Combined effects of cold atmospheric pressure plasma and electrical stimulation on biofilms of Staphylococcus epidermidis

Adherence to biomaterials and formation of biofilms, are important factors in the pathogenicity of microorganisms, which may result in persistent infections despite aggressive antibiotic therapy. Within biofilms, bacteria are protected from host´s own defense mechanisms and antibiotics. Atmospheric pressure plasma, ionized electrical discharged gas-flows, might be an alternative method dealing with implant-related infections. Previous research showed the antimicrobial potential of cold atmospheric pressure plasma, by altering the morpholohgy and reducing viability of bacterial biofilms of Staphylococcus epidermidis.

Electrical stimulation as well shows promising results inhibiting bacterial growth. It has been shown, that alternating electric field stimulation has an influence on growth of S. epidermidis after electrical stimulations with 0.2V_RMS and 1.4V_RMS after 48 and 72h, respectively.

A newly custom-made stimulation chamber, described by Dauben et al. 2016 was developed to simulate implant-associated infections in vitro. The objective of this experimental study is the examination of the influence of cold atmospheric pressure plasma combined with electrical stimulation on biofilm formation of S. epidermidis, antimicrobial potential as well as gentamicin susceptibility. In our experiments, sinusoidal alternating electrical fields are applied on plasma-treated bacteria for the duration of 24 h. The results might demonstrate the potential of atmospheric pressure plasma and electrical stimulation combining major purposes dealing with infected implants: to inhibit biofilm formation of S. epidermidis and simultaneously increase the gentamicin-susceptibility.

• Analysis of potential inhibitory effects of electrical stimulation with 5.6 V_RMS on plasma-treated S. epidermidis
• Analysis of gentamicin-susceptibility after electrical stimulation of plasma-treated S. epidermidis
• Determination of bacterial count, biofilm mass quantification, scanning electron microscopy, confocal laser scanning microscopy

Peer-reviewed journal papers:

PRINZ, C., WEGNER, K., SCHNABELRAUCH, M., BERGEMANN, C., KAUTZ, R. and NEUMANN, H.G., 2016. Copper as an alternative antimicrobial coating. Frontiers in Bioengineering and Biotechnology 4. 10th World Biomaterials Congress, Montréal, Canada. DOI: 10.3389/conf.FBIOE.2016.01.00855.

• Prof. Dr. Bernd Kreikemeyer
• Prof. Dr. Barbara Nebe