Therapeutic efficacy of three silver dressings in an infected animal model

The organic salt AgNO3 has been available as a topical armamentarium to the medical arena for centuries and for burns for the past 60 years. Thirty-five (1968) years later, Charles Fox introduced and popularized a new topical agent known as silver sulfadiazine. More recently, several new slow-release silver dressings came to the forefront. Acticoat (Smith & Nephew, Largo, FL) Silverlon (Argentum, Lakemont, GA) & Silvasorb (Medline Industries, Inc, Mundelein, IL). Because the standard of care is to change dressings daily, our study focused in on weekly dressing changes as a cost-containment issue. Sprague-Dawley rats received a standard contact burn (20% TBSA). On day 3, the wound was excised and infected with Pseudomonas aeruginosa and Staphylococcus aureus at 5.0 x 10 cfu/ml. The animals were divided into four groups (n = 5 each group): untreated control, Acticoat group, Silvasorb group, and Silverlon group. The dressings remained on the wounds for 10 days when the wounds were quantitatively assessed. Mean wound counts of the control ranged from 1.2 x 10(5) to 6.5 x 10(5) for P. aeruginosa and S. aureus, respectively. Acticoat dressing counts for both organisms were 0 and 1.8 x 10(3) (median alpha); Silvasorb was 0 and 6.3 x 10(3) and Silverlon was 1.5 x 10(4) x 7.4 x 10(4) (median), Acticoat and Silvasorb were both significantly lower (P < .05) than the control for P. aeruginosa, and Acticoat was significantly lower (P < .05) than the control for S. aureus. Although counts for Silvasorb (M) appear significantly lower than the controls for S. aureus, the numbers were not sufficient to be significant. However, Silverlon did achieve a slight significance. These preliminary data suggest that weekly dressing changes with these new silver dressings are feasible and economically and medically congruous.