Ability of Different Non-Antimicrobial Wound Dressings to Remove Bacteria from Surfaces Using in vitro Planktonic and Mature Biofilm Models

Introduction: Non-antimicrobial wound dressings can remove bacteria from wound surfaces through mechanisms such as binding and immobilization, which may contribute to antimicrobial stewardship. Methods: This study evaluated four different types of dressings (gauze, carboxymethylcellulose gelling fiber [CMC], dialkylcarbamoyl chloride [DACC] hydrophobic coated fibers, and polyurethane [PU] foam) for removal of planktonic bacteria (all dressings) and mature biofilm bacteria (CMC, DACC and PU foam dressings) in vitro. Total viable counts were performed after incubation for 2, 4 and 6 hours. Results: The percentage of CA-MRSA removed by CMC dressing was significantly (p< 0.05) greater than all other dressings at all timepoints in the planktonic and biofilm models. A significantly greater percentage of planktonic ESBL P. aeruginosa was removed by CMC dressings than other test dressings with the exception of when compared to PU Foam at the 6-hour time point. Differences in the removal of ESBL P. aeruginosa biofilms between CMC dressings and other dressings were less pronounced, which is likely due to the nature of the biofilm formed. Conclusion: CMC dressings may play an effective role in reducing bioburden of acute and hard-to-heal wounds in a clinical setting. Keywords: antimicrobial stewardship, biofilms, microbial drug resistance, wound healing, wound infection