TABLE 1.

Number of CFU of four microorganisms (dry 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
P. aeruginosa
0	2.4 × 107 ± 6.8 × 106	2.7 × 107 ± 9.6 × 106	0.810
1 h	2.3 × 107 ± 1.2 × 107	2.9 × 107 ± 1.4 × 107	0.128
24 h	3.3 × 107 ± 1.5 × 107	3.0 × 107 ± 1.2 × 107	0.809
7 days	1.5 × 106 ± 7.1 × 105	1.7 × 106 ± 8.0 × 105	0.625
S. aureus
0	1.2 × 106 ± 7.0 × 105	2.9 × 106 ± 2.5 × 106	0.197
1 h	2.3 × 106 ± 2.5 × 106	8.7 × 105 ± 9.8 × 105	0.200
24 h	5.3 × 106 ± 7.9 × 106	1.8 × 106 ± 1.5 × 106	0.037
7 days	22 ± 40	1 ± 2	0.775
E. coli
0	6.7 × 106 ± 4.0 × 106	5.2 × 106 ± 5.3 × 106	0.297
1 h	193 ± 396	529 ± 816	0.297
24 h	0.2 ± 0.4	132 ± 180	0.059
7 days	0	8 ± 20	0.317
C. albicans
0	3.5 × 107 ± 8.6 × 106	8.3 × 106 ± 5.8 × 106	0.873
1 h	4.0 × 106 ± 5.2 × 106	3.3 × 106 ± 3.0 × 106	0.749
24 h	2.3 × 106 ± 2.2 × 106	9.2 × 107 ± 2.7 × 106	0.004
7 days	2.2 × 106 ± 9.2 × 105	1.4 × 106 ± 5.9 × 105	0.078

^aDerived by Mann-Whitney U test.