Antibiotic resistance of Helicobacter pylori isolated from children in Chongqing, China.

The resistance of Helicobacter pylori (H. pylori) to antibiotics has been increasing worldwide and varies across different geographic areas and times. Limited studies reported the prevalence of antibiotic resistance and its related gene mutations in children in Chongqing, a city located in southwest China. We collected 112 H. pylori strains isolated from gastric biopsies of 156 children at Children's Hospital of Chongqing Medical University and calculated resistance rates of these strains to six antibiotics. The A2143G and A2142G mutations in 23S rRNA gene, which are related to clarithromycin resistance, and Asn87 and Asp91 mutations in gyrA gene, which are related to levofloxacin resistance, were investigated in 102 strains. The resistance rates to clarithromycin, metronidazole, and levofloxacin were 47.3% (53/112), 88.4% (99/112), and 18.8% (21/112), respectively. No resistance to amoxicillin, tetracycline, and furazolidone was observed. Dual and triple resistance percentages were 37.5% (42/112) and 10.7% (12/112), respectively. The detection rate of A2143G mutation in 23S rRNA gene was 83.3% (40/48). The detection rates of mutations of Asn87 and Asp91 in gyrA gene were 52.6% (10/19) and 36.8% (7/19), respectively. Conclusion: The prevalence of H. pylori resistance to clarithromycin, metronidazole, and levofloxacin was high in children in Chongqing, China. The A2143G mutation was detected in most clarithromycin-resistant strains, and Asn87 and Asp91 of gyrA mutation points were common in levofloxacin-resistant strains. In clinical practice, anti-H. pylori therapy should be individualized based on a susceptibility test.  What is Known: • The resistance of H. pylori to antibiotics changes with the geographic areas and that in Asia the resistance rate is high. • Mutation plays a vital role in antibiotics resistance of H. pylori. What is New: • High resistance rates to single and multiple antibiotics in children of Chongqing, a city located in southwest China, were observed. • Molecular assays showed good conformance with susceptibility test results to direct antibiotic resistance of H. pylori.