Effects of Environmental Sea Water Factors on the Isolation of Vibrio vulnificus in the Western Coastal Area of Korea

Shin, Sung Wook; Park, Seok Don

Abstract

BACKGROUND: Vibrio vulnificus(V. vulnificus) is a pathogenic, marine, halophilic, Gram negative bacillus which causes fulminant infection in humans through skin wounds. or the ingestion of raw seafoods or Most cases are reported sporadically in summer in the south-western coastal area of Korea.
OBJECTIVE
We studied the distribution of V. vulnificus in sea water, fishes, shellfish and sea mud from May to October in 1996 and the relationship between regional distribution and environmental factors.
METHODS
We collected the sea water, sea mud, fishes and seafoods from May to October in Kunsan, Daechun, Moochangpo, Puan, Youngkwang and cultured it in Thiosulfate-Citrate-Bile salt-Sucrose(TCBS) agar, Cellobiose-Polymyxin B-Colistin(CPC) agar, and Sodium dodecyl sulfate- Polymyxin B-Sucrose(SPS) agar. At the same time we investigated environmental factors such as temperature, pH, salinity, turbidity, dissolved oxygen(DO), NO3 of sea water.
RESULTS
Twelve strains(2.17%) of V. vulnificus were isolated from a total of 552 specimens. The V. vulnificas isolation rate from sea mud was higher than in sea water and shellfish. Areas where V. vulnipcus was isolated were Kunsan and Daechun. It was isolated during June, July and August. The Isolation rate was higher with CPC agar than TCBS, SPS agar. When V.vulnificus was isolated at Kunsan, the environmental factors of sea water noted were as follows: temperature, 25.3C; turbidity, 121Formazine turbidity units; salinity, 12.2%; DO, 7.3mg/L; pH, 7.37 and NO3, 1.18mg/L.
CONCLUSION
CPC agar is the best medium of the three above used for the isolation of V. vulnificus from environmental samples. V. vulnificus was highly isolated in the Kunsan area because of the high water temperature and turbidity, low salinity and weak alkali state of the sea water in comparision with other areas. We suggest that high temperature and turbidity, low salinity and weak alkalinity of sea water are very important environmental factors for the growth of V. vulnificus.