Antimicrobial efficacy and safety of a novel gas plasma-activated catheter lock solution

Antimicrobial lock solutions are important for prevention of microbial colonization and infection of long-term central venous catheters. We investigated the efficacy and safety of a novel antibiotic-free lock solution formed from gas plasma-activated disinfectant (PAD). Using a luminal biofilm model, viable cells of methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Candida albicans in mature biofilms were reduced by 6 to 8 orders of magnitude with a PAD lock for 60 min. Subsequent 24-h incubation of PAD-treated samples resulted in no detectable regrowth of viable bacteria or fungi. As a comparison, the use of a minocycline-EDTA-ethanol lock solution for 60 min led to regrowth of bacteria and fungi, up to 10⁷ to 10⁹ CFU/ml, in 24 h. The PAD lock solution had minimal impact on human umbilical vein endothelial cell viability, whereas the minocycline-EDTA-ethanol solution elicited cell death in nearly half of human endothelial cells. Additionally, PAD treatment caused little topological change to catheter materials. In conclusion, PAD represents a novel antibiotic-free, noncyto-toxic lock solution that elicits rapid and broad-spectrum eradication of biofilm-laden microbes and shows promise for the prevention and treatment of intravascular catheter infections.