Fecal microbiota is related with activity and remission phases of Inflammatory Bowel Disease, and healthy condition in Mexican patients

Inflammatory bowel disease (IBD) is defined as a group of chronic inflammatory disorders of unknown cause that affect the gastrointestinal tract and encompasses two diseases: Crohn's disease (CD) and ulcerative colitis (UC), which are characterized by chronic gastrointestinal inflammatory disease manifested by periods of remission and exacerbation, with an abnormal immune response to the components of the gut microbiota. Gut microbiota dysbiosis has been proposed to influence pathophysiology and clinical response in IBD. Aim: To evaluate whether gut microbiota is related to the active and remission phases of IBD versus healthy subjects, as well as to explore its role as biomarker. Methods: Cross-sectional study. Fecal samples from 20 patients with IBD (clinically characterized as active (n=10), remission (n=10), and healthy subjects (n=10)) were collected. After fecal DNA extraction, the 16S rRNA gene was amplified and sequenced (Illumina MiSeq platform), operational taxonomic units were analyzed with the QIIME software. Alpha and beta diversities were compared between clinical settings, and diagnostic performances were evaluated. Results: Gut microbiota composition revealed higher abundance of the phyla Proteobacteria and Fusobacteria in active IBD, as compared with remission IBD and healthy subjects. Likewise, marked abundance of the genus Bilophila and Fusobacteria was present in active IBD, as compared with the other groups; whereas higher abundance of Faecalibacterium characterized both, remission IBD and healthy subjects. Microbial community's richness (Index of Chao) and diversity (Index of Shannon and Simpson) in active IBD were significantly different from the other groups, which was reflected at their diagnostic ability, particularly for Bilophila and Fusobacterium to discriminate active IBD vs. remission IBD and healthy subjects. Conclusion: Our study characterized gut microbiota dysbiosis in relation to IBD in a Mexican study population. The genus Bilophila and Fusobacterium were identified as useful, non-invasive biomarkers with the ability to discriminate clinical-therapeutic phases of IBD.