Department of Medical Bacteriology, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
Department of Internal Medicine, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
J Med Microbiol. 2012 Jan;61(Pt 1):23-30. doi: 10.1099/jmm.0.027052-0. Epub 2011 Sep 8.
Recently, dupA was reported as a new virulence factor in Helicobacter pylori, but its association with gastroduodenal disorders and its mode of action are still unclear. Here, an association of the dupA status with different disease groups was determined and a biological explanation for the observed associations was tested. In total, 216 H. pylori isolates were obtained from 232 presumed H. pylori-infected patients. A positive association was observed between the occurrence of duodenal ulcer (DU) and the presence of dupA [odds ratio (OR) 24.2; 95 % confidence interval (CI) 10.6-54.8]. In addition, an inverse association between the occurrence of gastric cancer (GC) [OR 0.16; 95 % CI 0.05-0.47] and gastric ulcer (GU) [OR 0.34; 95 % CI 0.16-0.68] with the presence of dupA was observed. A putative explanation for the observed associations might be a more corpus-located infection (pan-gastritis) by the dupA-positive strains due to their increased acid resistance. Indeed, a strong association between dupA-positive H. pylori isolated from gastritis patients and in vitro acid resistance was observed (P<0.05). The observed higher acid resistance of the dupA-positive strains suggests that these strains are adapted to a stomach with high gastric acid output. This may in part explain the observed associations, as an increased gastric acid output is thought to be typical for an antrum-predominant H. pylori infection and, whilst this is associated with an increased risk of DU formation, it also decreases the risk for the genesis of GUs and GC.
最近，dupA 被报道为幽门螺杆菌的一个新的毒力因子，但它与胃十二指肠疾病的关系及其作用模式仍不清楚。在这里，我们确定了 dupA 状态与不同疾病组的关联，并测试了观察到的关联的生物学解释。总共从 232 名疑似幽门螺杆菌感染的患者中获得了 216 株幽门螺杆菌分离株。十二指肠溃疡（DU）的发生与 dupA 的存在呈正相关[比值比（OR）24.2；95%置信区间（CI）10.6-54.8]。此外，还观察到胃癌（GC）[OR 0.16；95%CI 0.05-0.47]和胃溃疡（GU）[OR 0.34；95%CI 0.16-0.68]的发生与 dupA 的存在呈负相关。观察到的关联的一个可能的解释可能是由于耐酸能力的提高，dupA 阳性菌株更易引起胃体感染（全胃炎）。事实上，我们观察到胃炎患者分离的dupA 阳性幽门螺杆菌与体外耐酸能力之间存在很强的关联（P<0.05）。dupA 阳性菌株较高的耐酸能力表明这些菌株适应了胃酸分泌较高的胃。这可能部分解释了观察到的关联，因为胃酸分泌增加被认为是一种典型的以胃窦为主的幽门螺杆菌感染，而这与 DU 形成的风险增加有关，但也降低了 GU 和 GC 发生的风险。
