Evaluation of the microbiome prior to and following administration of FMT. Longitudinal changes in (A) inverse Simpson index, (B) Clostridiales abundance, and (C) UniFrac distance before allo-HCT and after FMT administration in the early posttransplant period, as determined from 16S rRNA sequencing of stool specimens. (D) Longitudinal changes in the origin of operational taxonomic units. Four selected patients shown.