Vibrio vulnificus was discovered in 1976 as a lactose- fermenting, gram-negative bacterium that is in the same family as those that cause cholera. It is halophilic (salt requiring), so it thrives mainly in warm saltwater. It is found in all coastal waters of the United States. Environmental factors that contribute to levels of Vibrio vulnificus in seafood and in the environment include temperature, pH, salinity, and increased dissolved organics. Vibrio vulnificus is capable of causing infection in two ways: 1) through open wounds or 2) by ingestion. In the former, someone may come in contact with the bacterium by having an open wound that gets exposed in contaminated water, or one may puncture oneself while handling contaminated animals such as clams, oysters, or crabs. These infections may lead to skin breakdown and ulceration. The latter occurs by the ingestion of uncooked seafood that is contaminated. All individuals who consume foods contaminated with this organism are susceptible to gastroenteritis, which usually develops within 16 hours of eating the contaminated food. Symptoms of this type of infection are vomiting, diarrhea, and abdominal pain. In immunocompromised individuals, Vibrio vulnificus can infect the bloodstream, causing a severe illness characterized by fever and chills, decreased blood pressure (septic shock), and blistering skin lesions. Bloodstream infections are fatal about 50% of the time.
Oysters are filter-feeding animals that can concentrate Vibrio bacteria from the water into their system. The bacteria are not a result of pollution, so, eating oysters from "clean" waters does not provide protection. Eating raw oysters with hot sauce or while drinking alcohol does not kill the bacteria, either. Infections by Vibrio vulnificus may be diagnosed using routine stool samples, wound, or blood cultures, and may be treated with antibiotics. The minimal infection causing dose is still unknown. Exposing wounds to potentially contaminated waters should be avoided. High risk individuals should avoid intake of any seafood that may not be properly cooked. Thorough cooking kills the Vibrio bacteria and lowers the risk of becoming ill. However, steaming does not always provide enough heat to kill all the Vibrio bacteria, and additional heat must be used. Infected individuals that recover do not suffer from any long-term damages.
References:
US FDA Bad Bug Book. Vibrio vulnificus. January 1992. 4 April 2003.
http://www.cfsan.fda.gov/~mow/chap10.htmlVibrio vulnificus. Center for Disease Control and Prevention 4 April 2003.
http://www.cdc.gov/ncidod/dbmd/diseaseinfo/vibriovulnificus_g.htm
Vibrio vulnificus. 4 April 2003. http://www.vibrio.com/VibrioFacts.htm
*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.
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