Prevalence of Helicobacter pylori Resistance to Antibiotics and its Influence on the Treatment Outcome in China:A Multicenter Clinical Study

The increase in resistance to antibiotics emerged as a significant clinical problem seems to result in a decrease in the efficacy of Helicobacter pylori (H.pylori) eradication therapy in recent years.The information about H,pylori resistance status to antibiotics in China has not been very clear,but is important for improving the efficacy by establishing a reasonable first-line therapy.Aims:To investigate the prevalence of H.pylori resistance to metronidazole, clarithromycin and amoxicillin in China and to evaluate the effect of H.pylori resistance to antibiotics on the cure rates of anti-H,pylori 7-day triple therapies.Methods:Sixteen medical centers joined this multicenter randomized trial.Nine hundreds and ten H.pylori infected patients with upper abdominal symptoms referred for gastroendoscopy were enrolled. Patients were randomized into 2 groups:Group LCA (lansoprazole 30 mg bid,clarithromycin 500 mg bid,amoxicillin 1000 mg bid,for 7days) and Group LCM (lansoprazole 30 mg bid,clarithromycin 500 mg bid,metronidazole 400 mg bid,for 7 days).H.pylori was cultured from gastric biopsy specimens and the isolated strains were tested for metronidazole, clarithromycin and amoxicillin resistance by E-test.Minimum inhibitory concentration (MIC)≥8 mg/L for metronidazole,≥2 mg/L for clarithromycin and≥1 mg/L for amoxicillin were considered resistant.Results:The per protocol (PP) eradication rates of H.pylori were 82.7% for LCA group and 68.6% for LCM group (P0.001),respectively.H.pylori strains were cultured from gastric biopsy specimens obtained from 340 patients among the 910 patients.The resistance rates were 75.6% for metronidazole,27.6% for clarithromycin and 2.7% for amoxicillin.In group LCM,the PP eradication rates in patients with strains sensitive to both metronidazole and clarithromycin,and strains resistant to both metronidazole and clarithromycin were 84.4% and 42.1% (P0.001),respectively.The PP eradication rates in patients with strains sensitive to clarithromycin and resistant to clarithromycin in group LCA were 91.6% and 58.1% (P0.001),respectively. Conclusions:The resistance rates of H.pylori to metronidazole and clarithromycin are high and the resistance rate to amoxicillin is relatively low in China.It suggests that resistance to metronidazole and clarithromycin is the main cause of failure of eradication therapy for H.pylori infection.