Staphylococcal enterotoxin A gene (sea) expression is not affected by the accessory gene regulator (agr).

The goal of this work was to determine whether staphylococcal enterotoxin type A gene (sea) expression is regulated by an accessory gene regulator (agr). The Tn551 insertionally inactivated agr allele of Staphylococcus aureus ISP546 was transferred to three Sea+ S. aureus strains. Each of the Agr- strains produced as much staphylococcal enterotoxin A (SEA) as its parent strain. These results suggest that sea expression is regulated differently from that of seb, sec, and sed, which previously have been shown to require a functional agr system for maximal expression.