儿童幽门螺杆菌CagA基因和VacA基因的研究

发布时间：2018-06-22 19:57

本文选题：幽门螺杆菌 + CagA　；参考：《广西医科大学》2005年硕士论文

【摘要】：目的:研究广西南宁儿童幽门螺杆菌空泡毒素(VacA)基因和细胞毒素相关蛋白(CagA)基因的存在情况并分析各基因与胃十二指肠疾病的关系。方法:(1) 应用奥林巴斯GIF-XQ20 纤维胃镜或GIF-XQ230 电子胃镜对有上消化道症状的156 例儿童进行胃镜检查。(2)进行胃粘膜快速尿素酶检测、Warthin-Starry 银染色和HE 染色,采用PCR 方法测定胃粘膜中的Hpylori 尿素酶C 基因,并应用间接酶联免疫吸附法测定血清抗H.pylori-IgG,其中两项结果阳性诊断为H.pylori 感染。(3)对诊断H.pylori 感染的80 例儿童的胃粘膜提取DNA,采用PCR 法对CagA 基因及VacA 基因亚型进行分析。结果:(1)80 例患儿胃粘膜H.pylori 菌株应用CagA 基因的5 对引物分别扩增CagA 基因DNA400bp、280bp、349bp、298bp 和191bp 五个片段,CagA基因的检出率分别为43.75%、20%、55%、32.5%和61.2%,五者间差别有显著性。(P0.01)CagA 基因总检出率为83.7%,显著高于单一引物扩增的CagA 基因检出率。轻度炎症CagA 基因检出率为81%,中重度炎症CagA 基因检出率为86.8%,差异无显著性(P0.05)。(2)所有菌株均扩增出VacA 基因亚型,其中s 区中s1a 检出率为100%,s1b 和s2 未检出,m 区中m1 检出率为3.75%,m2 检出率为66.25%,另有13.75%为m1、m2 均检出,提示混合感染,而约16.25%的菌株不能用m1、m2 分型。剔除混合感染和不能用VacAm1、VacAm2 分型的病例,南宁儿童H.pyloriVacA 基因亚型有s1a/m1 和s1a/m2 两种组合,各亚型所占比例分别为3.75%、66.25%。(3)南宁儿童的幽门螺杆菌的优势基因型以CagA~+、VacAs1a/m2 为主。(4)CagA 基因及VacA 基因各亚型在慢性浅表性胃炎及消化性溃疡中的检出率无显著性差异(P0.05)。结论:(1)广西南宁儿童幽门螺杆菌以CagA~+基因为主,单对引物中,以扩增CagA 基因DNA191bp 片段的引物的CagA 阳性检出率最高;增加引物对数量,可提高CagA 基因的检出率。CagA 基因存在变异性和多态性。(2)CagA基因与胃粘膜炎症程度无关。(3)s1a/m2 为本地区儿童幽门螺杆菌的VacA 优势基因型,部分患儿同时感染多株不同VacA 基因型H.pylori。(4)CagA 基因及VacA 基因各亚型均不能作为本地区H.pylori 菌株毒力强弱的指标。
[Abstract]:Objective: to study the existence of Vaca gene and CagA gene in Nanning children and to analyze the relationship between Vaca gene and gastroduodenal disease. Methods: (1) 156 children with upper gastrointestinal symptoms were examined with Olympus GIF-XQ20 fibergastroscope or GIF-XQ230 electronic gastroscope. (2) Warthin-Starry silver staining and HE staining were detected by rapid urease staining in gastric mucosa. The Hpylori urease C gene in gastric mucosa was detected by PCR. Indirect enzyme-linked immunosorbent assay (Elisa) was used to detect anti-H.pylori-IgG, two of which were positive for H.pylori infection. (3) the gastric mucosal DNA was extracted from 80 children with H.pylori infection. The CagA gene and Vaca gene subtype were analyzed by PCR. Results: (1) five pairs of primers of CagA gene were used to amplify the CagA gene of H. pylori in gastric mucosa of 80 children. The detectable rates of CagA gene were 43.7575 ~ 205.55% and 61.2%, respectively. (P0.01) the total detection rate of CagA gene was 83.7, and the total detection rate of CagA gene was 83.7, which was significantly higher than that of the control group. (P0.01) the total detection rate of CagA gene was 83.7, and the detection rate of CagA gene was 83.70.The detection rate of CagA gene was 32.5% and 61.2%, respectively. (P0.01) the detection rate of CagA gene was 83.7. The detection rate of CagA gene was detected by single primer amplification. The detection rate of CagA gene was 81% in mild inflammation and 86.8% in moderate and severe inflammation (P0.05). (2). The detection rate of s1a in s1a region was 100 and that in s2 region was 3.75m2.The detection rate of M1 was 66.25m 2, and 13.75% was m1m2, indicating mixed infection, and about 16.25% strains could not be typed with m1m2. Excluding mixed infections and cases that could not be typed by VacAm1VacAm2, H.pylori Vaca gene subtypes in Nanning children were combined with s1a/m1 and s1a/m2. (3) the dominant genotype of Helicobacter pylori in Nanning children was CagA- VacAs1a / m2. (4) there was no significant difference in the detection rate of CagA gene and Vaca gene subtypes in chronic superficial gastritis and peptic ulcer (P0.05). Conclusion: (1) CagA~ gene is the dominant gene of Helicobacter pylori in Nanning, Guangxi. Among the single pairs of primers, the positive rate of CagA with the primers amplified by the 191bp fragment of CagA gene DNA was the highest, and the number of primer pairs was increased. (2) CagA gene was not related to the degree of gastric mucosal inflammation. (3) s1a/m2 was the dominant genotype of Helicobacter pylori in children. Some children were also infected with different Vaca genotypes H. pylori. (4) neither the CagA gene nor the Vaca gene subtypes could be used as an indicator of the virulence of H. pylori strains in our region.
【学位授予单位】：广西医科大学
【学位级别】：硕士
【学位授予年份】：2005
【分类号】：R346

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