Date of Award

2018

Document Type

Open Access Dissertation

Department

Biological Sciences

Sub-Department

College of Arts and Sciences

First Advisor

Charles R. Lovell

Abstract

Vibrio bacteria are Gram negative, motile organisms that occur naturally in most coastal and estuarine ecosystems. Some vibrios are important human pathogens, including Vibrio parahaemolyticus and Vibrio vulnificus. The CDC estimates that vibrios cause 80,000 cases of disease each year in the United States alone. Most cases are caused by V. parahaemolyticus, which infects humans after the consumption of contaminated raw or undercooked seafood, primarily oysters. V. parahaemolyticus causes mild gastroenteritis that is self-limiting unless the patient is immunocompromised. V. vulnificus has a much lower incidence of disease (100 cases in the USA yr-1); however, this organism causes much more severe infections, including necrotizing fasciitis (flesh eating disease) and sepsis when introduced into an open wound. With global climate change, Vibrio outbreaks are expanding in size, frequency, and latitude. This investigation examined the reliability of using “species specific” marker genes to identify a Vibrio strain, the distribution of pathogenicity islands (PAIs) within Vibrio genomes, and the distributions of potential pathogenic V. parahaemolyticus within oysters and oyster tissues. We determined that some oysters, designated as “hot” oysters, can harbor significantly more vibrios than surrounding oysters. These “hot” oysters, which occur at low frequency, may explain the sporadic (and difficult to predict) nature of V. parahaemolyticus infections. The cytotoxic effects of environmental Vibrio strains and the interactions of vibrios with various marine microalgae were also studied.

Rights

© 2018, Savannah Leigh Klein

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