Analysis of virulence factors of Helicobacter pylori isolates from Vietnam

幽门螺杆菌被认为在胃癌的发病机制中起致病作用。本研究的目的是调查越南人幽门螺杆菌分离株中几种被认为是毒力或分子流行病学标志的遗传因素。采用聚合酶链式反应和测序法对103株越南来源的幽门螺杆菌菌株进行了cagA、VacA和cag右端连接基因分型。在位于cagA Glu-Pro-Ile-Tyr-Ala(EPIYA)重复区域上游的区域，发现了三种类型的缺失：39bp的缺失型、18bp的缺失型和非缺失型。所研究的大多数菌株(77%；80/103)有18个碱基缺失。在胃癌发病率较高的河内分离的菌株中，VacA M1基因明显比来自胡志明的菌株更常见。

Helicobacter pylori is recognized to play a causative role in the pathogenesis of gastric cancer. The aim of this study was to investigate several genetic factors regarded as virulence or molecular epidemiologic markers in H. pylori isolates from Vietnamese subjects. The cagA, vacA and cag right-end junction genotypes of 103 H. pylori strains from Vietnam were determined by PCR and sequencing. Three types of deletion in the region located upstream of the cagA Glu-Pro-Ile-Tyr-Ala (EPIYA) repeat region were identified : the 39-bp deletion type, the 18-bp deletion type, and the no-deletion type. The majority of strains studied (77% ; 80/103) had the 18-bp deletion. The vacA m1 genotype was significantly more common in strains isolated in Hanoi, where the incidence of gastric cancer is higher, than in strains from Ho Chi Minh.