HIGH-MOLECULAR-WEIGHT PROTEIN FROM STAPHYLOCOCCUS-INTERMEDIUS CROSS-REACTS WITH STAPHYLOCOCCUS-AUREUS ENTEROTOXIN ANTIBODIES

Enterotoxin production by Staphylococcus species other than Staphyloco ccus aureus has been reported. Staphylococcus strains (104 in tote) re presenting twelve species and subspecies were examined for enterotoxin s using a commercial staphylococcal enterotoxin ELISA immunoassay (TEC RA, International Bioproducts). Staphylococcus intermedius (24 strains ) and S. aureus (7 strains) were positive with this test. Western blot s of S. aureus exoproteins demonstrated proteins of similar to 30 kD, consistent with known staphylococcal enterotoxins. The major antigen i n all S. intermedius strains, a 75 kD protein, was not analogous to pr eviously described staphylococcal enterotoxins. This protein was uniqu e to S. intermedius. Gel filtration data indicate that the protein is a subunit of a larger protein in vivo. The 75 kD protein cross-reacts with several enterotoxin antibodies. it is unclear whether the protein is a toxin, but its homology with S. aureus enterotoxins may indicate a shared toxic region, or this protein may create false positive resu lts in screening for enterotoxin.