Public health aspects of Vibrio spp. related to the consumption of seafood in the EU

Abstract

<i>Vibrio parahaemolyticus</i>, <i>Vibrio vulnificus</i> and non-O1/non-O139 <i>Vibrio cholerae</i> are the <i>Vibrio</i> spp. of highest relevance for public health in the EU through seafood consumption. Infection with <i>V. parahaemolyticus</i> is associated with the haemolysins thermostable direct haemolysin (TDH) and TDH-related haemolysin (TRH) and mainly leads to acute gastroenteritis. <i>V. vulnificus</i> infections can lead to sepsis and death in susceptible individuals. <i>V. cholerae</i> non-O1/non-O139 can cause mild gastroenteritis or lead to severe infections, including sepsis, in susceptible individuals. The pooled prevalence estimate in seafood is 19.6% (95% CI 13.7-27.4), 6.1% (95% CI 3.0-11.8) and 4.1% (95% CI 2.4-6.9) for <i>V. parahaemolyticus</i>, <i>V. vulnificus</i> and non-choleragenic <i>V. cholerae</i>, respectively. Approximately one out of five <i>V. parahaemolyticus</i>-positive samples contain pathogenic strains. A large spectrum of antimicrobial resistances, some of which are intrinsic, has been found in vibrios isolated from seafood or food-borne infections in Europe. Genes conferring resistance to medically important antimicrobials and associated with mobile genetic elements are increasingly detected in vibrios. Temperature and salinity are the most relevant drivers for <i>Vibrio</i> abundance in the aquatic environment. It is anticipated that the occurrence and levels of the relevant <i>Vibrio</i> spp. in seafood will increase in response to coastal warming and extreme weather events, especially in low-salinity/brackish waters. While some measures, like high-pressure processing, irradiation or depuration reduce the levels of <i>Vibrio</i> spp. in seafood, maintaining the cold chain is important to prevent their growth. Available risk assessments addressed <i>V. parahaemolyticus</i> in various types of seafood and <i>V. vulnificus</i> in raw oysters and octopus. A quantitative microbiological risk assessment relevant in an EU context would be <i>V. parahaemolyticus</i> in bivalve molluscs (oysters), evaluating the effect of mitigations, especially in a climate change scenario. Knowledge gaps related to <i>Vibrio</i> spp. in seafood and aquatic environments are identified and future research needs are prioritised.