Figure 3.

Bacillus subtilis natto supernatant interferes with E. faecalis biofilm production but not growth. (A,B) Growth curves of E. faecalis OG1RF WT and OG1RF::p23cfp in the absence or presence of B. subtilis natto supernatant (10% v/v) for 24h. In (A) and (B), the Y axis shows the OD₆₀₀ values of the bacterial cultures at different time points. The data are presented as the means±SDs (n=8). (C) Biofilm production in the absence or presence of B. subtilis natto supernatant (10% v/v) for 24h. Biofilm production is expressed as an index of the biomass stained with safranin (OD₄₅₀ value) normalized to the cell growth (OD₆₀₀ value at 24h). Relative biofilm production (%) was calculated by further normalizing the biofilm index values of the treated group to those of the negative control group to which no B. subtilis natto supernatant was added. The data are presented as the means±SDs (n=8). ^**p<0.01 and ^***p<0.001 compared with each negative control group (Student’s t-test).