Study of the Esophageal String Test (EST) for the Diagnosis of Helicobacter Pylori

Background:

Helicobacter pylori is a bacterium that infects the lining of the stomach and intestines. It can cause peptic ulcers, cancers, and infections. Current methods of diagnosing H. pylori infections have limitations. Researchers want to test a new method of testing for H. pylori.

Objective:

To compare the esophageal string test (EST) to standard tests for detecting H. pylori infection.

Eligibility:

People aged 18 years or older with persistent H. pylori infection.

Design:

Participants will have 3 or 4 clinic visits over 2 to 4 months.

Screening visit: Participants will have a physical exam. They will provide a stool sample.

Baseline visit: Participants will have blood tests. Then they will have the EST: One end of a string will be taped to the outside of their cheek; the other end will be packed into a capsule. Participants will swallow the capsule, and the string will unwind down their throat into their stomach. The string will be left in for at least 1 hour. Then researchers will gently pull out the string. The fluids soaked into the string will be studied. Some participants will be prescribed antibiotics.

Follow-up visit 1: Participants whose H. pylori infection was cured by the antibiotics may leave the study. Those who are still infected will have an endoscopy: A flexible tube will be inserted down the throat and into the stomach. It will take tissue samples from the stomach lining. These participants will then receive antibiotics again.

Follow-up visit 2: The physical exam, blood test, and stool sample will be repeated.

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Study Description:

Adults with active Helicobacter pylori infection and a history of treatment failure will undergo an esophageal string test (EST). The gastric portion of the string will be used for detection of H. pylori by polymerase chain reaction (PCR), as well as assessment of resistance genes to clarithromycin, levofloxacin, and metronidazole. Participants who have failed one course of H. pylori therapy will be treated per current American Gastroenterological Association (AGA) guidelines. A stool antigen test for H. pylori will be performed 4 weeks after completion of therapy to assess cure. Participants who have failed \>=2 courses of therapy will undergo endoscopy with resistance testing per AGA recommendations. Patients will be offered antibiotic therapy based on the EST results and will have a repeat H. pylori stool antigen test 4 weeks after completion of therapy.

Primary Objective:

To assess the sensitivity of the gastric portion of the EST in detecting H. pylori infection.

Secondary Objectives:

To assess the ability of the gastric portion of the EST in detecting antimicrobial resistance to clarithromycin, levofloxacin, and metronidazole.

Primary Endpoint:

Proportion of the study population identified positive for H. pylori in EST eluates by PCR.

Secondary Endpoint:

Detection of H. pylori antibiotic resistance genes in EST eluates.

Eligibility Criteria:
* INCLUSION CRITERIA:

In order to be eligible to participate in this study, an individual must meet all of the following criteria:

* Aged \>=18 years
* Diagnosed with persistent H. pylori infection (by endoscopy, stool antigen, or urea breath testing) after at least one course of antimicrobial therapy
* Agreement to adhere to lifestyle considerations throughout study duration
* Ability of participant to provide informed consent

EXCLUSION CRITERIA:

An individual who meets any of the following criteria will be excluded from participation in this study:

* Pregnancy or lactation
* Use of antibiotics with activity against H. pylori within 4 weeks of enrollment
* Anaphylaxis to amoxicillin, tetracycline, clarithromycin, metronidazole, or levofloxacin
* Inability to swallow pills
* Biopsy-proven high grade dysplastic Barrett s esophagus, active peptic ulcer disease, recent (within 4 weeks) upper GI bleed, and/or history of Zollinger Ellison syndrome or gastric bypass surgery