Dual Clarithromycin and Metronidazole Resistance Is the Main Cause of Failure in Ultimate Helicobacter pylori Eradication

Abstract

<b><i>Background/Aim:</i></b> Antimicrobial resistance significantly affects the cure rate of <i>Helicobacter pylori (H. pylori)</i> eradication. We evaluated the risk factor of failure in ultimate <i>H. pylori</i> eradication and assessed the efficacy of current regimens to overcome antibiotic resistance. <b><i>Methods:</i></b> Patients with <i>H. pylori</i> infection were prospectively enrolled in a single center. They were classified into 3 groups according to the previous history of <i>H. pylori</i> eradication, and antibiotic susceptibility was evaluated by culture and minimum inhibitory concentrations (MICs). <b><i>Results:</i></b> Ninety-seven patients were successfully cultured for <i>H. pylori</i> and 81 (83.5%), 7 (7.2%), and 9 (9.3%) were classified into primary resistance, 1st eradication failure, and 2nd or more eradication failure groups; the resistance to clarithromycin (CLA), metronidazole (MET), and levofloxacin increased in the 1st eradication failure (85.7, 57.1, and 42.9%) and 2nd or more eradication failure (88.9, 88.9, and 55.6%) groups. The prevalence of MDR was 21.0% (17/81), 57.1% (4/7), and 88.9% (8/9) in the primary, 1st eradication failure, and 2nd or more eradication failure groups, respectively. In multivariate analysis, dual CLA/MET resistance (CLA/MET-R) (OR = 31.432, 95% CI: 3.094–319.266, <i>p</i> = 0.004) was an independent risk factor for ultimate <i>H. pylori</i> eradication failure. In patients with dual CLA/MET-R, the eradication ratio of concomitant therapy was 57.1% (4/7), whereas that of bismuth-containing quadruple therapy was 27.3% (3/11) (<i>p</i> = 0.350). <b><i>Conclusions:</i></b> Dual CLA/MET-R was the main cause of failure in ultimate <i>H. pylori</i> eradication, and 7-day bismuth quadruple or concomitant regimen would not be suitable for <i>H. pylori</i> eradication in the dual CLA/MET-R group.