Activity of a nitric oxide-generating wound treatment system against wound pathogen biofilms

Wound bioburden plays an important role in impaired healing and development of infection-related complications. The objective of this study was to determine the efficacy of an innovative two-layer nitric oxide-generating system (NOx) to prevent and treat biofilms formed by bacterial and fungal pathogens commonly associated with wound infection, and activity against Pseudomonas aeruginosa virulence factors. Single- and mixed-species biofilms were grown for 24 h on nitrocellulose filters placed on agar. Filters were covered with either NOx or placebo, before and after biofilm formation. Populations of bacteria and yeasts were determined using viable counts. Pyocyanin and elastase production from P. aeruginosa were determined in supernatants derived from suspended biofilms. Efficacy of NOx was demonstrated against Staphylococcus aureus, P. aeruginosa, Acinetobacter baumannii, Escherichia coli and Candida spp. Population reductions between 2- and 10-log fold were observed. Pyocyanin and elastase activities from P. aeruginosa were reduced 1.9- and 3.2-fold, respectively. This study demonstrated activity of NOx against formation and treatment of single- and mixed-species biofilms, including multidrug-resistant strains. NOx represents a new generation of antimicrobial agent with potent, broad-spectrum activity, and with no evidence of resistance development.