Distribution of Pathogenic Vibrio spp. in Ocean Areas near Harbors in Taiwan, 2009

Vibrio spp. is naturally found in sea water and estuary. Taiwan is located in subtropical area and surrounded by ocean, which is suitable for growth of Vibrio spp. National Quarantine Service (one of the antecedents of Taiwan Centers for Disease Control) proceeded an investigation from 1991 to 1998 and revealed that Vibrio cholerae existed in all coastal harbors, including pathogenic (non-O1, non-139) and non-pathogenic serotypes (O1). Vibrio parahaemolyticus was also noted. Extensive environmental investigation of these pathogens is necessary in order to update the database established a decade ago. In this study, samples were collected from 17 harbors located in northern, central, southern and eastern Taiwan areas. From 204 collected samples, 476 Vibrio spp. were isolated. In which, Vibrio parahaemolyticus was the most commonly found strain (181 strains, 38%), followed by Vibrio alginolyticus (154 strains, 32.4%), Vibrio vulnificus (94 strains, 19.7%), Vibrio metschnikovii (21 strains, 4.4%), Vibrio fluvialis (18 strains, 3.8%) and Aeromonas sobria (7 strains, 1.5%). No Vibrio cholerae was isolated. The results indicated that the isolation rate of Vibrio parahaemolyticus and Vibrio vulnificus was higher than 10 years ago. On the contrary, the Vibrio cholerae used to have high isolation rate was not found in this investigation. There was no statistical difference in isolation of each Vibrio spp. in all areas. However, there was statistical difference in the isolation of Vibrio parahaemolyticus, Vibrio vulnificus and Vibrio metschnikovii in different seasons. Furthermore, statistical difference was also noted in isolation of Vibrio vulnificus comparing temperature and salinity. We recommend authorities of public health, environmental protection and fishery should monitor the environmental risk of Vibrio spp. in coastal areas around Taiwan regularly, and general public should be informed on the related information. Moreover, database of environmental, clinical bacterial strains, bacterial gene mapping and drug resistance should be established and compared with related data from overseas. This investigation updated environmental monitoring data and also provided a reference for disease prevention and food hygiene policy.