Background: Multidrug resistant bacteria pose an impending catastrophe for human health around the world. Even minor injuries and common infections are becoming more difficult to treat, with dire consequences for people needing invasive and life-saving surgery. Bacteria naturally reside in biofilms as complex communities encased in a self-assembled matrix. This lifestyle protects bacteria from medical therapies and promotes resistance contributing to therapeutic failure and exacerbation, which stresses the need for more effective treatments.
Aim: This talk will cover new antibiofilm strategies in the development pipeline, including a patented treatment combination of diethyldithiocarbamate and copper (DDC-Cu), and plasma activated water (PAW), which utilises a physical process to enhance the surface properties of materials.
Methods: The minimum inhibitory concentration was determined in multiple ESKAPE pathogens. Antibiofilm efficacy was assessed via the Alamarblue viability assay, confocal microscopy with live/dead staining and in a 3D biofilm model (bioflux system coupled to a brightfield microscope). Cytotoxicity was determined in human keratinocytes (HaCaT) by the lactate dehydrogenase assay.
Results: DDC-Cu showed synergistic effects compared to the individual compounds against Staphylococci in planktonic and biofilm form, but was not active against gram negative bacteria. PAW effectively inhibited bacterial growth of gram positive and gram negative bacteria. Significant antibiofilm activity (p<0.0001) was observed, showing 99% biofilm killing for all bacteria tested. These results were further confirmed by microscopy. Both DDC-Cu and PAW in therapeutic concentrations showed no substantial toxicity in keratinocytes.
Conclusion: DDC-Cu exhibited narrow spectrum efficacy and PAW exhibited broad spectrum efficacy against multidrug resistant bacteria and biofilms. Both strategies have the potential to progress into antimicrobial treatments for clinical application, e.g. as antibiotic-free therapy for surgical procedures or wounds.