Microbiota rarefaction curves showing fecal microbiota diversity in RCDI (red) and post-FMT (blue) patient and donor (green) samples.

Each curve shows the average number of OTUs found in a given number of sampled sequences. OTUs can be treated as equivalent to taxonomic species in the sequence space. RCDI samples are marked from patient #6a (*), who experienced antibiotic-induced relapse and was treated by FMT again as patient #6b (**).