Occurrence of Vibrio vulnificus Biotypes in Danish Marine Environments

Abstract

During the unusually warm summer in Denmark in 1994, 11 clinical cases of Vibrio vulnificus infection were reported. These reports initiated an investigation of the occurrence of V. vulnificus biotypes in Danish marine environments. Samples of coastal water, sediment, shellfish, and wild fish were analyzed by preenrichment in alkaline peptone water amended with polymyxin B (2.0 × 104 U/liter) followed by streaking onto modified cellobiose-polymyxin B-colistin agar. V. vulnificus-like colonies were tested with a V. vulnificus-specific DNA probe. Low densities of V. vulnificus were detected in water (0.8 to 19 CFU/liter) from June until mid-September and in sediment (0.04 to >11 CFU/g) from July until mid-November. The presence of V. vulnificus was strongly correlated with water temperature. However, we isolatedV. vulnificus from water from a mussel farm at a lower temperature than previously reported (7°C). In 1 of the 13 locations studied, V. vulnificus was found in mussels in 7 of 17 samples analyzed; this is the first report of V. vulnificusin European shellfish. V. vulnificus was also isolated from gills, intestinal contents, and mucus from wild fish. Although biotyping of 706 V. vulnificus strains isolated during our investigations revealed that the majority of the strains (99.6%) belonged to biotype 1, biotype 2 was detected in seawater at a low frequency (0.4%). Our findings provide further evidence that seawater can serve as a reservoir and might facilitate spread of V. vulnificus biotype 2 to eels, with subsequent spread to persons handling eels. In conclusion, our data demonstrate that V. vulnificus is ubiquitous in a temperate marine environment and that V. vulnificus biotype 2 is not strictly confined to eels.

Occurrence, seasonality and genetic diversity of Vibrio vulnificus in coastal seaweeds and water along the Kii Channel, Japan

“…Immediate chilling after the harvest and storage at a low temperature (0-4 1C) can lower its cultivable population to reduce its threat (Cook & Ruple, 1992). According to previous findings, the V. vulnificus biotype 1 strains, capable of infecting humans, is overwhelmingly dominant (c. 99%) among the total V. vulnificus population in coastal and marine environments (Hor et al, 1995;Høi et al, 1998). However, a latest study has revealed that among coastal biotype 1 strains the virulence-correlated gene responsible for human infection (vcgC) comprises a minor fraction of the total population (c. 15%) but increases its percentage as the water temperature increases (Warner & Oliver, 2008).…”

“…(DePaola et al, 1994Wright et al, 1996;Høi et al, 1998). Two major biotypes of V. vulnificus are known: biotype 1 is related to human infection while biotype 2 is exclusively found among diseased fish, particularly eel (Høi et al, 1998). Recent findings indicate the spread of pathogenic V. vulnificus strains into new regions of the earth, e.g.…”

Vibrio vulnificus: new insights into a deadly opportunistic pathogen

“…Vibrio vulnificus is part of the normal microbiota of estuarine waters and occurs in high numbers in molluscan shellfish around the world, particularly in warmer months. This opportunistic pathogen is common in estuarine waters and has been isolated from a range of different environmental sources, including water, sediment and seafood produce (O'Neill et al, 1992;DePaola et al, 1994;Høi et al, 1998;Bisharat et al, 1999;do Nascimento et al, 2001;Baffone et al, 2006;Baker-Austin et al, 2010). Human infections associated with this bacterium originate from two distinct sources: consumption of seafood (primary septicemias) or exposure to seawater or seafood products (wound infections).…”

Seasonal seawater temperature as the major determinant for populations of culturable bacteria in the sediments of an intact mangrove in an arid region

“…A component of the heterotophic bacteria is the genus Vibrio spp., one of the most common bacterial genera in marine environments. Some species may cause infections in humans and aquaculture resources (Baross & Liston, 1970;Kaneko & Colwell, 1973;Hi et al, 1998). Physicochemical factors determine to a great extent the growth rate and biomass production of heterotrophic bacteria and Vibrio spp.…”