The increasing risk of antibiotic failure in the treatment of Pseudomonas aeruginosa infections is largely related to the production of a wide range of virulence factors. The use of non-thermal plasma (NTP) is a promising alternative to antimicrobial treatment. Nevertheless, there is still a lack of knowledge about the effects of NTP on the virulence factors production. We evaluated the ability of four NTP-affected P. aeruginosa strains to re-form biofilm and produce Las-B elastase, proteases, lipases, haemolysins, gelatinase or pyocyanin. Highly strains-dependent inhibitory activity of NTP against extracellular virulence factors production was observed. Las-B elastase activity was reduced up to 82% after 15-min NTP treatment, protease activity and pyocyanin production by biofilm cells was completely inhibited after 60 min, in contrast to lipases and gelatinase production, which remained unchanged. However, for all strains tested, a notable reduction in biofilm re-development ability was depicted using spinning disc confocal microscopy. In addition, NTP exposure of mature biofilms caused disruption of biofilm cells and their dispersion into the environment, as shown by transmission electron microscopy. This appears to be a key step that could help overcome the high resistance of P. aeruginosa and its eventual elimination, for example in combination with antibiotics still highly effective against planktonic cells.

• Keywords
• antivirulence factors, biofilm disruption, cold atmospheric plasma (CAP), combined therapy, haemolytic activity,
• MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Biofilms MeSH
• Endopeptidases pharmacology   MeSH
• Virulence Factors MeSH
• Hemolysin Proteins pharmacology   MeSH
• Humans MeSH
• Pancreatic Elastase MeSH
• Plankton MeSH
• Plasma Gases * pharmacology   MeSH
• Peptide Hydrolases MeSH
• Pseudomonas Infections * MeSH
• Pseudomonas aeruginosa MeSH
• Pyocyanine MeSH
• Quorum Sensing MeSH
• Gelatinases pharmacology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH
• Endopeptidases MeSH
• Virulence Factors MeSH
• Hemolysin Proteins MeSH
• Pancreatic Elastase MeSH
• Plasma Gases * MeSH
• Peptide Hydrolases MeSH
• Pyocyanine MeSH
• Gelatinases MeSH

A non-thermal plasma (NTP) is a promising tool against the development of bacterial, viral, and fungal diseases. The recently revealed development of microbial resistance to traditional drugs has increased interest in the use of NTPs. We have studied and compared the physical and microbicidal properties of two types of NTP sources based on a cometary discharge in the point-to-point electrode configuration and a corona discharge in the point-to-ring electrode configuration. The electrical and emission properties of both discharges are reported. The microbicidal effect of NTP sources was tested on three strains of the bacterium Staphylococcus aureus (including the methicillin-resistant strain), the bacterium Pseudomonas aeruginosa, the yeast Candida albicans, and the micromycete Trichophyton interdigitale. In general, the cometary discharge is a less stable source of NTP and mostly forms smaller but more rapidly emerging inhibition zones on agar plates. Due to the point-to-ring electrode configuration, the second type of discharge has higher stability and provides larger affected but often not completely inhibited zones. However, after 60 min of exposure, the NTP sources based on the cometary and point-to-ring discharges showed a similar microbicidal effect for bacteria and an individual effect for microscopic fungi.

• Keywords
• Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus, Trichophyton interdigitale, corona discharge, microbicidal effect,
• Publication type
• Journal Article MeSH