In this randomized-controlled trial , the investigator recruited participants with H pylori infection after failure of first line standard triple therapy. Using a computer-generated randomization sequence, the investigators randomly allocated patients to either 10-day levofloxacin-containing sequential (EALM, esomeprazole 40 mg b.d., amoxicillin 1 g b.d.for 5 days and followed by esomeprazole 40 mg b.d., levofloxacin 500 mg qd and metronidazole for 5 days) or 10-day levofloxacin-containing triple therapy (EAL, esomeprazole 40 mg b.d., amoxicillin 1 g b.d., and levofloxacin 500 mg qd) at a 1:1 ratio. The primary outcome was the eradication rate by intention-to-treat and per-protocol analyses.