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Chapter 25 : Vibrio vulnificus †
Category: Environmental Microbiology
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This chapter discuss the taxonomy, infections, pathogenesis, genetic heterogeneity, distribution in estuarine environments and the environmental parameters that contribute to the ecology of this organism, and methods to eliminate this pathogen from foods. Of the several human pathogens now realized to occur naturally in seawater, the most significant, in regard to virulence, is Vibrio vulnificus. Three biotypes of V. vulnificus are recognized. Whereas each is known to be a human pathogen, biotype 1 is almost exclusively associated with human disease, and this is the biotype of greatest public health concern. Since the first study on experimental pathogenesis in V. vulnificus, a considerable amount has been learned regarding the virulence factors important for V. vulnificus infection. The major symptoms associated with V. vulnificus infections, including fever, tissue edema, hemorrhage, and especially hypotension, are classic symptoms associated with endotoxic shock. A study that examined 62 biotype 3 strains from Israel, as well as 82 biotype 1 and 15 biotype 2 strains, indicated that biotypes 1 and 2 are not entirely distinct but are present in two genetic subpopulations. While thiosulfate citrate bile salts sucrose agar (TCBS) is the most commonly employed medium for the isolation and initial differentiation of marine vibrios, most studies on the distribution of V. vulnificus in marine environments now employ colistin-polymyxin B-cellobiose agar or one of its modifications.
Key Concept Ranking
- Restriction Fragment Length Polymorphism
Seasonal distribution of V. vulnificus infection (primary septicemia) following ingestion of raw or undercooked oysters in the United States between 2000 and 2004 (J. D. Oliver, unpublished data).
Randomly amplified polymorphic DNA (RAPD)-PCR of 11 individual V. vulnificus strains isolated from oysters (Y. Yano and J. D. Oliver, unpublished data).
Variation in levels of V. vulnificus in oysters (Cras-sostrea virginica). Oysters (n = 155) were taken from a small, environmentally homogeneous site in North Carolina and were sampled for their resident load of V. vulnificus. Shown is the log of V. vulnificus loads (CFU g-1 wet weight) vs. the frequency (%) that each load was identified ( Sokolova et al., 2005 ).
Correlation between water temperature (°C) and numbers (CFU/ml) of V. vulnificus cells isolated from the water over a 12-month period. Sampling sites were estuarine sites in eastern North Carolina (K. Dyer-blackwell and J. Oliver, unpublished data).
Symptoms and traits of persons contracting V. vulnificus infections following ingestion of oysters a