Zhou Jianchang, Zhang Jianzhong, Xu Caipu, He Lihua
National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, 102206 Beijing, P.R. China 2Department of Gastroenterology, Southwest Hospital, Third Military Medical University, 400038 Chongqing, P.R. China.
J Med Microbiol. 2004 Mar;53(Pt 3):231-235. doi: 10.1099/jmm.0.05366-0.
Previous studies have implicated CagA [encoded by cytotoxin-associated gene A (cagA)] in Helicobacter pylori-associated gastroduodenal pathology and distinct subgenotypes of cagA may circulate in different pathological manifestations of cagA-positive H. pylori infection. To investigate cagA genotype and variants in Chinese H. pylori strains and explore their relationship with gastroduodenal diseases, the cagA status of 82 Chinese H. pylori strains was examined and variation in size of the 3' region of cagA in 71 of these strains was analysed by PCR. cagA was detected in 28 (100%) of 28 strains from peptic ulcer patients, two (100%) of two strains from gastric cancer patients, 32 (94.1%) of 34 strains from chronic gastritis patients and 17 (94.4%) of 18 strains from healthy volunteers. PCR products of the cagA 3' variable region were obtained from 71 (92.2%) of 77 Chinese H. pylori strains and could be classified into subgenotypes I, II and III, which gave PCR products of around 825, 900 and 950 bp, respectively. Subgenotype I cagA predominated in Chinese H. pylori strains (67/71), whereas subgenotype II cagA presented in two isolates from patients with chronic gastritis and subgenotype III presented in two isolates from healthy volunteers. Therefore, neither cagA nor its 3' region variants can be used as a sole marker for the presence of particular H. pylori-related gastroduodenal diseases in the Chinese population.
先前的研究表明，细胞毒素相关基因A（cagA）编码的CagA与幽门螺杆菌相关的胃十二指肠病变有关，并且cagA的不同亚型可能在cagA阳性幽门螺杆菌感染的不同病理表现中传播。为了研究中国幽门螺杆菌菌株中的cagA基因型和变异体，并探讨它们与胃十二指肠疾病的关系，检测了82株中国幽门螺杆菌菌株的cagA状态，并通过PCR分析了其中71株菌株cagA 3'区域大小的变异。在28例消化性溃疡患者的28株菌株中检测到cagA（100%），2例胃癌患者的2株菌株中检测到cagA（100%），34例慢性胃炎患者的32株菌株中检测到cagA（94.1%），18例健康志愿者的17株菌株中检测到cagA（94.4%）。从77株中国幽门螺杆菌菌株中的71株（92.2%）获得了cagA 3'可变区的PCR产物，这些产物可分为I、II和III亚型，其PCR产物大小分别约为825、900和950 bp。I型cagA在中国幽门螺杆菌菌株中占主导地位（67/71），而II型cagA出现在2例慢性胃炎患者的分离株中，III型cagA出现在2例健康志愿者的分离株中。因此，在中国人群中，cagA及其3'区域变异体均不能作为幽门螺杆菌相关特定胃十二指肠疾病存在的唯一标志物。
