Fig. 1

FMT led to prominent shifts in the gut microbiome composition towards particular donors. a Design of the Gut Bugs trial. Circles represent stool sample collection time points with corresponding participant numbers indicated. *One male donor was replaced during the trial; hence, 5 male donors were recruited. b Multidimensional scaling plots based on species-level Bray-Curtis dissimilarities, subset by sex and surveyed time point. Multiple samples from each donor, corresponding to each donation batch, were averaged to generate a composite donor profile. c Shifts in similarity of FMT recipients’ fecal metagenome to each contributing donor after adjusting for baseline similarity. d Alpha diversity of the gut microbiome of donors as measured by Shannon’s diversity index. Multiple points correspond to separate donations. e, f Prevotella/Bacteroides ratio of the gut microbiome of donors (e) and FMT and placebo recipients (f). Differences from baseline to week 6 were measured by Wilcoxon signed-rank test