Protein A In Staphylococcus Aureus Strains of Human and Bovine Origin

Staphylococcus aureus strains from human infections and from bovine cases of acute and of chronic mastitis were studied regarding protein A content. Human strains as well as bovine strains from acute mastitis showed high levels of protein A production in parallel with a high incidence of cell wall associated protein A. In contrast, S. aureus strains from bovine cases of chronic mastitis showed a significantly lower production of protein A. Only about 50 per cent of these strains had detectable cell wall associated protein A. Host‐parasite relationship in staphylococcal infections might favour the presence of protein A in strain from acute infections. In chronic bovine mastitis, however, the low levels of protein A detected in these strains seem to indicate that other factors play a more important role.