Novel PCR primers for specific detection of C1, C2 and C3 enterotoxin genes in Staphylococcus aureus

Abstract

Staphylococcus aureus is the major pathogen that causes clinical infection as well as food poisoning. Enterotoxin produced by Staphylococcus aureus strains are, among others, staphylococcal enterotoxin (SE) A, SEB, SEC, SED, SEE, SEG, SEH, SEI, SEJ, SEK, SEL and SEM. For SEC, there are three major antigentically distinct SEC subtypes, i.e. SEC1, SEC2 and SEC3, in addition to other molecular variants. The nucleotide sequence homology between SEC1, SEC2, and SEC3 genes is higher than 97%; however, we were able to develop a second set of PCR primers that allowed us to differentiate the three SECs, i.e., SEC1, SEC2 and SEC3, S. aureus strains. These PCR primers and their combinations were C12F/C1BR, C12F/C23R and C3BF/C23R, for specific detection of the SEC1, SEC2 and SEC3 genes of S. aureus strains, respectively. Using these primers, we examined 39 SEC S. aureus isolates, which were obtained from foods that were likely the source of food-borne outbreaks between 1995 and 1997 in central Taiwan, and from the patients of the outbreaks. The results were consistent with those obtained from the first set of primers reported earlier, indicating that the present primers could be used for specific detection of these three toxin types.