Helicobacter species in the human colon.

OBJECTIVE: To determine the prevalence, frequency and colonization patterns of Helicobacter species throughout the colon. METHOD: Patients having initial colonoscopy for nonspecific gastrointestinal disturbance had colonic biopsies taken from up to four sites during colonoscopy and examined for evidence of the Helicobacteraceae family using a group-specific PCR. Serum was also collected and examined for IgG reactivity to Helicobacter pylori. RESULTS: 100 patients had colonoscopy of whom 35 were found to have DNA evidence of Helicobacter species throughout the colon, with 22 having H. pylori. Fifteen patients had a demonstrable serum IgG response to H. pylori that was not always associated with molecular evidence of H. pylori DNA in colon biopsies and vice versa. No specific association with colon disease was found in patients with H. pylori infection. CONCLUSION: We found evidence of Helicobacter infection in a significant number of patients presenting for colonoscopy but no specific association between the presence of these bacteria and colon disease. Our finding of disparity between molecular and serological techniques to detect Helicobacter species suggests that future studies should not rely on serology alone to detect these bacteria in the human colon.

Ovine small intestinal adenocarcinomas are not associated with infection by herpesviruses, Helicobacter species or Mycobacterium avium subspecies paratuberculosis.

Sheep in New Zealand more frequently develop small intestinal adenocarcinoma (SIA) than sheep in other countries. The reasons for this high rate of intestinal neoplasia are not known. In man, differences between countries in the incidence of neoplasia are often due to differences in the rate of infection by carcinogenic viruses or bacteria. Therefore, it was hypothesized that New Zealand sheep more frequently develop SIA as they are more frequently exposed to an infectious agent. This study compared rates of detection of herpesviruses, Helicobacter species, and Mycobacterium avium subspecies paratuberculosis (MAP) in ovine SIA to rates of detection in samples of intestine with non-neoplastic disease. These infectious agents were chosen as all three have been associated with human intestinal cancer. Microscopical examination did not reveal helical bacteria within sections of SIA or non-neoplastic jejunum. Polymerase chain reaction amplified herpesviral DNA more frequently from samples of non-neoplastic jejunum than samples of SIA. MAP DNA was not amplified from either neoplastic or non-neoplastic jejunum. These results suggest that the high rates of SIA in New Zealand sheep are not due to frequent infection by herpesviruses, Helicobacter species or MAP.