Gastroenterology

Gastroenterology

Volume 115, Issue 2, August 1998, Pages 281-286
Gastroenterology

Alimentary Tract
Association between intraepithelial Escherichia coli and colorectal cancer

https://doi.org/10.1016/S0016-5085(98)70194-5Get rights and content

Abstract

Background & Aims: Although multiple studies have focused on Helicobacter pylori, little is known about the mucosa-associated flora of the colon. The aim of this study was to detect bacteria directly in colonic mucosa from patients screened for colorectal cancer. Methods: Bacteria were quantified with the polymerase chain reaction and identified by comparative sequence analysis in colonoscopic biopsy specimens from 31 asymptomatic and 34 symptomatic controls with normal colonoscopic findings, 29 patients with colonic adenoma, and 31 patients with colorectal carcinoma. In 41 patients, intra- and extracellular location of bacteria was confirmed with the gentamicin protection assay. Results: No bacteria were detected in biopsy specimens from 97% of asymptomatic and 69% of symptomatic controls. In contrast, bacterial concentrations of 103–105 colony-forming units per microliter were detected in biopsy specimens from both malignant and macroscopically normal tissue in 90% and 93% of patients with adenoma and carcinoma, respectively. E. coli and coli-like bacteria were shown to colonize the colonic mucosa in 82% of these patients. The gentamicin protection assay indicated that E. coli was partially intracellular in 87% of patients with adenoma and carcinoma and in none of the controls. Conclusions: The colonic mucosa of patients with colorectal carcinoma but not normal colonic mucosa is colonized by intracellular E. coli.

GASTROENTEROLOGY 1998;115:281-286

Section snippets

Patients

This study was performed at the IVth Medical Clinic, Charité University Hospital, Berlin, Germany, with prior approval of the institutional review board and the patients' informed consent. One hundred twenty-five consecutive patients underwent colonoscopy for screening or staging for colorectal malignancies. Patients with inflammatory bowel disease (IBD) or macroscopic signs of inflammation were excluded. None of the patients had a history of familial polyposis, and none received antibiotics 8

Results

No bacteria were detected in any of the mucosal biopsy specimens from 30 of 31 asymptomatic controls and 24 of 34 symptomatic controls. In contrast, bacterial concentrations between 103 and 105 CFU/μL were detected in at least one biopsy specimen from 55 of 60 patients in the adenoma and carcinoma groups. This difference between the adenoma and carcinoma groups and both normal groups was statistically significant (P < 0.001). In 90% of the positive biopsy specimens from the adenoma and

Discussion

In the early 1970s, the observation of marked geographic variations in the incidence of colorectal cancer, which could not be explained by racial and dietary differences, lead to the hypothesis that intestinal bacteria might play a key role in cancerogenesis.8 However, the etiologic relationship of intestinal bacteria and colorectal cancer could not be definitively documented. In the 1980s and 1990s, extensive investigations linked a permanent colonization of the gastric mucosa with H. pylori

Acknowledgements

The authors thank MWG-BIOTECH GmbH for lending the LI-COR sequencer throughout the duration of the study and H. Poczewski for her excellent technical assistance in creating immunohistological stainings.

References (12)

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Address requests for reprints to: Alexander Swidsinski, M.D., IV Medizinische Klinik der Charité, Gastroenterology, Humboldt Universität, 10098 Berlin, Germany. Fax: (49) 30-2802-89-78.

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