The influence of substrate surface conditioning and biofilm age on the composition of Enterococcus faecalis biofilms

Aim To investigate the null hypothesis that neither the surface conditioning (collagen, serum, saliva) of hydroxyapatite (HA) discs, nor the biofilm age (3 days vs. 21 days) has a significant effect on the cellular and matrix composition of biofilms, using Enterococcus faecalis as the model organism. Methodology Sterile HA discs were conditioned with collagen, saliva or serum, and inoculated with E. faecalis to form 3‐day and 21‐day‐old biofilms. Unconditioned discs served as controls. The biofilms were analysed using culture‐dependent and independent (confocal microscopy and biochemical analysis) methods, to determine the colony‐forming units and the biofilm matrix composition (polysaccharides and proteins), respectively. Statistical analyses were performed using appropriate parametric and nonparametric tests (P = 0.05). Results Collagen conditioning significantly increased the number of CFUs in the 21‐day biofilms, compared to the 3‐day biofilms (P