Comparison of Vibrio parahaemolyticus hemolysin (Vp-TRH) produced by environmental and clinical isolates

TDH-related hemolysin (Vp-TRH) produced by Kanagawa-phenomenon-negative (KP-) Vibrio parahaemolyticus has been demonstrated to be a possible virulence determinant. Though almost half of KP- isolates examined from diarrhoeal patients produced Vp-TRH, few reports mentioned the ability of environmental isolates to produce Vp-TRH. Considering the route of infection with V. parahaemolyticus, this toxin must be produced by the organisms in the sea or in sea food. To confirm that Vp-TRH produced by V. parahaemolyticus could be involved in sea-food-borne diarrhoeas, Vp-TRH-producing strains were isolated from the environment, identified and hemolysin purified from these strains was compared to hemolysin (Vp-TRH) isolated from diarrhoeal patients. The results showed that the hemolytic activity, antigenicity, reactivity in the rabbit ileal loop test and N-terminal amino acid sequence of Vp-TRH from environmental strains was indistinguishable from the toxin of clinical origin.