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* = Presenting author

P724 Gut microbiota molecular spectrum in healthy controls, diverticular disease, IBS and IBD patients: Time for microbial marker of gastrointestinal disorders?

F. Scaldaferri1, L. Lopetuso*1, S. Pecere1, V. Petito1, E. Schiavoni1, V. Gerardi1, L. Laterza1, M.T. Pistone1, D. D'Ambrosio1, O. Ricca1, A. D'Agostino1, D. Zambrano1, F. Paroni Sterbini2, E. Gaetani1, F. Franceschi1, G. Cammarota1, M. Sanguinetti2, L. Masucci2, A. Gasbarrini1

1Catholic University of Sacred Heart, Internal Medicine Department, Gastroenterology division, Rome, Italy, 2Catholic University of Sacred Heart, Microbiology, Rome, Italy

Background

Increasing evidences have emerged on the analysis of bacterial species making up the gastrointestinal microbiota. However few data exist on differences in gut microbiota composition in GI diseases, such as IBD, IBS and diverticular disease compared to healthy controls.

Aim of our study was to evaluate the differences in gut microbiota composition between IBD, IBS and diverticular disease (DD) patients.

Methods

10 Crohn's Disease (CD), 5 Ulcerative Colitis (UC), 4 DD, 3 IBS patients, and 8 controls (CD) were enrolled and fecal samples collected from each. Microbiota composition was assessed by a metagenomic gene-targeted approach (16S rRNA) using the Roche 454 GS Junior, following DNA isolation from stool samples stored at -80 °C. Data were analyzed in Qiime. Individual species richness was estimated using Chao1 alpha-diversity index. We also explored the differential relative abundance of several taxa of interest, selected according to literature.

Results

Bacteria amplicons were detected in all samples. Prevalent classes of bacteria were: Bacteroidia (min 13,06% - max 91,55%), Firmicutes (min 7,48% - max 86,10%) and Proteobacteria (min 0,48% - max 46,48%). Fusobacteria were found only in CD and DD patients (min 0,67%- max 50,71%). IBD microbiota composition differed significantly compared to all other. In particular, UC patients showed a reduced concentration in Bacteroidetes and an increased presence of Firmicutes vs. CT, DD and IBS. On the other side, Bacteroidetes and Firmicutes composition varied among CD patients, being increased or reduced when compared to the other groups. Proteobacteria were increased in all diseased group compared to CT, being more represented in CD and IBS-D. Moreover, Actinobacteria were increased in IBD and DD vs. IBS and CT. The most represented species in IBD and DD vs. other groups was Collinsella Aerofaciens. Rikenellaceae were suppressed in IBD patients, as well as Fecalibacterium Prausnitzii. Akkermansia Muciniphila was present only in IBS patients. Enterobacteriaceae were increased only in CD patients vs. other groups. Finally, while chao1 score was similar between CT, IBS and DD, it was deeply reduced in IBD patients.

Conclusion

These preliminary data show that starting from microbiota, gastro-intestinal disease represent a spectrum of continues diseases where IBD display one extreme in gut microbiota composition while controls display the other. Furthermore, GI diseases share some microbial patterns, sharing perhaps common pathophysiological pathways. New analyses are needed to confirm this hypothesis and evaluate therapeutical implications.