EXAMINING THE MICROBIOME COMPOSITION IN PATIENTS WITH GASTROESOPHAGEAL REFLUX DISEASE: A SYSTEMATIC REVIEW

Abstract

Background: Gastroesophageal reflux disease (GERD) is a multifactorial disorder characterized by the reflux of gastric contents into the esophagus, leading to mucosal injury and chronic inflammation. Recent evidence implicates microbial dysbiosis—both local and systemic—in its pathogenesis. This systematic review synthesizes current findings on the composition, diversity, and functional implications of the microbiome in patients with GERD. Methods: Following PRISMA 2020 guidelines, eleven peer-reviewed studies published between 2015 and 2025 were systematically reviewed. Eligible studies included those examining esophageal, gastric, intestinal, oral, and salivary microbiota profiles in GERD patients compared with healthy controls. Data extraction focused on microbial diversity, dominant taxa, associated metabolic pathways, and host inflammatory responses. Results: Most studies demonstrated decreased Streptococcus abundance and enrichment of Prevotella, Veillonella, and Leptotrichia in GERD and Barrett’s esophagus patients. Dysbiosis was consistently associated with altered metabolic pathways, notably those involving arachidonic acid, glutathione, and ABC transporters. PPI therapy, small intestinal bacterial overgrowth, and psychological stress were identified as key modulators of microbial imbalance. Mendelian randomization studies further supported a genetic causal relationship between gut microbiota and GERD risk. Conclusion: Microbial dysbiosis appears central to GERD pathogenesis, influencing mucosal integrity, inflammation, and symptom persistence. Future studies should adopt longitudinal multi-omics approaches to clarify causal mechanisms and evaluate microbiota-targeted interventions for prevention and therapy.