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Updated: May 15, 2026
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The Citrobacter rodentium Mouse Model: Studying Pathogen and Host Contributions to Infectious Colitis
Published on: February 19, 2013
Hypervirulent-host-associated Citrobacter rodentium cells have poor acid tolerance
Allen Smith1, Arvind A Bhagwat
1Diet Genomics and Immunology and Laboratory, Henry A. Wallace Beltsville Agricultural Research Center, Agricultural Research Service, USDA, 10300 Baltimore Avenue, BARC-E, Beltsville, MD 20705-2350, USA.
Current Microbiology
|January 19, 2013
Summary
Citrobacter rodentium can become hyperinfectious after passing through mice. However, these hypervirulent cells are surprisingly acid-sensitive, challenging the role of stomach acidity in this phenomenon.
Area of Science:
- Microbiology
- Pathogen Biology
- Infectious Diseases
Background:
- Enteric food-borne pathogens can increase virulence after mammalian host passage.
- Citrobacter rodentium is a mouse model for enterohemorrhagic Escherichia coli infections, known to develop hyperinfectivity.
- The mechanisms underlying C. rodentium hypervirulence require further investigation.
Purpose of the Study:
- To investigate if increased acid tolerance explains the hypervirulent status of C. rodentium after host passage.
- To determine the effect of in vitro acid adaptation and anaerobic growth on fecal components on C. rodentium infectivity.
Main Methods:
- Passaging C. rodentium through a mouse gastrointestinal tract to induce hypervirulence.
- Culturing C. rodentium under mildly acidic conditions (pH 5.5) to assess acid tolerance.
- Evaluating the infectivity of adapted C. rodentium strains in a mouse model.
- Culturing C. rodentium anaerobically on fecal components.
Main Results:
- A hyperinfectious state of C. rodentium was observed after host passage.
- Hypervirulent C. rodentium cells exhibited extreme acid sensitivity.
- Growth in mildly acidic conditions induced acid tolerance but did not enhance infection establishment.
- Anaerobic growth on fecal components did not induce hypervirulence.
Conclusions:
- Hypervirulent C. rodentium is paradoxically acid-sensitive, not acid-tolerant.
- Mouse gastric acidity alone is insufficient to explain the hypervirulent phenotype of C. rodentium.
- Further research is needed to elucidate the factors contributing to C. rodentium hypervirulence.
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