Resistance Of Fluoroquinolone On Helicobacter Pylori In Vitro

Objective: The aim of this study was to investigate the resistance of fluoroquinolone against Helicobacter pylori (H.pylori) in vitro.Methods:Brain-heart infusion medium was used to culture helicobacter pylori in Microaerophilic environment, then the MIC of Levofloxacin and moxifloxacin were determined with agar dilution . Fluoroquinolone resistance of H. pylori genomic DNA was performed with PCR amplification and nucleotide sequence to detect gene mutation of the quinolone resistance determining regions (QRDR) of the A subunit of the DNA gyrase(gyrA).Results: A totle of 67 H.pylori clinical isolates were cultured from the patients'gastric mucosal biopsy specimens .The proportion of Levofloxacin-resistant strains was 5.97%, and the moxifloxacin-resistant strains 2.99%. Two strains were resistant both to levofloxacin and moxifloxacin. Sequence analysis in half(2/4) of fluoroquinolone-resistant strains showed new point mutations.Conclusion: These results suggest that resistance to fluoroquinolones is low. the resistance is most likely correlated with point mutation in QRDR of the gyrA that is probably not the same in different areas.