P1226 Determination of oral and gut mucosal microbiome profiles of patients with treatment-naïve ulcerative colitis

Abstract Background The oral microbiome in ulcerative colitis (UC) patients and its role in the pathogenesis of the disease are still poorly understood. Although there are studies investigating the composition of oral microbiome in UC, there are no studies on concomitant analyses of oral and colonic mucosal samples in treatment-naïve patients. In this study, the oral and mucosal gut microbiome of UC patients and oral microbiota of healthy individuals (HC) were compared. Methods Sixty patients with newly-diagnosed active (mild-moderate severity) UC patients (n=30) and HC (n=30) were included in the study. Dietary habits were stable in the last three months of participants (checked by dietary recall questionnaires) and co-morbidities affecting microbiota profiles were excluded. Multiple colonic mucosa biopsies were obtained from inflamed areas before treatment in UC group. Simultaneously, subgingival plaque samples were analyzed. All samples were identified through next-generation DNA sequencing analysis, evaluated using bioinformatic tests. Results The potential signature bacterial species associated with UC were determined by examining of both gut and oral microbiomes. According to the Microbiome Lefse analysis, Prevotella copri emerged as the prominent common species in the colonic mucosal and subgingival plaque biopsies of UC group. Oral microbiome comparison between UC and HC patients revealed increased Haemophilus parainfluenza and Corynebacterium durum species and decreased F. prastnutzii and Akkermansia muciniphilia in the UC group (p