Methods: 48 patients were enrolled over an 18 month period. Stool samples were studied from patients prior to and every 90 days following stool transplantation for 12 months. Only four patients completed the entire 12 month post-FMT followup portion of the study.
Results: Fecal bacterial operational taxonomic units (OTUs) and phylogenetic diversity (PD) were greater in the donor than patients at baseline, (ie, day 0 (p<0.05)). Patient OTUs and PD increased at each interval following FMT from day 0 to day 90, day 180 and day 360 (p<0.05). OTUs and PD were not different in DD vs. patients at 3 months, 6 months, or one year (p>0.05).
Conclusion: Patients tended (p=0.07) to have more OTUs at 3 months compared to baseline. Microbiota diversity (as measured by OTU) continued to evolve over 6 and even 12 months for 3/4 patients. Based on our long term followup studies of patients following FMT, gut microbiota recovery following FMT is not instantaneous, but appears to be a process of evolution following FMT that occurs over ≥ 12 months.