Characterization of Gastric Ulcer Associated Bacteria and Their Virulence Genes by PCR

Abstract

The bacterium that is associated with the development of various conditions of gastric illness is Helicobacter pylori. It is resistant to many treatments because it tolerates acidic environments. Over time, when it does not respond to treatment, it causes gastric ulcers, atrophic gastritis, and ultimately stomach cancer. The present study focuses on the isolate and identify samples of stool collected from 200 sick persons presenting a clinical picture of gastric ulcer symptoms. These samples were subjected to bacteriological culture to isolate Helicobacter pylori. Following the initial isolation, molecular identification by PCR for the bacterium. This combined approach allowed for accurate detection and verification of the pathogen in symptomatic individuals, as well as detecting the genes responsible for the virulence caused by these bacteria, such as cagA, vacA, and ureC, through Gram staining, biochemical assays, and PCR tests targeting the cagA, vacA, and ureC genes. Of the 200 stool samples, 125 showed positive results for H. pylori colonies in males and 75 in females on agar plates, which were confirmed by Gram staining and biochemical assays. Genomic DNA of Helicobacter pylori was taken based on the cetyl trimethyl ammonium bromide protocol (CTAB). Nested PCR was performed using specific primers (HP-F and HP-R), (cagA-F and cagA-R), (vacAs1 and vacAs2), (vacAm1 and vacAm2), and (VacAF and VacAR) sets for the ureC gene, as well as the virulence genes cagA and vacA, which were targeted for molecular detection. The presence and molecular weights of these genes were confirmed by analyzing DNA bands obtained through gel electrophoresis following PCR amplification. The PCR results demonstrated isolates with H. pylori contain genes (cagA, vacA, & ureC). The top incidence of H. pylori infection, alongside detection of these virulence factors, was closely associated with the development of peptic ulcer disease.