Identifying the optimal agent for irrigation for periprosthetic joint infection remains challenging as there is limited data. The ideal solution should have minimal cytotoxicity while maintaining bactericidal activity. We developed a novel activated-zinc solution containing zinc-chloride (ZnCl2) and sodium-chlorite (NaClO2). The purpose of this study was 1.) to investigate the antimicrobial efficacy of 2 concentrations (“CZ1”, “CZ2”) against Staphylococcus aureus and Pseudomonas aeruginosa and 2.) to evaluate untoward effects of the solution on local wound tissue 24 hours after solution exposure in pig wound models.
The study was conducted and reported in accordance to ARRIVE guidelines. We created twenty-four 1.5cm wounds on the back of a Yorkshire-cross pig. Wounds were inoculated with standardized Pseudomonas and S. aureus. 8 wounds were designated as controls (inoculum without treatment), 8 treated with CZ1, and 8 with CZ2. Punch biopsies were taken 1 hour after treatment and bacteria quantified. Wound necrosis/neutrophil infiltrate was measured 24-hours post-exposure.
After 1-hour, the control, CZ1 and CZ2 wounds had total bacteria of 5.7, 2.8 and 3.5 logCFU/g, respectively (p=0.017). The control, CZ1 and CZ2 wounds had S. aureus of 5.3, 2.3 and 1.6 logCFU/g, respectively (p=0.009). The control, CZ1 and CZ2 wounds had Pseudomonas of 5.5, 0.3 and 0.0 logCFU/g, respectively (p=0.000). After 24 hours of exposure to CZ1 and CZ2, there was no statistically significant increased necrosis (p=0.12, p=0.31, respectively). CZ1 had increased, moderate neutrophil infiltrate (p=0.04) when compared to controls, however CZ2 was not significant (p=0.12).
Our novel solution demonstrated 99.5–99.9% reduction in total bacteria, 99.9–99.98 % reduction in S. aureus, and 100% eradication of Pseudomonas 1-hour after exposure, without significantly increased necrosis and no-to-minimally-increased neutrophil infiltrate. This novel solution may provide another significant tool in the arsenal to treat and/or prevent PJI and other wound infections.