Topical Sulfamylon* reduces engraftment of cultured skin substitutes on athymic mice

Sulfamylon (mafenide acetate) remains extremely valuable for the control of the bacterial contamination of burn wounds, but it is cytotoxic to culture d keratinocytes used for wound closure. Because composite skin substitutes develop a partial epidermal barrier in vitro, they may hypothetically toler ate the use of topical Sulfamylon. To test this hypothesis, cultured skin s ubstitutes were prepared from cultured human fibroblasts; keratinocytes wer e attached to these collagen-based substrates, which were grafted to full-t hickness wounds in athymic mice (n = 8 per group). Wounds were irrigated tw ice daily with 5% (wt/vol) Sulfamylon solution or with a formulation of non cytotoxic antimicrobials (0% Sulfamylon). On day 9 after grafting, the woun ds were treated with dry dressings and assessed at 4 weeks for expression o f human leukocyte antigens-A, B, C and at 2, 3, and 4 weeks for percentage of original wound area and surface electrical capacitance in picofarads (pF ). Data were analyzed for statistical significance (P < .05) by Fisher's ex act test, Student's t test, and repeated measures analysis of variance: [GRAPHICS] The data demonstrate that irrigation of cultured skin substitutes with a so lution of 5% Sulfamylon results in smaller wound area, fewer wounds that co ntain human cells, and greater surface hydration (higher surface electrical capacitance) than irrigation with noncytotoxic antimicrobial agents. These results support the conclusion that cultured skin substitutes of this type do not tolerate the chemical toxicity of Sulfamylon as well as skin autogr afts. Further improvements in the properties of the epidermal barrier of cu ltured skin substitutes may facilitate the use of Sulfamylon or other poten t antimicrobial agents for the management of microbial contamination during engraftment of transplanted skin cells.