Sebastian von Podewils

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.

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.

In vitro susceptibility of methicillin-resistant and methicillin-susceptible strains of Staphylococcus aureus to two different cold atmospheric plasma sources

BackgroundStaphylococcus aureus may be the most important wound pathogen and causative for most of surgical site infections. As many anti-staphylococcal drugs are useless because of resistance, novel antimicrobial strategies are strongly needed and may be provided by cold atmospheric plasma (CP), which is being currently investigated for antiseptic efficacy.MethodsTo test the antimicrobial properties of CP against Staphylococcus aureus, 168 methicillin-susceptible isolates (MSSA) and 50 methicillin-resistant isolates (MRSA) were treated with two technically different plasma sources [an atmospheric pressure plasma jet (APPJ) and a dielectric barrier discharge plasma (DBD)] in vitro.ResultsCP treatment allowed a reproducible and significant growth reduction of MRSA and MSSA. However, MRSA was significantly less susceptible to treatment with DBD than was MSSA, while no difference between MRSA and MSSA was found using APPJ.ConclusionsAs the initial physical antiseptic on skin, CP may be suitable for rapid decolonization of microbial pathogens in vivo. Each device must undergo validated efficacy testing prior to clinical application, as device related differences may occur.

Antimicrobial Efficacy of a Historical High-Frequency Plasma Apparatus in Comparison With 2 Modern, Cold Atmospheric Pressure Plasma Devices.

Background. Today, highly sophisticated devices deliver cold atmospheric pressure plasma (CAPP) with a multitude of bioactive properties, opening the window to a new medical field: plasma medicine. Different techniques to create the optimal plasma device for different medical indications are currently being explored. However, even a 100 years ago, CAPP was briefly used in the related form of high-frequency therapy. The objective of our study was to compare historic with modern techniques regarding antimicrobial efficacy. Methods. First, 26 different clinical isolates of relevant wound pathogens were treated in vitro with a historic violet wand (VW) and 2 modern plasma sources (kINPen 09 and dielectric barrier discharge [DBD]) and the obtained inhibition areas (IAs) were compared. Second, a biofilm model was used to compare biofilm inactivation by VW, DBD, ethanol, and polyhexanide treatment. Results. DBD with the largest electrode produced the largest IAs. VW showed results similar to 2 different modes of the kINPen 09. IAs of VW were enlargeable by attaching a larger electrode. Against biofilms, VW was less effective than DBD but more effective than ethanol 70% and polyhexanide. Conclusion. The proven antimicrobial efficacy of VW may encourage the development of new, potent plasma devices based on the very simple and inexpensive technique of the historic high-frequency apparatus.

Risk factors for MRSA colonization in dermatologic patients in Germany.

Detection of methicillin‐resistant Staphylococcus aureus (MRSA) carriage requires well‐defined risk factors (RFs). Except for “chronic wounds”, RFs are mostly specified in national recommendations. To avoid ineffective and expensive screening, we divided the entity “wounds” into different categories and calculated further RFs in dermatologic patients.

Influence of preoperative skin sealing with cyanoacrylate on microbial contamination of surgical wounds following trauma surgery: a prospective, blinded, controlled observational study

OBJECTIVE Intraoperative bacterial contamination is a risk factor for surgical site infections (SSIs). This prospective, randomized, blinded, controlled trial (Reg. No. BB08/12) investigated the effect of a cyanoacrylate-based skin sealant (InteguSeal) on intraoperative wound contamination during trauma surgery. METHODS A total of 128 patients undergoing trauma surgery were assigned randomly to an intervention (n=62) or a control group (n=66). Surgical sites were investigated at three locations: maximum incision depth (base), wound margin prior to wound closure (margin), and the surgical sutures (suture). Colony-forming units (CFU) were counted after 48h of incubation. RESULTS Overall, significantly lower CFU counts were obtained for samples from the intervention group at all three sample sites compared to the control group. The difference, however, was only significant for the suture site (p=0.040). CONCLUSIONS Preoperative sealing reduced microbial contamination on sutures during surgery, while the overall wound contamination remained unchanged. Hence, prevention of the clinically more relevant deep SSIs may not be expected. However, this study was not designed to detect differences in the rate of SSI. The role of the reduction in suture contamination with regard to the prevention of SSI remains to be evaluated.

Triple swabbing allows sensitive MRSA detection in dermatologic patients of a university tertiary care hospital.

To optimize preventive measures to control MRSA, we investigated retrospectively the suitability of a multiple site screening model and the optimal sampling technique to detect MRSA in a university‐based phlebology and skin cancer center in Germany.

Does antibiotic resistance impair plasma susceptibility of multi-drug resistant clinical isolates of enterococci in vitro?

AbstractBackgroundCold atmospheric plasma could constitute an alternative against multi-drug resistant pathogens. Susceptibility of enterococci to cold atmospheric plasma was investigated in vitro.Methods39 clinical isolates of enterococci were grouped dependent on the most important resistance patterns and treated on agar using dielectric barrier discharge plasma. These included enterococci with combined vancomycin- and high-level gentamicin resistance, high-level resistance to gentamicin (HLGR) only, vancomycin resistance alone (VRE), and enterococci susceptible to both. Susceptibility to cold atmospheric plasma was evaluated based on the zones of inhibition and examined in terms of the enterococcal group and the “degree” of drug resistance.ResultsCold atmospheric plasma treatment killed all groups. Comparison of VRE and HLGR strains with non-VRE and non-HLGR isolates concerning zones of inhibition revealed that enterococci with special resistance patterns (VRE and HLGR) showed significantly smaller zones of inhibition than the sensitive ones. The mean of all isolates, irrespective of belonging to groups, showed smaller zones of inhibition with increasing “degree” of drug resistance.ConclusionsCold atmospheric plasma treatment killed all isolates of enterococci, but its efficacy depended on the “degree” of drug resistance and on membership in special resistance groups with particular clinical-outbreak importance. However, a possible role of the different genetic lineages, which might be prone to acquiring more or less resistance phenotypes, may also play a role in this context.

Treatment of recalcitrant actinic keratosis (AK) of the scalp by cold atmospheric plasma

Abstract Background and objectives: Actinic keratosis (AK) is a frequent cutaneous lesion usually developing on sun-exposed skin and may be evolving into invasive squamous cell carcinoma requiring expensive therapy. Size, site or number of lesions limits the efficacy and/or acceptability of surgical and chemical therapies. Up to now photodynamic therapy (PDT) is recommended as treatment of choice. Material and methods: A patient (75y, m) suffered from recalcitrant AK lesions on the scalp, forearms and face for more than 20y. Various treatments including PDT, ablative laser and cryotherapy or chemical treatments failed to eradicate these lesions especially on the scalp. We used a CE-certified cold atmospheric plasma (CAP) jet, the Maxium® electrosurgery unit with maxium® beamer (KLS Martin GmbH + Co. KG), to treat one scalp lesion in one session (60 s, 20 W, 6 L/min). Results: CAP was able to eradicate AK of the patient in one session and was well tolerated. Histologic examination showed complete cure of AK. Control histology and visits up to 26 months after treatment do not show relapse or other skin deterioration. Conclusion: CAP seems to be an effective, curative and economic (one single treatment) alternative to conventional treatment of recalcitrant AK with field cancerization with excellent tolerability.

Hyperspectral imaging as a possible tool for visualization of changes in hemoglobin oxygenation in patients with deficient hemodynamics – proof of concept

Abstract There is a lack of imaging tools for the evaluation of spatial alterations in microcirculation including blood oxygen saturation and hemoglobin distribution but recent innovative developments in hyperspectral technology may offer a solution. We examined different hemodynamic disorders in patients suffering from scleroderma, Dupuytren surgery, chronic foot ulcera and skin infections. Superficial and deeper blood oxygen saturation, hemoglobin distribution and water content were determined using hyperspectral imaging (HSI). In the patient with scleroderma, distinct cutaneous low perfused regions correlated with macroscopic skin aspects and seem to be potential therapy control marker. With HSI accurate clinical evaluation of a macroscopic conspicuous wound after Dupuytren surgery was possible and influenced further surveillance decisions. HSI clearly revealed the spatial geometry and also the clinically related perfusion parameters of abscess formation and chronic ulcer wounds. The hemodynamically relevant parameters like blood oxygen saturation (1 mm to approx. 6 mm subcutaneous), total hemoglobin distribution and tissue water content can be easily determined and visualized with HSI in near real time. Hence, this technique seems to be suitable for routine diagnostics of acute and chronic wounds as well as for the examination of systemic hemodynamic disturbances. Special indications may be transplant surveillance and monitoring of therapeutical interventions.