The modification of the microbiome through fecal microbiota transplantation (FMT) is becoming a very promising therapeutic option for inflammatory bowel disease (IBD) patients. Our pilot study aimed to assess the effectiveness of multi-session FMT treatment in active ulcerative colitis (UC) patients. Ten patients with UC were treated with multi-session FMT (200 mL) from healthy donors, via colonoscopy/gastroscopy. Patients were evaluated as follows: at baseline, at week 7, and after 6 months, routine blood tests (including C reactive protein (CRP) and calprotectin) were performed. 16S rRNA gene (V3V4) sequencing was used for metagenomic analysis. The severity of UC was classified based on the Truelove-Witts index. The assessment of microbial diversity showed significant differences between recipients and healthy donors. FMT contributed to long-term, significant clinical and biochemical improvement. Metagenomic analysis revealed an increase in the amount of Lactobacillaceaea, Micrococcaceae, Prevotellaceae, and TM7 phylumsp.oral clone EW055 during FMT, whereas Staphylococcaceae and Bacillaceae declined significantly. A positive increase in the proportion of the genera Bifidobacterium, Lactobacillus, Rothia, Streptococcus, and Veillonella and a decrease in Bacillus, Bacteroides, and Staphylococcus were observed based on the correlation between calprotectin and Bacillus and Staphylococcus; ferritin and Lactobacillus, Veillonella, and Bifidobacterium abundance was indicated. A positive change in the abundance of Firmicutes was observed during FMT and after 6 months. The application of multi-session FMT led to the restoration of recipients' microbiota and resulted in the remission of patients with active UC.
Keywords: fecal microbiota transplantation (FMT); gut microbiota; inflammatory bowel disease (IBD); ulcerative colitis (UC).