Therapeutic Efficacy of Three Silver Dressings in an Infected Animal Model

Abstract

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 × 105 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 × 105 to 6.5 × 105 for P. aeruginosa and S. aureus, respectively. Acticoat® dressing counts for both organisms were 0 and 1.8 × 103 (median α); Silvasorb® was 0 and 6.3 × 103 and Silverlon was 1.5 × 104 × 7.4 × 104 (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.