Seoson-specific Occurrence of Potentially Pathogenic Vibio spp. On the Southern Coast of South Korea

Abstract

Vibrio species are widely distributed in warm estuarine and coastal environments, and they can infect humans through the consumption of raw and mishandled contaminated seafood. In this study, we aimed to isolate and observe the distribution of enteropathogenic Vibrio spp. from environments of the southern coast of South Korea over a season cycle. A total of 10,983 Vibrio spp. were obtained from tidal water and mud samples over a one-year period from five sampling sites along the southern west coast of South Korea. We found that Vibrio alginolyticus (n = 6,262) and Vibrio parahaemolyticus (n = 1,757) were ubiquitous in both tidal water and mud year round, whereas Vibrio cholerae (n = 24) and Vibrio vulnificus (n = 130) were seasonally specific to summer. While all V. cholerae isolates were nontoxigenic (non-O1 and non-O139), more than 88% of V. vulnificus isolates possessed the virulence factors elastolytic protease (vvp) Interestingly, V. parahaemolyticus, which was omnipresent in all seasons, contained the virulence factors thermostable direct hemolysin (tdh) and TDH-related hemolysin (trh) in higher amounts in June (29 trh) and September (14 tdh; 36 trh; 12 tdh and trh) than in December (4 trh) and February (3 tdh), and virulence factors were absent from isolates detected in April. To understand the phenomena where virulence factors were only detected in warm season but absent in cold season although the locations are static, long-term monitoring and particular seasonal study are necessary.