Efficacy and Mechanism of Fecal Microbiota Transplantation of the Bai Nationality in the Treatment of IBD

Inclusion Criteria: * Age 18-80 years inclusive (no limit on gender) * Confirmed diagnosis of ulcerative colitis for \> 3 months, according to established clinical,endoscopic and histologic criteria * Currently active mild-moderate ulcerative colitis, as measured by a Mayo score of 4-10, in which endoscopy sub-score ≥ 1 and physician's global assessment sub-score ≤ 2 * Written informed consent obtained. Exclusion Criteria: * Subjects who are unable to give consent or who have conditions rendering them incapable to answer questionnaires or provide samples. * Females who are pregnant or actively trying to fall pregnant * Subjects unwilling to practice an effective method of contraception throughout the study period * Subjects defined as in remission by the investigator * Evidence or history of toxic megacolon * Isolated proctitis \< 5 cm * A diagnosis of Crohn's Disease or indeterminate colitis * Subjects with perianal disease (e.g. fistulae, pre-existing fissures) * Significant gastrointestinal surgery e.g. colon resection, colectomy :Minor gastrointestinal surgery will be reviewed on a case by case basis by the investigator;Regarding appendicectomy, only exclude patients who had appendicectomy \< 3 months ago) * Subjects taking antimicrobials (antibiotics, antifungals, antivirals) for any reason, including antibiotics for ulcerative colitis, in the preceding 4 weeks * Subjects who are steroid dependent and requiring \> 20mg prednisone or \> 9mg budesonide daily at the time of enrolment * Subjects who have recently taken or are actively taking or expected to require prohibited medication/s during the study period including follow-up. These include:Rectal therapy including corticosteroid, 5-aminosalicylate within 2 weeks before first FMT;Treatment with biologic agents e.g. infliximab, adalimumab, vedolizumab, within 12 weeks before first FMT;Treatment with other major immunosuppressant agents including calcineurin inhibitors, anti-neoplastic agents, lymphocyte depleting biological agents within 12 weeks before first FMT;Probiotic therapy within 4 weeks before first FMT;Experimental / trial drug protocol involvement within 12 weeks before first FMT;Anti-mycobacterial (TB or MAC) therapy within 4 weeks before first FMT Allowed concomitant medications: The following drugs are allowed as long as the dose is stable preceding first FMT for the noted time: * oral 5-aminosalicylates (stable dose for 4 weeks) * thiopurines and methotrexate (on medication for ≥ 90 days and dose stable for 4 weeks) * oral prednisolone (dose ≤ 20mg daily and stable for 2 weeks) During the study, subjects should remained on the same dose of oral 5-aminosalicylate, thiopurine, and methotrexate. For oral prednisolone, dose must be tapered at a rate up to 2.5mg per week so that subjects would be steroid-free by week 8. Prohibited medications: The following drugs for are prohibited for the noted time: * Rectal therapies including corticosteroid, 5-aminosalicylate (for 2 weeks before first FMT and during study period) * Antibiotics, antibiotics, antifungals, antivirals, probiotic or prebiotic preparations (for 4 weeks before first FMT and during study period) * Rectal therapies including corticosteroid, 5-aminosalicylate (for 2 weeks before first FMT and during study period) * Biological therapies or calcineurin inhibitors (for 12 weeks before first FMT and during study period)