The use of DNA probes for confirming enterotoxin production by Staphylococcus aureus and micrococci

DNA-DNA colony hybridization was employed to evaluate the results obtained by different immunological methods for detection of staphylococcal enterotoxin. Staphylococcus aureus strains tested for staphylococcal enterotoxin production by immuno-assays and micrococci not previously tested for staphylococcal enterotoxin production were examined for presence of the genes encoding for staphylococcal enterotoxin A, B, C and E by using three corresponding DNA probes. The staphylococcal enterotoxin A probe also detected staphylococcal enterotoxin E gene because of 100% homology. The optimal sensitivity plate method showed the best accordance between the immuno-assay and the hybridization reactions. The enzyme-linked immunosorbent assay detected 12.5 to 17% staphylococcal enterotoxin producers without hybridization reactions. The microslide gel double diffusion test and the reversed passive latex agglutination test showed rather poor accordance with the hybridization reactions. All 17 strains of different micrococci investigated were negative in hybridization with all three DNA probes.