Influence of Ca²⁺ in biofilm formation before and after DNase I treatment and eDNA concentration during biofilm growth.

<p>Biofilm biomass quantification over 24(black) or absence (white) of naturally occurring eDNA (A). Error bars represents standard deviations from multiple cultures (n = 5). Asterisks and hash indicate statistically significant (<i>P</i><0.05) differences between data obtained in the presence or absence of eDNA and in presence or absence of Ca²⁺ respectively. Concentration of eDNA at different growth time of biofilm formation for Gram-negative and Gram-positive bacterial strains (B). Error bars represent standard deviations from multiple cultures (n = 4). Asterisks indicate statistically significant (<i>p</i><0.05) differences in eDNA concentration in comparison to both <i>S. aureus</i> and <i>E. faecalis</i>. Hash indicates the difference is statistically significant only in comparison to <i>E. faecalis</i>.