New insights in Ulcerative Colitis Associated Gut Microbiota in South American Population: Akkermansia and Collinsella, two distinctive genera found in Argentine subjects.

ROSSO, AYELÉN DAIANA; MILANO, CLAUDIA; AGUILERA, PABLO; CEREZO, JIMENA; BELFORTE, FIORELLA S.; QUESADA, SOFÍA; PENAS-STEINHARDT, ALBERTO

Congreso; LXVI Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica; 2020

Ulcerative colitis (UC) is the most common form of intestinal inflammation, which is believed to be the result of a deregulated immune system response to commensal microbiota in a genetically susceptible host. In the present study we aim to describe the gut microbiota of patients with UC in comparison with non-UC controls. We evaluated 46 individuals, 26 non-UC controls and 20 UC patients, from the metropolitan area of Buenos Aires (BA), Argentina. The hypervariable regions V3-V4 of the bacterial 16SR gene were sequenced using a MiSeq platform and sequences were analyzed using the QIIME2 environment. In addition, we looked for differential functional pathways using PICRUSt and compared the performance of three machine learning models to discriminate the studied individuals, using taxa and functional annotations. We found no significant differences in gut microbiota richness or evenness between UC patients and non-UC controls (alpha diversity). Remarcably, beta diversity showed significant differences. At the phylum level, Verrucomicrobia was overrepresented in controls while Actinobacteria was distinctive of UC patients; At the genus level Bacteroides and Akkermancia were significantly more abundant among controls while Eubacterium and Collinsella in UC patients. In addition, our results showed that carbohydrates metabolism was preponderant in UC patients, not observing a distinctive biochemical pathway for the healthy non-UC controls. Finally, in order to define a robust classifying method in our population, we evaluated the capability of three machine learning random forest models to classify individuals. Our results reinforced the idea of functional compensation in microbiome communities, as models that used KEGG orthologs annotations had better capabilities than taxonomy to distinguish UC patients. Our study provides new knowledge on the differences and similarities of the gut microbiota of UC patients as compared to non-UC controls of our population.