Therapeutic effects of silver nylon dressings with weak direct current on Pseudomonas aeruginosa-infected burn wounds.

Abstract

The therapeutic and prophylactic effects of nylon dressings coated with metallic silver in a direct current circuit have been examined in a rat model of fatal burn wound sepsis. Male Sprague-Dawley rats weighing 325 +/- 25 grams with 20% full-thickness scald injuries were used. Therapeutic effects were examined at 4 or 24 hours after surface inoculation with a lethal dose of Pseudomonas aeruginosa (Strain 59-1244). When used as a surface anode with an implanted silver needle cathode, the silver nylon was therapeutic at currents between 0.4 and 40 microA when applied at either test time and continued for 5 days (p less than 0.001). When used as a cathode, silver nylon was not effective. Nylon cloth without a silver metal coating was not effective without applied current or when used as an anode. Silver nylon dressings placed at 4 hours after inoculation but without applied current showed significant effectiveness (p less than 0.01). This effect, however, was significantly less than that seen with silver nylon used as an anode (p less than 0.001). Barrier prophylactic effects were examined by placing silver nylon or uncoated nylon on burn wounds before inoculation with Pseudomonas aeruginosa. The uncoated nylon had no barrier effect. Silver nylon was found protective but applied current was not required for significant (p less than 0.001) barrier effect. These results indicate silver nylon dressings may be a valuable antimicrobial burn wound covering device.