Genotyping of Helicobacter pylori Virulence Genes cagA and vacA: Regional and National Study

Abstract

Helicobacter pylori (H. pylori) plays a crucial role in the pathogenesis of gastritis, peptic ulcer, and gastric cancer. The presence of pathogenicity islands (PAI) genes contributes to the pathogenesis of many gastrointestinal disorders. Cytotoxin-associated gene A (cagA) and vacuolating cytotoxin gene (vacA) are the most known virulence genes in H. pylori. So, our aim was to study H. pylori virulence genes’ role in gastric disorders pathogenesis. Our study included 150 adult patients who suffered dyspeptic symptoms and were referred to the GIT endoscopy unit. Gastric biopsies were attained for rapid urease test (RUT) and histopathological examination, and multiplex PCR technique for detection of virulence genes was performed. It was found that 100 specimens were (RUT) positive, of which sixty samples (60%) were PCR positive for H. pylori ureC gene. The vacA and cagA genes were identified in 61.6% and 53% of H. pylori strains, respectively. Only 5 cases were vacA-positive and cagA-negative. The most virulent vacA s1 allele existed in 56.6% of cases. Out of the 60 H. pylori strains, 66% had at least one virulence gene and 34% did not show any virulence gene. H. pylori infection showed significant increase with age. H. pylori are prevalent amid dyspeptic patients in our region. The main genotype combinations were vacA+/cagA+ of s1m1 genotype and they were frequently associated with peptic ulcer diseases, gastritis, and gastroesophageal reflux disease.