Ag Oxysalts™ – In Vivo Assessment of Antibiofilm Efficacy and Effects on Healing

Background: Potent antimicrobial dressings are required to effectively combat biofilm infections; however, their potent nature should not adversely affect the wound environment. Ag Oxyalts™ produce higher oxidative states of silver (Ag2+/Ag3+), making them potently antimicrobial. In this study, the efficacy of Ag Oxysalts™ dressings against biofilms and the effects on healing independent of infection was compared to traditional silver dressings (Ag1+). Methods: Excisional mouse wounds infected with mature Pseudomonas aeruginosa or Staphylococcus aureus biofilms were treated with control or silver dressings for three days. Biofilms were visualized by fluorescence in-situ hybridization (FISH) and scanning electron microscopy (SEM). Wound area and reepithelialization was assessed by histological analysis. The effects on healing independent of infection were assessed in uninfected excisional mouse wounds.

Results: FISH and SEM indicated that Ag Oxysalt™ dressings reduced biofilm biomass to a greater extent than Ag1+ dressings. Biofilm infected wounds treated with Ag Oxysalt™ dressings were significantly smaller (2.2 mm² ± 0.1) than control (3.3 mm² ± 0.3) and Ag1+ (3.6 mm² ± 0.3) treated wounds. Furthermore, reepithelialization was enhanced in Ag Oxysalt™ treated infected wounds (34% ± 6%) compared to control (15% ± 2%) and Ag1+ (10% ± 3%) treated wounds. Uninfected mouse wounds treated with Ag Oxysalt™ dressings were significantly smaller (2.2 mm² ± 0.3) than control (3.1 mm² ± 0.4) and Ag1+ (3.5 mm² ± 0.4) treated wounds and showed greater reepithelialization (30% ± 3%, 23% ± 3%, 20% ± 3%, respectively).

Conclusion: In these in vivo studies, Ag Oxysalt™ dressings effectively reduce biofilm biomass and do not adversely affect the wound environment, promoting healing independent of infection.