Gastroenterology

Gastroenterology

Volume 117, Issue 5, November 1999, Pages 1089-1097
Gastroenterology

Alimentary Tract
The intestinal mucus layer from patients with inflammatory bowel disease harbors high numbers of bacteria compared with controls,☆☆

https://doi.org/10.1016/S0016-5085(99)70393-8Get rights and content

Abstract

Background & Aims: Whether the bacterial flora contributes to the pathogenesis of inflammatory bowel disease (IBD) by increased penetration in mucus, increased adherence to epithelial cells, or invasion of the epithelium is unknown. We therefore studied the spatial distribution of bacteria in the mucosa of rectal biopsy specimens from patients with IBD and from controls. Methods: Rectal biopsy specimens from 19 patients with IBD and from 14 controls were studied by using nonradioactive ribosomal RNA in situ hybridization. Total mucosal surface length examined for each patient was measured, and the number of bacteria visualized was estimated semiquantitatively. Results: No bacteria were observed in biopsy specimens from 10 controls (71%) and 6 IBD patients (32%) (P = 0.04; odds ratio, 5.42; 95% confidence interval, 1.23–23.9). IBD rectal specimens contained significantly more bacteria than control samples (P = 0.004). Bacteria were localized within the mucus layer but did not adhere to the epithelial cells and were not present within the lamina propria. There was no correlation between the numbers of bacteria present and either the degree of inflammation or the use of anti-inflammatory agents or sulfasalazine compounds. Conclusions: The intestinal mucus in IBD patients is less protective against the endogenous microflora than in controls, resulting in increased association of luminal bacteria with the mucus layer.

GASTROENTEROLOGY 1999;117:1089-1097

Section snippets

Patients and controls

Nineteen consecutive patients with IBD visiting the Department of Gastroenterology for endoscopy were included. Patients were enrolled in the study if they had clinically active UC, CD, or indeterminate colitis. Diagnosis was confirmed by endoscopy and histology. Controls were 9 patients who required endoscopy for reasons other than IBD (e.g., irritable bowel syndrome) and who did not complain of diarrhea. Controls were only included if results from endoscopy and histological analysis of biopsy

ISH of sheep collagen-colon cell specimens

Sections of sheep collagen specimens containing HT-29 cells and different species of Enterobacteriaceae, H. pylori, and S. aureus were hybridized with probes Eub338M, dT35f, and EB1f. After hybridization with Eub338M, bacteria of all species tested stained bright brown in contrast to the HT29-19A cells and the collagen in the tissue (Figure 1A).

. Results of RISH of sheep collagen sections containing HT-29 cells and E. coli, K. pneumoniae, and S. typhi in equal amounts. (A) Hybridization with

Discussion

In this study we investigated the spatial distribution of intestinal bacteria in the rectal and colonic mucosa in paraffin-embedded biopsy specimens from 19 patients with IBD and from 14 controls. We developed a nonradioactive method for ISH enabling us to study the distribution of intestinal bacteria by light microscopy. To detect as many bacteria as possible, we used a probe that has been shown to detect rRNA of eubacteria present in the human large intestine.12, 13 In our ISH reconstruction

Acknowledgements

The authors thank P. van Amstel en W. van Est for technical assistance, P. Fockens for assistance with sample collection, R. van Leeuwen for assistance with statistical analyses, and M. D. de Jong for critically reviewing the manuscript.

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    Address requests for reprints to: Constance Schultsz, M.D., Department of Medical Microbiology, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. e-mail: [email protected].

    ☆☆

    Dr. Cohen has worked as a consultant to Centocor, Inc. Dr. Cominelli has a grant from Centocor, Inc. to study the incidence of lymphoma among hospitalized Crohn's disease patients. He is also a member of the speaking bureau for Centocor, Inc. Drs. Cominelli and Bickston are currently clinical trial investigators of CDP571 (CellTech Therapeutic Ltd., Berkshire, England).

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