Trial to Assess the Effects of an Antimicrobial Mouthwash on the Esophageal Microbiome

Patients scheduled for upper endoscopy for clinical indications will be randomized to 3 weeks
of either no treatment or use of twice daily chlorhexidine mouthwash leading up to the
endoscopy. There will be 2-3 study visits, at Day 0 and Day 21, and for those subjects in the
mouthwash arm, a final visit 1-2 weeks following the Day 21 visit. Subjects will be required
to fast overnight prior to the visits on Days 0 and 21.

Inclusion Criteria:

- Age >18

- Scheduled for upper endoscopy for clinical indications

- No allergy or other contraindication to chlorhexidine

Exclusion Criteria:

- Use of proton pump inhibitors or H2 receptor antagonists within 1 month of enrollment.
Acid suppressant medications raise the gastric pH and can dramatically alter the
gastric and esophageal microbiome.

- History of upper gastrointestinal cancer

- History of histologically proven Barrett's esophagus

- History of antireflux or bariatric surgery, or other gastric or esophageal surgery

- Use of antimicrobial mouthwash within 1 month of enrollment

- Use of antibiotics or immunosuppressant medications within 3 months of enrollment

- Use of steroid inhalers or nasal sprays within 1 month of enrollment

- HIV or other immunosuppressed states or conditions (e.g. active malignancy)

- Pregnant or breast feeding

- Inability to give informed consent