Abstract: Various kinds of primers were designed to detect the genetypes of Staphylococcal enterotoxins(SEs) by bioinformatics analysis of enterotoxin genes. Lysozyme was added in the process of DNA extraction to enrich the DNA, encoding SEs. The detection rate and specificity were improved by anneal temperature gradient PCR method. 14 Kinds of enterotoxins were detected from the 28 isolates which indicate that their corresponding primers can effectively amplify the target genes while having high specificities. The three most common types of enterotoxins (sek, seq and sea ) in this research are approximately 15. 50%, 14.30% and 10.70% respectively. Whereas none of the isolates possesses the sem or sej genes. Different genotypes of SEs in stains have different degrees of correlation, and the genotypes of sek and seq, seb and sed, sec, sei, sen and seu display intimate positive correlations. Moreover, the results also suggested that the distribution of SEs has a close relationship with the source, which the Staphylococcus aureus is isolated from. The developed PCR method is useful in differentiating the genetypes and the distribution of S.aureus isolates.

Key words: Staphylococcus aureus, staphylococcal enterotoxins, PCR, detection