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目的:幽门螺杆菌(Helicobacter pylori,H.pylori)产生的细胞毒素相关蛋白A(cytotoxin associated antigen A,Cag A)羧基末端的EPIYA序列与胃十二指肠疾病的关系一直存在争议。本研究采集大量H.pylori高感染率同时也是胃癌高发病率的中国重庆地区的病例,通过检测患者感染的H.pylori Cag A羧基末端EPIYA基序的多态性,探讨EPIYA基序与临床胃十二指肠疾病发生的潜在关系。方法:收集消化不良患者的胃黏膜标本分离培养H.pylori,提取细菌基因组DNA,PCR扩增Cag A基因的3’端区域并分型,根据分型结果随机抽样测序确认,结合分离出H.pylori患者的病历资料,分析EPIYA类型与胃十二指肠疾病之间的关系。结果:292(97.3%)株为Cag A阳性,但Cag A阳性与胃十二指肠疾病病型无关(P>0.5)。19例(6.51%)为不同EPIYA类型菌株混合感染,胃癌病例中混合感染出现的概率明显高于NUD者(OR=4.46,95%CI=1.17~17.03)。单一菌株感染者273株(93.49%),其中EPIYA-ABD型254株(93.04%),EPIYA分型和胃十二指肠疾病的临床病型之间无显著性差异。另外,基因测序标本中发现8株EPIYA-B基序的核苷酸序列存在基因突变。结论:该研究中EPIYA-ABD型占H.pylori感染者的绝大多数,但Cag A阳性和EPIYA-ABD型均与H.pylori感染引起的胃十二指肠疾病无关;然而胃癌患者中混合感染出现的概率明显高于非溃疡性胃炎患者。
OBJECTIVE: The relationship between the carboxy-terminal EPIYA sequence of cytotoxin-associated antigen A (Cag A) and gastroduodenal diseases caused by Helicobacter pylori (H. pylori) has been controversial. This study collected a large number of high H.pylori infection is also a high incidence of gastric cancer in Chongqing, China by detecting the infection of patients with H.pylori Cag A carboxyl-terminal EPIYA motif polymorphism, EPIYA motif and clinical stomach Potential for the occurrence of duodenal diseases. Methods: Gastric mucosa specimens from patients with dyspepsia were collected for H.pylori isolation and bacterial genomic DNA isolation. The 3 ’end region of Cag A gene was amplified by PCR and sequenced. pylori patients with medical records, analysis of EPIYA type and the relationship between gastroduodenal diseases. Results: 292 (97.3%) strains were positive for Cag A, but Cag A positive was not associated with gastroduodenal disease (P> 0.5). 19 cases (6.51%) were mixed infection with different strains of EPIYA. The probability of mixed infection in gastric cancer cases was significantly higher than that in NUD patients (OR = 4.46, 95% CI = 1.17-17.03). There were 273 strains (93.49%) infected with a single strain, of which 254 strains (93.04%) were EPIYA-ABD type, and there was no significant difference in the clinical type of EPIYA type and gastroduodenal disease. In addition, there were gene mutations in the nucleotide sequence of 8 EPIYA-B motifs found in the gene sequencing samples. CONCLUSIONS: The EPIYA-ABD type accounted for the vast majority of H.pylori infections in this study, but both CagA-positive and EPIYA-ABD-type were unrelated to gastroduodenal diseases caused by H.pylori infection; however, patients with gastric cancer had mixed The probability of infection is significantly higher than non-ulcer gastritis patients.