Fig. 4.
Biofilm structure and thickness. 3D CLSM images of S. epidermidis 1585 WT and mutant strains grown in TSB, BHI, BHI with 10 % (v/v) plasma, or BHI with 50 % (v/v) human plasma (a–p). Images show bacteria (green) and extracellular DNA (red). Evaluated by visualization and quantification of biofilm thickness (q), S. epidermidis 1585 WT and 1585Pxyl/tetembp did not form biofilm in TSB and BHI, unless amended with 10 or 50 % (v/v) human plasma [P<0.05 (two-tailed), Mann–Whitney test]. S. epidermidis 1585pTXica and 1585Δembp formed biofilm in all four media, but made significantly thicker biofilms when human plasma was added [P<0.005 (two-tailed), Mann-Whitney test]. The bars represent the median and range of at least three biological replicates with at least three technical replicates.