Testing of cadexomer Iodine against a variety of micro-organisms grown in single and mixed species biofilms

The simplistic definition of a biofilm is a structured community of bacterial cells enclosed in a self-produced polysaccharide matrix, which adheres to an inert or living surface. Several authors have stated that nearly 2/3 of chronic wounds contain bioburden in the form of biofilms^1,2. It has been reported that biofilm-associated infections exceeds $1 billion/year in the US^3-5. The purpose of this study⁶ was to evaluate the ability of cadexomer iodine dressings to prevent biofilm formation in vitro over a 48 h period using single and mixed species biofilm models.  Biofilms were grown in a 96-well microtitre plate. The lid was sealed with parafilm and incubated at 37^OC for 48 hours. For each dressing tested, replicates were aseptically placed into appropriate wells of a fresh 96-well microtitre plate. Following two wash steps to remove excess stain and subsequent elution of the remaining stain in ethanol, the optical density (OD) at 570 nm was then measured for each well. The results were grouped into strong biofilm, moderate biofilm, weak biofilm or no biofilm categories. The mixed bacterial species used are common to DUs and PUs. The results indicate that in contrast to a filter paper control (upon which biofilms grew freely) cadexomer iodine prevented biofilm formation against P. aeruginosa, S. aureus and mix species biofilms. The data suggests that rapid intervention with cadexomer iodine may be useful in preventing biofilm formation in wounds. It is hoped that studies of this type will allow for enhanced clinician education, patient safety and prove beneficial to facilities with respect to wound care.