Detection of staphylococcal exfoliative toxin by slide latex agglutination

A simple and rapid method in which slide latex agglutination was used was developed to detect the exfoliative toxin (ET) elaborated by clinical isolates. ET types A and B (ET-A and ET-B) were purified by plate gel isoelectrofocusing, and anti-ET sera were obtained by immunizing rabbits. A specific immunoglobulin G antitoxin was then prepared from the immunized rabbit sera by fast protein liquid chromatography, and latex particles were coated with the antitoxin. Of 74 staphylococcal strains isolated from patients with staphylococcal scalded skin syndrome, 61 strains were found to produce ET by the newborn mouse bioassay. All 61 strains were shown to be positive for ET-A and ET-B production by the slide latex agglutination method. The lowest concentration of ETs detected by the latex agglutination method was 0.5 microgram/ml, which was much lower than that detected by the double immunodiffusion method, with a sensitivity of 50 micrograms/ml. It is crucial to prove ET production by clinical isolates for the diagnosis and surveillance of staphylococcal scalded skin syndrome. The latex agglutination method is a sensitive, simple, and rapid test which can be used as an alternative to the newborn mouse bioassay.