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Investigate the role of the L. monocytogenes serotype 4b-associated gtcA gene in the ability of the organism to cause systemic infection following ingestion. The gtcA gene product alters the surface of L. monocytogenes in a way that maximizes its ability to attach to and invade intestinal epithelial cells and other cells that are involved in the pathogenesis of foodborne listeriosis.
APPROACH: Construct gtcA gene mutants (transposon and deletion) in food and patient isolates of L. monocytogenes recovered from relatively recent outbreaks of listeriosis. Compare the ability of these mutant strains with their wild type parent strains to adhere to and grow on RTE meat products, and cause systemic infection following their instillation into the gastrointestinal tract of susceptible A/J mice. Evaluate the influence of the gtcA gene on the ability of L. monocytogenes to attach to and invade intestinal epithelial cells and hepatocytes, and its potential influence on the intracellular niche and signaling pathways activated as a result of these processes. Integrate these observations into outreach programs designed to educate appropriate entities and individuals about the risks posed by L. monocytogenes and other foodborne disease agents.