Efficacy of a 14-day quadruple-therapy regimen for third-line Helicobacter pylori eradication

To assess the efficacy of amoxicillin, tetracycline, high-dose metronidazole, and a proton-pump inhibitor for third-line Helicobacter pylori eradication.

We enrolled 70 consecutive patients who had registered, failed to respond to two rounds of H. pylori eradication, and undergone endoscopy for H. pylori culture. Seven patients were lost to follow-up. Patients were treated according to the results of antibiotic-susceptibility testing reports (cultured group, n=39). Those who failed the H. pylori culture were prescribed 14-day quadruple therapy containing esomeprazole 40 mg twice daily, amoxicillin 1 g twice daily, tetracycline 500 mg four times daily, and metronidazole 500 mg three times daily (empirical group, n=24). A follow-up urea breath test was performed 8 weeks later.

Antibiotic-resistance rates were 79.5% (clarithromycin), 94.9% (levofloxacin), 66.7% (metronidazole), 2.6% (amoxicillin), and 0 (tetracycline). Eradication rates attained by the cultured and empirical group were 89.7% (95% CI 72.7%-97.1%) and 58.3% (95% CI 36.6%-77.9%) in per-protocol analysis (P=0.004) and 81.4% (95% CI 66.6%-91.6%) and 51.8% (95% CI 31.9%-71.3%) in intention-to-treat analysis (P=0.014), respectively. Culture-guided therapy was the only clinical factor influencing the efficacy of H. pylori eradication (OR 0.16, 95% CI 0.04-0.60; P=0.006). Despite the high metronidazole-resistance rate (66.7%) after two treatment failures, the eradication rate in patients with this condition was 84%.

Empirical 14-day modified quadruple therapy is not acceptable as an alternative third-line rescue H. pylori treatment. The success rate of third-line susceptibility-guided treatment was near 90%. This report is valuable as a reminder to medical practitioners that rather than a try-and-see approach, susceptibility-guided therapy should always be considered whenever possible for patients who have undergone several treatment failures.