Background: Knowledge about a patients' microbiota profiles might give useful information in diagnosing, early relapse prediction and to distinguish responders from non-responders to treatment. Fecal calprotectin (FCal) is used as a marker in diagnosis and follow-up of patients with inflammatory bowel diseases (IBD). The IBD-Character project aims to analyse fecal microbiota profiles, microbial diversity and concentration of FCal in treatment naive newly diagnosed IBD patients, symptomatic non-IBD patients and healthy controls.
Methods: Patients were diagnosed according to international criteria, including endoscopic and histopathologic assessment. Patients with ulcerative colitis (UC) and Crohn's disease (CD) were classified based on anatomic distribution of inflammation according to the Montreal classification. Stool samples were stored at −80°C before microbiota 16S rRNA analysis (GA-map™ Dysbiosis Test) (1) of dysbiosis defined as non, mild or severe, and analysis of specific microbial taxa. High FCal (fCAL® ELISA, Bühlmann laboratories AG) was defined as >100 μg/g. Stool samples collected within 369 days prior to and within 14 days after diagnosis (= onset of treatment), and with no antibiotic treatment last two months, were included.
Results: Data on dysbiosis, bacteria profiles and FCal were available in 41 CD, 58 UC, 8 IBD-U patients, and 129 symptomatic non-IBD and 45 healthy controls. There was a relationship between FCal and dysbiosis in UC patients (p=0.0249, ANCOVA), which was not the case for CD and the control groups. Univariate analysis of the bacterial profiles among the Montreal classified subgroups identified bacteria that could differentiate between one or more of the subgroups, see Table 1. Increasing UC severity consistently yielded lower bacteria abundance, e.g. Bifidobacterium. For CD patients no significant relationship was found, however the strongest nonsignificant bacteria; Bifidobacterium showed increased abundance. (Kruskal-Wallis Rank Sum test, Benjamini & Hochberg p-value adjustment).
Conclusions: We have identified a relationship between gut microbiota profiles and UC diagnosed patients, and showed that specific bacteria profiles are able to stratify subgroups of UC. Relationship between FCal and dysbiosis was significant in the UC group only. The data demonstrate a diagnostic potential for a microbiota test in IBD .
 Casen et al. (2015), Deviations in human gut microbiota: a novel diagnostic test for determining dysbiosis in patients with IBS or IBD, Aliment Pharmacol Ther 42: 71–83