Esophageal Microbiome in Eosinophilic Esophagitis

Abstract

ObjectiveThe microbiome has been implicated in the pathogenesis of a number of allergic and inflammatory diseases. The mucosa affected by eosinophilic esophagitis (EoE) is composed of a stratified squamous epithelia and contains intraepithelial eosinophils. To date, no studies have identified the esophageal microbiome in patients with EoE or the impact of treatment on these organisms. The aim of this study was to identify the esophageal microbiome in EoE and determine whether treatments change this profile. We hypothesized that clinically relevant alterations in bacterial populations are present in different forms of esophagitis.DesignIn this prospective study, secretions from the esophageal mucosa were collected from children and adults with EoE, Gastroesophageal Reflux Disease (GERD) and normal mucosa using the Esophageal String Test (EST). Bacterial load was determined using quantitative PCR. Bacterial communities, determined by 16S rRNA gene amplification and 454 pyrosequencing, were compared between health and disease.ResultsSamples from a total of 70 children and adult subjects were examined. Bacterial load was increased in both EoE and GERD relative to normal subjects. In subjects with EoE, load was increased regardless of treatment status or degree of mucosal eosinophilia compared with normal. Haemophilus was significantly increased in untreated EoE subjects as compared with normal subjects. Streptococcus was decreased in GERD subjects on proton pump inhibition as compared with normal subjects.ConclusionsDiseases associated with mucosal eosinophilia are characterized by a different microbiome from that found in the normal mucosa. Microbiota may contribute to esophageal inflammation in EoE and GERD.

Eosinophilic esophagitis is characterized by a non-IgE-mediated food hypersensitivity

“…Microbiota research aims at elucidating their role in initiating and perpetuating inflammation and, conversely, the effect of diseases and treatment procedures on the microbiota. Compared to healthy controls, the bacterial load of the esophagus is increased in patients with EoE regardless of treatment and disease activity, with a relative abundance of gram-negative bacteria in active EoE (68,69). Recently, IgE sensitization to Candida albicans has been reported in pediatric and adult patients with EoE (14,70).…”

Novel immunologic mechanisms in eosinophilic esophagitis

“…These exposures impact the intestinal and potentially the esophageal microbiome, both of which have recently come under intensive study. Alterations in the esophageal microbiome have been observed in EoE, including increased total bacterial load and increased levels of proteobacteria [10,11]. Interestingly, preclinical studies in mice suggest that specific probiotics alleviate experimental EoE [12].…”

The Immunologic Mechanisms of Eosinophilic Esophagitis

“…It is known that patients with EoE have dysregulated commensal bacterial populations compared to healthy controls [183]. Additionally, the total bacterial load is increased in patients with EoE compared to healthy subjects [184]. With regards to specific bacteria, Haemophilus is present in a higher proportion in subjects with untreated EoE [184].…”