The influence of the pectin structure on the properties of hydrogel dressings doped with octenidine-containing antiseptic

This article presents a method for producing hydrogel dressings using high methylated pectin from apples or citrus, doped with the antiseptic agent, octenidine dihydrochloride. Octenidine was incorporated in-situ during the polymer crosslinking. The pectins were characterized by their varying molecular weight characteristics, monosaccharide composition, and degree of esterification (DE). The study assessed the feasibility of producing biologically active hydrogels with pectin and delved into how the polymer's characteristics affect the properties of the resulting dressings. The structure evaluation of hydrogel materials showed interactions between individual components of the system and their dependence on the type of used pectin. Both the antimicrobial properties and cytotoxicity of the dressings were evaluated. The results suggest that the primary determinants of the functional attributes of the hydrogels are the molecular weight characteristics and the DE of the pectin. As these values rise, there is an increase in polymer-polymer interactions, overshadowing polymer-additive interactions. This intensification strengthens the mechanical and thermal stability of the hydrogels and enhances the release of active components into the surrounding environment. Biological evaluations demonstrated the ability of octenidine to be released from the dressings and effectively inhibit the growth of microbial pathogens.

Effect of Cold Atmospheric Plasma on Epigenetic Changes, DNA Damage, and Possibilities for Its Use in Synergistic Cancer Therapy

Cold atmospheric plasma has great potential for use in modern medicine. It has been used in the clinical treatment of skin diseases and chronic wounds, and in laboratory settings it has shown effects on selective decrease in tumour-cell viability, reduced tumour mass in animal models and stem-cell proliferation. Many researchers are currently focusing on its application to internal structures and the use of plasma-activated liquids in tolerated and effective human treatment. There has also been analysis of plasma's beneficial synergy with standard pharmaceuticals to enhance their effect. Cold atmospheric plasma triggers various responses in tumour cells, and this can result in epigenetic changes in both DNA methylation levels and histone modification. The expression and activity of non-coding RNAs with their many important cell regulatory functions can also be altered by cold atmospheric plasma action. Finally, there is ongoing debate whether plasma-produced radicals can directly affect DNA damage in the nucleus or only initiate apoptosis or other forms of cell death. This article therefore summarises accepted knowledge of cold atmospheric plasma's influence on epigenetic changes, the expression and activity of non-coding RNAs, and DNA damage and its effect in synergistic treatment with routinely used pharmaceuticals.

Antibacterial and safety tests of a flexible cold atmospheric plasma device for the stimulation of wound healing

Cold atmospheric plasma (CAP) devices generate an ionized gas with highly reactive species and electric fields at ambient air pressure and temperature. A flexible dielectric barrier discharge (DBD) was developed as an alternative antimicrobial treatment for chronic wounds. Treatment of Staphylococcus aureus in collagen-elastin matrices with CAP for 2 min resulted in a 4 log reduction. CAP treatment was less effective on S. aureus on dermal samples. CAP did not affect cellular activity or DNA integrity of human dermal samples when used for up to 2 min. Repeated daily CAP treatments for 2 min lowered cellular activity of dermal samples to 80% after 2 to 4 days, but this was not significant. Repeated treatment of ex vivo human burn wound models with CAP for 2 min did not affect re-epithelialization. Intact skin of 25 healthy volunteers was treated with CAP for 3× 20" to determine safety. Although participants reported moderate pain scores (numerical rating scale 3.3), all volunteers considered the procedure to be acceptable. Severe adverse events did not occur. CAP treatment resulted in a temporarily increased local skin temperature (≈3.4°C) and increased erythema. Lowering the plasma power resulted in a significantly lower erythema increase. Good log reduction (2.9) of bacterial load was reached in 14/15 volunteers artificially contaminated with Pseudomonas aeruginosa. This study demonstrated the in vitro and in vivo safety and efficacy in bacterial reduction of a flexible cold plasma device. Trial registration number NCT03007264, January 2, 2017 KEY POINTS: • CAP strongly reduced bacterial numbers both in vitro and in vivo. • Re-epithelialization of burn wound models was not affected by repeated CAP. • CAP treatment of intact skin was well tolerated in volunteers.

Gas Plasma Technology-An Asset to Healthcare During Viral Pandemics Such as the COVID-19 Crisis?

The COVID-19 crisis profoundly disguised the vulnerability of human societies and healthcare systems in the situation of a pandemic. In many instances, it became evident that the quick and safe reduction of viral load and spread is the foremost principle in the successful management of such a pandemic. However, it became also clear that many of the established routines in healthcare are not always sufficient to cope with the increased demand for decontamination procedures of items, healthcare products, and even infected tissues. For the last 25 years, the use of gas plasma technology has sparked a tremendous amount of literature on its decontaminating properties, especially for heat-labile targets, such as polymers and tissues, where chemical decontamination often is not appropriate. However, while the majority of earlier work focused on bacteria, only relatively few reports are available on the inactivation of viruses. We here aim to provide a perspective for the general audience of the chances and opportunities of gas plasma technology for supporting healthcare during viral pandemics such as the COVID-19 crisis. This includes possible real-world plasma applications, appropriate laboratory viral test systems, and critical points on the technical and safety requirements of gas plasmas for virus inactivation.

Bacterial skin recolonization in the operating room: comparison between various antisepsis protocols

BACKGROUND

Surgical site infection (SSI) largely implicates the patient's endogenous skin microbiota. Perioperative disinfection protocols do not follow a general agreement.

AIM

To compare antisepsis and skin protection protocols on quantitative analysis of recolonization in the operating room at regular time-steps. The study hypothesis was that one protocol would be more effective than others.

METHODS

A single-centre prospective interventional study was conducted between January and June 2019. Healthy volunteers were randomized between protocols and served as their own controls. The protocols began ahead of scheduled orthopaedic surgery with a preoperative shower, mechanical cleansing, application of major antiseptics (alcoholic Bétadine™ 5% or alcoholic chlorhexidine 0.5%), sterile draping, then adhesive draping (3M™ Steri-Drape™ or iodine-impregnated 3M™ Ioban2™). Sampling was by swabbing in the operating room at 30 min intervals up to 90 min after draping. Cultures were performed under aerobic and anaerobic conditions. Qualitative and quantitative (cfu/mL) bacteriology was performed in the laboratory by direct reading on the blood agar plates.

FINDINGS

Thirty subjects were included; none was lost to follow-up or excluded from analysis. Bacterial load before manipulation (T0) was significantly higher in males (P < 0.0001) despite a significantly shorter shower-to-sampling interval (P = 0.03). Smoking (P = 0.85), body mass index (P = 0.38), and depilation (P = 0.50) did not significantly affect preoperative load. Mean load increased significantly under all protocols up to T90 min, without significant superiority for any one protocol. Associated Bétadine™/Ioban™ showed the lowest T90 load, and chlorhexidine alone the highest, but without significant difference. Isolates at T0 were predominantly healthy skin commensals: coagulase-negative staphylococci, micrococci, and coryneforms.

CONCLUSION

No one protocol demonstrated superiority, whether in immediate bactericidal action or in preventing skin recolonization in the operating room. Further studies are needed to define generally agreed protocols for SSI risk management.

In vitro evaluation of the decontamination effect of cold atmospheric argon plasma on selected bacteria frequently encountered in small animal bite injuries

Beneficial effects of cold atmospheric argon plasma (CAAP) on wound healing and its capacity for bacterial decontamination has recently been documented. First, in vivo studies in small animals did not prove any decontamination effect in canine bite wounds. The present study evaluated the overall decontamination effect of CAAP for different bacteria frequently encountered in canine bite wounds with respect to growth phase, initial bacteria concentration and treatment duration. Standard strains of Escherichia (E.) coli, Staphylococcus (S.) pseudintermedius, S. aureus, Streptococcus (S.) canis, Pseudomonas (P.) aeruginosa and Pasteurella multocida were investigated. To evaluate the influence of the bacterial growth phase, each bacterium was incubated for three and eight hours, before CAAP treatment. Three different bacterial concentrations were created per bacterium and growth phase, and were exposed to CAAP for 30 s, 1 min and 2 min. CAAP treatment resulted in acceptable decontamination rates (range 98.9-99.9%) in all bacteria species in vitro; however, differences in susceptibility were detected. Decontamination rate was mainly influenced by initial bacterial concentration and treatment time. Growth phase only influenced decontamination in S. pseudintermedius. Treatment time significantly (P < .05) correlated with the decontamination rate in E. coli, S. canis and S. aureus, with an exposure time of 2 min being most effective. Initial bacterial concentration significantly (P < .05) influenced decontamination in Pasteurella multocida and P. aeruginosa, in which treatment time was not as important. CAAP exerts effective antibacterial activity against the tested bacteria strains in vitro, with species specific effects of treatment time, growth phase and concentration.

ROS from Physical Plasmas: Redox Chemistry for Biomedical Therapy

Physical plasmas generate unique mixes of reactive oxygen and nitrogen species (RONS or ROS). Only a bit more than a decade ago, these plasmas, operating at body temperature, started to be considered for medical therapy with considerably little mechanistic redox chemistry or biomedical research existing on that topic at that time. Today, a vast body of evidence is available on physical plasma-derived ROS, from their spatiotemporal resolution in the plasma gas phase to sophisticated chemical and biochemical analysis of these species once dissolved in liquids. Data from in silico analysis dissected potential reaction pathways of plasma-derived reactive species with biological membranes, and in vitro and in vivo experiments in cell and animal disease models identified molecular mechanisms and potential therapeutic benefits of physical plasmas. In 2013, the first medical plasma systems entered the European market as class IIa devices and have proven to be a valuable resource in dermatology, especially for supporting the healing of chronic wounds. The first results in cancer patients treated with plasma are promising, too. Due to the many potentials of this blooming new field ahead, there is a need to highlight the main concepts distilled from plasma research in chemistry and biology that serve as a mechanistic link between plasma physics (how and which plasma-derived ROS are produced) and therapy (what is the medical benefit). This inevitably puts cellular membranes in focus, as these are the natural interphase between ROS produced by plasmas and translation of their chemical reactivity into distinct biological responses.

Cold atmospheric pressure plasma for treatment of chronic wounds: drug or medical device?

OBJECTIVE

The use of cold atmospheric pressure plasma (CAPP) as a new therapeutic option to aid the healing of chronic wounds appears promising. Currently, uncertainty exists regarding their classification as medical device or medical drug. Because the classification of CAPP has medical, legal, and economic consequences as well as implications for the level of preclinical and clinical testing, the correct classification is not an academic exercise, but an ethical need.

METHOD

A multidisciplinary team of physicians, surgeons, pharmacists, physicists and lawyers has analysed the physical and technical characteristics as well as legal conditions of the biological action of CAPP.

RESULTS

It was concluded that the mode of action of the locally generated CAPP, with its main active components being different radicals, is pharmacological and not physical in nature.

CONCLUSION

Depending on the intended use, CAPP should be classified as a drug, which is generated by use of a medical device directly at the point of therapeutic application.

Side effects by oral application of atmospheric pressure plasma on the mucosa in mice

Cold atmospheric pressure plasma (CAP) has been investigated with promising results for peri-implant diseases treatment. However, prior to in-vivo applications of CAP sources in humans, short-term harmful mucosal damage or other unwanted side effects have to be reviewed. 180 male mice (B6C3F1) were divided into twelve treatment groups (n = 15). The right buccal cheek mucosa was treated with CAP. The first and second group each received continuous 10 sec irradiation with 2 different plasma sources (kINPen09, PS-MWM). The third group was treated with the kINPen09 for one minute. Control groups were treated with a corresponding dose of ultraviolet light for 8 seconds or 48 seconds and the other one was left untreated. The animals were weighed before and after treatment. The animals were sacrificed one day or one week after exposure. Stained tissue samples were histologically examined for tissue damage independently by two experienced pathologists. One day after CAP treatment histological analysis showed focal mucosal erosion with superficial ulceration and necrosis accompanied by a mild inflammatory reaction. One week after CAP treatment, the mucosal defects were completely re-epithelialized, associated with remnants of granulation tissue in the stroma irrespective of treatment duration. Furthermore, no cytological atypia was found and no severe weight loss occurred. The control groups did not show any alterations at all. CAP treatment led to a superficial mucosal damage that healed within few days. Nonetheless, further long-term experiments are necessary to exclude undesirable side effects after longer observation time. Particularly, potential carcinogenic effects must be ruled out prior to the application of CAP treatment in daily dental practice.

Argon Cold Plasma-A Novel Tool to Treat Therapy-resistant Corneal Infections

PURPOSE

To test whether therapy-resistant corneal infections can be successfully treated with argon cold plasma to reduce or eliminate pathogen microorganisms without affecting corneal cell viability.

DESIGN

First-in-human case series and experimental study.

METHODS

Cold plasma effects on viability of primary human corneal limbal epithelial cells were studied using exposure times from 0.5 to 10 minutes (metabolic activity, oxidative stress, apoptosis). Disinfective potential of cold plasma was tested against common pathogens (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans) on culture medium and evaluated by counting colony-forming units and optical density measurements, as well as against S aureus in a human cornea infection model. Additionally, in a first-in-human trial 4 patients with therapy-resistant corneal ulcers were treated to evaluate the clinical potential of cold plasma.

RESULTS

Cells treated for 0.5-5 minutes completely recovered within 24 hours without changes in morphology; only 10-minute treatment impaired the cells permanently. No evident oxidative stress, apoptosis, or damage to the corneal structure could be found. All pathogens were susceptible to cold plasma treatments, with different levels of sensitivity. The condition of all 4 patients significantly improved after cold plasma treatment combined with antibiotic therapy.

CONCLUSIONS

Our results indicate that argon cold plasma treatment reduces or eliminates common pathogens without impairing corneal epithelial cells in vitro, ex vivo, and in direct application on patients' eyes. We conclude that argon cold plasma therapy offers a potential supplement or alternative therapy for therapy-resistant corneal infections. A larger, comparative study is necessary to further confirm these findings.

Effects of plasma jet, dielectric barrier discharge, photodynamic therapy and sodium hypochlorite on infected curved root canals

The aim of this investigation was to evaluate the effects of 2 different cold atmospheric plasma (CAP) sources, photodynamic therapy and sodium hypochlorite (NaOCl), on infected root canals. Therefore, 50 standardized curved human root canals were infected with Enterococcus faecalis and assigned to 5 groups-negative control (NC), plasma jet (CAP I), dielectric barrier discharge (CAP II), photodynamic therapy (PDT) and NaOCl + passive ultrasonic irrigation-for 30 s. Colony forming units (CFUs) were determined. NaOCl was significantly more effective at reducing CFUs than all test groups (P < .0001 [Mann-Whitney U test]) in both parts of the root canal. CFUs in PDT were significantly lower than those in CAP II (P = .015), and those in CAP I were lower than those in CAP II (P = .05). Among all other groups and in the apical parts, no significant differences were found (P > .05).

Consensus on Wound Antisepsis: Update 2018

Wound antisepsis has undergone a renaissance due to the introduction of highly effective wound-compatible antimicrobial agents and the spread of multidrug-resistant organisms (MDROs). However, a strict indication must be set for the application of these agents. An infected or critically colonized wound must be treated antiseptically. In addition, systemic antibiotic therapy is required in case the infection spreads. If applied preventively, the Wounds-at-Risk Score allows an assessment of the risk for infection and thus appropriateness of the indication. The content of this updated consensus recommendation still largely consists of discussing properties of octenidine dihydrochloride (OCT), polihexanide, and iodophores. The evaluations of hypochlorite, taurolidine, and silver ions have been updated. For critically colonized and infected chronic wounds as well as for burns, polihexanide is classified as the active agent of choice. The combination 0.1% OCT/phenoxyethanol (PE) solution is suitable for acute, contaminated, and traumatic wounds, including MRSA-colonized wounds due to its deep action. For chronic wounds, preparations with 0.05% OCT are preferable. For bite, stab/puncture, and gunshot wounds, polyvinylpyrrolidone (PVP)-iodine is the first choice, while polihexanide and hypochlorite are superior to PVP-iodine for the treatment of contaminated acute and chronic wounds. For the decolonization of wounds colonized or infected with MDROs, the combination of OCT/PE is preferred. For peritoneal rinsing or rinsing of other cavities with a lack of drainage potential as well as the risk of central nervous system exposure, hypochlorite is the superior active agent. Silver-sulfadiazine is classified as dispensable, while dyes, organic mercury compounds, and hydrogen peroxide alone are classified as obsolete. As promising prospects, acetic acid, the combination of negative pressure wound therapy with the instillation of antiseptics (NPWTi), and cold atmospheric plasma are also subjects of this assessment.

Bactericidal efficacy of tissue tolerable plasma on microrough titanium dental implants: An in-vitro-study

Surface decontamination remains challenging in peri-implant infection therapy. To investigate the bactericidal efficacy of tissue tolerable plasma, S. mitis biofilms were created in vitro on 32 microrough titanium dental implants. Biofilm imaging was performed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The implants were either rinsed with 1% NaCl as negative control (C) or irradiated with a diode laser (DL) for 60 sec as positive control or plasma (TTP60, TTP120) for 60 or 120 sec. Subsequently, colony forming units (CFU) were counted. Post-treatment, implants were further examined using fluorescence microscopy (FM). Median CFU counts differed significantly between TTP60, TTP120 and C (2.19 and 2.2 vs. 3.29 log CFU/ml; p = 0.012 and 0.024). No significant difference was found between TTP60 and TTP120 (p = 0.958). Logarithmic reduction factors were (TTP60) 2.21, (TTP120) 1.93 and (DL) 0.59. Prior to treatment, CLSM and SEM detected adhering bacteria. Post-treatment FM recorded that the number of dead cells was higher using TTP compared to DL and C. In view of TTP's effectiveness, regardless of resistance patterns and absence of surface alteration, its use in peri-implant infection therapy is promising. The results encourage conducting clinical studies to investigate its impact on relevant parameters.

Adjuvant antifungal therapy using tissue tolerable plasma on oral mucosa and removable dentures in oral candidiasis patients: a randomised double-blinded split-mouth pilot study

Extended use of antimycotics in oral candidiasis therapy gives rise to problems related to fungal drug resistance. The aim of this pilot study was to investigate the efficacy of tissue tolerable plasma (TTP) in denture stomatitis patients. It was hypothesised that (I): erythema and (IIa): complaint remission would be accelerated and (IIb): colony forming unit (CFU) reduction would be improved. The halves of the upper jaws of eight patients were randomly assigned to control (nystatin, chlorhexidine and placebo treatment) and test sides (nystatin, chlorhexidine and TTP administered six times each 7 days). The patients and the investigators, who were different from the therapists, were both blinded. Compared to the control sides, the erythema surface was reduced significantly more extensively on the test sides between 2 and 6 weeks of antifungal therapy (P ≤ 0.05). Visual analogue scale values and the frequency of moderate or heavy growth of Candida post-treatment did not differ significantly between both sides (P > 0.05). The primary hypothesis was confirmed, which may be interpreted as an accelerated remission. As drug therapy is usually limited to the time in which signs of infection are present, TTP might help reducing antifungal use. Even though the secondary hypotheses were not confirmed, persistence of Candida might be only colonisation.

Bactericidal Efficacy of Cold Plasma at Different Depths of Infected Root Canals In Vitro

Objectives:

Cold plasma (CP) has been shown to be effective even against multiresistant microorganisms. As previous investigations on the effect of CP in root canals showed promising results, the aim of the present study was to analyze the bactericidal efficacy of CP in different depths of infected dentin.

Methods:

32 standardized root canals of human mandibular premolars were infected with Enterococcus faecalis and incubated for one week. Specimens were randomly selected for one of four disinfection methods: control (5mL NaCl), 5mL chlorhexidine (CHX), CP alone (CP), and a combination of 5mL CHX and cold plasma (CHX+CP). CHX was ultrasonically activated for 30s, while cold plasma was used for 60s in the root canals. Dentin samples at depths of 300, 500 and 800 µm were obtained and diluted serially. Colony forming units (CFUs) were counted on agar plates after 24h of incubation.

Results:

The highest overall logarithmic reduction factors (RF) were obtained from CHX+CP (log RF 3.56 p<0.01; Mann-Whitney U test), followed by CP (log RF 3.27 p<0.01) and CHX alone (log RF 2.65 p<0.01) related to the control. All disinfection methods showed significantly lower CFU counts compared to the control group in 300 µm and 800 µm (both p<0.01, Kruskal-Wallis test).

Discussion:

The adjuvant use of CP might be beneficial in highly infected root canals to improved disinfection. However, the disinfection effect against Enterococcus faecalis of CP is comparable to ultrasonically activated CHX.

Non-Equilibrium Dielectric Barrier Discharge Treatment of Mesenchymal Stem Cells: Charges and Reactive Oxygen Species Play the Major Role in Cell Death

Atmospheric pressure non-equilibrium plasmas are efficacious in killing both prokaryotic and eukaryotic cells. While the mechanism of plasma induced cell death has been thoroughly studied in prokaryotes, detailed investigation of plasma mediated eukaryotic cell death is still pending. When plasma is generated, four major components that interact with cells are produced: electric fields, radiation, charged particles, and neutral gas species. The goal of this study was to determine which of the plasma components are responsible for plasma-induced cell death by isolating and removing each from treatment. The C3H10T1/2 murine mesenchyme stem cell line was treated in six well plates, stained with Propidium Iodide to determine viability, and analyzed by image cytometry. Our results show that plasma-generated charges and reactive oxygen species are the primary contributors to cell death.

Clinical use of cold atmospheric pressure argon plasma in chronic leg ulcers: A pilot study

OBJECTIVE

In the age of multiresistant microbes and the increasing lack of efficient antibiotics, conventional antiseptics play a critical role in the prevention and therapy of wound infections. Recent studies have demonstrated the antiseptic effects of cold atmospheric pressure plasma (APP). In this pilot, study we investigate the overall suitability of one of the first APP sources for wound treatment focusing on its potential antimicrobial effects.

METHOD

The wound closure rate and the bacterial colonisation of the wounds were investigated. Patients suffering from chronic leg ulcers were treated in a clinical controlled monocentric trial with either APP or octenidine (OCT). In patients who presented with more than one ulceration in different locations, one was treated with APP and the other one with OCT. Each group was treated three times a week over a period of two weeks. The antimicrobial efficacy was evaluated immediately after and following two weeks of treatment.

RESULTS

Wounds treated with OCT showed a significantly higher microbial reduction (64%) compared to wounds treated with APP (47%) immediately after the treatment. Over two weeks of antiseptic treatment the bacterial density was reduced within the OCT group (-35%) compared to a slight increase in bacterial density in the APP-treated group (+12%). Clinically, there were no signs of delayed wound healing observed in either group and both treatments were well tolerated.

CONCLUSION

The immediate antimicrobial effects of the APP prototype source were almost comparable to OCT without any signs of cytotoxicity. This pilot study is limited by current configurations of the plasma source, where the narrow plasma beam made it difficult to cover larger wound surface areas and in order to avoid untreated areas of the wound bed, smaller wounds were assigned to the APP-treatment group. This limits the significance of AAP-related effects on the wound healing dynamics, as smaller wounds tend to heal faster than larger wounds. However, clinical wound healing studies on a larger scale now seem justifiable. A more advanced plasma source prototype allowing the treatment of larger wounds will address APP's influence on healing dynamics, synergetic treatment with current antiseptics and effects on multiresistant bacteria.

On the history of plasma treatment and comparison of microbiostatic efficacy of a historical high-frequency plasma device with two modern devices

Background: Cold atmospheric pressure plasma (CAP) with its many bioactive properties has defined a new medical field: the plasma medicine. However, in the related form of high-frequency therapy, CAP was even used briefly a century ago. The aim of this study was to review historic CAP treatments and to obtain data regarding the antimicrobial efficacy of a historical high-frequency plasma device.

Methods: First, historic literature regarding the history of CAP treatment was evaluated, because in the modern literature no data were available. Second, the susceptibility of 5 different bacterial wound isolates, cultured on agar, to a historic plasma source (violet wand [VW]) and two modern devices (atmospheric pressure plasma jet [APPJ] and Dielectric Barrier Discharge [DBD]) was analyzed . The obtained inhibition areas (IA) were compared.

Results: First, the most convenient popular historical electromedical treatments produced a so-called effluvia by using glass electrodes, related to today’s CAP. Second, all three tested plasma sources showed complete eradication of all tested microbial strains in the treated area. The “historical” cold VW plasma showed antimicrobial effects similar to those of modern APPJ and DBD regarding the diameter of the IA.

Conclusion: Some retrograde evidence may be deducted from this, especially for treatment of infectious diseases with historical plasma devices. The underlying technology may serve as model for construction of modern sucessive devices.

Combined antibacterial effects of tissue-tolerable plasma and a modern conventional liquid antiseptic on chronic wound treatment

Potential antimicrobial effects of sequential applications of tissue-tolerable plasma (TTP) and the conventional liquid antiseptic octenidine dihydrochloride (ODC) were investigated. 34 patients with chronic leg ulcers were treated with TTP, ODC or a combination of both. The bacterial colonization was measured semi-quantitatively before and immediately after treatment and changes in the microbial strains' compositions before and after antiseptic treatments were analyzed. All antiseptic procedures reduced the bacterial counts significantly. The sequential application of TTP and ODC displayed the highest antimicrobial efficacy. Me combined use of TTP and conventional antiseptics might represent the most efficient strategy for antiseptic treatment of chronic wounds.

New strategies for preoperative skin antisepsis

During the past decades, encouraging progress has been made in the prevention of surgical site infections (SSI). However, as SSI still occur today, strategic prevention measures such as standardized skin antisepsis must be implemented and rigorously promoted. Recent discoveries in skin physiology necessitate the development of novel antiseptic agents and procedures in order to ameliorate their efficacy. In particular, alternate target structures in the skin need to be taken into consideration for the development of the next generation of antiseptics. Recent investigations have shown that a high number of microorganisms are located within and in the close vicinity of the hair follicles. This suggests that these structures are an important reservoir of bacterial growth and activity in human skin. To date, it has not been fully elucidated to what extent conventional liquid antiseptics sufficiently target the hair follicle-related microbial population. Modern technologies such as tissue-tolerable plasma (TTP) have been tested for their potential antiseptic efficiency by reducing the bacterial load in the skin and in the hair follicles. First experiments using liposomes to deliver antiseptics into the hair follicles have been evaluated for their potential clinical application. The present review evaluates these two innovative methods for their efficacy and applicability in preoperative skin antiseptics.

[Significance and prevention of post-operative wound complications]

Although surgical site infections (SSI) in dermatologic operative procedures are extremely rare, it is important to understand risks and etiological factors to initiate risk assessment and specific preventive measures. SSI commonly are associated with a complicated, long-term and expensive outcome. Typical wound pathogens of these infections include a variety of multiresistant organisms along with Staphylococcus aureus, Staphylococcus epidermidis, hemolytic streptococci and the gram-negative bacilli Escherichia coli and Pseudomonas aeruginosa. Effective hygienic measures as part of an adequate quality management system should consider the critical points in the development of SSI, particularly in the setting of an outpatient dermatologic unit, such as preparation of the operative area, preoperative skin antisepsis, hand hygiene, safe and skilled technique by surgeons, and barrier nursing to prevent spread of pathogens. The baseline infection incidence in dermatologic surgery inherently is low; nevertheless significant improvements can be achieved by implementation of risk-adapted infection control measures.

Rapid emergence of secondary resistance to gentamicin and colistin following selective digestive decontamination in patients with KPC-2-producing Klebsiella pneumoniae: a single-centre experience

After a single patient was transferred to Leipzig University Hospital from a hospital in Rhodes, Greece, the hospital experienced the largest outbreak due to a KPC-2-producing Klebsiella pneumoniae (KPC-2-KP) strain thus far observed in Germany. Ninety patients hospitalised between July 2010 and October 2012 were affected. In an attempt to eliminate KPC-2-KP from their digestive tracts, 14 consecutive patients (16%) were treated with a short course (7 days) of selective digestive decontamination (SDD), employing colistin (1 million units q.i.d.) and gentamicin (80 mg q.i.d.) as oral solutions, and applying colistin/gentamicin gel (0.5 g) to the oral cavity. In a retrospective analysis, these 14 SDD patients were compared with the remaining 76 patients harbouring KPC-2-KP. KPC-2-KP carrier status was followed in all 14 SDD patients by submitting stool samples to KPC-specific PCR. The mean follow-up period was 48 days (range 12-103 days). Successful elimination of KPC-2-KP was defined as a minimum of three consecutive negative PCR test results separated by ≥48 h each. Decolonisation of KPC-2-KP was achieved in 6/14 patients (43%) after a mean of 21 days (range 12-40 days), but was also observed in 23/76 (30%) of the non-SDD controls (P = 0.102). SDD treatment resulted in the development of secondary resistance to colistin (19% increase in resistance rate) and gentamicin (45% increase) in post-treatment isolates. In the control group, no secondary resistance occurred. We conclude that the SDD protocol applied in this study was not sufficiently effective for decolonisation and was associated with resistance development.

Antimicrobial efficacy of two surface barrier discharges with air plasma against in vitro biofilms

The treatment of infected wounds is one possible therapeutic aspect of plasma medicine. Chronic wounds are often associated with microbial biofilms which limit the efficacy of antiseptics. The present study investigates two different surface barrier discharges with air plasma to compare their efficacy against microbial biofilms with chlorhexidine digluconate solution (CHX) as representative of an important antibiofilm antiseptic. Pseudomonas aeruginosa SG81 and Staphylococcus epidermidis RP62A were cultivated on polycarbonate discs. The biofilms were treated for 30, 60, 150, 300 or 600 s with plasma or for 600 s with 0.1% CHX, respectively. After treatment, biofilms were dispensed by ultrasound and the antimicrobial effects were determined as difference in the number of the colony forming units by microbial culture. A high antimicrobial efficacy on biofilms of both plasma sources in comparison to CHX treatment was shown. The efficacy differs between the used strains and plasma sources. For illustration, the biofilms were examined under a scanning electron microscope before and after treatment. Additionally, cytotoxicity was determined by the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay with L929 mouse fibroblast cell line. The cell toxicity of the used plasma limits its applicability on human tissue to maximally 150 s. The emitted UV irradiance was measured to estimate whether UV could limit the application on human tissue at the given parameters. It was found that the UV emission is negligibly low. In conclusion, the results support the assumption that air plasma could be an option for therapy of chronic wounds.