Killing biofilm cells of S. epidermidis by potential YycG inhibitors. Mature biofilm of S. epidermidis RP62A strain were formed in 12-wells polystyrene plates (see Methods). The effect of various compounds (dissolved in DMSO) on biofilm-covered cells was investigated: TSB medium (control, the first column); TSB medium with an equal volume of DMSO solution (control, the second column); TSB medium with various compounds at their MIC values (black columns); TSB medium with various compounds at their MBC values (white columns). This assay was repeated three times and the values represented the mean and SD from three experiments. The concentrations we used in this assay (MBC/MIC): C1 (200 μM/50 μM), C2 (100 μM/25 μM), C3 (100 μM/25 μM), C4 (100 μM/12.5 μM), C5 (25 μM/6.25 μM), and Van (4 μg/ml/1 μg/ml), according to the results from MBC/MIC assays with planktonic cells of S. epidermidis RP62A strain. C: compound, Van: vancomycin.