Fig. 6: Faecal culture supernatants suppressed VRE growth through nutrient depletion.

Minimal medium was supplemented with a mixture of nutrients that were increased with antibiotics and inoculated with either fresh healthy human faeces (n = 3 donors for 9 replicates from 3 independent experiments, shown in brown), a single VRE strain (E. faecium NCTC 12202 shown in blue or E. faecalis NCTC 12201 shown in green; n = 9 replicates from 3 independent experiments), or left uninoculated (shown in grey, n = 9 replicates from 3 independent experiments). Spent supernatants were filter sterilised and then inoculated with (a) E. faecium NCTC 12202 or (b) E. faecalis NCTC 12201. As a control, spent supernatants were also supplemented with 0.5% glucose to confirm nutrient depletion. VRE growth was measured after overnight incubation using plate counts. a, b comparisons between growth in the spent supernatants and fresh medium were assessed using a Kruskal-Wallis with Dunn’s multiple comparison test, and comparisons of unsupplemented vs glucose-supplemented supernatants was assessed through a Wilcoxon signed rank test (two-sided). ** = P ≤ 0.01, *** = P ≤ 0.001, **** = P ≤ 0.0001. Data are presented as medians ± IQR.