 Eradication Therapy Using a computer-generated number sequence, patients who meet the inclusion criteria and do not have any one of the exclusion criteria will be randomized to receive one of the following regimens: 1 CALa regimen: clarithromycin 500mg twice daily, amoxicillin 1000mg twice daily, and lansoprazole 30mg twice daily for 7 days, or 2 LALa regimen: levofloxacin 750mg levofloxacin500 1.5 tablets once daily, amoxicillin 1000mg twice daily, lansoprazole 30mg twice daily for 7 days Figure 1. Adverse events will be recorded throughout the trial and during the follow-up period. Patients who do not return for 13C-UBT at 6 weeks after completion of treatment will be considered lost-to-follow-up and will be excluded from the per protocol PP analysis. 