Sacred Heart University, Bauru, São Paulo State, Brazil.
J Venom Anim Toxins Incl Trop Dis. 2014 Jan 23;20(1):1. doi: 10.1186/1678-9199-20-1.
Only a few Helicobacter pylori-infected individuals develop severe gastric diseases and virulence factors of H. pylori appear to be involved in such clinical outcomes. Duodenal ulcer promoting gene A (dupA) is a novel virulence factor of Helicobacter pylori that is associated with duodenal ulcer development and reduced risk for gastric carcinoma in some populations. The aims of the present study were to determine the presence of dupA gene and evaluate the association among dupA and other virulence factors including cagA and vacA in Brazilian patients. Gastric biopsies were obtained from 205 dyspeptic patients (100 children and 105 adults). DNA was extracted and analyzed for the presence of H. pylori and its virulence factors using the polymerase chain reaction method.
Patients with gastritis tested positive for H. pylori more frequently. The dupA gene was detected in 41.5% of them (85/205); cagA gene was found in 98 isolates (47.8%) and vacA genotype s1/m1 in 50.2%, s1/m2 in 8.3%, s2/m2 in 36.6%, s2/m1 in 0.5% and s1/s2/m1/m2 in 4.4%. We also verified a significant association between cagA and dupA genes [p = 0.0003, relative risk (RR) 1.73 and confidence interval [CI] = 1.3-2.3]. The genotypes s1/m1 were also associated with dupA gene (p = 0.0001, RR: 1.72 and CI: 1.3-2.2). The same associations were found when analyzing pediatric and adult groups of patients individually.
Ours results suggest that dupA is highly frequent in Brazilian patients and is associated with cagA gene and vacA s1/m1 genotype, and it may be considered an important virulence factor in the development of gastric diseases in adults or children.
只有少数幽门螺杆菌感染个体发展为严重的胃部疾病，而幽门螺杆菌的毒力因子似乎与这些临床结局有关。十二指肠溃疡促进基因 A（dupA）是一种新型的幽门螺杆菌毒力因子，与某些人群的十二指肠溃疡发展和胃癌风险降低有关。本研究的目的是确定 dupA 基因的存在，并评估其与其他毒力因子（包括 cagA 和 vacA）之间的关联在巴西患者中的情况。从 205 例消化不良患者（100 例儿童和 105 例成人）中获取胃活检组织。使用聚合酶链反应方法提取和分析 DNA，以检测 H. pylori 及其毒力因子的存在。
患有胃炎的患者 H. pylori 检测呈阳性的频率更高。在他们中，dupA 基因的检出率为 41.5%（85/205）；cagA 基因在 98 株菌中被发现（47.8%），vacA 基因型 s1/m1 为 50.2%，s1/m2 为 8.3%，s2/m2 为 36.6%，s2/m1 为 0.5%，s1/s2/m1/m2 为 4.4%。我们还验证了 cagA 和 dupA 基因之间存在显著关联[p=0.0003，相对风险（RR）1.73，置信区间（CI）=1.3-2.3]。s1/m1 基因型也与 dupA 基因相关（p=0.0001，RR：1.72，CI：1.3-2.2）。在分别分析儿科和成人患者组时，也发现了相同的关联。
我们的结果表明，dupA 在巴西患者中高度频繁，与 cagA 基因和 vacA s1/m1 基因型相关，它可能是成人或儿童胃部疾病发展的一个重要毒力因子。
