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 underlyingmechanisms,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 NTsys2 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 was31.3%.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.