Serum antibody response to Staphylococcus aureus enterotoxins and TSST-1 in patients with septicaemia

The prevalence of enterotoxins and toxic shock syndrome toxin (TSST-1) production in strains isolated from patients with Staphylococcus aureus septicaemia, and the serum antibody response in relation to toxin production in vitro of each isolate, were investigated. Among 63 strains of S. aureus isolated from the blood of patients with septicaemia, 51 from patients with superficial wounds and 49 from nasal carriers, 50-60% produced at least one of the enterotoxins A-D or TSST-1. The most frequent toxins produced were enterotoxins A and C and TSST-1. Among the 63 patients with staphylococcal septicaemia, 51 (81%) had a significant rise or a high antibody titre, or both, to at least one of the toxins. A positive serological response to toxin A was found in 78%, to enterotoxin B in 83%, to enterotoxin C in 80%, to enterotoxin D in 86% and to TSST-1 in 92% of the patients from whom the isolated strain produced the respective toxin. Antibodies against enterotoxins A, B, C and D and TSST-1 were also seen in 35%, 16%, 32%, 59% and 10%, respectively, in patients infected by strains that did not produce the specific toxin. Immunological cross-reactions between the toxins were demonstrated both in hyperimmune sera obtained from rabbits and in patients' sera, particularly between enterotoxins B and C. It is concluded that these potent toxins with superantigenic properties are produced in vivo during S. aureus septicaemia. No differences with regard to enterotoxin or TSST-1 production or antibody response were noted between patients with complicated versus uncomplicated septicaemia.