Polyester Mesh Functionalization with Nitric Oxide-Releasing Silica Nanoparticles Reduces Early Methicillin-Resistant <i>Staphylococcus aureus</i> Contamination.

Abstract

<b><i>Background:</i></b> Infected hernia mesh is a cause of post-operative morbidity. Nitric oxide (NO) plays a key role in the endogenous immune response to infection. We sought to study the efficacy of a NO-releasing mesh against methicillin-resistant <i>Staphylococcus aureus</i> (MRSA). We hypothesized that a NO-releasing polyester mesh would decrease MRSA colonization and proliferation. <b><i>Materials and Methods:</i></b> A composite polyester mesh functionalized with <i>N</i>-diazeniumdiolate silica nanoparticles was synthesized and characterized. <i>N</i>-diazeniumdiolate silica parietex composite (NOSi) was inoculated with 10⁴,10⁶, or 10⁸ colony forming units (CFUs) of MRSA and a dose response was quantified in a soy tryptic broth assay. Utilizing a rat model of contaminated hernia repair, implanted mesh was inoculated with MRSA, recovered, and CFUs were quantified. Clinical metrics of erythema, mesh contracture, and adhesion severity were then characterized. <b><i>Results:</i></b> Methicillin-resistant <i>Staphylococcus aureus</i> CFUs demonstrated a dose-dependent response to NOSi in vitro. In vivo, quantified CFUs showed a dose-dependent response to NOSi-PCO. Treated rats had fewer severe adhesions, less erythema, and reduced mesh contracture. <b><i>Conclusions:</i></b> We demonstrate the efficacy of a NO-releasing mesh to treat MRSA in vitro and in vivo. Creation of a novel class of antimicrobial prosthetics offers new strategies for reconstructing contaminated abdominal wall defects and other procedures that benefit from deploying synthetic prostheses in contaminated environments.