Enterotoxin Production by Staphylococcus warneri CCRC 12929, a Coagulase-Negative strain

Production of staphylococcal enterotoxin A (SEA) and enterotoxin D (SED) by Staphylococcus warneri was first examined in three different media including brain heart infusion (BHI) broth, NZ-amine (NZA) medium, and 3 + 3 medium containing 3% NZ-amine A plus 3% Hy-Case Amino. Results of these investigations revealed that S. warneri produced the highest amount of SEA in BHI broth. SED yields were higher when BHI broth or NZA medium was used as the culture medium. On the other hand, SEA and SED production was found to be lowest in 3 + 3 medium. Further study showed that the optimum pH, for both SEA production and SED production was 7.0. Addition of 10% (wt/vol) sodium chloride to BHI broth reduced enterotoxin production by S. warneri . SEA production was reduced and SED production was completely inhibited in the presence of 15% (wt/vol) NaCl. Supplementation of the media with 0.4 or 1.5 mM magnesium sulfate markedly reduced SED production by S. warneri . Reduced production of both SEA and SED was also observed when BHI broth was supplemented with 0.1 M glucose or glycerol.