Abstract: Objective To investigate the efficacy of eradication therapy and antimicrobial resistance rate of Helicobacter pylori (H.pylori) strains among children in Shanghai.Methods From 1st January 2014 to 19th September 2017, patients who were diagnosed as H.pylori infection, completed the eradication therapy and reassessed the H.pylori status in Children's Hospital of Fudan University were enrolled in the restrospective study. All data were extracted from medical record system of the hospital including sex, age at diagnosis, endoscopy findings, rapid urease test (RUT) results, histology findings, microbiological culture with anti-microbial susceptibility results, treatment composition and duration. H. pylori infection was evaluated at least 4 weeks after the completion of the treatment. Negative urea breath test (UBT) or RUT was indicated successful eradication.Results A total of 1 558 patients with the mean age of (8.5±3.1) years and male of 56.5% were enrolled in the study. Abdominal discomfort and non-ulcer disease were common manifestations occurred in 74.6% and 85.0% of the patients, respectively. All patients received the empiric treatment for two weeks (10 days for sequential therapy). Total eradication rate in first-line and rescue therapy was 56.7%(883/1 558). The successful eradication rate was 56.4%(751/1 331) in first-line therapy and 58.1%(132/227) in rescue therapy. No significant difference was observed between the two groups. For first-line therapy, the eradication rate was 57.9% (659/1 139) in OCA/OCAc therapy (omeparaole, clarithromycin and amoxicillin/amoxicillin-clavulanic acid), 31.8%(34/107) in OCM therapy (omeparaole, clarithromycin and metronidazole) and 68.2%(58/85) in other therapies. The eradication rate of OCM therapy was lower than that of the other two groups. For rescue therapy, the eradication rate was 57.6%(87/151) in OCA/OCAc therapy with bismuth, 52.3%(23/44) in OCM therapy with bismuth and 68.8%(22/32) in other therapies. No significant difference was observed among each two groups. The resistance rates to clarithromycin, metronidazole and amoxicillin in 579 strains were 31.8%, 45.1% and 1.4%, respectively. Double resistance rates to clarithromycin and metronidazole were 23.0%. There were 259 strains in successful theatment group and 320 strains in treatment failure group. The latter got higher resistance rates in clarithromycin (44.0% vs 21.9%), metronidazole (52.5% vs 39.1%) and double resistance (32.4% vs 15.3%). Four hundred and seventy-five strains were in first-line therapy group and 104 strains in rescue therapy group. The resistance rates in rescue therapy group were all higher than that in first-line therapy group with clarithromycin (42.3% vs 29.5%), metronidazole (55.8% vs 42.7%) and double resistance (34.6% vs 20.4%).Conclusion The eradication rate of standard triple therapy in children was only 56.4% because of the high resistance in clarithromycin and metronidazole. It may not be suitable as the first-line therapy in clinical practice. Whether increasing the compliance of the patients and the dose of drugs (PPI and amoxicillin) will improve the eradication rate needs further investigation.

Key words: Children, Eradication rate, Helicobacter pylori, Resistance