GENOTYPING OF HELICOBACTER PYLORI GRAM-NEGATIVE PATHOGEN STRAINS BY CAGA, VACA AND ICEA VIRULENCE GENES: A MOLECULAR EPIDEMIOLOGICAL STUDY IN A CENTRAL ASIAN POPULATION

Background: Helicobacter pylori is a gram-negative, microaerophilic spiral bacterium colonising the gastric mucosa of approximately half of the world's population. Virulence gene polymorphisms—particularly in cagA (cytotoxin-associated gene A), vacA (vacuolating cytotoxin A), and iceA (induced by contact with epithelium)—determine the risk of progression from asymptomatic colonisation to peptic ulcer disease, gastric atrophy, and gastric adenocarcinoma. The distribution of these genotypes varies substantially among geographic populations, yet no systematic genotyping study has been conducted in Uzbekistan or the broader Central Asian region.背景：幽门螺杆菌（Helicobacter pylori）是一种革兰氏阴性、微需氧的螺旋形细菌，可定植于全球约半数人口的胃黏膜组织中。其毒力基因多态性——尤其是在cagA（细胞毒素相关基因A，cytotoxin-associated gene A）、vacA（空泡细胞毒素A，vacuolating cytotoxin A）以及iceA（上皮接触诱导基因，induced by contact with epithelium）——决定了从无症状定植进展为消化性溃疡、胃萎缩及胃腺癌的风险。这类基因型的地理分布在不同人群间存在显著差异，但目前乌兹别克斯坦乃至更广阔的中亚地区尚未开展过系统性的基因分型研究。