The effect of Collagen-based wound dressings on bacterial growth

Non-healing wounds are generally characterized as having a hostile environment, which contains high levels of destructive proteases, which are detrimental to the healing process. Collagen/ORC is a wound therapy, which is designed to promote healing by rebalancing this wound environment, thereby supporting cell growth, whilst simultaneously reducing proteases. However, the presence of bacteria can complicate the wound healing process and it is a concern that if we provide a positive environment for cells that this may also aid bacterial growth in the wound. While the antimicrobial properties of ORC have already been reported, the effect of collagen on bacterial cell growth is unknown.   This study investigates the effect of collagen-based dressings on bacterial growth; in particular we examined the effect on common wound pathogens. These dressings were assessed using zone of inhibition and bacterial log reduction experiments, techniques, which are recognized as industry standards for assessing antimicrobial activity.   Our results demonstrate that Collagen/ORC reduces bacterial growth producing a zone of inhibition, which was sustained even when the product was transferred to a freshly colonized agar plate. This bactericidal effect was confirmed in quantitative assays, examining bacterial growth within the 3-hour time frame. This antimicrobial effect was not observed with other collagen only based wound dressings, when tested in both these assay systems.   This data demonstrates that Collagen/ORC does not support bacterial growth in vitro, and comparative data with collagen only products suggests that it is the ORC component, which provides this antimicrobial benefit.