Determination of the Debridement Effects of an Enzymatic Hydrogel on Deep Dermal Wounds using a Porcine Model
Establishing and maintaining a pathogen-free environment of acute and chronic wounds is vital for optimum healing.1-4 One of the first steps in preventing biofilm consists of debriding the wound surgically or enzymatically.
The purpose of this study was to assess the ability for a novel enzymatic hydrogel solution (EHS)* that uses an enzyme cloned from medical maggots, to remove slough and reduce the bacterial bioburden in a porcine deep dermal wound model.5,6
Thirty-three deep dermal wounds (22mmx22mmx3mm) were made using an electrokeratome on two animals. Wounds were inoculated with 25µl of Methicillin Resistant Staphylococcus aureus (MRSA USA300) and covered with a polyurethane film to allow biofilm formation.7 After 3 days, three wounds were recovered as a baseline and the other thirty wounds were randomly assigned to one of five treatment groups: A.) EHS 0.05g/L, B.) EHS 0.125g/L, C.) EHS 0.25g/L D.) Hydrogel Control, or E.) Untreated Tegaderm Control.
Wounds were treated on days 2, 4, 7, 10 and 14. Degree of slough that removed from wounds was observed. Wounds were recovered on day 2 and 14 for microbiological and histopathology analysis. On day 2, wounds treated with EHS 0.25g/L showed a p< 0.05 lower level of MRSAUSA300 compared with all treatment groups with a reduction in counts over 99.9%. EHS 0.05g/L and EHS 0.125g/L resulted in significant lower MRSA counts as compared to baseline.
Similar levels of total bacteria counts were observed between all enzymatic solutions evaluated with a p< 0.05 compared with baseline wounds, vehicle control and untreated control. Bacterial results were confirmed based on PCR amplification of 16S rRNA gene.
Wounds treated with enzymatic solutions 0.125g/L had lower slough scores on days 4,7 and 10 as compared with the other treated wounds (p=NS), however this difference was not significant. All wounds on day 2 revealed similar histopathological results of inflammation, granulation tissue and crust formation. All wounds were fully re-epithelialized by day 14. EHS 0.25g/L exhibited significantly (p< 0.05) increase in vascularization.
These results show the potential for an enzymatic hydrogel to reduce the bacterial count and maintain an ideal environment for the process of wound healing.
References
1. Mercandetti, M. and A. Cohen, Wound healing: healing and repair. Emedicine. com. Accessed January, 2005. 20(2008): p. 38.2. Zhao, G., et al., Biofilms and inflammation in chronic wounds. Advances in wound care, 2013. 2(7): p. 389-399.3.
Davis, S.C., et al., Microscopic and physiologic evidence for biofilm‐associated wound colonization in vivo. Wound repair and Regeneration, 2008. 16(1): p. 23-29.4.
Donlan, R.M., Biofilm formation: a clinically relevant microbiological process. Clinical Infectious Diseases, 2001. 33(8): p. 1387-1392.5.
Davis SC, Gil J, Solis M, Higa A, Mills A, Simms C, Valencia-Pena P, Li J, Raut V Antimicrobial Effectiveness of Wound Matrices containing Native Extra Cellular Matrix (ECM) with Polyhexamethylene Biguanide (PHMB), Int Wound J. 2021;1–14.6.
Davis SC, Gil J, Li J, Simms C, Valdes J, Solis M, Higa A. Effect of Mechanical Debridement and Irrigation with Hypochlorous Acid Wound Management Solution to Reduce Methicillin Resistant Staphylococcus aureus Biofilms and Infections using an in-vivo Porcine Deep Dermal Wound Model, Wound Management & Prevention 2021; 67(8), 24-31. 7.
Davis SC, Ricotti C, Cazzaniga AL, Welch E, and Mertz PM. Microscopic and Physiological Evidence for Biofilm-Associated Wound Colonization In-vivo Wound Repair Regen 2008, 16(1):23-9.
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