Table 1.

Effect of cranberry NDM on the metabolic activity of S. gordonii growing in culture media measured by XTT assay.

NDM Concentration (μg/mL)	Metabolic activity
0	2.4 ± 0.3
2.5	1.73 ± 0.2
5.0	1.38 ± 0.11
7.5	1.19 ± 0.24
10	0.86 ± 0.12
20	0.65 ± 0.11
25	0.37 ± 0.1
50	0.23 ± 0.02
100	0
200	0
Heat-killed bacteria (control)	0

Bacterial biofilm prepared as described previously was treated with varying concentrations of NDM (2.5 μg/mL to 100 μg/mL) for 60 minutes and 4 hours. The metabolic activity was determined by XTT assay and the biofilm mass determined by the crystal violet staining.