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目的探讨幽门螺杆菌(Hp)根除失败后甲硝唑的耐药机制。方法通过纸片扩散法选取原始敏感菌株、原始耐药菌株及根除治疗失败后的Hp耐药菌株;从原始敏感菌株、原始耐药菌株及根除治疗失败后的Hp耐药菌株扩增rdxA基因,聚合酶链式反应(PCR)产物进行DNA测序以探讨甲硝唑耐药机制。结果将甲硝唑的原始敏感菌株、原始耐药菌株、根除失败后耐药菌株的rdxA基因与标准菌株进行对比,核苷酸同源性较高(P>0.05);氨基酸同源性分析示,原始耐药菌株的氨基酸同源性低于原始敏感菌株和根除失败后的耐药菌株(P<0.05)。结论 rdxA基因突变可能是甲硝唑原始耐药菌株产生耐药性的主要原因,但是根除失败后甲硝唑耐药菌株耐药性的产生可能还有其他原因。
Objective To investigate the mechanism of metronidazole resistance after helicobacter pylori (Hp) eradication failure. Methods The primary sensitive strains, the original drug-resistant strains and the drug-resistant strains of Hp after eradication therapy were selected by disk diffusion method. The rdxA gene was amplified from the original sensitive strains, the original drug-resistant strains and the Hp-resistant strains after the eradication failure. Polymerase chain reaction (PCR) products were sequenced to explore the mechanism of metronidazole resistance. Results Compared with the standard strains, the rdxA gene of the original sensitive strains, the original drug-resistant strains and the drug-resistant strains of eradication of metronidazole were highly homologous (P> 0.05). The analysis of amino acid homology The amino acid homology of the original drug-resistant strains was lower than that of the original sensitive strains and the resistant strains after the failure of eradication (P <0.05). Conclusion The mutation of rdxA gene may be the main reason for the drug resistance of the original drug resistant metronidazole strains. However, there may be other reasons for the drug resistance of the metronidazole drug resistant strains after the eradication failure.