Georg Daeschlein

Skin decontamination by low-temperature atmospheric pressure plasma jet and dielectric barrier discharge plasma

BACKGROUND Over the past few years, plasma medicine has become an important field in medical science. Cold plasma has proven anti-inflammatory, antimicrobial and antineoplastic effects. AIM To test the decontamination power of two cold plasma sources [low-temperature atmospheric pressure plasma jet (APPJ) and dielectric barrier discharge plasma (DBD)] in vivo on human fingertips. METHODS After 3, 15, 30, 60, 90, 120, 150, 180, 210 and 240 s of spot treatment with the APPJ and DBD, the log reduction factors (RFs) of physiological (PF) and artificially (AF) contaminated flora (Staphylococcus epidermidis and Micrococcus luteus) were calculated. The bacterial load was determined after counting. Tolerance (paresthesia, pain and heat) was measured using a numerical rating scale. FINDINGS Both plasma devices led to a significant reduction in PF and AF. The maximum log reduction factors for PF were 1.3 for the DBD at 210 s and 0.8 for the APPJ at 60 s. For AF, the maximum log reduction factors were 1.7 for the DBD at 90 s and 1.4 for the APPJ at 120 s. Treatment with both devices was well tolerated. CONCLUSION Both the APPJ and DBD were highly effective in eradicating PF and AF from the fingertips of healthy volunteers. No plasma-resistant isolates were observed. Cold plasma appears to have potential for skin disinfection. For hand hygiene purposes, plasma exposure times would need to be reduced significantly by technical means.

Feasibility and Clinical Applicability of Polihexanide for Treatment of Second-Degree Burn Wounds

Objectives: Due to a partial rejection of mesh split-thickness skin grafts (mesh grafts) after application of povidone-iodine and silver nitrate and due to its better in vitro tolerance, polihexanide was investigated as an alternative and its applicability in the treatment of second-degree burn wounds. Methods: In 4 patients with poorly healing decubitus ulcers the mesh grafts were each divided into three areas which were pre-treated with either undiluted povidone-iodine solution, 1% silver nitrate solution or 0.04% polihexanide solution. After 7 days of application the wound areas were compared clinically and histologically. Thereafter 14 patients (average extent of burns 28% TBSA) were treated in the same way. Results: Clinically and histologically the mesh grafts treated with polihexanide showed by far the best re-epithelialization compared with the deep tissue necrosis and marked fibrin discharge observed for application of povidone-iodine and silver nitrate. The second-degree burn wounds treated with polihexanide epithelialized without any further débridement after an average of 10 days with remarkable freedom from pain. Compared with silver nitrate treatment, no fibrin film was observed on the wound. Conclusion: Polihexanide proved clinically and histologically superior to povidone-iodine and silver nitrate. For the treatment of second-degree burns, which cannot primarily be covered by plastic surgery, polihexanide is suitable because in addition to its antiseptic efficacy it does not inhibit the re-epithelialization process.

In vitro Antibacterial Activity of Lucilia sericata Maggot Secretions

Maggots of the green blowfly, Lucilia sericata, are used as an alternative to surgical intervention and long-term antiseptic therapy for the treatment of chronic wounds. The secretions of maggots are known to have antibacterial properties. To quantify the bactericidal effect of secretions from larvae of L. sericata, an in vitro test model based on the modified European quantitative suspension test (EN 1040) was developed, in which a co-culture of maggots and bacteria (Micrococcus luteus,Escherichia coli, methicillin-sensitive Staphylo-coccus aureus) in tryptic soy broth was tested. The numbers of bacterial colonies with and without maggot exposure were compared after 24, 48 and 72 h of exposure. The mean log10 reduction factor (RF) for bacterial elimination per maggot was >4 at all examined times for all tested bacteria. Thus, maggot secretion fulfilled the required definitions of an antiseptic. In addition, the maggots’ ability to ingest bacteria was also evaluated. Maggots contained viable bacteria after 48 h of contact with the respective organisms. These maggots also continued excreting bacteria. Therefore, maggots should be disposed of after use as they must be regarded as medical waste.

Cold plasma is well‐tolerated and does not disturb skin barrier or reduce skin moisture

Background: Cold plasma, a new treatment principle in dermatology based on ionic discharge delivering reactive molecular species and UV‐light, exhibits strong antimicrobial efficacy in vitro and in vivo. Before implementing plasma as new medical treatment tool, its safety must be proven, as well as assessing skin tolerance and patient acceptance.

In Vitro Killing of Clinical Fungal Strains by Low-Temperature Atmospheric-Pressure Plasma Jet

Plasma medicine is an expanding focus and offers new aspects of therapy combining potent physical partial efficacies, like such as ultraviolet, infrared, and reactive species and particles, and nowadays, many successful treatments of different illnesses have been described. Fungal skin and nail infections pose significant therapeutic and economical problems. To test the plasma susceptibility of clinical strains of the most frequently encountered fungal species involved in dermatomycosis, clinical isolates of Trichophyton interdigitale, Trichophyton rubrum, Microsporum canis, and Candida albicans were irradiated by a cold atmospheric pressure plasma jet. Punctual plasma irradiation eradicated fungal growth of all species with the largest inactivation zones with most progress in the first 15 s of treatment, treating C. albicans and least progress in that of , the lowest being M. canis. No isolate exhibited resistance to plasma treatment. Plasma treatment also completely eradicated reproductive fungal elements of T. interdigitale in dandruff of patients with tinea pedis ex vivo and in the environment in contaminated shoes. Accordingly, cold plasma seems suited to antifungal in vivo treatment of fungal skin infections and decontamination of environmental infective material.

Skin and wound decontamination of multidrug-resistant bacteria by cold atmospheric plasma coagulation

Novel concepts to limit the spread of multidrug‐resistant bacteria (MDR) are urgently needed. Since treatment with cold atmospheric plasma (CAP) has shown significant antibacterial properties, the purpose of this study was to evaluate the ability of CAP to eliminate MDR‐ compared to non‐MDR‐pathogens in chronic wounds.

Antimicrobial and antiseptic strategies in wound management

Wounds, especially chronic wounds, represent a global problem costing millions of dollars per year in developed countries and are characterised by microbial complications including local or overt infection, delayed healing and spread of multiresistant germs. Therefore, antimicrobial wound management is a major challenge that continues to require new solutions against microbes and their biofilms. As systemic antibiotics can barely penetrate into wound biofilms and topically applied ones can easily lead to sensitisation, antisepsis is the method of choice to treat germs in wounds. This brief review discusses the role of antiseptics in reducing bioburden in chronic wounds. Balancing antimicrobial potency and tolerability of antiseptic procedures is critical in wound therapy. However, antiseptics alone may not be able to achieve wound healing without addressing other factors regarding the patients general health or the wounds physical environment. Although the precise role of bioburden in chronic wounds remains to be evaluated, planktonic as well as biofilm‐bound microbes are indications for antiseptic intervention. Octenidine dihydrochloride and polyhexanide are the most effective, as well as best tolerated, antiseptics in wound management today, and new strategies to reduce bacterial wound burden and support the bodys immune response are being developed.

Comparison between cold plasma, electrochemotherapy and combined therapy in a melanoma mouse model.

The study was undertaken to compare antitumor efficacy of electrochemotherapy (ECT) with cold plasma therapy (CP) in a melanoma mouse model. After melanoma implantation into the flank of C57BL/6N mice, CP by two different plasma sources (APPJ and DBD) was applied directly to the tumor surface. ECT was performed with bleomycin intravenously at a field strength of 1000 V/cm without or combined with CP. Primary endpoints were tumor growth acceleration (TGA), daily volume progression (DVP) and survival after treatment. Both plasma sources as single treatment showed a significant TGA delay, which proved less effective than ECT. CP (APPJ) combined with ECT (ECJ) significantly improved per cent mouse survival, with significant superiority compared with ECT. Plasma therapy alone albeit less effective seems a potential alternative to ECT in patients with melanoma and can be applied manifold in a session without general anaesthesia. Accordingly, CP alone and combined with ECT may serve as new option in palliative skin melanoma therapy.

Evaluation of an innovative antimicrobial surgical glove technology to reduce the risk of microbial passage following intraoperative perforation.

BACKGROUND Surgical gloves provide a protective barrier for patients and members of the surgical team. Although glove integrity is important in an era of blood-borne pathogens, little data exist on bacterial passage after glove perforation. This study evaluated the impact of antimicrobial surgical gloves in reducing microbial passage after glove puncture in a model of wound contamination. METHODS Staphylococcus aureus (ATCC 6538) and Brevundimonas diminuta (DSM 1639) were used to prepare a standardized suspension for testing bacterial passage after glove puncture in volunteers wearing single-layer gloves (group A), double-layer gloves (group B), or antimicrobial trilayer gloves (group C). After exposure periods of 5, 10, 30 and 45 minutes, the outer test gloves were removed and microbial passage was measured on the inner surface of the base gloves. Multiple repetitions (5 or 6) were performed at each sampling time. RESULTS Microbial passage at 5-, 10-, 30-, and 45-minute exposures were analyzed both separately and combined (5 and 10 minutes and 30 and 45 minutes). No difference was observed in microbial passage between group A and group B at the 10-, 30-, and 45-minute exposures for S aureus, whereas a significant reduction in microbial passage was observed in group C compared with group A (P ≤ .05 to < .005) at the 5-, 30-, and 45-minute exposures for both S aureus and B diminuta. When timed groups were combined (5 and 10 minutes and 30 and 45 minutes), a significant reduction (P ≤ .01 to ≤ .005) in microbial passage of S aureus and B diminuta was observed in group C compared with both group A and group B. CONCLUSION These findings represent the first evidence that microbial passage across surgical gloves can be reduced significantly using an innovative antimicrobial glove technology.

In Vitro Activity of Atmospheric Pressure Plasma Jet (APPJ) Plasma Against Clinical Isolates of Demodex Folliculorum

Rosacea is a frequent and often disfiguring and chronic dermatologic disease mainly of the midface causing central facial erythema, teleangiectasia, papules, and pustules. In the context of complex pathogenicity, Demodex folliculorum plays an important role showing significant density in the skin of patients with papulopustular rosacea. Rosacea belongs to the hard-to-heal diseases, and new approaches for treatment are strongly required. As atmospheric low-temperature plasma [atmospheric pressure plasma jet (APPJ)] proved high efficacy against bacterial and fungal pathogens, we tested its potency as nonantibiotic-based method to inactivate Demodex folliculorum. We isolated five parasites of Demodex folliculorum from a 54-year-old patient suffering from chronic pustulous rosacea and irradiated the living parasites by APPJ ex vivo. The APPJ plasma killed Demodex folliculorum after an exposure time of 2 resp. 60 s. Low-temperature atmospheric pressure plasma seems suitable for the treatment of dermatologic and veterinarian diseases caused by Demodex spp.