Genotyping of Helicobacter pylori Strains Isolated from Patients with Gastric Ulcer and Non Ulcer Disease using RFLP-PCR of ureAB, vacA, cagA Genes

Introduction & Different studies show that the reasons for clinically diverse outcomes of infections caused by H. pylori may include host and environmental factors as well as differences in the prevalence or expression of bacterial virulence factors. The aim of this study was to study the distribution of different genotypes of major virulence factors cagA, vacA and ureAB among H. pylori strains isolated from patients with gastric ulcer (ulcerative disease) and patients with gastritis (non ulcerative disease). In this cross sectional study 65 H. pylori strains, 30 from patients with gastric ulcer and 35 from patients with non ulcerative gastritis disease were investigated by RFLP-PCR. The prevalence of vacA-positive strains in ulcerative patients was significantly more than that in non ulcerative patients (P<0.05). RFLP analysis revealed two different patterns for cagA gene. The prevalence of pattern β with three bands was significantly higher in both groups of patients. Enzymatic digestion resulted in a strictly homogeneous pattern for 83.33% of the vacA+ strains isolated from the patients with ulcer. This pattern was significantly associated with ulcerative status (P<0.05). ureAB polymorphism analysis revealed 10 distinguishable DNA banding patterns among them the pattern named ureAB 5a was the most prevalent (47.61%) in all isolates. No association between a specific DNA pattern and clinical disease was observed for cagA and ureAB (P>0.05). It seems that in the patients under our study the presence of cagA gene may not necessarily be a risk factor for ulcer disease, while a homologous genotype of vacA appears to be associated with an increase risk of ulcer development. Lastly, despite the existence of a high degree of genomic variability within ureAB, conserved DNA banding profiles are distributed in our areas.