Phylogenic analysis of Helicobacter pylori detected in Al-Najaf province, Iraq

Background: Helicobacter pylori (H. pylori) remains a major global health concern due to its well-established role in various gastrointestinal disorders, including gastric cancer. The global prevalence of H. pylori infection varies widely, ranging from 24.4% to 79.1%. Objective: This study aimed to compare the prevalence of H. pylori infection between symptomatic and asymptomatic individuals in Al-Najaf province, Iraq, in relation to demographic factors. Additionally, the study sought to perform phylogenetic analysis of selected local H. pylori isolates. Methodology: A cross-sectional study was conducted on 180 individuals: 90 patients presenting with gastrointestinal symptoms and 90 asymptomatic, apparently healthy controls. Demographic data were collected from all participants. Fresh stool samples were analyzed for current H. pylori infection using polymerase chain reaction (PCR), and venous blood samples were tested for IgG antibodies using enzyme-linked immunosorbent assay (ELISA). DNA from 10 PCR-positive samples was sequenced and analyzed phylogenetically using MEGA-11 software and the NCBI-MSA Viewer. Results: H. pylori was detected by PCR in 31.1% (56/180) of individuals. Adults exhibited significantly higher infection rates compared to children and young adults in both study groups (P < 0.05). Male participants had significantly higher odds ratios and relative risk values for H. pylori infection than females in both symptomatic and asymptomatic groups (P < 0.0001). Phylogenetic analysis revealed a high degree of similarity (96.93%–98.22%) between local isolates and the Iranian reference strain (NCBI accession no. MT160753.1). Conclusion: Older age and male gender are associated with increased risk of H. pylori infection in Al-Najaf province. Phylogenetic analysis indicates a close genetic relationship between local H. pylori strains and those from neighboring regions, suggesting potential implications for understanding human migration patterns.