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The goal of this research is to investigate the pathoecology (reservoirs/transmission mechanisms) of Clostridium perfringens type A food poisoning, the 3rd most common food-borne illness in the USA. This work will build upon our previous studies demonstrating that a) C. perfringens isolates carrying a chromosomal enterotoxin (cpe) gene are a much more common cause of food poisoning than C. perfringens isolates carrying a plasmid-borne cpe gene, b) chromosomal cpe isolates are the predominant cpe-positive isolates found in the American food supply, and c) chromosomal cpe isolates are much more heat-resistant than plasmid cpe isolates.
NON-TECHNICAL SUMMARY: Clostridium perfringens type A food poisoning ranks among the most common food-borne illnesses in the USA. The symptoms of this food poisoning are caused by an enterotoxin named CPE. That toxin is coded by the cpe gene, which can be present on the chromosome or a plasmid; however, isolates carrying a chromosomal enterotoxin gene cause nearly all food poisoning outbreaks. We recently provided two explanations for this association: 1) chromosomal cpe isolates are the predominant isolates found in raw foods, and 2) chromosomal cpe isolates are exceptionally heat-resistant, allowing them to survive incomplete cooking. We now want to investigate the point in the food chain where chromosomal cpe isolates enter foods, as that information could lead to steps to reduce food contamination. In addition, we wish to determine the biochemical basis behind the unusual heat-resistance of chromosomal cpe isolates, as that could lead to steps to make these isolates more susceptible to cooking. <P>
APPROACH: As described above, Aim #1 will involve optimization of a recently developed PCR assay, Aim #2 will use that optimized PCR assay to screen C. perfringens isolates provided by our collaborators at USDA and elsewhere, Aim #3 will involve standard food microbiology plate count techniques to compare isolate survival under different food environment stresses, and Aim #4 will involve the first use of comparative proteomic to compare the spore proteins of chromosomal cpe isolates vs. plasmid cpe isolates. Aim #4 will also rely upon Western blot and DNA sequencing approaches to compare the small acid soluble proteins of chromosomal cpe isolates vs. plasmid cpe isolates.