Project Number: 3620-42000-037-00
Project Type: Appropriated

Start Date: Jan 21, 2006
End Date: Jan 20, 2011

Objective:
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. The specific objectives are: 1) Characterize lineage evolution, population structure and demographic history of species within the genera Listeria, Clostridium, and Enterococcus; 2) Determine patterns of selective constraint throughout the genomes of species within the genera Listeria, Clostridium, and Enterococcus; and 3) Develop molecular subtyping methods for L. monocytogenes and C. perfringens.

Approach:
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.