Factors affecting the secretion of staphylococcal enterotoxin A.

The biosynthesis of enterotoxin A by replicating and nonreplicating cells was investigated. Unlike enterotoxin B, a secondary metabolite, enterotoxin A secretion resembled that of a primary metabolite by being secreted during the exponential phase of growth. The amount of toxin produced per unit of growth was not influenced by NaCl, NaNO(2), or NaNO(3). Several surfactants increased toxin secretion. Toxin secretion by nonreplicating cells was inhibited by chloramphenicol and 2, 4-dinitrophenol but not by streptomycin or penicillin G. The optimal pH for enterotoxin A production was 6.5 to 7.0. The findings suggest a number of possible reasons for the higher incidence of food poisonings caused by enterotoxin A as compared to enterotoxin B.