Atherton J C
Department of Medicine, University of Nottingham, UK.
Br Med Bull. 1998;54(1):105-20. doi: 10.1093/oxfordjournals.bmb.a011662.
Among people infected with Helicobacter pylori, the virulence of the infecting strain is a major determinant of who develops disease. Strains producing vacuolating cytotoxin activity are more commonly isolated from people with peptic ulcers than without. The gene encoding the toxin, vacA, varies between strains, especially in its signal sequence and mid regions. vacA genotype influences cytotoxin activity, and signal sequence type correlates closely with peptic ulceration. Infection with strains possessing cagA (cytotoxin associated gene A) is more common among people with peptic ulceration or gastric adenocarcinoma than without. cagA is a marker for the cag pathogenicity island, which includes genes necessary for the enhanced inflammation induced by pathogenic strains. Serological detection of infection with cagA+ strains is at present the best practical test for virulence. However, before a strategy of screening and selective treatment can be considered, it is important to assess whether cagA- strains are entirely non-pathogenic.
在感染幽门螺杆菌的人群中，感染菌株的毒力是决定谁会发病的主要因素。产生空泡毒素活性的菌株在患有消化性溃疡的人群中比未患消化性溃疡的人群中更常见。编码该毒素的基因vacA在不同菌株间存在差异，尤其是在其信号序列和中间区域。vacA基因型影响细胞毒素活性，信号序列类型与消化性溃疡密切相关。携带cagA（细胞毒素相关基因A）的菌株感染在患有消化性溃疡或胃腺癌的人群中比未患这些疾病的人群中更常见。cagA是cag致病岛的标志物，cag致病岛包含致病菌株诱导增强炎症所需的基因。目前，血清学检测cagA+菌株感染是评估毒力的最佳实用检测方法。然而，在考虑筛查和选择性治疗策略之前，评估cagA-菌株是否完全无致病性很重要。
