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

<jats:title>ABSTRACT</jats:title> <jats:p> Historically 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(Ag <jats:sub>3</jats:sub> O <jats:sub>4</jats:sub> ) <jats:sub>2</jats:sub> NO <jats:sub>3</jats:sub> or Ag <jats:sub>7</jats:sub> NO <jats:sub>11</jats:sub> ], against other metal compounds with documented antimicrobial activity, including Ag <jats:sub>2</jats:sub> SO <jats:sub>4</jats:sub> , AgNO <jats:sub>3</jats:sub> , silver sulfadiazine (AgSD), AgO, Ag <jats:sub>2</jats:sub> O, and CuSO <jats:sub>4</jats:sub> . Our findings reveal that Ag <jats:sub>7</jats:sub> NO <jats:sub>11</jats:sub> eradicates biofilm and planktonic populations of <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="genus-species" xlink:type="simple">Pseudomonas aeruginosa</jats:named-content> , <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="genus-species" xlink:type="simple">Escherichia coli</jats:named-content> , <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="genus-species" xlink:type="simple">Staphylococcus aureus</jats:named-content> , uropathogenic <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="genus-species" xlink:type="simple">Escherichia coli</jats:named-content> (UPEC), fluoroquinolone-resistant <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="genus-species" xlink:type="simple">Pseudomonas aeruginosa</jats:named-content> (FQRP), and methicillin-resistant <jats:named-content xmlns:xlink="http://www.w3.org/1999/xlink" content-type="genus-species" xlink:type="simple">Staphylococcus aureus</jats:named-content> (MRSA) at lower concentrations than those of the other tested metal salts. Altogether, our results demonstrate that Ag <jats:sub>7</jats:sub> NO <jats:sub>11</jats:sub> has an enhanced efficacy for the treatment of biofilm-forming pathogens. </jats:p>