Quadruple therapy is effective for eradicating Helicobacter pylori after failure of triple proton-pump inhibitor-based therapy: A detailed, prospective analysis of 21 consecutive cases

Background. Data regarding the effectiveness of second-line treatment of He licobacter pylori infection are limited, especially if microbiological stud ies are considered. Methods and Patients, We conducted a prospective, uncontrolled study of a c onsecutive series of 21 peptic ulcer patients with failure of 1-week lansop razole, amoxicillin, and clarithromycin. H. pylon status was evaluated by u rease test, histology, culture, and urea breath test. Susceptibility to amo xicillin, clarithromycin, and metronidazole was studied by E-test. Cure of infection was defined as negative results from endoscopy-based tests 1 mont h after treatment and negative results from a urea breath test at 2 months. Treatment consisted of a 1-week combination of lansoprazole (30 mg bid), t etracycline (500 mg qid), metronidazole (500 mg tid), and bismuth subcitrat e (120 mg qid). Results. H. pylori was resistant to metronidazole in three cases, to clarit hromycin in three cases, and to both clarithromycin and metroinidazole in a n additional three patients. No resistance to amoxicillin was found. Eradic ation was obtained in 20 cases (95.2% confidence interval [CI], 76.2-99.9). The only patient in whom infection was not eradicated harbored a metronida zole-resistant (minimum inhibitory concentration >32 mu g/ml) strain. No si gnificant side effects were reported. Conclusion. Quadruple therapy obtains a high eradication rate even in patie nts with clarithromycin- and metronidazole-resistant strains. Further rando mized and controlled studies are warranted and are urgently needed.