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The overall objective for this project is to produce an evolutionary framework for
understanding the ecology, virulence and epidemiology of Listeria, Clostridium, and
Enterococcus that will contribute to the development and implementation of effective
control strategies for these species. <P>
The specific objectives are:<ol> <li> Characterize
lineage evolution, population structure and demographic history of species within the
genera Listeria, Clostridium, and Enterococcus. <li> Determine patterns of selective
constraint throughout the genomes of species within the genera Listeria, Clostridium,
and Enterococcus. <li> Develop molecular subtyping methods for L. monocytogenes and C. perfringens.</ol>
Multilocus DNA sequence datasets will be developed for diverse collections of
Listeria, Clostridum and Enterococcus from food, veterinary, clinical and
environmental sources. These data will be combined with data from complete genome
sequences and analyzed in order to provide an evolutionary framework for
understanding the ecology, virulence, and epidemiology of pathogenic and toxigenic
species of Listeria, Clostridium, and Enterococcus. In addition, results of the
molecular evolutionary analyses will be used to determine if there is an association
between a specific adaptive variant and subtypes most frequently associated with food
borne illness in humans, providing a scientific basis for subtype-specific risk
assessments, regulatory policies, and intervention strategies that provide maximum
protection to consumers while limiting the number and size of product recalls.
Finally, the evolutionary framework and information on the distribution and adaptive
significance of genetic variation within the pathogens examined will be used to
develop DNA sequence-based subtyping technologies that will enhance pathogen
surveillance, outbreak detection, epidemiological investigation, and source-tracking
efforts.