PRODUCTION OF THERMOSTABLE DIRECT HEMOLYSIN BY VIBRIO-PARAHAEMOLYTICUS ENHANCED BY CONJUGATED BILE-ACIDS

The effects of conjugated bile acids, glycocholic acid, and taurocholi c acid (TC) on production of thermostable direct hemolysin (TDH) by Vi brio parahaemolyticus were determined by a reversed passive latex aggl utination assay against TDH. The amount of TDH excreted in growth medi um containing either glycocholic acid or taurocholic acid (5 mM/liter) was, on a per-cell basis, 4- to 16-fold greater than that excreted in medium without the bile acids. The amounts of TDH released from lysed cells grown with the bile acids (5 mM/liter) were 4- to 32-fold great er than those from lysed cells gro,vn without, suggesting that the bil e acids enhanced synthesis of TDH within bacterial cells. These data i mply that the conjugated bile acids play a key role in the pathogenici ty of V. parahaemolyticus.