贵州省幽门螺杆菌CagA基因表达与甲硝唑耐药性

目的:探讨贵州地区上消化道疾病患者幽门螺杆菌(H pylori)细胞毒素相关蛋白(CagA)基因的表达及其与甲硝唑(MTZ)耐药的相关性。方法:从上消化道疾病患者胃黏膜分离50株H pylori,经聚合酶链反应(PCR)检测CagA基因,E-test法检测MTZ耐药情况,测序并应用BLAST分析MTZ敏感株(MTZS)与耐药株(MTZR)CagA基因的分子差异。结果:50株H pylori中有92%的菌株表达CagA,其阳性表达率在消化性溃疡患者与慢性胃炎患者无差异;50株H pylori对MTZ总耐药率为54%,CagA阳性及阴性菌株耐药率分别为54.3%及50.0%(P>0.05);基因测序结果显示MTZS及MTZR两组间CagA基因突变无统计学差异。结论:贵州地区CagA阳性菌株与上消化道疾病密切相关,但与疾病的严重程度无明显关系,CagA基因表达及基因变异与MTZ耐药性之间无明显关系。

CagA Gene Expression in Helicobacter pylori and Its Relationship with Metronidazole Resistance in Guizhou Province

Objective: To explore the expression of cytotoxin associated protein(CagA) gene in Helicobacter pylori(H.pylori) in patients with upper gastrointestinal diseases,and to observe the relationship of CagA gene with metronidazole resistance in Guizhou province.Methods: Fifty H.pylori strains were isolated from gastric mucosa of patients with upper gastrointestinal diseases.CagA gene expression in H.pylori was detected with PCR,and metronidazole resistance was determined by E-test.Differences in CagA gene sequences between metronidazole-sensitive(MTZS) strains and metronidazole-resistance(MTZR) strains were analyzed.Results: 92% H.pylori strains expressed CagA gene.There was no significant difference in positive expression rate of CagA gene between patients with peptic ulcer and chronic gastritis.MTZR rate of 50 H.pylori strains was 54 %.MTZR rates of CagA+ strains and CagA-strains were 54.3% and 50.0% respectively(P>0.05).Gene sequencing and analysis results showed that there was no significant difference in CagA gene mutation between MTZR and MTZR strains.Conclusions: CagA positive expression strain is closely related to upper gastrointestinal disease in Guizhou province,but not related to severity of disease.CagA gene expression or gene mutation is not related with metronidazole resistance.