The Efficacy of Tetrasodium EDTA on Biofilms

The aetiology of delayed wound healing characteristic of a chronic wound is relatively unknown but is thought to be due to a combination of the patient's underlying pathophysiology and external factors including infection and biofilm formation. The invasion of the wound by the hosts' resident microbiome and exogenous microorganisms can lead to biofilm formation. Biofilms have increased tolerance to antimicrobial interventions and constitute a concern to chronic wound healing. Consequently, anti-biofilm technologies with proven efficacy in areas outside of wound care need evaluation to determine whether their efficacy could be relevant to the control of biofilms in wounds. The aim of this study was to assess the anti-biofilm capabilities of tetrasodium EDTA (t-EDTA) as a stand-alone liquid and when incorporated in low concentrations into wound dressing prototypes. Results demonstrated that a low concentration of t-EDTA (4%) solution was able to kill Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), S. epidermidis, Pseudomonas aeruginosa and Enterococcus faecalis within in vitro biofilms after a 24-h contact time. The incorporation of low levels of t-EDTA into prototype fibrous wound dressings resulted in a 3-log reduction of bacteria demonstrating its microbicidal ability. Furthermore, hydrogels incorporating only a 0.2% concentration of t-EDTA (at preservative levels) caused a small reduction in biofilm. In conclusion, these studies show that t-EDTA as a stand-alone agent is an effective anti-biofilm agent in vitro. We have demonstrated that t-EDTA is compatible with numerous wound dressing platforms. EDTA could provide an essential tool to manage biofilm-related infections and should be considered as an anti-biofilm agent alone or in combination with other antimicrobials or technologies for increased antimicrobial performance in recalcitrant wounds.