Decontamination of Polymeric Surgical Sutures Covered with Bacterial Biofilms Using Nonthermal Plasma

Abstract

The objective of the study was to investigate the bactericidal effectiveness of atmospheric pressure nonthermal plasma (NTP) on biofilms of Staphylococcus aureus and Escherichia coli formed on the surface of surgical sutures. Tests were carried out for polyamide nonabsorbable monofilament sutures and mid-term absorbable synthetic monofilament sutures made of glyconate. Dielectric barrier discharge reactor providing atmospheric air plasma and constant discharge power density of 70 mW/cm2 was used in the experiments. The colonization/decontamination efficacy was quantified by colony-counting assay. It was shown that decontamination efficacy of the studied surgical sutures was time-dependent i.e. the effect was more visible for longer exposure times ranging from 60 to 360 s. It was proposed to combine plasma treatment with washing the biofilms with a phosphate buffered saline to to allow the plasma to interact with cells in the deeper layers of bacterial biofilm. The application of the original method of treatment of biofilms was more effective than the separate plasma treatment. As a result, the lethal effect was most often achieved after 300 s regardless of the type of suture and biofilm. The results of the comparative studies on the decontamination efficiency of polymeric surgical suture surface by disinfectants and NTP technique have shown unequivocally that plasma treatment is the most effective way to deactivate bacterial cells and ensures a lethal effect for most of the tested cases.