Faecal microbiota transplantation (FMT) using anaerobically-processed donor stool is showing promise for patients with mild to moderate ulcerative colitis.
An Australian study, published in JAMA, randomised 73 adults to FMT with either pooled donor stool or autologous stool.
The relatively low intensity FMT regimen comprised an initial dose delivered via colonoscopy and two subsequent doses administered via enemas within seven days.
The researchers found 32% of patients who received donor FMT were able to achieve steroid-free remission at eight weeks compared to just 9% of patients who received an autologous FMT.
Five of the 12 participants (42%) who achieved steroid-free remission at week 8 following donor FMT were still in remission at 12-months follow-up.
Lead researcher Dr Sam Costello, from the Inflammatory Bowel Disease Service at the Queen Elizabeth Hospital and the University of Adelaide, said the remission rate was similar to that achieved with the best currently available therapies.
“The most important difference in this trial compared to previous studies is the use of anaerobic stool processing,” he said.
“Many gut bacteria die with exposure to oxygen and we know that with anaerobic stool processing a large number of donor bacteria survive so that they can be administered to the patient.”
“We believe that this may be the reason that we had a good therapeutic effect with only a small number of treatments.”
The study found the 10 bacteria and the archaea Methanobrevibacter smithii whose increased abundance at four and eight weeks were most strongly associated with donor FMT were all anaerobes.
Increased abundance of Anaerofilum pentosovorans and Bacteroides coprophilus species was strongly associated with disease improvement following donor FMT.
Meanwhile, another Australian FMT team lead by the University of New South Wales have identified the specific bacteria and metabolites associated with response to a more intensive regimen of multidonor FMT.
Patients with ulcerative colitis received an initial dose of FMT or placebo via colonoscopy then enemas five days per week for eight weeks.
The study, published in Gastroenterology, found increases in the relative abundances of Eubacterium hallii and Roseburia inulivorans were the strongest and most consistent associations with positive clinical outcomes.
“Further, functional analyses demonstrated that Eubacterium and Roseburia contributed to increases in beneficial metabolic pathways. Specifically, metabolic shifts to SCFA biosynthesis (such as pyruvate fermentation to acetate and lactate) and starch degradation were associated with positive outcomes,” it said.