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Miranda Suchomel - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of World Health Organization-Recommended Hand Hygiene Formulations.
Emerging infectious diseases, 2020Co-Authors: Miranda Suchomel, Maren Eggers, Steffen Maier, Axel Kramer, Stephanie Dancer, Didier PittetAbstract:As a result of the coronavirus disease pandemic, commercial hand hygiene products have become scarce and World Health Organization (WHO) alcohol-based hand rub formulations containing ethanol or isopropanol are being produced for hospitals worldwide. Neither WHO formulation meets European Norm 12791, the basis for approval as a surgical hand preparation, nor satisfies European Norm 1500, the basis for approval as a hygienic hand rub. We evaluated the efficacy of modified formulations with alcohol concentrations in mass instead of volume percentage and glycerol concentrations of 0.5% instead of 1.45%. Both modified formulations met standard requirements for a 3-minute surgical hand preparation, the usual duration of surgical hand treatment in most hospitals in Europe. Contrary to the originally proposed WHO hand rub formulations, both modified formulations are appropriate for surgical hand preparation after 3 minutes when alcohol concentrations of 80% wt/wt ethanol or 75% wt/wt isopropanol along with reduced glycerol concentration (0.5%) are used.
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Chlorhexidine-coated surgical gloves influence the bacterial flora of hands over a period of 3 hours
Antimicrobial Resistance and Infection Control, 2018Co-Authors: Miranda Suchomel, Markus Brillmann, Ojan Assadian, Karen Ousey, Elisabeth PresterlAbstract:The risk of SSI increases in the presence of foreign materials and may be caused by organisms with low pathogenicity, such as skin flora derived from hands of surgical team members in the event of a glove breach. Previously, we were able to demonstrate that a novel antimicrobial surgical glove coated chlorhexidine-digluconate as the active ingredient on its inner surface was able to suppress surgeons’ hand flora during operative procedures by a magnitude of 1.7 log10 cfu/mL. Because of the clinical design of that study, we were not able to measure the full magnitude of the possible antibacterial suppression effect of antimicrobial gloves over a full 3 h period. The experimental procedure followed the method for assessment of the 3-h effects of a surgical hand rub’s efficacy to reduce the release of hand flora as described in the European Norm EN 12791. Healthy volunteers tested either an antimicrobial surgical glove or non-antimicrobial surgical latex gloves in a standardized laboratory-based experiment over a wear time of 3 h. Wearing antimicrobial surgical glove after a surgical hand rub with 60% (v/v) n-propanol resulted in the highest 3-h reduction factor of 2.67 log10. Non-antimicrobial surgical gloves demonstrated significantly lower (p ≤ 0.01) 3-h reduction factors at 1.96 log10 and 1.68 log10, respectively. Antibacterial surgical gloves are able to maintain a sustainable bacterial reduction on finger tips in a magnitude of almost 3 log10 (log10 2.67 cfu) over 3 h wear time. It was demonstrated that wear of an antibacterial surgical glove coated with chlorhexidine-digluconate is able to suppress resident hand flora significantly over a period of 3-h.
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influence of glycerol and an alternative humectant on the immediate and 3 hours bactericidal efficacies of two isopropanol based antiseptics in laboratory experiments in vivo according to en 12791
Antimicrobial Resistance and Infection Control, 2017Co-Authors: Miranda Suchomel, M Weinlich, Michael KundiAbstract:Guidelines for hand hygiene recommend the use of alcohol-based hand rubs containing humectants in order to improve dermal tolerance. However, the bactericidal efficacy of pre-surgical hand rubs is negatively affected by the WHO-recommended humectant glycerol, especially the 3-h efficacy. The aim of this study was to investigate whether replacing glycerol as humectant increases the bactericidal efficacy of surgical hand rubs based on isopropanol (75%, wt/wt). The efficacy of 3 and 5 min applications of a modified WHO II-formulation (containing lower glycerol concentrations) and the TPH 5766 hand rub which contains a new humectant (containing ethylhexylglycerin, dexpanthenol and a fatty alcohol) were compared to the European Norm 12,791 reference (n-propanol, 60%, vol/vol) immediately following and 3 h after application. Immediately after application both isopropanol-based surgical rubs approximated the performance of the reference. The 3-h effect of the modified WHO II-formulation was found to be less efficacious than the EN 12791, showing a 30% decrease in log10 reduction values. The 3-h post application effect for the TPH 5766 hand rub was found to not be different from EN 12791. Based on our data, the bactericidal efficacy of isopropanol-based surgical hand rubs can best be obtained if glycerol is not used in the formulation. Unlike glycerol, a humectant comprised of ethylhexylglycerin, dexpanthenol and a fatty alcohol was found not to decrease hand rub effectiveness. Further investigation of the bactericidal efficacy of other humectants is necessary and may prove useful.
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testing of the world health organization recommended formulations for surgical hand preparation and proposals for increased efficacy
Journal of Hospital Infection, 2011Co-Authors: Miranda Suchomel, Didier Pittet, Michael Kundi, Benedetta Allegranzi, M RotterAbstract:The 2009 World Health Organization (WHO) Guidelines on hand hygiene in health care recommend alcohol-based hand rubs for both hygienic and pre-surgical hand treatment. Two formulations based on ethanol 80% v/v and 2-propanol 75% v/v are proposed for local preparation in healthcare settings where commercial products are not available or too expensive. Both formulations and our suggested modifications (using mass rather than volume percent concentrations) were evaluated for their conformity with the efficacy requirements of the forthcoming amendment of the European Norm (EN) 12791, i.e. non-inferiority of a product when compared with a reference procedure (1-propanol 60% v/v for 3 min) immediately and 3 h after antisepsis. In this study, the WHO-recommended formulations were tested for 3 min and 5 min. Neither formulation met the efficacy requirements of EN 12791 with 3 min application. Increasing the respective concentrations to 80 w/w (85% v/v) and 75 w/w (80% v/v), together with a prolonged application of 5 min, rendered the immediate effect of both formulations non-inferior to the reference antisepsis procedure. This was not the case with the 3h effect, which remained significantly inferior to the reference. Although the original formulations do not meet the efficacy requirements of EN 12791, the clinical significance of this finding deserves further clinical trials. To comply with the requirement of EN 12791, an amendment to the formulations is possible by increasing the alcohol concentrations through changing volume into mass percent and prolonging the duration of application from 3 min to 5 min.
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ethanol in pre surgical hand rubs concentration and duration of application for achieving European Norm en 12791
Journal of Hospital Infection, 2011Co-Authors: Miranda Suchomel, M RotterAbstract:In Europe, ethanol is a common active agent in hand rub formulations and nowadays it is also recommended in guidelines for hand hygiene published by the Centers for Disease Control and Prevention and by the World Health Organization. However, data on the range of concentrations and durations of application providing a basis for passing the efficacy test of the European Norm EN 12791 are still lacking. Therefore, the bactericidal efficacy of rubbing clean hands with pure ethanol in volume concentrations of 95%, 85% or 75% during 3 min was compared with that of the reference procedure of EN 12791 employing n-propanol 60% v/v for 3 min, immediately and 3h after disinfection. Ethanol 85% was also tested at a 5 min application. A Latin-square design was used with 20 randomly allotted volunteers. Whereas the mean immediate bacterial reductions caused by ethanol at concentrations of 75% (log RF 1.68) and 95% (log RF 2.70) were significantly less efficacious compared to that of the reference (log RF 3.27), at 85% they were not significantly less active with both applications, 3 and 5 min (log RFs 2.90 and 3.12, respectively). Three hours after antisepsis, the bacterial reduction on the gloved hand was only significantly less efficacious than that of the reference when 75% ethanol was used. It is concluded that ethanol-based hand rubs have a good chance of meeting the EN 12791 requirements if their ethanol concentration is >75% v/v but <95% v/v and if they are applied for at least 3 min.
Didier Pittet - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of World Health Organization-Recommended Hand Hygiene Formulations.
Emerging infectious diseases, 2020Co-Authors: Miranda Suchomel, Maren Eggers, Steffen Maier, Axel Kramer, Stephanie Dancer, Didier PittetAbstract:As a result of the coronavirus disease pandemic, commercial hand hygiene products have become scarce and World Health Organization (WHO) alcohol-based hand rub formulations containing ethanol or isopropanol are being produced for hospitals worldwide. Neither WHO formulation meets European Norm 12791, the basis for approval as a surgical hand preparation, nor satisfies European Norm 1500, the basis for approval as a hygienic hand rub. We evaluated the efficacy of modified formulations with alcohol concentrations in mass instead of volume percentage and glycerol concentrations of 0.5% instead of 1.45%. Both modified formulations met standard requirements for a 3-minute surgical hand preparation, the usual duration of surgical hand treatment in most hospitals in Europe. Contrary to the originally proposed WHO hand rub formulations, both modified formulations are appropriate for surgical hand preparation after 3 minutes when alcohol concentrations of 80% wt/wt ethanol or 75% wt/wt isopropanol along with reduced glycerol concentration (0.5%) are used.
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simplifying the who how to hand rub technique three steps are as effective as six results from an experimental randomized crossover trial
Clinical Microbiology and Infection, 2017Co-Authors: Sarah Tschudinsutter, Didier Pittet, M Rotter, Reno Frei, Danica Nogarth, P Hausermann, Anne Stranden, Andreas F WidmerAbstract:Abstract Objectives The World Health Organization (WHO) issued guidelines on hand hygiene recommending a six-step ‘how to hand rub' technique for applying alcohol-based hand rub. However, adherence to all six steps is poor. We assessed a simplified three-step technique and compared it to the conventional WHO six-step technique in terms of bacterial count reduction on healthcare workers' hands. Methods Thirty-two participants were randomly assigned to clean their hands following the six-step ‘how to hand rub' technique (WHO reference group) or a simplified three-step technique (intervention group). Assignments were reversed after 1 day. The degree of bacterial killing was assessed following the European Norm for testing hand hygiene products. Hands were contaminated with Escherichia coli, and the mean logarithmic reduction in bacterial counts was compared between both techniques. Results Bacterial density before hand hygiene performance did not differ between the WHO reference group (median 6.37 log 10 CFU, interquartile range (IQR) 6.19–6.54) and the intervention group (median 6.34 log 10 CFU, IQR 6.17–6.60, p 0.513). After hand hygiene, the logarithmic reduction factor was higher in the intervention group (median 4.45, IQR 4.04–5.15) compared to the WHO reference group (median 3.91, IQR 3.69–4.62, p 0.021). Conclusions The WHO six-step ‘how to hand rub' technique can be simplified to a 3-step procedure based on the reduction of bacterial counts on healthcare workers' hands achieved under experimental conditions. The proposed technique is easier to perform and could improve adherence to the execution of hand hygiene action.
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testing of the world health organization recommended formulations for surgical hand preparation and proposals for increased efficacy
Journal of Hospital Infection, 2011Co-Authors: Miranda Suchomel, Didier Pittet, Michael Kundi, Benedetta Allegranzi, M RotterAbstract:The 2009 World Health Organization (WHO) Guidelines on hand hygiene in health care recommend alcohol-based hand rubs for both hygienic and pre-surgical hand treatment. Two formulations based on ethanol 80% v/v and 2-propanol 75% v/v are proposed for local preparation in healthcare settings where commercial products are not available or too expensive. Both formulations and our suggested modifications (using mass rather than volume percent concentrations) were evaluated for their conformity with the efficacy requirements of the forthcoming amendment of the European Norm (EN) 12791, i.e. non-inferiority of a product when compared with a reference procedure (1-propanol 60% v/v for 3 min) immediately and 3 h after antisepsis. In this study, the WHO-recommended formulations were tested for 3 min and 5 min. Neither formulation met the efficacy requirements of EN 12791 with 3 min application. Increasing the respective concentrations to 80 w/w (85% v/v) and 75 w/w (80% v/v), together with a prolonged application of 5 min, rendered the immediate effect of both formulations non-inferior to the reference antisepsis procedure. This was not the case with the 3h effect, which remained significantly inferior to the reference. Although the original formulations do not meet the efficacy requirements of EN 12791, the clinical significance of this finding deserves further clinical trials. To comply with the requirement of EN 12791, an amendment to the formulations is possible by increasing the alcohol concentrations through changing volume into mass percent and prolonging the duration of application from 3 min to 5 min.
M Rotter - One of the best experts on this subject based on the ideXlab platform.
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simplifying the who how to hand rub technique three steps are as effective as six results from an experimental randomized crossover trial
Clinical Microbiology and Infection, 2017Co-Authors: Sarah Tschudinsutter, Didier Pittet, M Rotter, Reno Frei, Danica Nogarth, P Hausermann, Anne Stranden, Andreas F WidmerAbstract:Abstract Objectives The World Health Organization (WHO) issued guidelines on hand hygiene recommending a six-step ‘how to hand rub' technique for applying alcohol-based hand rub. However, adherence to all six steps is poor. We assessed a simplified three-step technique and compared it to the conventional WHO six-step technique in terms of bacterial count reduction on healthcare workers' hands. Methods Thirty-two participants were randomly assigned to clean their hands following the six-step ‘how to hand rub' technique (WHO reference group) or a simplified three-step technique (intervention group). Assignments were reversed after 1 day. The degree of bacterial killing was assessed following the European Norm for testing hand hygiene products. Hands were contaminated with Escherichia coli, and the mean logarithmic reduction in bacterial counts was compared between both techniques. Results Bacterial density before hand hygiene performance did not differ between the WHO reference group (median 6.37 log 10 CFU, interquartile range (IQR) 6.19–6.54) and the intervention group (median 6.34 log 10 CFU, IQR 6.17–6.60, p 0.513). After hand hygiene, the logarithmic reduction factor was higher in the intervention group (median 4.45, IQR 4.04–5.15) compared to the WHO reference group (median 3.91, IQR 3.69–4.62, p 0.021). Conclusions The WHO six-step ‘how to hand rub' technique can be simplified to a 3-step procedure based on the reduction of bacterial counts on healthcare workers' hands achieved under experimental conditions. The proposed technique is easier to perform and could improve adherence to the execution of hand hygiene action.
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testing of the world health organization recommended formulations for surgical hand preparation and proposals for increased efficacy
Journal of Hospital Infection, 2011Co-Authors: Miranda Suchomel, Didier Pittet, Michael Kundi, Benedetta Allegranzi, M RotterAbstract:The 2009 World Health Organization (WHO) Guidelines on hand hygiene in health care recommend alcohol-based hand rubs for both hygienic and pre-surgical hand treatment. Two formulations based on ethanol 80% v/v and 2-propanol 75% v/v are proposed for local preparation in healthcare settings where commercial products are not available or too expensive. Both formulations and our suggested modifications (using mass rather than volume percent concentrations) were evaluated for their conformity with the efficacy requirements of the forthcoming amendment of the European Norm (EN) 12791, i.e. non-inferiority of a product when compared with a reference procedure (1-propanol 60% v/v for 3 min) immediately and 3 h after antisepsis. In this study, the WHO-recommended formulations were tested for 3 min and 5 min. Neither formulation met the efficacy requirements of EN 12791 with 3 min application. Increasing the respective concentrations to 80 w/w (85% v/v) and 75 w/w (80% v/v), together with a prolonged application of 5 min, rendered the immediate effect of both formulations non-inferior to the reference antisepsis procedure. This was not the case with the 3h effect, which remained significantly inferior to the reference. Although the original formulations do not meet the efficacy requirements of EN 12791, the clinical significance of this finding deserves further clinical trials. To comply with the requirement of EN 12791, an amendment to the formulations is possible by increasing the alcohol concentrations through changing volume into mass percent and prolonging the duration of application from 3 min to 5 min.
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ethanol in pre surgical hand rubs concentration and duration of application for achieving European Norm en 12791
Journal of Hospital Infection, 2011Co-Authors: Miranda Suchomel, M RotterAbstract:In Europe, ethanol is a common active agent in hand rub formulations and nowadays it is also recommended in guidelines for hand hygiene published by the Centers for Disease Control and Prevention and by the World Health Organization. However, data on the range of concentrations and durations of application providing a basis for passing the efficacy test of the European Norm EN 12791 are still lacking. Therefore, the bactericidal efficacy of rubbing clean hands with pure ethanol in volume concentrations of 95%, 85% or 75% during 3 min was compared with that of the reference procedure of EN 12791 employing n-propanol 60% v/v for 3 min, immediately and 3h after disinfection. Ethanol 85% was also tested at a 5 min application. A Latin-square design was used with 20 randomly allotted volunteers. Whereas the mean immediate bacterial reductions caused by ethanol at concentrations of 75% (log RF 1.68) and 95% (log RF 2.70) were significantly less efficacious compared to that of the reference (log RF 3.27), at 85% they were not significantly less active with both applications, 3 and 5 min (log RFs 2.90 and 3.12, respectively). Three hours after antisepsis, the bacterial reduction on the gloved hand was only significantly less efficacious than that of the reference when 75% ethanol was used. It is concluded that ethanol-based hand rubs have a good chance of meeting the EN 12791 requirements if their ethanol concentration is >75% v/v but <95% v/v and if they are applied for at least 3 min.
Mohand Tazerout - One of the best experts on this subject based on the ideXlab platform.
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Biodiesel from Waste Cooking Oil: Elaboration and Combustion Modeling
2015Co-Authors: Sary Awad, Mohand TazeroutAbstract:Modern society is facing two major problems: energy sources depletion and environment degradation because of wastes accumulation. The waste to energy vector contributes to simultaneous solutions of both problems. In this chapter biodiesel production via alkali catalyzed process was produced from waste cooking oils having different acid values. It was concluded that the yield of reaction and final product purity were sensitive to free fatty acid content of raw material, this remark is also true for optimal conditions. Yield of reaction decreased from 105 to 83% reported to oil mass by using waste cooking oil having 0.8 and 6.5 mgKOH/goil acid values respectively. Biodiesel produced from waste cooking oils having acid values lower than 6 mgKOH/goil respects European Norm limits. Produced biodiesel resulted in a 5% energy output increase while used on a diesel engine and a 20% increase in its energy consumption at 1500 rpm. Produced biodiesel was tested over the whole functioning engine range and correlations between operating conditions and heat release parameters were elaborated. The prediction model was compared to biodiesel produced from animal fat residues and the results were very satisfactory.
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EFFECT OF FREE FATTY ACIDS AND SHORT CHAIN ALCOHOLS ON CONVERSION OF WASTE COOKING OIL TO BIODIESEL
International Journal of Green Energy, 2014Co-Authors: Sary Awad, Maria Paraschiv, V. Edwin Geo, Mohand TazeroutAbstract:In this article, the transesterification of three types of waste cooking oil (WCO) with methanol and ethanol was studied using alkali catalyzed process. The catalyst used in this study was sodium hydroxide. The effects of temperature, catalyst amount, alcohol to oil ratio, and the time of reaction on the yield were studied. The temperature and the catalyst amount were the most important factors affecting the yield of biodiesel. Also the process exhibited some sensitivity to the level of free fatty acids (FFA) in the WCO and to the type of alcohol. The yields of methyl esters varied from 97% with the lowest acidity (0.4% FFA WCO) to 76% with the highest acidity (3.25% FFA WCO). The ethyl esters yields were lower and the difference increased with the level of FFA in the oil, the maximum yield was 95% and 73% with the lowest and the medium acidities respectively and no reaction was registered with the highest one. The chromatographic analysis of the produced biodiesel showed high contents of fatty acid methyl esters varying from 96.5% to 98%. The physical-chemical characteristics of produced biodiesel were studied and compared to the European Norm, EN 14214.
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Optimization of biodiesel production from animal fat residue in wastewater using response surface methodology
Bioresource Technology, 2013Co-Authors: Sary Awad, Maria Paraschiv, Edwin Geo Varuvel, Mohand TazeroutAbstract:Animal fat residues (AFR) from waste water were used as feedstock to produce biodiesel by a two-step acid-catalyzed process. Treatment of the AFRs with 5.4% (w/w) of 17 M H2SO4 at a methanol/AFR ratio of 13:1 (50% w/w) at 60 degrees C converted more than 95% of the triglycerides into fatty acid methyl esters (FAMEs) with an acid value (AV) of 1.3 mg(KOH)/g(biodiesel). Response surface methodology indicated that a lower AV cannot be reached using a one-step acid catalyzed process. Thus a two-step acid catalyzed process was employed using 3.6% catalyst and 30% methanol for 5 h for the first step and 1.8% catalyst and 10% methanol for I h in the second step, resulting in a yield higher than 98% and an AV of 0.3 mg(KOH)/g(biodiesel). The product thus conforms to the European Norm EN14214 concerning biodiesel. (C) 2012 Elsevier Ltd. All rights reserved.
Michael Kundi - One of the best experts on this subject based on the ideXlab platform.
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influence of glycerol and an alternative humectant on the immediate and 3 hours bactericidal efficacies of two isopropanol based antiseptics in laboratory experiments in vivo according to en 12791
Antimicrobial Resistance and Infection Control, 2017Co-Authors: Miranda Suchomel, M Weinlich, Michael KundiAbstract:Guidelines for hand hygiene recommend the use of alcohol-based hand rubs containing humectants in order to improve dermal tolerance. However, the bactericidal efficacy of pre-surgical hand rubs is negatively affected by the WHO-recommended humectant glycerol, especially the 3-h efficacy. The aim of this study was to investigate whether replacing glycerol as humectant increases the bactericidal efficacy of surgical hand rubs based on isopropanol (75%, wt/wt). The efficacy of 3 and 5 min applications of a modified WHO II-formulation (containing lower glycerol concentrations) and the TPH 5766 hand rub which contains a new humectant (containing ethylhexylglycerin, dexpanthenol and a fatty alcohol) were compared to the European Norm 12,791 reference (n-propanol, 60%, vol/vol) immediately following and 3 h after application. Immediately after application both isopropanol-based surgical rubs approximated the performance of the reference. The 3-h effect of the modified WHO II-formulation was found to be less efficacious than the EN 12791, showing a 30% decrease in log10 reduction values. The 3-h post application effect for the TPH 5766 hand rub was found to not be different from EN 12791. Based on our data, the bactericidal efficacy of isopropanol-based surgical hand rubs can best be obtained if glycerol is not used in the formulation. Unlike glycerol, a humectant comprised of ethylhexylglycerin, dexpanthenol and a fatty alcohol was found not to decrease hand rub effectiveness. Further investigation of the bactericidal efficacy of other humectants is necessary and may prove useful.
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testing of the world health organization recommended formulations for surgical hand preparation and proposals for increased efficacy
Journal of Hospital Infection, 2011Co-Authors: Miranda Suchomel, Didier Pittet, Michael Kundi, Benedetta Allegranzi, M RotterAbstract:The 2009 World Health Organization (WHO) Guidelines on hand hygiene in health care recommend alcohol-based hand rubs for both hygienic and pre-surgical hand treatment. Two formulations based on ethanol 80% v/v and 2-propanol 75% v/v are proposed for local preparation in healthcare settings where commercial products are not available or too expensive. Both formulations and our suggested modifications (using mass rather than volume percent concentrations) were evaluated for their conformity with the efficacy requirements of the forthcoming amendment of the European Norm (EN) 12791, i.e. non-inferiority of a product when compared with a reference procedure (1-propanol 60% v/v for 3 min) immediately and 3 h after antisepsis. In this study, the WHO-recommended formulations were tested for 3 min and 5 min. Neither formulation met the efficacy requirements of EN 12791 with 3 min application. Increasing the respective concentrations to 80 w/w (85% v/v) and 75 w/w (80% v/v), together with a prolonged application of 5 min, rendered the immediate effect of both formulations non-inferior to the reference antisepsis procedure. This was not the case with the 3h effect, which remained significantly inferior to the reference. Although the original formulations do not meet the efficacy requirements of EN 12791, the clinical significance of this finding deserves further clinical trials. To comply with the requirement of EN 12791, an amendment to the formulations is possible by increasing the alcohol concentrations through changing volume into mass percent and prolonging the duration of application from 3 min to 5 min.
