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Published on: February 19, 2013
Microbial colonization of rat colonic mucosa following intestinal perturbation
1School of Microbiology, The University of New South Wales, P.O. Box 1, 2033, Kensington, N.S.W., Australia.
Abstract:
An allochthonous population of spiral-shaped bacteria was found colonizing the surfaces of the colonic mucosa of rats after they had been given magnesium sulphate (MgSO4)-induced diarrhea. These organisms were rarely seen in normal control rats and were not displaced when the treatment was ceased, remaining associated with the tissue for periods of up to 180 days. Similar bacteria were also found when specific pathogen-free rats, lacking mucosa-associated populations, were inoculated with homogenized rat intestine from conventional animals. Light and electron microscopic observations showed that the organisms were attached to the surface of the colon, orientated at right angles to the tissue, with one end inserted into the microvillus border. This is the first report of long-term colonization, following perturbation of the gut ecosystem, of a site on the gastrointestinal mucosa not normally associated with bacteria. The ultrastructure and mode of attachment of these organisms were very similar to that of spiral-shaped bacteria known to associate with the colonic mucosa in monkeys and man.
Insights
Following magnesium sulphate-induced diarrhea, spiral-shaped bacteria colonized rat colonic mucosa long-term. These allochthonous organisms attached to microvilli, persisting for up to 180 days.
Area of Science:
- Microbiology
- Gastroenterology
- Microbial Ecology
Background:
- The colonic mucosa in rats is typically sparsely colonized by spiral-shaped bacteria.
- Gut microbiota can be perturbed by various factors, including induced diarrhea.
Purpose of the Study:
- To investigate the colonization dynamics of spiral-shaped bacteria in the rat colon after induced diarrhea.
- To characterize the attachment and persistence of these bacteria on the colonic mucosa.
Main Methods:
- Induction of diarrhea using magnesium sulphate (MgSO4) in rats.
- Microscopic (light and electron) examination of colonic tissues to identify and characterize bacteria.
- Inoculation of specific pathogen-free rats with homogenized intestinal contents.
Main Results:
- Allochthonous spiral-shaped bacteria colonized the colonic mucosa of rats post-diarrhea.
- These bacteria attached to the mucosa at a right angle, with one end inserted into microvilli.
- Colonization persisted for up to 180 days, even after cessation of diarrhea.
- Similar bacteria were found in rats inoculated with conventional gut microbiota.
Conclusions:
- This study reports the first instance of long-term colonization by allochthonous spiral-shaped bacteria on a normally unassociated gastrointestinal mucosal site.
- The observed ultrastructure and attachment mode resemble those of spiral bacteria found in primates.
- These findings suggest a potential for specific bacterial populations to establish long-term niches following gut ecosystem perturbation.
