Cross-reactions between Staphylococcus aureus and fifteen other bacterial species

Fifty-five different antigens were demonstrated in an antigen preparation obtained by sonication of a protein A-free strain of Staphylococcus aureus, using crossed immunoelectrophoresis and antiserum obtained from rabbits. The antigens were characterized by absorption experiments with formalin-killed bacterial cells, temperature resistance and protein and polysaccharide staining. One of the antigens showed reaction of identity with a preparation of teichoic acid from S. aureus. Using this reference system, cross-reactions between the S. aureus reference strain and S. aureus strains from the four phage groups as well as 15 other bacterial species, were studied by various quantitative immunoelectrophoretic methods. The S. aureus antigens from the four phage groups showed almost 100% cross-reactivity for all antigens, while antigens from nine other bacterial species cross-reacted to varying degrees with one to four S. aureus antigens. All of 12 S. aureus antigens cross-reacted with the four S. epidermidis biotypes.