The Esophageal Microbiota in Esophageal Health and Disease

The esophagus, traditionally viewed as a sterile conduit, is now recognized as a dynamic habitat for diverse microbial communities. The emerging evidence suggests that the esophageal microbiota plays an important role in maintaining esophageal health and contributing to disease. The aim of this systematic review was to synthesize the current knowledge on the esophageal microbiota composition, its variation between healthy individuals and those with esophageal diseases, and the potential mechanisms through which these microorganisms influence esophageal pathology. A systematic literature search was conducted using multiple databases, including PubMed, Scopus, and Web of Science, to identify relevant studies published up to July 2024. The inclusion criteria encompassed original research articles that used molecular techniques to characterize the esophageal microbiota in human subjects, comparing healthy individuals with patients affected by esophageal conditions such as gastroesophageal reflux disease (GERD), Barrett’s esophagus, eosinophilic esophagitis, and esophageal cancer. The primary outcomes were the composition and diversity of the esophageal microbiota, and the secondary outcomes included the correlations between microbial profiles and disease states. The esophageal microbiota of healthy individuals was dominated by Gram-positive bacteria, particularly Streptococcus. Conversely, the esophageal microbiota is considerably altered in disease states, with decreased microbial diversity and specific microbial signatures associated with these conditions, which may serve as biomarkers for disease progression and as targets for therapeutic intervention. However, the heterogeneous study designs, populations, and analytical methods underscore the need for standardized approaches in future research. Understanding the esophageal microbiota’s role in health and disease could guide microbiota-based diagnostics and treatments, offering novel avenues for managing esophageal conditions.