The significance of the esophageal microbiota in pediatric esophageal eosinophilia (EE) was little understood. For a study, researchers sought to examine the esophageal microbiota in pediatric patients with and without EE. In the prospective investigation, 41 children had esophagus mucosal biopsies taken. There were 22 children with normal esophageal mucosal biopsies (“healthy”), six with reflux esophagitis (RE), and four with proton pump inhibitor (PPi)-responsive esophageal eosinophilia (PPi-REE), and nine with eosinophilic esophagitis (EoE). The makeup of the microbiome was determined using 16S rRNA gene sequencing. The healthy, RE, PPi-REE, and EoE groups had median (range) ages of 10 (1.5–18), 6 (2–15), 6.5 (5–15), and 9 (1.5–17), respectively.

The most common bacterial phyla were Actinobacteria, Bacteroidetes, Firmicutes, Fusobacteria, and Proteobacteria. The classes Epsilonproteobacteria, Betaproteobacteria, Flavobacteria, Fusobacteria, and Sphingobacteria, were all underrepresented. The Vibrionales were more prevalent in the healthy and EoE groups but less in the RE and PPi-REE groups. The genera Streptococcus, Rahnella, and Leptotrichia accounted for 29.65% of the variation in the data, whereas Microbacterium, Prevotella, and Vibrio explained 10.86% of the variation in the data. When compared to the other groups, the healthy group had a greater diversity and richness score, although this was not statistically significant. The juvenile esophagus possesses an extensive and varied microbiome in both healthy and sick stages. When compared to the other groups, the healthy group had a higher, but not substantially different, diversity and richness index.