Silver Oxynitrate, an Unexplored Silver Compound with Antimicrobial and Antibiofilm Activity

Abstract

ABSTRACTHistorically it has been accepted, and recent research has established, that silver (Ag) is an efficacious antimicrobial agent. A dwindling pipeline of new antibiotics, combined with an increase in the number of antibiotic-resistant infections, is bringing Ag to the fore as a therapeutic compound to treat infectious diseases. Currently, many formulations of Ag are being deployed for commercial and medical purposes, with various degrees of effectiveness at killing microbial cells. Here, we evaluated the antimicrobial and antibiofilm capacity of our lead compound, silver oxynitrate [Ag(Ag3O4)2NO3or Ag7NO11], against other metal compounds with documented antimicrobial activity, including Ag2SO4, AgNO3, silver sulfadiazine (AgSD), AgO, Ag2O, and CuSO4. Our findings reveal that Ag7NO11eradicates biofilm and planktonic populations ofPseudomonas aeruginosa,Escherichia coli,Staphylococcus aureus, uropathogenicEscherichia coli(UPEC), fluoroquinolone-resistantPseudomonas aeruginosa(FQRP), and methicillin-resistantStaphylococcus aureus(MRSA) at lower concentrations than those of the other tested metal salts. Altogether, our results demonstrate that Ag7NO11has an enhanced efficacy for the treatment of biofilm-forming pathogens.