Comparison of V. parahaemolyticus isolated from seafoods and cases of gastrointestinal disease in the UK

Abstract

In this study the prevalence of Vibrio parahaemolyticus in shellfish and estuarine waters from the UK was examined using cultural and nucleic acid hybridisation approaches. Forty-nine isolates derived from environmental sources were characterised using serotyping, PCR, nucleic acid hybridisation and pulsed field gel electrophoresis (PFGE). The serotypic and molecular profiles of these isolates were compared to 20 clinical isolates, including representatives of the pandemic O3:K6 clone. Thirty percent of environmental samples were positive for V. parahaemolyticus. The tdh gene was identified in 12% of samples tested. Environmentally derived tdh+ strains were highly heterogeneous with neither association between isolates from similar origins nor seafood type. Previously uncharacterised clinical strains from UK patients with travel related V. parahaemolyticus associated gastroenteritis, were unrelated to tdh+ or tdh- environmental isolates but 2 were clonally indistinguishable from the pandemic O3:K6 strain responsible for outbreaks in Spain, Korea, Japan and Laos.

Keywords:

• Vibrio parahaemolyticus
• bivalve molluscan shellfish
• pulse field gel electrophoresis (PFGE)
• environmental
• clinical