Fig. 4 |. Metabolic-dependent threshold for lethality and generality.

a, Metabolic state correlates better with antibiotic lethality than growth rate for all data. The pooled 96 data points were normalized and sorted by either increasing ATP/OD (top row) or growth rate (bottom row). The effects on growth and metabolism are shown in the grey bar graphs (left two panels) and survival is shown in the coloured bar graphs for 2× (lighter) and 20× (darker) MIC (right three panels). b, Critical metabolic threshold for antibiotic lethality. Survival is measured at CAA concentrations of 0, 0.001, 0.0025, 0.01, 0.025 and 0.1%; shading (dark to light) represents increasing concentrations. ATP/OD is normalized to ATP_crit. Horizontal (100% survival ratio) and vertical (critical threshold) dotted lines are drawn as guides. Survival is normalized to the ATP value immediately preceding the threshold. Data are the mean survival of four biological replicates. c, Corresponding ATP_crit value from b. The y axis shows ATP_crit before normalization, and the x axis shows temperature. Data are the mean survival of four biological replicates. d, Mathematical schematic with simplified assumptions. Survival undergoes a switch-like transition at a normalized metabolic state of m = 1 and decreases linearly at a rate α. M and M₀ are the non-dimensionalized metabolic states of ATP and ATP_crit, respectively. e, Results are general to malic acid at concentrations of 0, 4, 12.6, 40 and 126.5 μg ml⁻¹; shading (dark to light) indicates increasing concentrations. Data are the mean survival of four biological replicates. f, Increasing metabolic sensitivity using ΔatpA. The following CAA concentrations were used: 0%, 0.01% and 0.1%; shading (dark to light) represents increasing concentrations. Data are the mean ± s.d. survival of three biological replicates. g, Decreasing metabolic sensitivity using glutathione. CAA-treated cells (0%, 0.0025%, 0.01% and 0.1%) were supplemented with 10 mM reduced glutathione. Non-normalized data are provided in Supplementary Fig. 11e. Shading (dark to light) represents increasing CAA concentrations. Data are the mean ± s.d. of three biological replicates. In all cases, the error bars indicate s.d. The y axis for e-g shows the survival ratio and the x axis shows ATP_N. 20× MIC was used for all drugs (Supplementary Table 4). In all cases except for d, colours indicate drug (gentamicin (green), ciprofloxacin (yellow), ampicillin (red) and control (grey)). The control (dotted line) for f and g is the linear regression fit of BW25113 data using the corresponding subset of CAA concentrations for each panel.