DEVELOPMENT OF INTEGRATED FUNCTIONAL GENOMICS-BASED APPROACHES FOR BACILLUS CEREUS EXPOSURE ASSESSMENT

Bacillus cereus group is represented by eighteen species with varying abilities to cause a range of foodborne disease, from vomiting and diarrhea to gastrointestinal anthrax. Identification and exposure assessment of these organisms is currently challenging as traditional species classification methods are not precise enough to allow for prediction or their pathogenic potential that depends on the genotype, food matrix and bacterial concentration. We thus propose the development of an integrated phenotypic and genomics-based exposure assessment to allow for improved assessment of the food safety risks posed by the presence and growth of these organisms in milk. These efforts are also essential for safety assessment of biocontrol/bioprotective strains (e.g., B. thuringiensis). The goal of this project will be achieved by (I) characterizing food-associated and clinical B. cereus group isolates using whole genome sequencing data and comprehensive bioinformatics analyses, (ii) performing tissue culture assays to assess expression of toxins and other virulence characteristics in B. cereus group isolates representing different phylogenetic clades and virulence gene profiles, (iii) assessing the growth capabilities, as well as toxin expression and other virulence characteristics of diverse B. cereus group strains, using different food-relevant environmental conditions, and (iv) integrating genomic and phenotypic data into a virulence characterization and exposure assessment tool, and assessing human exposure to B. cereus by consumption of food contaminated with different B. cereus group genotypes.