Comparison of a Copper-based Antimicrobial Burn Dressing and KerraCel-Ag, a Commercial Silver Burn Dressing

Introduction: Reported here is a preliminary study of a cost-effective copper-based antimicrobial hydrogel wound dressing intended for the treatment of burn wounds for military applications. The dressing is being developed for long-term protection (at least 6 days) in austere environments.

Recent research has demonstrated that wound colonization by MDR organisms occurs primarily within Military Field Hospitals [1, 2], suggesting that nosocomial transmission is a key source of these life-threatening infections [3-6] in addition to the obvious risks associated with infection at the point of injury, and there currently does not exist a standard-issue antimicrobial wound dressing for the military.

Methods: In this study, we describe the production of a hydrogel nonwoven dressing comprised of a blend of fibers, including a novel copper-loaded carboxymethyl cellulose fiber (Cu-CMC). In this preliminary study, we show the broad antimicrobial properties of copper against 3 Gram positive and 3 Gram negative bacteria, yeast, and mold using the FDA recognized in vitro assay, AATCC Test Method 100. The prototype Cu-CMC dressing were also tested within a preclinical porcine in vivo model using both methicillin-resistant S. aureus and P. aeruginosa, and was compared with a commercial silver burn dressing, Kerracel-Ag.

Results and Discussion: In this study we show that the prototype Cu-CMC dressings exhibit broad spectrum antimicrobial activity (e.g., greater than 99.99% reduction) against P. aeruginosa, E. coli, A. baumannii, S. aureus, S. epidermidis, S. pyogenes, C. albicans, and A. brasiliensis using a standard in vitro assay in simulated wound fluid. We also present pilot data in a porcine model of biofilm prevention using P. aeruginosa (BAA-47), S. aureus (MRSA USA300), drug resistant A. baumannii, showing that the prototype Cu-CMC dressings outperform Kerracel-Ag at both 3-day and 6-day treatment timepoints without impacting wound healing (as measured by % re-epithelialization). The Cu-CMC showed 2-3 log reduction relative to the untreated control, whereas Kerracel-Ag showed no statistically significant reduction in bacterial load.