EDTA Complexes with Metal Ions Demonstrate Outstanding Synergism for Antibiofilm Efficacy Against Wound Pathogens

Background: There is increasing evidence showing the presence of biofilms on surfaces, such as wounds, leading to infection, inflammation and delayed wound healing. Microbes growing in biofilms exhibit increased tolerance to antimicrobials and antibiotics in comparison to their planktonic counterparts and are therefore difficult to treat.

Purpose: The aim of this study was to evaluate antimicrobial and antibiofilm activity of several patent pending EDTA based complexes against common wound pathogens.

Methods: The minimum inhibitory concentration (MIC) of EDTA alone and in several different complexes with silver and various metal ions was determined using a broth microdilution method. The minimum biofilm eradication concentration (MBEC) was determined following ASTM E2799 - 17. Synergistic interactions between components of the complexes was evaluated using a 2D checkerboard MIC method and determining the fractional inhibitory concentration index (FICI).

Results: Following MIC and MBEC testing of EDTA alone and in complexes with silver and various other metal ions, significant increases in antimicrobial and antibiofilm potency was found with all complexes tested. Checkerboard assays showed synergistic interactions between several metal ion compounds and EDTA, with an FICI of 0.2 – 0.5 against Pseudomonas aeruginosa and Staphylococcus aureus.

Conclusion: The results highlight the use of patent pending EDTA complexes to be used for the next generation antibiofilm technologies for treating the difficult to heal wound infections, due to biofilms, and the inflammatory effects they cause.