The antimicrobial and tissue healing efficacy of the atmospheric pressure cold plasma on grade III infected pressure ulcer: randomized controlled in vivo experiment.

AIM: To evaluate the antimicrobial efficacy and wound healing effect of atmospheric pressure cold plasma (APCP) on an infected pressure ulcer (IPUs) model that was created on rats. METHODS: A total of 18 rats was divided into APCP, silver sulfadiazine (AgS) and control groups to have six rats in each group. A third-grade pressure ulcer model was developed on the back of each of the rats, and pressure ulcers were infected by inoculation of multidrug resistance (MDR) Pseudomonas aeruginosa. A portable dielectric barrier discharge device was used to generate cold air plasma. APCP, AgS and saline treatments were carried out once a day for 14 days. The effectiveness of the treatment was evaluated on days 5, 10 and 15. Surface area, depth, pressure ulcer healing scale (PUSH) and microbiological examination were used for evaluation. RESULTS: The results of this study showed that APCP was superior over AgS application and irrigation with saline by means of the reduction in surface area and depth of ulcers. Furthermore, PUSH score in plasma group was lower than other groups and histopathological examination showed a higher epithelization in APCP group. The average reductions of MDR P. aeruginosa for APCP, AgS and control groups were determined as 5·64 ± 1·87, 1·91 ± 0·90 and 1·22 ± 0·88 log10 CFU per gram tissue, respectively. CONCLUSION: Atmospheric pressure cold plasma healed IPUs better than AgS. SIGNIFICANCE AND IMPACT OF THE STUDY: Portable cold plasma devices could be a potential novel treatment modality for the patients who have IPUs.

Antibiofilm efficacies of cold plasma and er: YAG laser on Staphylococcus aureus biofilm on titanium for nonsurgical treatment of peri-implantitis.

OBJECTIVES: The aim of the present study was to compare antibiofilm efficacies of the laser in contact and noncontact application modes and cold atmospheric plasma (CAP) on Staphylococcus aureus biofilm grown on sandblasted, large grit, acid-etched (SLA) titanium discs as an in vitro model of biofilm eradication on dental implant materials. METHODS: S. aureus biofilm was matured on titanium discs for 7 days then, treated with contact and noncontact Er:YAG laser and CAP. Antibiofilm efficacy of laser and plasma treatments were evaluated with colony counting and safranin assays. Surface characteristics of titanium disc were analyzed with scanning electron microscopy and surface roughness measurements. Temperature distribution over titanium discs were presented for the thermal safety assessment of laser and plasma treatments. RESULTS: : CAP resulted in 6-log inactivation of S. aureus biofilm, whereas biofilm inactivation was determined as 1 and 2.7-log for noncontact and contact laser treatments, respectively. Laser and plasma treatments did not cause any alterations on the roughness of titanium discs. Contact laser treatment caused a focal temperature increase up to 58°C, whereas plasma treatment led a uniform temperature distribution on the disc within safe limits. CONCLUSION: CAP showed superior antibiofilm activity on 7-day-old S. aureus biofilm grown over SLA titanium discs, compared to contact and noncontact laser treatment without temperature increase and any damage to the surface of titanium discs.

Escherichia coli cellular responses to exposure to atmospheric-pressure dielectric barrier discharge plasma-treated N-acetylcysteine solution.

AIM: To understand the underlying cellular mechanisms during inactivation of Escherichia coli in response to antimicrobial solution of nonthermal plasma-activated N-acetylcysteine (NAC). METHODS AND RESULTS: The recommended techniques were used to demonstrate E. coli cellular and transcriptomic changes caused associated with peroxynitrite and compared with plasma-treated NAC solution. The findings demonstrate that E. coli cells respond to plasma-treated NAC and undergo severe oxidative and nitrosative stress, and leading to stress-induced damages to different components of bacterial cells, which includes loss of membrane potential, formation of oxidized glutathione (GSSG), formation of nitrotyrosine (a known marker of nitrosative stress), DNA damage, and generated a prominent pool of peroxynitrite. Reverse-transcriptase (RT)-polymerase chain reaction analysis of reactive nitrogen species (RNS) responsive genes indicated their differential expressions. CONCLUSION: For the first time, we report that the plasma-treated NAC solution activates predominantly nitrosative stress-responsive genes in E. coli and is responsible for cell death. SIGNIFICANCE AND IMPACT OF THE STUDY: The reactive species generated in solutions by nonthermal plasma treatment depends on the type of solution or solvent used. The plasma-treated NAC solution rapidly inactivates E. coli, mostly involving highly RNS generated in NAC solution, and has high potential as disinfectant.