【摘要】 目的:研究幽门螺杆菌(Hp)编码基因(rdxA)和细胞毒素相关基因A(cagA)突变与Hp对甲硝唑耐药的关系。方法:从贵阳某医院60例消化内科患者胃黏膜标本中分离出Hp临床分离株11株,体外微需氧条件下培养,用E试验(E-test)检测各株Hp临床分离株对甲硝唑的最低抑菌浓度(MIC),聚合酶链式反应(PCR)方法扩增Hp的rdxA和cagA基因并测序,再将耐药株与标准株Hp26695PCR产物进行碱基序列分析。结果:11株Hp临床分离株的MIC均≥256μg·mL-1,rdxA和cagA基因的扩增率均为100%。与标准株Hp26695相应基因序列对比,11株临床分离株的rdxA基因同源性为95%～98%,cagA基因同源性低于94%,rdxA、cagA基因分别有4、10个规律性突变点。结论:贵阳地区Hp对甲硝唑的耐药性可能与rdxA和cagA基因突变有关,其中高耐药性可能与cagA基因有关。更多还原

【Abstract】 OBJECTIVE:To investigate the relationship between cagA gene and rdxA gene mutation of H.pylori and drug resistance of metronidazole.METHODS:11 strains of H.pylori were isolated from gastric mucosa samples of 60 patients in digestive system department of a hospital and cultured in vitro under microaeropgilic condition.E-test was done by testing the MIC of H.pylori to metronidazole.rdxA gene and cagA gene of H.pylori were amplified by PCR and sequenced.PCR products of drug resistant strain and standard strain H.pylori 26695 were sequenced.RESULTS:MIC of 11 strains of clinical isolated H.pylori were ≥256 μg·mL-1.Amplified rate of rdxA gene and cagA gene were both 100%.Compared with standard strain H.pylori 26695,the DNA homology of rdxA was 95%～98% respectively,and that of cagA was less than 94% respectively.The mutation of rdxA gene and cagA gene showed regularity that there were 4 and 10 common mutable points respectively.CONCLUSION:The resistance of H.pylori to metronidazole is probably relevant to the mutation of rdxA gene and cagA gene.And cagA gene plays an important role in high-level resistance to metronidazole.更多还原