EDTA as an adjunct to non-antimicrobial wound dressings enhances anti-biofilm ability.

Abstract: Biofilms have gained precedence in health care settings predominantly due to their association with persistent infections and increased tolerance to antimicrobials. The use of agents that help to break down biofilms to predispose them to other interventions is in great need. Despite this, there are currently no wound dressings on the market specifically developed to prevent and control biofilms. Therefore the aim of this study was to investigate whether the addition of a universally accepted anti-biofilm agent tetrasodium-EDTA (T-EDTA), enhances the anti-biofilm ability of existing fibrous, non-antimicrobial wound dressings. Methods: Non-antimicrobial wound dressings (woven and non-woven) were cut into 5cm x 5cm pieces and either soaked or sprayed with various concentrations of T-EDTA (2%-15%). The wound dressings were then and air-dried. Biofilms were created using the CDC Bioreactor model to test anti-biofilm efficacy. Briefly, Staphylococcus aureus, Pseudomonas aeruginosa or Candida albicans biofilms were grown for 48 hours before washing in 0.85% saline. Wound dressings impregnated with the T-EDTA were hydrated with sterile water before adding to the biofilms and incubating for 24 hours at 37°C. Wound dressings and biofilms were added to 10ml of sterile diluent, vortexed for 10 seconds and sonicated for 10 minutes before determining total viable counts (TVCs). Results: TVCs showed a 3-log reduction in planktonic and biofilm microorganisms in upon the application of T-EDTA* impregnated wound dressings for 24 hours. Significant bacterial number reductions were determined when compared to non-T-EDTA, non-antimicrobial wound dressings after 24 hours. Conclusions: The incorporation of T-EDTA into non-antimicrobial wound dressings successfully enhances the anti-biofilm efficacy of the commercially-available dressings. T-EDTA represents a potential adjunct therapy that could be used for next generation anti-biofilm management in hard-to-heal wounds.

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