Povidone-Iodine in Polyethylene Oxide Hydrogel Dressing

We studied the ability of a polyethylene oxide hydrogel dressing (Vigilon) containing povidone-iodine to prevent Staphylococcus aureus proliferation in partial-thickness wounds. We previously reported that a single application of povidone-iodine on wounds challenged with 2 X 10(6) S aureus was not effective in reducing the number of S aureus after 24 hours. It was therefore hypothesized that povidone-iodine might be effective if it was available continuously and applied to wounds containing a smaller number of bacteria. To test this hypothesis, we made multiple partial-thickness wounds (5 X 7 X 0.3 mm) on six domestic pigs. We then inoculated the wounds by scrubbing them with either a low concentration (log 3.5) or a high concentration (log 7) of S aureus suspension. The wounds were either treated with Vigilon or Vigilon containing povidone-iodine or left air exposed. Wounds from each of these treatment groups were cultured by the scrub technique for S aureus with a 0.5% sodium thiosulfate-polysorbate (Tween) 80 solution 5 minutes, 30 minutes, 24 hours, or 48 hours later. A significant reduction in the number of S aureus recovered from wounds treated with Vigilon containing povidone-iodine was seen with the group inoculated with a low bacterial concentration after 24 hours; but no reductions were observed when wounds were inoculated with the higher bacterial concentration of log 7. We found Vigilon containing povidone-iodine to be an effective inhibitor of S aureus in wounds over a 24-hour period when the organism was present in low numbers.