engleski

Mucosa-Associated Microbiota in Adult, Newly Diagnosed, Treatment-Naïve Crohn's Disease (CD) Patients and Controls with Irritable Bowel Syndrome (IBS)

Recent advancements in next-generation sequencing techniques have enabled culture-independent analysis of the gut microbiota, revealing that an altered balance of the gut microbiota constituents (rather than specific pathogens) is involved in the pathogenesis of Crohn’s disease (CD) - one of the principal subsets of inflammatory bowel disease (IBD). Thus far, there were only a handful studies with naïve CD patients on pediatric subjects, and many studies on adult CD patients in late disease stages or post treatment. The aim of our study was to determine differences in microbiota composition in adult, newly diagnosed and treatment-naïve CD and controls with irritable bowel syndrome (IBS) patients. Methods: Mucosal sample (terminal ileum) was collected from both groups of patients as part of diagnostic colonoscopy examination prior to the initiation of treatment and snap-frozen. DNA was extracted using MasterPure DNA purification kit (Epicentre). The composition of gut microbiota from mucosa was determined by amplification and sequencing of bacterial 16S rRNA gene using Illumina MiSeq according to manufacturer-recommended protocols. Raw sequencing files were processed using QIIME pipeline and Operational Taxonomic Units (OTUs) were assigned using the vsearch algorithm and PyNast alignment against the GreenGenes database (version 13_8, May 2013). Subsequent processing and analysis was done using ALDeX2 R package by utilizing multivariate generalized linear model. Results: The difference in abundance of several bacterial taxa was observed between CD and IBS groups. The analyses of effect sizes down to the genus level indicated that taxa belonging to Clostridia, Coriobacteriia and Actinobacteria classes were overrepresented in CD, while Betaproteobacteria were underrepresented, with respect to the IBS group. Conclusions: Preliminary results on limited patient cohort demonstrated differences in mucosa-associated microbiota populations between adult, newly diagnosed, treatment-naïve CD and IBS patients.

Crohn’s Disease ; Irritable Bowel Syndrome ; Mucosa-associated Microbiota ; Next-generation sequencing

nije evidentirano