Second line therapy: eligible patients will be randomized into one of the two groups Group (A): sequential therapy containing levofloxacin for 14 days (EAML) D1-D7: (esomeprazole 40mg bid + amoxicillin 1gm bid) for 7 days D8-D14: (esomeprazole 40mg bid + levofloxacin 250mg bid + metronidazole 500mg bid) for another 7 days