Fig 5. Metabolic competition scores and in vitro data indicate a non-metabolic interaction mechanism.

A) Competition scores for all pairs of genera with C. difficile. Notice that Barnesiella has nearly the lowest competition score. B) Maximum growth rates for all growth conditions. C. difficile grew more slowly in B. intestinihominis spent media (n = 16, p-value < 0.005, by one-sided Wilcoxon rank sum test). The co-culture with both B. intestinihominis and C. difficile grew more slowly than C. difficile alone (n = 16, p-value < 0.05, by one-sided Wilcoxon rank sum test). C) Area under the curve (AUC) was not significantly different for C. difficile in fresh media or B. intestinihominis spent media (n = 16, p-value = 0.22 by one-sided Wilcoxon rank sum test). D) The experimental (red, solid line) and simulated (blue, dashed line) co-culture growth curves. “Binte” indicates B. intestinihominis, while “Cdiff” stands for C. difficile. On average, the experimental co-culture growth curves maintained a lower density than the simply additive null model. Error bars represent the standard error of the mean from 16 independent replicates.