Clinical Trial: Clinical Experiment of Helicobacter Pylori Transmission

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Effect of Gastric Acid and H. Pylori Infection on Infection With Enteropathogenic E. Coli

Brief Summary: The study proposes to test whether chronic infection with Helicobacter pylori protects individuals from symptomatic infection with enteropathogenic E. coli. The study will also evaluate the effect of gastric acidity in this relationship.

Detailed Summary: Because H. pylori is an enteric infection, its prevalence may be linked to exposure to other enteric pathogens. Results of observational studies on the association between H. pylori and gastroenteritis, however, have been conflicting. Some have shown increased incidence of diarrhea in children with H. pylori infection, with one study attributing 11% of diarrhea cases to H. pylori. Other studies found no association, and still others found a protective effect of H. pylori against gastroenteritis. Dissecting out confounding from true physiological associations can be difficult in observational studies. To better elucidate the association between H. pylori and gastroenteritis, we performed a direct challenge experiment with a well-characterized gastrointestinal pathogen, enteropathogenic Escherichia coli (EPEC). EPEC is a leading cause of infantile gastroenteritis in the world and has a long history of safe use in human experiments. It is also acid sensitive: in our laboratory less than 0.001% of inoculated EPEC organisms survived at pH 2.5. Our goal was to test the hypothesis that chronic infection with H. pylori increases the risk of diarrheal illness after direct challenge with EPEC.
Sponsor: Stanford University

Current Primary Outcome: Development of Diarrhea [ Time Frame: 48 hours ]

Original Primary Outcome: Level of antigen-specific immune response [ Time Frame: 6 months of follow-up ]

Current Secondary Outcome: Intensity of Gastrointestinal Symptoms [ Time Frame: 48 hours ]

Composite gastrointestinal symptom score was on a scale from 0 (no symptoms) to 15 (severe symptoms). This composite was the sum of 5 self-reported, symptom scores, each ranging from 0 (none) to 3 (severe). The self-reported symptoms that subjects scored were: malaise, headache, nausea, vomiting, and loose stool.


Original Secondary Outcome: Patterns of immune response by PBMCs in response to antigen-specific challenge. [ Time Frame: 6 months of follow-up. ]

Information By: Stanford University

Dates:
Date Received: October 25, 2007
Date Started: August 2005
Date Completion:
Last Updated: October 13, 2016
Last Verified: October 2016