Listeria monocytogenes is one of several enteric microbes that is acquired orally, invades the gastric mucosa, and then disseminates to peripheral tissues to cause systemic disease in humans. Intravenous (i.v.) inoculation of mice with L. monocytogenes has been the most widely-used small animal model of listeriosis over the past few decades. The infection is highly reproducible and has been invaluable in deciphering mechanisms of adaptive immunity in vivo, particularly CD8⁺ T cell responses to intracellular pathogens. However, the i.v. model completely bypasses the gut phase of the infection. Recent advances in generating both humanized mice and murinized bacteria, as well as the development of a foodborne route of transmission has reignited interest in studying oral models of listeriosis. In this review, we analyze previously published reports to highlight both the similarities and differences in tissue colonization and host response to infection using either oral or i.v. inoculation.
Keywords: Listeria monocytogenes; foodborne pathogen; host susceptibility; intracellular bacteria; virulence.