@entity7808 ( @entity7808 ) is the most common disease affecting oral mucosae. Etiology is unknown, but several factors have been implicated, all of which influence the composition of microbiota residing on oral mucosae, which in turn modulates immunity and thereby affects disease progression. Although no individual pathogens have been conclusively shown to be causative agents of @entity7808 , imbalanced composition of the oral microbiota may play a key role. In this study, we sought to determine composition profiles of bacterial microbiota in the oral mucosa associated with @entity7808 . Using high-throughput 16S rRNA gene sequencing, we characterized the most abundant bacterial populations residing on healthy and ulcerated mucosae in @entity1 with @entity7808 (recruited using highly stringent criteria) and no associated medical conditions; we also compared these to the bacterial microbiota of healthy controls (HCs). Phylum-level diversity comparisons revealed decreased Firmicutes and increased Proteobacteria in ulcerated sites, as compared with healthy sites in @entity7808 @entity1 , and no differences between @entity7808 @entity1 with healthy sites and HCs. Genus-level analysis demonstrated higher abundance of total Bacteroidales in @entity7808 @entity1 with healthy sites over HCs. Porphyromonadaceae comprising species associated with @entity2520 predominated in ulcerated sites over HCs, while no quantitative differences of these families were observed between healthy sites in @entity7808 @entity1 and HCs. Streptococcaceae comprising species associated with oral health predominated in HCs over ulcerated sites but not in HCs over healthy sites in @entity7808 @entity1 . This study demonstrates that mucosal microbiome changes in @entity1 with idiopathic @entity7808 --namely, increased Bacteroidales species in mucosae of @entity7808 @entity1 not affected by active ulceration. While these changes suggest a microbial role in initiation of @entity7808 , this study does not provide data on causality. Within this limitation, the study contributes to the understanding of the potential role of mucosal microbiome changes in oral @entity3137 .

Mucosal microbiome in XXXX with recurrent aphthous stomatitis.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity2520 :: ('MESH:D010510', 'Disease') :: ['periodontal disease and Veillonellaceae'] @entity3137 :: ('MESH:D009059', 'Disease') :: ['mucosal disease'] @entity7808 :: ('MESH:C538145', 'Disease') :: ['Recurrent aphthous stomatitis', 'RAS']
@entity1 :: (9606,Species) :: ['patients']
