Sea Marine Mud And The Detection Of Pathogenic Vibrio Parahaemolyticus Time Distribution Study

Objective:There are Vibrio Parahaemolyticus pathogen and Vibrio Parahaemolyticus non-pathogen in coast seawater and marine foods and V.p pathogen often cause food poisoning in coast area; however, it is difficult to isolate TDH+ V.p strains from environmental samples, such as seawater and sea sand with conventional culture method. The purpose of the research is how to heighten the isolation rate of Vibrio parahaemolyticus pathogens from environmental materials. The results will provide scientific basis for the study of the distribution of TDH+ strains in environment as well as for the prevention of V.p food poisoning.Method:Detect the number of V.p in seawater and sea sand by MPN method. Isolate TDH+ V.p strains by the combination of three-time broth, PCR, immunomagnetic beads separation and Kanagawa phenomenon culture medium. Compare electrophoretic mobility of V.p O3:K6 strains isolated separately from seawater, sea sand and food poisoning patients by pulsed field gel electroporesis.Results: The number of V.p in seawater and sea sand is the most in July to in September, the MPN values of V.p is above 103/100mL(g). The number of tdh+ V.p approximately account for 1/1000~1/100 the total number of V.p in sea water and sea sand, sometimes even below 1/1000. The V.p from 45.5%(5/11) seawater and from 36.4% (4/11) sea sand have the tdh gene. Kanagawa phenomenon positive V.p strains, which produce thermostable direct hemolysin(TDH), were separately isolated from one seawater and one sea sand The serotype of these strains was O3:K6, which was the same as that of strains isolated from food poisoning patients. Pulsed field gel electroporesis patterns of TDH+ strains isolated from seawater and sea sand were the same as that of strains isolated from food poisoning(occurred at the same time) patients. The isolation rate of V.p O3:K6 by using three-time broth is higher than by only using alkalinity protein peptone. The identical sample, carrying on similarly three-time broth, the isolation rate of V.p O3:K6 by using immunomagnetic beads is higher than by not using. This indicated that the immunomagnetic beads play the obvious concentration and collection role to the specific K antigen V.p.Conclusion: These results showed that food poisoning-causative TDH+ V.p O3:K6 is distributed in sea water. This method solved the problem that it is difficult to isolate TDH+ V.p strains from environmental material with conventional culture method, and it provides scientific basis for the study of the distribution of TDH+ strains in environment as well as for the prevention of V.p food poisoning.