Related Experiment Videos
Vibrio parahaemolyticus and related halophilic Vibrios
Abstract:
Approximately 30 years have elapsed since Dr. Fujino's original discovery that Vibrio parahaemolyticus (then termed Pasteurella parahemolytica) was the cause of "summer diarrhea" in Japan. Since that finding, V. parahaemolyticus has been established as a cause of gastroenteritis in numbers and places approaching global proportions. It has been isolated in marine and estuarine areas almost worldwide and despite its halophilic nature, V. parahaemolyticus has been isolated from saline-free waters. The relationship of this organism to the environment reveals a close association with other marine organisms especially copepods on which the Vibrios depend for survival in winter months and growth in summer months. There is a uniquely provocative disparity between human strains of V. parahaemolyticus which are Kanagawa phenomenon (KP) positive and the environmental strains which to a large extent are KP negative, the significance being that pathogenicity is measured according to the Kanagawa phenomenon (hemolytic activity) reaction. The hemolysin of the pathogenic strains is a thermostable, cardiotoxic protein, which thus far has not been implicated in the mechanism(s) which causes human gastroenteritis. The interest in this organism has been widened in recent years by the finding that similar organisms, V. alginolyticus, lactose positive vibrios and group F vibrios also cause serious disease in humans.
Insights
Vibrio parahaemolyticus causes global gastroenteritis, thriving in marine environments and associating with copepods. Pathogenic strains are Kanagawa phenomenon positive, unlike most environmental strains.
Area of Science:
- Microbiology
- Environmental Science
- Public Health
Background:
- Vibrio parahaemolyticus identified as a cause of gastroenteritis globally.
- The bacterium is halophilic, found in marine/estuarine environments worldwide, even in freshwater.
- V. parahaemolyticus exhibits a close ecological relationship with marine organisms, notably copepods.
Purpose of the Study:
- To review the environmental associations and pathogenicity of Vibrio parahaemolyticus.
- To discuss the significance of the Kanagawa phenomenon (KP) in differentiating pathogenic and environmental strains.
- To highlight the emergence of related Vibrio species as human pathogens.
Main Methods:
- Literature review of Vibrio parahaemolyticus research.
- Analysis of environmental isolation data.
- Discussion of pathogenicity markers, including the Kanagawa phenomenon.
Main Results:
- V. parahaemolyticus is widespread in marine ecosystems and linked to copepods for survival.
- A significant difference exists between pathogenic (KP-positive) and environmental (KP-negative) strains.
- The hemolysin from pathogenic strains, while cardiotoxic, is not yet implicated in human gastroenteritis.
Conclusions:
- V. parahaemolyticus remains a significant cause of foodborne illness with a complex environmental ecology.
- The Kanagawa phenomenon is a key indicator of pathogenicity, though its role in disease mechanisms requires further study.
- Other Vibrio species, such as V. alginolyticus, also pose a threat to human health.