Isolation of Thermostable Direct Hemolysin-producingVibrio parahaemolyticusSeafrom Water by Immunomagnetic Separation

Abstract

Immunomagnetic particles Dynabeads M-280 sheep anti-rabbit immunoglobulin G (Dynabeads) coated with antibodies against the K6 antigen ofVibrio parahaemolyticuswere used for isolation of thermostable direct hemolysin-producingV. parahaemolyticusK6 serovar (TDH⁺V.pK6) from a sea water culture. Samples were collected at four major fishing ports in Toyama bay during September to November in 1998, and 1, 000ml of sample were cultured in Salt Polymyxin Broth after precultivation with Trypticase Soy Broth containing 3% NaCl. The isolation rate of the TDH⁺V.pK6 from sea water was 4/10 (40%), and the number of TDH⁺V.pK6 in sea water were 0-3.6/1, 000ml although the total number ofV. parahaemolyticuswere 2.3×10²-1.1×10⁴/1, 000ml.
Pulsed-field gel electrophoresis pattern of the TDH⁺V.pK6 strains from sea water were divided into two closely related types (provisional type: 1a, 1b). Most of TDH⁺V.pK6 isolates from food poisoning cases in Japan were also type 1a or 1b . The serotype of isolates fromV. parahaemolyticusfood poisoning that occurred in Toyama Prefecture during June to October, 1998 were 03: K6 in eight of 11 cases. These results show that food poisoning-causative TDH⁺V.pO3: K6 is distributed in sea water of fishing ports.