幽门螺杆菌甲硝唑诱导耐药的研究

目的通过甲硝唑诱导耐药这一方法来分析rdxA基因突变情况的可行性.方法用非混合感染、敏感的H.pylori菌株进行甲硝唑诱导实验,使其由敏感型转变为耐药型;再提取DNA,PCR扩增诱导前后rdxA基因并测序.结果甲硝唑诱导菌株12株,4株获得成功,诱导前后的M IC值增加了16~64倍;连续传代3次后,M IC值保持不变.诱导前后敏感型与耐药型菌株rdxA基因序列仅有0.2%~0.8%的差异,而不相关菌株间则有2.2%~2.7%的差异.结论甲硝唑诱导实验可以在较短时间内获得稳定的甲硝唑耐药性,并能排外不同菌株间存在差异的影响,有望成为一种研究甲硝唑耐药机制的好方法.

Study on Induced Metronidazole Resistance of Helicobacter Pylori

Objective To search the feasibility of mutation, RdxA gene was analyzed by the metronidazole induction experiment. Method The non -multiple, sensitive H. pylori strains, were selected and subjected to metronidazole induction experiment, which made H. pylori strains transform susceptibility to resistance. Extracted DNA of metronidazole sensitive and resistant pairs of H. pylori strains before and after induced, amplified by PCR and sequenced rdxA gene. Result 4 of 12 H. pylori strains were induced successfully with metronidazole whose MICs increased by 16 -64 times. Strains were transferred three times on metronidazole -free medium and the MICs redetermined were the same as those after induced. There was 0. 2 -0. 8% difference between pairs of metronidazole sensitive and resistant H. pylori strains. There was 2. 2 - 2. 7% difference between unrelated H. pylori strains. Conclusion The metronidazole induction experiment could make H. pylori acquire stable resistance to metronidazole in a short period and exclude that the natural polymorphism of rdxA gene influenced on mutation analysis. There was good hope that the experiment would become a good method to research metronidazole resistance mechanism .