Fig. 4

a BSI risk index based on the differentiated taxa (n = 28). We included in the BSI risk index all the taxa with a false discovery rate (FDR)-corrected p value less than 0.15. The BSI was then calculated using the sum of relative abundances of the taxa that were significantly associated with BSI minus the sum of the relative abundances of the taxa that were associated with protection from BSI. Mann–Whitney U test: ***p < 0.001. Boxplots denote top quartile, median, and bottom quartile. BSI, Bloodstream infection. b Receiving-operating characteristic (ROC) curve analysis of the BSI risk index in fecal samples collected prior to treatment, to differentiate patients who developed subsequent BSI and patients who did not develop BSI. We applied tenfold jack-knifing; the ten ROC curves are in blue and the mean ROC curve is in black. BSI, Bloodstream infection