Impact of minimal inhibitory concentration breakpoint of amoxicillin and clarithromycin on the efficacy of these containing regimens for Helicobacter pylori eradication / 中华消化杂志

ABSTRACT

Objective:To evaluate the impact of amoxicillin and clarithromycin resistance on the eradication rate of Helicobacter pylori ( H. pylori), and to explore the optimal minimal inhibitory concentration (MIC) breakpoint of amoxicillin and clarithromycin. Methods:From March 2008 to December 2010, patients with H. pylori positive received standard triple therapy to eradicate H. pylori were retrospectively analyzed, 140 patients with H. pylori infetion were included, of which 12 patients did not receive eradication treatment. At 8 to 12 weeks after treatment, the eradication rate of H. pylori of 140 and 128 patients was calculated by intention-to-treat (ITT) and per-protocol population (PP) analysis, respectively. The correlation between amoxicillin and clarithromycin resistance and failure of H. pylori eradication was analyzed. And the relation between different MIC breakpoints of amoxicillin and clarithromycin and failure of H. pylori eradication was also analyzed. Binary logistic regression analysis and consistency test were used for statistical analysis. Results:The results of ITT and PP analysis indicated that the eradication rate of H. pylori of the standard triple therapy was 66.4%(93/140)and 72.7% (93/128), respectively, 95% confidence interval ( CI) 59.3% to 74.3%, and 65.6% to 79.7%, respectively. The results of binary logistic regression analysis showed that amoxicillin resistance (odds ratio ( OR)=6.326, 95% CI 1.090 to 36.725, P=0.040) and clarithromycin resistance ( OR=10.686, 95% CI 4.031 to 28.326, P<0.01) were both independent risk factors of H. pylori eradication failure. The results of consistency test demonstrated that when the MIC breakpoint of amoxicillin was 0.125 mg/L, the correlation between amoxicillin resistance and H. pylori eradication failure was the highest (fair consistency, P<0.05); when the MIC breakpoint of clarithromycin was 2.000 mg/L, the correlation between clarithromycin resistance and H. pylori eradication failure was the highest (moderate consistency, P<0.05). Conclusions:The eradication rate of H. pylori of standard triple therapy dropped to <80%. The decrease of H. pylori eradication rate was related to the resistance of amoxicillin and clarithromycin. The best MIC breakpoints of amoxicillin and clarithromycin were 0.125 and 2.000 mg/L, respectively.