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The eae gene of Citrobacter freundii biotype 4280 is necessary for colonization in transmissible murine colonic
1Department of Microbiology and Immunology, Stanford University School of Medicine, California 94305-5402.
Abstract:
Transmissible murine colonic hyperplasia is characterized by proliferation of anchored stem cells in the mucosa of the descending colon of laboratory mice and is caused by Citrobacter freundii biotype 4280. This bacterium produces attaching and effacing lesions in the descending colon prior to the onset of gross hyperplasia. By mutational analysis, the chromosomal eae gene of C. freundii biotype 4280 was shown to be necessary for colonic colonization. Conversely, bacteria cured of a 65-kb plasmid, which was identified in C. freundii biotype 4280, were not attenuated for colonic colonization or for the induction of colonic hyperplasia.
Insights
Citrobacter freundii causes murine colonic hyperplasia by producing attaching and effacing lesions. The chromosomal eae gene is essential for colonization, but a specific plasmid is not required for hyperplasia.
Area of Science:
- Microbiology
- Gastroenterology
- Pathogenesis
Background:
- Transmissible murine colonic hyperplasia is a condition affecting laboratory mice.
- It involves the proliferation of stem cells in the colon's mucosa.
- Citrobacter freundii biotype 4280 is identified as the causative agent.
Purpose of the Study:
- To investigate the role of specific genes and plasmids in Citrobacter freundii-induced murine colonic hyperplasia.
- To understand the mechanism by which C. freundii colonizes the mouse colon and causes disease.
Main Methods:
- Mutational analysis of the chromosomal eae gene in C. freundii.
- Comparison of wild-type C. freundii with bacteria cured of a 65-kb plasmid.
- Assessment of colonic colonization and hyperplasia induction in laboratory mice.
Main Results:
- The chromosomal eae gene of C. freundii biotype 4280 is essential for colonic colonization.
- Bacteria lacking a specific 65-kb plasmid were still capable of colonizing the colon.
- The 65-kb plasmid was not required for the induction of colonic hyperplasia.
Conclusions:
- The eae gene plays a critical role in the pathogenesis of murine colonic hyperplasia by C. freundii.
- A specific 65-kb plasmid in C. freundii biotype 4280 is not essential for causing colonic hyperplasia or colonization.