幽门螺杆菌cagA及vacA亚型与胃肠疾病的关系

Prevalence of cagA and vacA subtypes of Helicobacter pylori and their relations to gastrointestinal diseases

目的调查石家庄地区慢性胃病患者感染幽门螺杆菌(H·pylori)的细胞毒素相关基因(cagA)及空泡毒素基因(vacA)亚型的流行情况;探讨H·pylori cagA、vacA亚型与胃肠疾病的关系。方法自石家庄地区慢性胃病患者胃黏膜中分离得到55株H·pylori,抽提各菌株的总DNA,采用特定引物对各菌株cagA3′端、vacA信号序列(s)及中间序列(m)进行PCR检测。结果H·pylori cagA的阳性者占89·1%(49/55),其在慢性胃炎和消化性溃疡中的阳性率差异无显著性(χ2=0·376,P=0·540)。H·pylori vacA基因亚型有s1a/m2、s1a/m1b-m2、s1a/m1b三种组合,各亚型所占比例分别为90·4%(47/52)、5·8%(3/52)、3·8%(2/52),其中最常见的vacA亚型s1a/m2在慢性胃炎与消化性溃疡中的阳性率差异无显著性(χ2=0,P=1·000)结论石家庄地区慢性胃病患者感染的幽门螺杆菌以cagA+、vacA s1a/m2亚型占优势,未发现H·pylori cagA及vacA亚型与特定胃肠疾病间存在显著相关性。

Objective To investigate the prevalence of cytotoxin associated gene （cagA） and vacuolating cytotoxin gene （vacA） subtypes of Helicobacter pylori （H. pylori） in patients with upper gastrointestinal disease in Shijiazhuang area, and to assess the relationship between cagA, vacA subtypes and H. pylori related gastrointestinal disease. Methods Totally 55 H. pylori strains were isolated from patients with chronic gastrointestinal disease in Shijiazhuang area. Bacterial DNA from all these strains was extracted. The prevalence and genetic diversity in cagA 3＇ region, vacA signal sequence and middle - region alleles were studied by the technique of polymerase chain reaction （PCR） . Results In Shijiazhuang area, H. pylori cagA positive rate was 89. 1% （49/55） ; cagA positive rate was not significant ly different between chronic gastritis and peptic ulcer （X2 =0. 376, P =0. 540） . There were three vacA subtypes, including sla/ m2 [90. 4% （47/52） ], sla/mlb - m2 [5.8% （3/52） ] and sla/mlb [3. 8% （2/52） ] . The vacA sla/m2 subtype showed no significant difference between chronic gastritis and peptic ulcer （ X^2 = 0, P = 1. 000） . Conclusion cagA^＋ and vaeA sl a/m2 subtype of H. pylori are predominant in patients with upper gastrointestinal disease in Shijiazhuang area. There is no relationship between cagA, vacA subtypes and H. pylori related gastrointestinal disease.