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Systemic dissemination by intrarectal infection with Listeria monocytogenes in mice
S Nishikawa1, M Hirasue, T Miura
1Department of Bacteriology, Hirosaki University School of Medicine, Aomori, Japan.
Abstract:
Orally ingested Listeria monocytogenes is known to penetrate into Peyer's patches (PP) and translocate to the spleen and liver. Herein, extraintestinal dissemination of the bacterium independent of PP was investigated. Dissemination of Listeriae to the spleen and liver was observed in intrarectally infected mice as well as in intragastrically infected animals in spite that no Listeriae were detected in the small intestines of mice infected intrarectally. Decreased numbers of intestinal intraepithelial lymphocytes (iIEL) and increased numbers of lymphocytes in the contents of the small and large intestines were observed after intragastric infection and in the large intestine after intrarectal infection, giving the assumption that the leakage of iIEL caused by injury of epithelial layers in intestines might occur during infection. These results suggest that L. monocytogenes might be able to disseminate through small and large intestines in part by a PP-independent mechanism.
Insights
Listeria monocytogenes can spread to the spleen and liver via a Peyer's patch (PP)-independent route. Intestinal injury may facilitate Listeria dissemination through the gut barrier.
Area of Science:
- Microbiology
- Immunology
- Gastroenterology
Background:
- Listeria monocytogenes typically invades Peyer's patches (PP) for systemic spread.
- The mechanisms of Listeria dissemination independent of PP are not fully understood.
Purpose of the Study:
- To investigate the extraintestinal dissemination of Listeria monocytogenes independent of Peyer's patches (PP).
- To explore the role of intestinal barrier integrity and immune cell changes in Listeria dissemination.
Main Methods:
- Intragastric and intrarectal infection models in mice.
- Bacterial load quantification in spleen and liver.
- Analysis of intestinal intraepithelial lymphocytes (iIEL) and luminal immune cells.
Main Results:
- Listeria disseminated to the spleen and liver following both oral and rectal infections.
- No Listeria were detected in the small intestine after rectal infection, suggesting a PP-independent route.
- Intestinal infection led to decreased iIEL and increased lymphocytes in intestinal contents, indicating potential epithelial injury.
Conclusions:
- Listeria monocytogenes can disseminate systemically through a Peyer's patch (PP)-independent mechanism.
- Intestinal epithelial injury and associated immune cell changes may contribute to Listeria translocation across the gut barrier.