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Shigella-type pathomechanism in the "mouse model"
Abstract:
A strain of Escherichia coli K-12 carrying the 140-Megadalton virulence plasmid of the enteroinvasive E. coli--J53(pSPl)--showed high virulence in the "mouse model", in chick embryos, but not in the Serény test. It expresses the outer membrane proteins thermoregulatedly, encoded also by the virulence plasmid. In orally infected streptomycin-pretreated mice this strain infects only the large bowel, shows adherence to the epithelial surface, but in its first step preferentially to the mucus excreted by the goblet cells. Epithelial penetration and intracellular multiplication occurs with a characteristic localization of bacteria in the depth of crypts. Consequence of the infection is degeneration of the epithelial surface, its denudation.
Insights
This study shows that Escherichia coli K-12 with a virulence plasmid infects the large bowel in mice, adhering to mucus and penetrating epithelial cells. This leads to significant damage and denudation of the intestinal lining.
Area of Science:
- Microbiology
- Infectious Diseases
- Bacterial Pathogenesis
Background:
- Enteroinvasive Escherichia coli (EIEC) possesses virulence plasmids encoding factors for intestinal colonization.
- Understanding the role of specific virulence plasmids in E. coli pathogenesis is crucial for developing targeted interventions.
Purpose of the Study:
- To investigate the virulence and pathogenic mechanisms of Escherichia coli K-12 harboring an enteroinvasive E. coli virulence plasmid (pSP1).
- To characterize the adherence, invasion, and tissue damage caused by this engineered E. coli strain in a mouse model.
Main Methods:
- Utilized a mouse model and chick embryos to assess virulence.
- Examined bacterial adherence to intestinal epithelial surfaces and mucus.
- Investigated bacterial localization within intestinal crypts and epithelial penetration.
Main Results:
- The J53(pSP1) E. coli strain demonstrated high virulence in mice and chick embryos, but not in the Serény test.
- The strain adhered preferentially to goblet cell mucus and showed characteristic intracellular localization within crypt depths.
- Infection resulted in epithelial surface degeneration and denudation.
Conclusions:
- The virulence plasmid confers significant pathogenic potential to E. coli K-12, enabling intestinal colonization and tissue damage.
- The adherence to mucus and invasion into crypts are key steps in the pathogenesis of this EIEC strain.
- This model provides insights into the mechanisms of enteroinvasive E. coli infections.