Segmental analysis of esophageal and gastric fundus microbiome diversity in reflux esophagitis

Microbiome dysbiosis in reflux esophagitis has been extensively studied. However, limited research has examined microbiota across different segments of the upper gastrointestinal tract in reflux esophagitis. In this study, we investigated microbial alterations in three esophageal segments (upper, middle, and lower) and the gastric fundus of reflux esophagitis patients and healthy controls. In healthy individuals, the gastric fundus harbored a microbiota composition distinct from that of all esophageal segments. In reflux esophagitis patients, the regional distinction was absent, with similar microbial profiles across the esophagus and gastric fundus. At the genus level, notable compositional shifts were observed between the healthy and reflux esophagitis groups. In controls, the microbiota was dominated by Streptococcus (24.45%), Achromobacter (14.14%), and Prevotella (6.58%). In reflux esophagitis patients, Streptococcus (20.03%) remained the dominant genus, followed by an increased abundance of Prevotella (9.38%). Multilevel LEfSe analysis identified Prevotella as a potential microbial marker of reflux esophagitis. These findings indicate that reflux esophagitis is associated with widespread microbiota alterations extending throughout the esophageal tract and the gastric fundus.