Molecular detection of helicobacter pylori based on the presence of caga and vaca virulence and gyra antibiotic resistance genes in Baghdad patients

Helicobacter pylori (H. pylori) is a gram-negative bacterium that infects large numbers of people worldwide and infects the epithelium of the human stomach. This study was conducted in Baghdad (Yarmouk Teaching Hospital, Al Kindi Hospital, Medical City) and included 100 patients. All patients were diagnosed by the attending physician and patient samples were collected between September 2022 and February 2023. RNA extracted from the collected gastric biopsy specimens was converted into cDNA using reverse transcription polymerase chain reaction. cDNA was amplified by Real Time polymerase chain reaction (RT-qPCR) using specific primer sets for VagA, CagA virulence and GyrA antibiotic resistance genes to assess gene expression and their association with gastrointestinal disease development. 16SrRNA was used as the reference gene mRNA for quantification, the fold change result for the VagA gene was 1.9113, indicating up-regulation of VagA gene expression level. On the other hand, the fold change result for the CagA gene was 4.6144, indicating up-regulation of the gene expression level. In addition, the fold change result for the GyrA gene was 4.3664, indicating up-regulation of the GyrA gene expression level. Overall, the results showed upregulation of gene expression level for VagA, CagA and GyrA and no significant difference between the genes (p ≤0.05). In the present study, the difference between gene expression for VagA, CagA and GyrA genes was determined by Tukey test. These results indicate that RT-qPCR is a sensitive and specific method to detect the presence of H. pylori and the expression of H. pylori genes in human gastric tissue. Detection of H. pylori gene expression in vivo with this approach may contribute to improving the diagnosis and understanding the pathogenesis of H. pylori infections.