TABLE 2.

Number of CFU of two microorganisms (liquid inoculum) on a polymer without and with silver after various exposure times

Species and exposure time	No. of CFU (mean ± SD)		P valuea
	Without silver	With silver
Pseudomonas aeruginosa
0	1.4 × 107 ± 6.2 × 106	1.4 × 107 ± 3.3 × 106	0.469
1 h	5.0 × 106 ± 3.0 × 106	5.2 × 106 ± 8.9 × 105	0.109
24 h	3.0 × 107 ± 7.3 × 106	2.6 × 107 ± 3.9 × 106	0.192
7 days	6.5 × 107 ± 1.0 × 107	6.9 × 107 ± 4.2 × 106	0.330
Staphylococcus aureus
0	5.4 × 106 ± 1.7 × 106	4.7 × 106 ± 1.2 × 106	0.520
1 h	6.7 × 106 ± 2.6 × 106	6.2 × 106 ± 2.9 × 106	0.630
24 h	1.1 × 107 ± 1.7 × 106	3.0 × 106 ± 2.1 × 106	0.004
7 days	1.7 × 106 ± 3.4 × 105	1.3 × 106 ± 5.5 × 105	0.125

^aDerived by Mann-Whitney U test.