Efficacy of Different Carrier Gases for Barrier Discharge Plasma Generation Compared to Chlorhexidine on the Survival of <b><i>Pseudomonas aeruginosa</i></b> Embedded in Biofilm in vitro

Abstract

Because of its antimicrobial properties, nonthermal plasma could serve as an alternative to chemical antisepsis in wound treatment. Therefore, this study investigated the inactivation of biofilm-embedded Pseudomonas aeruginosa SG81 by a surface barrier-discharged (SBD) plasma for 30, 60, 150 and 300 s. In order to optimize the efficacy of the plasma, different carrier gases (argon, argon admixed with 1% oxygen, and argon with increased humidity up to approx. 80%) were tested and compared against 0.1% chlorhexidine digluconate (CHG) exposure for 600 s. The antimicrobial efficacy was determined by calculating the difference between the numbers of colony-forming units (CFU) of treated and untreated biofilms. Living bacteria were distinguished from dead by fluorescent staining and confocal laser scanning microscopy. Both SBD plasmas and CHG showed significant antimicrobial effects compared to the untreated control. However, plasma treatment led to a higher antimicrobial reduction (argon plasma 4.9 log₁₀ CFU/cm², argon with admixed oxygen 3 log₁₀ CFU/cm², and with increased gas humidity 2.7 log₁₀ CFU/cm² after 300 s) compared to CHG. In conclusion, SBD plasma is suitable as an alternative to CHG for inactivation of Pseudomonas aeruginosa embedded in biofilm. Further development of SBD plasma sources and research on the role of carrier gases and humidity may allow their clinical application for wound management in the future.

One Year Follow-Up Risk Assessment in SKH-1 Mice and Wounds Treated with an Argon Plasma Jet

“…In this field called plasma medicine, encouraging results have been achieved for disinfection purposes [2], in vitro [3,4,5] and in patients [6,7,8]. Notably, a key feature determining healing is the state of wound oxygenation [9], and evidence suggests that the scavenging of active oxygen species impairs wound healing [10].…”

Redox‐regulation of activator protein 1 family members in blood cancer cell lines exposed to cold physical plasma‐treated medium

“…Plasma generates significant amounts of reactive components with biological importance such as reactive oxygen (ROS) and nitrogen species (RNS) . ROS and RNS are important as anti‐microbial effectors and in controlling redox signaling responses in eukaryotic systems . This also accounts for cancers which often show a pronounced sensitivity toward oxidative stress due to the malfunction of their anti‐oxidative defense .…”

Antibacterial Activity of Cold Atmospheric Pressure Argon Plasma against 78 Genetically Different (<b><i>mecA</i></b>, <b><i>luk-P</i></b>, <b><i>agr</i></b> or Capsular Polysaccharide Type) <b><i>Staphylococcus aureus </i></b>Strains

“…CAP has been investigated in the treatment of chronic wounds [3,4], including chronic ulcers without [5] and in combination with the antiseptic octenidine [6] (which increased the efficacy of CAP due to its residual antimicrobial effect [7]), on skin graft donor wounds [8], for skin antisepsis [9,10,11,12], and for the inactivation of microorganisms embedded in biofilms [13,14,15,16,17]. …”