Background/Preliminary Data
The spread of infectious diseases by water-borne human pathogens is a pressing problem, especially in tropical regions of the world. The genus Vibrio, which is naturally-abundant in subtropical coastal waters, is comprised of several species that are pathogens of invertebrate and vertebrate animals, including those capable of causing devastating human disease (Grimes et al., 1986). In humans, Vibrio species may cause a variety of illnesses (Table 1). This includes cholera, caused by V. cholerae, which is a severe infection of the gastrointestinal tract that can result in death within less than a day when left untreated (Collins, 2003). V. vulnificus and V. parahaemolyticus cause both gastroenteritis and septicemia as a result an of individual coming into contact with contaminated food or water. Both species are associated with high mortality rates, and V. vulnificus is believed to be responsible for 95% of shellfish-related human deaths in the United States (Oliver, Warner, & Cleland, 1982). Recent reports estimate that Vibrio infections in general have risen 41% when comparing data from 1996-1998 with data from 2005 (Dziuban et al., 2006). The potential causes of the increase in Vibrio infections are unknown; however, it has been suggested that factors causing environmental change, such as rising sea surface temperature and increased human population, may be causing increased presence of water-borne pathogens and the exposure of humans to pathogens (Thompson, Iida, & Swings, 2004).
This research will provide the first linked set of data the incorporates both a comprehensive analysis of the genomic differences between at least two major lineages of V. vulnificus, and empirical tests of their physiologies. Knowing what the genomic differences are, and how they relate to differences in the optimal growth conditions of these bacteria, is essential for providing more informed assessments of the risks of infection. Differences in gene content can be identified, and provide clues to the essential genes for virulence in V. vulnificus. This knowledge will allow the identification of optimal molecular targets for rapid molecular assays that can be used to monitor presence and abundance of the virulent strains (of benefit to microbial ecologists, environmental and clinical microbiologists, and agencies responsibility for water quality). Finally, the pangenome developed from this dataset can be used to evaluate the distribution of V. vulnificus strains in coastal environments throughout the Pacific.
