Reduction of a multidrug-resistant pathogen and associated virulence factors in a burn wound infection model: further understanding of the effectiveness of a hydroconductive dressing.

Objective: Drawtex's ability to remove pathogens and associated virulence factors has been demonstrated in vitro. A model of burn wound infection was used to characterize the in vivo impact of this dressing on infection and wound healing.

Methods: Paired burn wounds were created on the dorsum of Sprague Dawley rats and were inoculated with methicillin-resistant Staphylococcus aureus (MRSA). Animals were divided into 2 groups, half with wounds that received experimental dressing and the remaining half with control dressing-treated wounds. Dressings remained in place through 3, 6, 9, or 14 days after injury, and methicillin-resistant S aureus and virulence factors were quantified. Laser Doppler imaging was used to examine wound perfusion, and local host immune response was assessed through the quantification of mRNA expression.

Results: By day 3, less methicillin-resistant S aureus was measured in wounds treated with experimental-dressing compared to control-dressing wounds. Quantities remained lower in the experimental group through day 14 (P < .001). More methicillin-resistant S aureus was quantified in the experimental dressing itself than in control dressing at all time points (P < .05). Experimental dressing-treated wounds contained less toxic shock syndrome toxin 1 and Panton-Valentine leukocidin than controls (P < .01) on days 6, 9, and 14. Induction of toll-like receptor 2, NOD-like receptor family, pyrin domain containing 3, and interleukin 6 was significantly lower in experimental-dressing treated wounds than in controls on days 6 and 9 (P < .05).

Conclusions: The hydroconductive dressing provided a significant reduction in pathogen and virulence factors compared to a control dressing. As a result of clearance of virulence factors from the wound bed, a requisite alteration in host innate immune response was observed.