Fig 1. HtrA supports E. faecalis persistence in wounds.
(A) Growth phenotypes of E. faecalis WT and ΔhtrA strains. Growth curves performed in BHI broth at 37°C (n = 5) and 42°C (n = 2). CFU counts (CFU ml-1) are represented as dashed lines; OD600 readings are represented as solid lines. Standard deviation is indicated by bars. (B) Western blots of whole cell lysates of OG1RF WT and ΔhtrA grown at different temperatures. To detect HtrA, affinity purified α-HtrA was used. α-SecA was used as a loading control. (C) Wounds were infected with a 1:1 ratio of E. faecalis strains OG1X/OG1RF WT or OG1X/OG1RF ΔhtrA, at 106 CFU per inoculum, and harvested at 8 hpi or 72 hpi. Recovered bacteria were enumerated on selective media for each strain. Dashed lines separate strain pairs that were co-infected. Each dot represents a mouse. Competitive index was calculated using the final CFU ratio of OG1X with OG1RF WT or ΔhtrA (output) over the initial CFU ratio of OG1X with OG1RF or ΔhtrA (input). Solid horizontal line indicates the median. The limit of detection (LOD) of 40 CFU is indicated. For 8h, 4 mice per strain were tested. For 72h, 10–12 mice per strain were used. Statistical analysis was performed using the Kruskal-Wallis test with Dunn’s post-test to correct for multiple comparisons. **** P≤0.0001.