Title: 0213 - Cold-Atmospheric-Plasma Shows Antimicrobial Efficacy Towards Planktonic Bacteria And Biofilms


Fabian Cieplik (Presenter)
University Medical Center Regensburg

Felix Theinkom, University Medical Center Regensburg
Larissa Singer, University Medical Center Regensburg
Sylvia Binder, terraplasma GmbH
Julia Zimmermann, terraplasma GmbH
Karl-Anton Hiller, University Medical Center Regensburg
Wolfgang Buchalla, University Medical Center Regensburg
Tim Maisch, University Medical Center Regensburg


Objectives: Considering increasing resistances towards conventional antibiotics and antiseptics, cold-atmospheric plasma (CAP) may be a promising alternative antimicrobial approach in dental practice. Aims of this study were (I) to investigate the antimicrobial efficacy of CAP for inactivation of planktonic cultures and biofilms of oral pathogens and (II) to get first insights into its mechanism of action by assessing membrane damage after CAP treatment.

Methods: Planktonic suspensions (~108 cells/mL) of Enterococcus faecalis (ATCC 29212) and clinical isolates of Streptococcus agalactiae and S. constellatus were spread on Mueller-Hinton-Agar plates and treated with a CAP protoype device (Terraplasma GmbH, Garching, Germany). Monospecies biofilms of E. faecalis were grown for 24h, 48h or 72h in artificial saliva broth and then treated with CAP. For both, planktonic cells and biofilms, treatment periods ranged between 1 and 10 min. As positive controls, chlorhexidine (CHX; 0.2%, 2%) and UV-C irradiation (266 nm) were employed for identical treatment periods. Antimicrobial efficacy was evaluated by colony forming units (CFU) assay. Release of nucleic acids was measured spectrophotometrically to assess membrane damage after CAP-treatment of biofilms.

Results: CAP reduced CFU of all tested bacteria by ≥5 log10 when applied to planktonic cultures for 1 min. CAP-treatment for 5 min resulted in CFU-reductions of ≥5 log10 for 24h- and 48h-old biofilms and ≥3 log10 for 72h-old biofilms. CHX 0.2% and UV-C resulted in ≥3 log10 reduction of CFU, while CHX 2% led to inactivation by ≥5 log10. Spectrophotometric measurements showed no release of nucleic acids after treatment with CAP.

Conclusions: CAP exhibited similar antimicrobial efficacy as compared to positive controls CHX and UV-C. Thereby, CAP-treatment did not lead to release of nucleic acids indicating that no membrane damage occurred. As a contact-free procedure CAP may represent a valuable antimicrobial treatment modality for dental applications.

This abstract is based on research that was funded entirely or partially by an outside source:
Bavarian State Ministry for Economic Affairs and Media, Energy and Technology (Bay_MED, DERMA CARE Pro - klinische Forschung; Nr. 07 03/686 68/19/16/3/17/4/18).

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE