Fig. 4: VRE growth was highly suppressed by mixtures of SCFAs at high concentrations.

Vancomycin-resistant E. faecium and vancomycin-resistant E. faecalis strains were grown in tryptic soy broth supplemented with a mixture of propionate, butyrate, and valerate (PBV) or a mixture of acetate, propionate, butyrate, and valerate (APBV) at concentrations mimicking the high concentrations measured in human faeces, or unsupplemented (No metabolites control). Broth was adjusted to pH 6, 6.5, or 7 to mimic the pH of the healthy large intestine, and cultures were incubated under anaerobic conditions overnight. Data shown as medians ± IQR, with 12 replicates from 3 independent experiments. Kruskal-Wallis with Dunn’s multiple comparison test comparing the no metabolites control to each metabolite mixture at the same pH. * P ≤ 0.05, ** = P ≤ 0.01, *** = P ≤ 0.001, **** = P ≤ 0.0001. OD₆₀₀ optical density at 600 nm.