Tracking the change of human pathogenic vibrios in aquacultures of Taiwan

• Main Authors: Yao-Hsien Tey, 戴耀賢
• Other Authors: Hin-Chung Wong
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/42232924165413063459

碩士 === 東吳大學 === 微生物學系 === 101 === Vibrio parahaemolyticus is the most prevalent food poisoning bacterium in Taiwan via the consumption of contaminated seafood. The FDA of United States has finished a Risk Assessment of V. parahaemolyticus in raw molluscan shellfish for public health and monitoring raw oyster. Such risk assessment program consist of the harvest, post-harvest and public health modules, while the harvest module is based on the level of V. parahaemolyticus. Beside V. parahaemolyticus, V. cholerae and V. vulnificus are other important human pathogens in aquacultural environments. The aim of this study is to provide data for the establishment of domestic risk assessment for these pathogens by monitoring the dynamic changes of pathogenic V. parahaemolyticus, V. cholerae and V. vulnificusin in sediment, seawater and seafood from the aquacultural farms and focuses on the dynamic change and characteristic of Vibrio parahaemolyticus. Six fish aquaculture farms (ponds) were selected, two for Epinephelus, two for milk fish and two for tilapia. Sediment, water and cultured animals were sampled in September, December, March and June represent different seasons and the temperature, salinity and other environmental factors were also determinated. The results showed that the Kaohsiung's Yong' an Dist had the highest density of V.parahaemolyticus in the Epinephelus culturing pond and highest density of V. cholerae and V. vulnificus in milk fish culturing pond. As determined by linear multiple regression, the water temperatures significantly affected the the density of V. parahaemolyticus. Antibiotic susceptibilities of the V. parahaemolyticus isolates in this study had no significant difference from those of previous study. The pulsed-field gel electrophoresis (PFGE) results showed that the environmental V. parahaemolyticus isolates did not exhibit any geographic specificity. In the virulent gene experiment, we identified two tdh+, trh- pathogenic V. parahaemolyticus isolates, isolate SCS1112-1 contained the vcrD1, vopD2 andvopP and isolate SCS1112-2 contained the vcrD1, vopD2, vopB2, vopP and vopC virulence-associated genes. The MTase gene and some other virulence-associated genes were also present in a few of the environmental isolates, and these results suggest the horizontal transfer of these genes in the clinical and environmental isolates of this species. These data are the results of the first year of a two-year study, and the accumulated data will provide appropriate information for the establishment of the local risk assessment program for pathogenic vibrios.