Table 2.

Effects of repeated rinsing of multi-species biofilms with potential prebiotic substrates on virulence gene expression from A. actinomycetemcomitans.

Fold changes in virulence gene expression were determined relative to the control condition through the 2^−ΔΔCt method and are shown as the geometric mean (C.I.) (n = 3) of the 2^−ΔΔCt values. All substrates were dissolved in PBS at a concentration of 1 M (upper part) or 1%_(w/v) (lower part) (corresponding molar concentrations: 45 mM (NADG), 29 mM (α-D-lactose), 17 mM (D-(+)-raffinose) and 26 mM (D-(+)-trehalose)). Values between 0 and 1 represent relative downregulation, values >1 represent relative upregulation. Statistically, significantly different fold changes relative to the control (PBS) that are <0.5 (more than 2-fold downregulated) or >1.5 (more than 1.5-fold upregulated) are considered biologically relevant and are shown in bold and marked with ‘*’ (P < 0.05, ANOVA + Dunnett’s correction for simultaneous hypothesis testing). The color code represents the magnitude of the fold change in virulence gene expression relative to the control. NADG: N-acetyl-D-glucosamine; C.I.: 95% confidence interval.