesions. The endotoxin has recently been found to be a protein of approximately 30 kDa (Andresen et al 1993, 1997).