An Enterotoxin-Like Protein in Staphylococcus aureus Strains from Patients with Toxic Shock Syndrome

An enterotoxin-like protein, tentatively labeled enterotoxin F, was isolated from Staphylococcus aureus strains taken from patients with toxic shock syndrome. Antibodies specific for enterotoxin F were prepared in rabbits. Use of these antibodies showed that 130 (91.5%) of 142 S. aureus strains from patients with toxic shock syndrome produced enterotoxin F. Strains from toxic shock patients in eight other countries were identified as enterotoxin F producers. Only a small number of S. aureus strains from sources other than patients with toxic shock syndrome were found to produce enterotoxin F. Twenty-one of 111 controls had low antibody titers (less than 1:100) to enterotoxin F whereas 86 of 92 toxic shock patients had low acute phase antibody titers (less than 1:100) to enterotoxin F. Eight of 52 patients had serum conversion as shown by an increase in antibody titer to enterotoxin F in sera taken 21 to 60 days after onset of the illness. It may be possible to identify persons susceptible to toxic shock syndrome by measuring their antibody titer to enterotoxin F.