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Abstracts
Workgroup: Public Health and Processing
Use of Bacteriophage for the Decontamination of Oysters Infected with Vibrio vulnificus
Principal Investigator(s):
Donna H. Duckworth, Ph.D, University of Florida, College of Medicine, Gainesville, FL (no e-mail found)
Co-Investigator(s):
Paul Gulig, Ph.D., University of Florida, College of Medicine, Gainesville, FF
Funding Period: 10/1/00 - 3/31/02
The project was designed to make raw oysters safer for human consumption by killing, with bacteriophage, the Vibrio vulnificus that infects them. We proposed to also test to see whether the bacteriophage could prevent the human V. vulnificus disease in an animal model. To do this, we had to isolate and characterize phage, study the phage's killing ability and test the killing of bacteria in experimentally infected oysters and mice. We have isolated or obtained from other workers and purified over 20 different phages and we are studying their ability to kill 57 strains of V. vulnificus. We have found that some of the phage will only kill the bacteria when sea water is present, but that many times, this sea water requirement can be met with Mg++ and Ca++. We are working on the best ways to grow and store the different types of vulnificus phages. The work with the mice was highly successful. Iron-dextran-treated mice were injected subcutaneously with 10 times a lethal dose of V. vulnificus and injected intravenously, either simultaneously or at various times after infection, with a phage specific for the infecting bacteria. Treatment of mice with phages prevented virtually any sign of disease in the treated mice. The phage could prevent death, systemic disease (as measured by numbers of bacteria/gram of liver) and local disease (as measured by numbers of bacteria/gram of skin and also histopathological analysis). Two different phages were effective against three different V. vulnificus strains, while a third phage that required seawater to kill the bacteria was ineffective in the mice.
Work with the oysters has been slow because of the difficulty in experimentally infecting the oysters with specifically marked V. vulnificus strains. With continuing Sea Grant funds we are presently studying ways to do this and also are testing to see if we can devise conditions under which the oysters will take up specific phage. If these latter experiments are successful we will try decontaminating naturally infected oysters with a "cocktail" of phages designed to kill a variety of different strains of V. vulnificus.
IMPACTS and/or BENEFITS:
We have proven that a variety of different phages can act to kill various strains of Vibrio vulnificus both in vitro and in mice , raising the possibility that phage could be used both in oysters to make them safer and also as an alternative treatment in individuals infected with Vibrio vulnificus.
PROJECT PUBLICATIONS:
Cerveny, K.E., A. DePaola, D.H. Duckworth, and P.A. Gulig. 2002. Infection and Immunity 70, 6251-6262.
Cerveny, K.E. Master's Thesis submitted to the University of Florida, College of Medicine, 2000.
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