For UBT, breath samples will be collected at a visit scheduled 45+ after the end of the eradication treatment, in disposable bags with a one-way valve designed for the use of the UBit 300 (Meretek Diagnostics, LaFayette, CO). A baseline breath sample will be collected at the start of the interview then the subject will be given 150 ml of a drink containing citric acid and 75 mg of 13C-urea. After 20 minutes, a second breath bag will be collected.