Preliminary Evaluation of a Purified Native Collagen Matrix with Polyhexamethylene Biguanide Reducing Methicillin Resistant Staphylococcus aureus Infections and Altering Cytokine Profile Using a Porcine Deep Dermal Wound Model

Background: There are a variety of wound matrices designed to treat both acute and chronic wounds, and enhance the healing process. However, patients suffering from these wounds often encounter opportunistic microbes that can delay or prevent healing, potentially reducing the beneficial effects of these matrices. Therefore, a wound matrix that could potentially reduce bacterial growth is desirable.

Purpose: The aim of this pilot study was to examine the ability of purified Type-I collagen matrix with polyhexamethylene biguanide (PCMP) to reduce biofilm-associated bacteria. Thirty-six deep dermal wounds (15x15x2mm) were created and inoculated with Methicillin Resistant Staphylococcus aureus (MRSA). Wounds were covered for 48 hours to allow for biofilm formation. Wounds were then debrided and assigned to one of four treatment groups: 1) PCMP, 2) Antimicrobial dermal repair scaffold: ADRS, 3 Collagen Extracellular Matrix: CEM, or 4) untreated control. All wounds were initially covered with a polyurethane film, then replaced with a silicone dressing. Wounds were assessed for MRSA counts on Days 2, 3, 4, 7, 10 and 14 post-treatment.

Results: Results showed that PCMP-treated wounds achieved bacterial reductions >98% compared to baseline. PCMP-treated wounds also reduced bacterial counts >80% in comparison to ADRS- or CEM-treated wounds (all assessment days). There was a 96% reduction of MRSA in PCMP-treated wounds versus untreated controls. On day 7, PCMP-treated wounds had 2.4 and 1.4 Log CFU/g reduction versus untreated and CEM-treated wounds, respectively. Overall, PCMP-treated wounds resulted in the largest reduction in MRSA counts. Analysis of nine cytokines detected substantial reduction in IL-4 on Day 2 in wounds treated with PCMP compared to wounds in the other three treatment groups.

Conclusion: Our results suggest that an antimicrobial-containing wound matrix, like PCMP, may attenuate and contain bacterial growth and potentially augment wound healing. Additional studies in a larger sample size are needed to further evaluate and substantiate these findings.