Helicobacter pylori isolates from ethnic minority patients in Guangxi: resistance rates, mechanisms, and genotype.

AIM: To investigate the rate of Helicobacter pylori (H. pylori) resistance to clarithromycin among ethnic minority patients in Guangxi, explore the underlying mechanisms, and analyze factors influencing genotype distribution of H. pylori isolates. METHODS: H. pylori strains were isolated, cultured and subjected to drug sensitivity testing. The 23S rRNA gene of H. pylori isolates was amplified by PCR and analyzed by PCR-RFLP and direct sequencing to detect point mutations. REP-PCR was used for genotyping of H. pylori isolates, and NTsys_2 software was used for clustering analysis based on REP-PCR DNA fingerprints. Factors potentially influencing genotype distribution of H. pylori isolates were analyzed. RESULTS: The rate of clarithromycin resistance was 31.3%. A2143G and A2144G mutations were detected in the 23S rRNA gene of all clarithromycin-resistant H. pylori isolates. At a genetic distance of 78%, clarithromycin-resistant H. pylori isolates could be divided into six groups. Significant clustering was noted among H. pylori isolates from patients with peptic ulcer or gastritis. CONCLUSION: The rate of clarithromycin resistance is relatively high in ethnic minority patients in Guangxi. Main mechanisms of clarithromycin resistance are A2143G and A2144G mutations in the 23S rRNA gene. Clarithromycin-resistant H. pylori isolates can be divided into six groups based on REP-PCR DNA fingerprints. Several factors such as disease type may influence the genotype distribution of H. pylori isolates.