Molecular Detection and Clinical Impact of Helicobacter pylori Virulence Genes in Gastric Diseases: A Study in Arequipa, Peru.

Background

Helicobacter pylori is a globally prevalent pathogen and a major contributor to gastric diseases, including chronic gastritis, peptic ulcer disease, and gastric cancer. This study investigates the prevalence, distribution, and clinical relevance of its key virulence genes, vacA and cagA, in a Peruvian patient cohort. Materials and

Methods

Fifty-one gastric biopsies were collected from patients with a presumptive diagnosis of H. pylori-induced gastritis at Hospital Carlos Alberto Seguín Escobedo in Arequipa, Peru, in March 2024. Two biopsies per patient-one from the antrum and one from the gastric body-were obtained during endoscopy. DNA extraction was performed using the Quick-DNA Fungal/Bacterial Kit (Zymo Research, USA). Molecular identification of H. pylori was conducted via PCR targeting the glmM gene, while the vacA and cagA virulence genes were detected using specific primers. Statistical analyses, including Pearson's chi-square and Mann-Whitney tests, were applied to assess associations between virulence gene presence and clinical or histopathological variables.

Results

Among the gastric biopsies, the vacA gene was detected in 37.3% of samples, while cagA was present in 17.6%. Statistical analysis revealed significant associations between vacA and specific clinical and endoscopic features, including erythematous gastropathy, nodular gastritis, and emetic syndrome, suggesting its localized role in disease pathogenesis. Additionally, the presence of cagA was significantly linked to moderate inflammatory intensity in gastric body biopsies, indicating its association with more severe histopathological outcomes. Chronic gastritis was the most common histopathological finding, with moderate intensity correlating strongly with the presence of virulence genes.

Conclusions

These findings highlight substantial regional variability in the distribution and pathogenicity of H. pylori genotypes. This study underscores the importance of incorporating molecular diagnostics into routine clinical practice to improve diagnostic accuracy and inform region-specific therapeutic strategies. This is particularly crucial in endemic regions like Peru, where unique environmental and genetic factors may influence infection dynamics and disease outcomes.