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Updated: Aug 22, 2026
The Citrobacter rodentium Mouse Model: Studying Pathogen and Host Contributions to Infectious Colitis
Published on: February 19, 2013
Organ specificity, colonization and clearance dynamics in vivo following oral challenges with the murine pathogen
Siouxsie Wiles1, Simon Clare, James Harker
1Centre for Molecular Microbiology and Infection, Department of Biological Sciences, Imperial College London, London SW7 2AZ, UK.
Abstract:
Citrobacter rodentium belongs to a family of human and animal enteric pathogens that includes the clinically significant enterohaemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC). These pathogens use attaching and effacing (A/E) lesions to colonize the host gastrointestinal tract. In this study we have used bioluminescence imaging (BLI) to investigate the organ specificity, dynamics of colonization and clearance of mice by C. rodentium in situ and in real time. The bioluminescent C. rodentium derivative, strain ICC180, expresses the luxCDABE operon from the entemopathogenic nematode symbiont Photorhabdus luminescens and light levels accurately reflect bacterial numbers both in vitro and in vivo. We have demonstrated that primary colonization of the mouse by C. rodentium takes place within the caecum, specifically within the specialized patch of lymphoid tissue known as the caecal patch. Following colonization of the caecum C. rodentium established a colonic infection. Clearance of C. rodentium ICC180 parallels the colonization dynamics, i.e. the caecum was first to be cleared followed by the colon. A bioluminescent eae (encoding the outer membrane adhesin intimin) C. rodentium mutant failed to establish long-term colonization, although low levels of bacteria could be recovered for up to 3 days post challenge from the caecum.
Insights
Bioluminescence imaging reveals Citrobacter rodentium primarily colonizes the mouse caecal patch before spreading to the colon. Bacterial clearance follows this pattern, with the caecum cleared first, highlighting the importance of the caecal patch in C. rodentium infection dynamics.
Area of Science:
- Microbiology
- Infectious Diseases
- Gastroenterology
Background:
- Citrobacter rodentium is an enteric pathogen related to human pathogens like EHEC and EPEC.
- These pathogens cause disease by forming attaching and effacing (A/E) lesions in the gastrointestinal tract.
Purpose of the Study:
- To investigate the organ specificity, colonization dynamics, and clearance of Citrobacter rodentium in mice using real-time bioluminescence imaging.
- To understand the role of the caecal patch in C. rodentium infection.
Main Methods:
- Development of a bioluminescent C. rodentium strain (ICC180) expressing the luxCDABE operon for in vivo imaging.
- Utilizing bioluminescence imaging (BLI) to track bacterial load and distribution in mice over time.
- Comparison of wild-type C. rodentium colonization with an eae mutant strain.
Main Results:
- Primary colonization by C. rodentium occurred in the caecum, specifically within the caecal patch.
- Following caecal colonization, C. rodentium established infection in the colon.
- Bacterial clearance mirrored colonization, with the caecum cleared before the colon.
- A bioluminescent mutant lacking the eae gene (encoding intimin) failed to establish long-term colonization.
Conclusions:
- The caecal patch is the primary site for C. rodentium colonization in mice.
- The dynamics of colonization and clearance are site-specific within the gastrointestinal tract.
- The intimin adhesin, encoded by eae, is crucial for long-term C. rodentium colonization.
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