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Chapter 10 : Pathogenic Vibrios in Seafood
Category: Food Microbiology; Applied and Industrial Microbiology
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The primary pathogens in the genus Vibrio are Vibrio parahaemolyticus, V. cholerae, and V. vulnifius. Other Vibrio species that can cause human disease include V. hollisae, V. alginolyticus, V. damsela, V. mimicus, V. fluvialis , V. metschnikovii, V. furnissii, V. cincinnatiensis, and V. carchariae, but reported cases are either relatively rare or do not involve food-borne transmission. Nonepidemic V. cholerae is also responsible for occasional seafood-borne disease in the United States and can be distinguished from epidemic disease by the severity of symptoms, the serogroups of associated strains, and the capacity for global spread. V. vulnificus is the most common cause of serious wound infections associated with Vibrio species, and these infections may result from exposure of breached skin surface to seawater or contaminated seafood handling. This chapter talks about intrinsic factors and extrinsic factors. Comparison of heat resistances for pathogenic vibrios showed that D55 values varied among species. V. parahaemolyticus (D55 of 1.75 min) was considerably more resistant compared to V. vulnificus and V. cholera. Approved and validated treatments include high hydrostatic pressure, pasteurization (heat shock), and individual quick freezing. These treatments are generally used in combination with approved transport and storage practices involving icing, refrigeration, and/or freezing. Greater understanding of the role of the bacteria in estuarine ecosystems and the risks associated with environmental, bacterial, and host factors is crucial for control and safety of seafood products.
V. vulnificus bacteria that are attached to diatom are indicated by arrow. (Figure provided by Maria Chatzidaki-Livanis.)
Activity of CT. CT B subunits bind host intestinal cells, followed by endocytosis and release of the A subunit (black circle), which ribosylates G proteins to activate adenylate cyclase. The subsequent increase in cyclic AMP (cAMP) results in protein phosphorylation, extrusion of chloride ions, and massive diarrhea. (Adapted from Kaper et al., 1995 .)
Bollous lesions associated with V. vulnificus septicemia.
Colony morphology of V. vulnificus showing opaque (right) and translucent (left) phenotypes associated with virulence and capsule expression.
Global distribution of “pandemic” V. parahaemolyticus disease. (Reprinted from Nair et al., 2007 .)
Reported cases of V. vulnificus in Florida from 1990 to 2005. Recent reports show increases in the number of cases associated with wounds compared to other sources. (Data provided by Roberta Hammond.)
Typical symptoms associated with different Vibrio species