Clinical Experiment of Helicobacter Pylori Transmission

• Sponsor: Stanford University (Other)
• Overall Status: Completed
• CT.gov ID: NCT00550368
• Collaborator: (none)
• Enrollment: 45
• Location: 1
• Arms: 2
• Duration (Months): 44
• Patients Per Site Per Month: 1

Study Details

Study Description

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.

Condition or Disease	Intervention/Treatment	Phase
Infection; Achlorhydria	Biological: Biological intervention: Enteropathogenic E. coli	N/A

Detailed Description

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.

Study Design

• Study Type: Interventional
• Actual Enrollment: 45 participants
• Allocation: Non-Randomized
• Intervention Model: Single Group Assignment
• Masking: None (Open Label)
• Primary Purpose: Basic Science
• Official Title: Effect of Gastric Acid and H. Pylori Infection on Infection With Enteropathogenic E. Coli
• Study Start Date: Aug 1, 2005
• Actual Primary Completion Date: Apr 1, 2009
• Actual Study Completion Date: Apr 1, 2009

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Helicobacter pylori negative Persons who tested negative for H. pylori by both serology and Urea breath test. All participants will receive the Biological intervention: Enteropathogenic E. coli.	Biological: Biological intervention: Enteropathogenic E. coli; 5x10^8 or 1x10^9 organisms of EPEC were administered to all participants.
Experimental: Helicobacter pylori positive Persons who tested positive for H. pylori by both serology and Urea breath test. All participants will receive the Biological intervention: Enteropathogenic E. coli.	Biological: Biological intervention: Enteropathogenic E. coli; 5x10^8 or 1x10^9 organisms of EPEC were administered to all participants.

Outcome Measures

Primary Outcome Measures

1. Development of Diarrhea [48 hours]

Secondary Outcome Measures

1. Intensity of Gastrointestinal Symptoms [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.

Eligibility Criteria

Criteria

• Ages Eligible for Study: 35 Years to 59 Years
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: Yes

Inclusion Criteria:Healthy Exclusion Criteria:prior gastrointestinal disease prior treatment of H. pylori infection immune suppression or deficiency history of cancer, diabetes, or other co-morbidity

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Stanford University School of Medicine	Stanford	California	United States	94305

Sponsors and Collaborators

• Stanford University

Investigators

• Principal Investigator: Julie Parsonnet, Stanford University

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

• Responsible Party: Julie Parsonnet, Principle Investigator, Stanford University
• ClinicalTrials.gov Identifier: NCT00550368
• Other Study ID Numbers: 688; NCT00549224
• First Posted: Oct 29, 2007
• Last Update Posted: Dec 6, 2016
• Last Verified: Oct 1, 2016

• Additional relevant MeSH terms: Infections; Achlorhydria

Study Results

Participant Flow

Recruitment Details	Patients were recruited for the study from 2005 to 2008. Enrollment began 6/2005 and ended 5/2008. Healthy individuals were sought with no chronic medical conditions or symptoms.
Pre-assignment Detail	Participants were assigned to one of two groups: Helicobacter pylori positive, or Helicobacter pylori negative. Assignment was based on results of H. pylori serology and Urea Breath Test. Test results had to be concordant for group assignment.

Arm/Group Title	H. Pylori Negative	H. Pylori Positive
Arm/Group Description	Participants who tested negative for H. pylori infection.	Participants who tested H. pylori positive
Period Title: Overall Study
STARTED	26	19
COMPLETED	26	19
NOT COMPLETED	0	0

Baseline Characteristics

Arm/Group Title	H. Pylori Negative	H. Pylori Positive	Total
Arm/Group Description	Participants who tested negative for H. pylori infection.	Participants who tested H. pylori positive	Total of all reporting groups
Overall Participants	26	19	45
Age (years) [Mean (Standard Deviation) ]
Mean (Standard Deviation) [years]	48.1 (7.3)	49.4 (6.7)	48.6 (7)
Sex: Female, Male (Count of Participants)
Female	11 42.3%	4 21.1%	15 33.3%
Male	15 57.7%	15 78.9%	30 66.7%
Ethnicity (NIH/OMB) (Count of Participants)
Hispanic or Latino	5 19.2%	12 63.2%	17 37.8%
Not Hispanic or Latino	21 80.8%	7 36.8%	28 62.2%
Unknown or Not Reported	0 0%	0 0%	0 0%
Race (NIH/OMB) (Count of Participants)
American Indian or Alaska Native	0 0%	0 0%	0 0%
Asian	2 7.7%	2 10.5%	4 8.9%
Native Hawaiian or Other Pacific Islander	0 0%	0 0%	0 0%
Black or African American	2 7.7%	3 15.8%	5 11.1%
White	21 80.8%	13 68.4%	34 75.6%
More than one race	1 3.8%	1 5.3%	2 4.4%
Unknown or Not Reported	0 0%	0 0%	0 0%
BMI (kg/m2) [Mean (Standard Deviation) ]
Mean (Standard Deviation) [kg/m2]	27 (4.5)	28.7 (3.8)	27.7 (4.3)
Gastric pH, Median (units on a scale) [Median (Full Range) ]
Median (Full Range) [units on a scale]	1.5	1.6	1.5
Hypochlorhydric (participants) [Number]
Number [participants]	2 7.7%	7 36.8%	9 20%

Outcome Measures

1. Primary Outcome

Title	Development of Diarrhea
Time Frame	48 hours

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	H. Pylori Negative	H. Pylori Positive
Arm/Group Description	Participants who tested negative for H. pylori infection.	Participants who tested H. pylori positive
Measure Participants	26	19
Number [participants]	5 19.2%	6 31.6%

2. Secondary Outcome

Title	Intensity of Gastrointestinal Symptoms
Description	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.
Time Frame	48 hours

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	H. Pylori Negative	H. Pylori Positive
Arm/Group Description	Participants who tested negative for H. pylori infection.	Participants who tested H. pylori positive
Measure Participants	26	19
Median (Full Range) [units on a scale]	3	3

Adverse Events

Time Frame	Participants were monitored for 48 hours as inpatients following ingestion of 5x10^8 or 1 x10^9 organisms of Enteropathogenic E. coli. After discharge, participants were further followed for 4 weeks from the time of discharge from the hospital.
Arm/Group Title	H. Pylori Negative		H. Pylori Positive
Arm/Group Description	Participants who tested negative for H. pylori infection.		Participants who tested H. pylori positive
All Cause Mortality
	H. Pylori Negative		H. Pylori Positive
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	/ (NaN)		/ (NaN)
Serious Adverse Events
	H. Pylori Negative		H. Pylori Positive
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/26 (0%)		0/19 (0%)
Other (Not Including Serious) Adverse Events
	H. Pylori Negative		H. Pylori Positive
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/26 (0%)		0/19 (0%)

Limitations/Caveats

[Not Specified]

More Information

Certain Agreements

Principal Investigators are NOT employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.