Vibrio bacteria found in Norwegian seafood and seawater

Feb 24, 2009
Vibrio bacteria found in Norwegian seafood and seawater
Mixed culture of Vibrio species from a mussel sample.

(PhysOrg.com) -- While working on her doctorate, Anette Bauer Ellingsen discovered potentially disease-causing vibrios (Vibrio cholerae, V. parahaemolyticus and V. vulnificus) in Norwegian seafood and inshore seawater.

Anette Bauer Ellingsen studied the occurrence of potentially pathogenic vibrios in Norway. These species include the cholera bacterium (V. cholerae) and the lesser-known species V. parahaemolyticus and V. vulnificus. All of these species may cause disease in people who eat raw or lightly-cooked seafood, and they can also cause extremely serious wound infection.

In Japan, V. parahaemolyticus is one of the most common causes of food poisoning, due to the Japanese predilection for sushi. In the USA, food poisoning caused by this bacterium is primarily associated with eating oysters. Vibrio vulnificus is also associated with oyster eating, and this bacterium causes the greatest number of deaths from seafood poisoning in the USA.

That these bacteria also occur in Norway was previously unknown, and this is the first time that V. cholerae and V. vulnificus have been isolated from the Norwegian environment. All of the three vibrios were demonstrated in Norwegian mussels (at fewer than 100 bacteria /gram) and in Norwegian seawater (up to 30,000/litre) during the course of the study. They were first and foremost demonstrable when the water temperature rose above 20°C.

It's important to emphasise that there can be big differences in pathogenicity within a species. Both V. cholerae and V. parahaemolyticus have their "dangerous" and "benign" variants, based on the toxins they produce. All V. vulnificus are assumed to be more or less equally dangerous, primarily in people with predisposing illnesses such as diabetes or hepatitis, and for people with weakened immunity.

Part of Anette Bauer Ellingsen's work was to investigate whether the "dangerous" variants of V. cholerae and V. parahaemolyticus occur in Norway. None of the cholera toxin-producing variants of V. cholerae were found among the Norwegian samples. However, it was discovered that some of the V. parahaemolyticus bacteria produce a toxin liable to cause diarrhoea.

The study showed that the danger of food poisoning posed by vibrios in Norwegian food products is extremely small. Nonetheless, toxin-producing V. parahaemolyticus was demonstrated, so one should be careful when eating raw or lightly-cooked seafood, for example, oysters.

In fact, the greatest risk of infection from vibrios is not food. There is possibly a greater chance of being infected in connection with recreational activities such as swimming or handling marine fish and shellfish in periods with high water temperature. All of the bacteria that were discovered during this study, are liable to produce serious wound infection, especially in people with reduced immunity.

The study was carried out under the auspices of the Norwegian School of Veterinary Science, The Norwegian Food Safety Authority and the The Fishery and Aquaculture Industry Research Fund.

Anette Bauer Ellingsen B. Sc. (hons) defended her thesis, entitled "Vibrio parahaemolyticus, V. cholerae and V. vulnificus in Norway, with special attention to V. parahaemolyticus), on December 22, 2008, at the Norwegian School of Veterinary Science.

Provided by Norwegian School of Veterinary Science

Explore further: Pact with devil? California farmers use oil firms' water

Related Stories

C is for chicken (and campylobacter)

Jun 18, 2015

The Cambridge Animal Alphabet series celebrates Cambridge's connections with animals through literature, art, science and society. Here, C is for Chicken – a popular source of protein that carries a hidden ...

The protein problem

Jun 17, 2015

The importance of proteins is difficult to overstate; they play a critical role in countless biological processes. An enhanced understanding of their structure and function is essential to advancing the state ...

Recommended for you

Gimmicks and technology: California learns to save water

23 hours ago

Billboards and TV commercials, living room visits, guess-your-water-use booths, and awards for water stinginess—a wealthy swath of Orange County that once had one of the worst records for water conservation ...

Cities, regions call for 'robust' world climate pact

Jul 03, 2015

Thousands of cities, provinces and states from around the world urged national governments on Thursday to deliver a "robust, binding, equitable and universal" planet-saving climate pact in December.

Will climate change put mussels off the menu?

Jul 03, 2015

Climate change models predict that sea temperatures will rise significantly, including in the tropics. In these areas, rainfall is also predicted to increase, reducing the salt concentration of the surface ...

As nations dither, cities pick up climate slack

Jul 02, 2015

Their national governments hamstrung by domestic politics, stretched budgets and diplomatic inertia, many cities and provinces have taken a leading role—driven by necessity—in efforts to arrest galloping ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.