Nasal bacterial composition in Gastroesophageal reflux disease (GERD) is associated with decreased Clostridia in subjects with chronic rhinosinusitis (CRS). human nasopharyngeal metagenome

Gastro-esophageal reflux disease(GERD) is a common condition that is linkedto increased sinusitis symptoms and a younger onset of CRS. The previous microbiome studies in CRS have shown changes in the nasal microbiome in the context of CRS but there is no data on the effect of GERD on the nasal microbiome. We have assessed the nasal microbiota composition of CRS cases with and without GERD and found that CRS patients with comorbid GERD have a decrease in multiple microbial taxa, stemming from classes Clostridia and Bacteroidia. Clostridia have been shown to regulate innate lymphoid cell function and intestinal epithelial permeability, and regulate the allergic response. Furthermore, Clostridia are important in maintaining a healthy metabolism and controlling pathogenic invasion in mucosa. Therefore the extra insult caused by decreased Clostridia in the setting of GERD may promote uncontrolled inflammation and result in the previously reported more severe CRS in GERD+CRS cases.