Bacteriology, inflammation, and healing: a study of nanocrystalline silver dressings in chronic venous leg ulcers.

Abstract

BACKGROUND: Healing of venous leg ulcers (VLUs) is often stalled despite compression therapy. Increased bacterial burden and chronic inflammation are 2 factors that may prevent these chronic VLUs (CVLUs) from healing. There is evidence that nanocrystalline silver dressings may reduce bacterial levels, decrease the chronic inflammatory response, and thus promote wound healing. OBJECTIVE: To determine the effects of a nanocrystalline silver barrier dressing on wound microflora, wound inflammation, and healing in CVLUs. METHOD: Stalled VLUs in 15 patients were managed using nanocrystalline silver dressings under 4-layer compression bandages. Paired skin biopsies at baseline and at an average of study week 6.5 were analyzed for bacteria and inflammatory infiltrates. Serum silver levels were monitored, and wound healing was assessed using planimetry. RESULTS: VLUs in 4 patients healed, and 8 other patients completed the 12-week study. There was a significant reduction in the log10 total bacterial count between baseline and final biopsies (P = .011). Greater numbers of lymphocytes were associated with an increased reduction of ulcer size at week 6.5 and final assessment at week 12 (P < .05). Heavy neutrophilic infiltration in skin biopsies at week 6.5 was associated with high bacterial counts and delayed healing (P = .037). The median reduction in ulcer surface area for all patients was 83.5%. Serum silver levels increased slightly, but values were within the normal range. CONCLUSION: A nanocrystalline silver dressing combined with 4-layer bandaging was safe and successful in promoting healing in stalled CVLUs. Healing was associated with a reduction in wound bacteria and neutrophilic inflammation with an associated persistent or high lymphocyte count, as determined by wound biopsy.