Hand disinfectants and their activity against clinical isolates of Bordetella pertussis.

OBJECTIVES: The aim of the study was to investigate possible emergence of resistance to disinfectants in Bordetella pertussis strains isolated from patients with whooping cough in the Czech Republic in 2014 and 2015. METHODS: In an EN1500-based study, clean and dry fingertips of volunteers were always contaminated with one of the two clinical isolates of B. pertussis. Clinical isolates of B. pertussis were obtained from the National Reference Laboratory for Pertussis and Diphtheria, National Institute of Public Health (NIPH), Prague, Czech Republic. Dry and contaminated fingertips were immersed in 10 ml medium and then rubbed with the fingers for 1 minute. After that, the hands were treated with isopropanol 60% v/v or tested products, and then the fingertips were rubbed again into 10 ml of pure medium for 1 minute. The suspensions obtained were immediately diluted and plated on charcoal medium. RESULTS: Ethanol-based product A and propanol-based product B showed bactericidal activity after 30 s of contact. The confidence interval limit for product A and B was 0.12 and 0.19, respectively. Quaternary ammonium compound-based product C was found to be ineffective after 30 s of contact. The confidence interval limit for product C was 0.62. CONCLUSION: Products A and B were assessed as effective against clinical isolates of B. pertussis in accordance with EN 1500. Quaternary ammonium compound-based product C did not comply with the requirements of EN 1500.

How reliable are test results from 17 laboratories on the basis of EN 1500 for a hand rub based on 80% (w/w)?

INTRODUCTION: A ring trial organized by the Association of Applied Hygiene (VAH) on the bactericidal efficacy of an ethanol-based hand rub was carried out in 17 laboratories according to EN 1500 with the aim of describing the variability of test results and fulfilment of the methodological acceptance criteria. METHOD: As a test product, a hand rub based on 80% ethanol (w/w) was tested in comparison with the reference alcohol (60% iso-propanol, v/v) in a crossover design. After pre-washing and contamination following the norm, hands were treated either with the reference alcohol (2 × 3 mL for 2 × 30 s) or the test product (3 mL in 30 s). Post-decontamination values were determined immediately after the rub-in period. Validated neutralizers were used. The arithmetic means of all individual log10 pre-values, post-values and reduction values were calculated per laboratory. Non-inferiority was assumed when the Hodges-Lehmann 97.5% confidence limit was <0.6 in comparison with the reference. A z-score was calculated to determine the laboratory performance. RESULTS: Two laboratories did not meet the acceptance criteria and were excluded from the analysis. The bactericidal efficacy of the test product was non-inferior to the reference product in four laboratories and not non-inferior in 11 laboratories. The z-score for the Hodges-Lehmann 97.5% confidence limit indicated a satisfactory performance in all laboratories. CONCLUSION: We consider the EN 1500 test method to be robust in terms of the variability of test results. For products of borderline efficacy, the evaluation should be based on more than one test.

Prospective Study on the Influence of Occupational Hand Protection Products on the Efficacy of Hand Disinfection.

BACKGROUND: To prevent occupational skin diseases, employees are instructed to periodically apply hand protection products as a barrier to protect their hands from water, cleaning agents or other irritants. The aim of this work was to investigate whether bacteria present on the skin at the time of protection product application are enclosed underneath this protective layer, if they can be transferred to other surfaces and if a standard isopropanol-based skin disinfectant can nonetheless reduce the bacterial burden. METHODS: This prospective study was conducted in human volunteers based on the European Standard (EN 1500) to assess the burden of microorganisms before and after the application of various protection product formulations and subsequent hand disinfection. RESULTS: All protection products, with the exception of alcohol-based gels, enclosed bacteria underneath a lipid layer which could be transferred onto other surfaces. Still, the hand disinfectant efficiently reduced the bacteria burden. DISCUSSION: In occupations where proper hand hygiene is vital, alcohol-based gels might be the best option for the protection of the skin barrier as well as for reducing the contamination risk. CONCLUSION: An alcohol-based disinfection agent can dissolve the lipid film of protection products following the standard protocol for hygienic hand disinfection.

Alcohol-based hand rubs can fulfil efficacy requirements of EN 1500 in 15 seconds.

Aim: Correct hand hygiene is widely regarded as an important measure to prevent healthcare-associated infections. Guidelines on how to perform hand antisepsis are often inspired by laboratory tests that focus on reproducibility rather than ease of use. These cumbersome recommendations can become barriers to hand hygiene, as optimal user acceptance requires a small rub volume and a short application time with an intuitive rubbing technique. Here we modified the EN 1500 to test the efficacy of hand rubs under more user-friendly conditions, using a highly intuitive rubbing technique in 15 seconds. Methods: The efficacy of an ethanolic and a propanolic hand rub in inactivating E. coli on the hands of volunteers was tested according to EN 1500 with modifications in rubbing technique and time. Pre-tests were conducted to find a suitable volume for "responsible application", a procedure without clearly defined steps. Finally, 20 volunteers applied both rubs for 15 seconds using 3 mL and "responsible application" and 5 mL using the WHO 6-step technique. Results: Both hand rubs, ethanolic and propanolic, were non-inferior to an unmodified EN 1500 reference for both application methods, 3 mL with "responsible application" and 5 mL with the WHO 6-step method. Conclusion: Reducing the complexity of hand rub application can have a positive impact on hand hygiene adherence. With our results showing that antimicrobial efficacy comparable to an unmodified EN 1500 can be achieved in 15 seconds using an intuitive rubbing technique, further barriers to more user-friendly hand rub application have been removed.

Failure of sodium hypochlorite to meet the EN 1500 efficacy requirement for hygienic hand disinfection.

This study evaluated the bactericidal efficacy of two alternative hand antiseptics, based on sodium hypochlorite or sodium hypochlorite and hypochlorous acid, compared with isopropanol on the hands of volunteers artificially contaminated with Escherichia coli using EN 1500. The reference alcohol was applied according to the norm, and the study formulations were used as in common practice (3 mL for 30 s). The products showed mean log10 reductions of 1.63 and 1.89, both of which were inferior to the reference treatment (4.78). Due to the failure to achieve sufficient bactericidal efficacy within 30 s, sodium hypochlorite (0.05-0.06%) should not be considered for hand disinfection.

Evolving the EN 1500 test method for alcohol-based hand rub closer to clinical reality by reducing the organic load on hands and enabling product to be applied to dry hands.

BACKGROUND: The methods currently used in Europe and North America to evaluate the bactericidal efficacy of hand hygiene products have some limitations (e.g. selection of test organism, method of contamination), and none of the methods allow prediction of actual clinical efficacy. Therefore, the World Health Organization has proposed the development of methods that better reflect typical clinical reality. METHODS: In Experiment 1, two contamination methods (immersion method according to EN 1500 and low-volume method according to ASTM E2755) were tested with the EN 1500 test organism Escherichia coli using 60% v/v iso-propanol. Experiment 2 compared the two contamination methods with Enterococcus faecalis. Experiment 3 compared the two test organisms using the low-volume contamination method. Data within each experiment were compared using the Wilcoxon test for paired samples, and data from all experiments were combined and fit to linear mixed-effects models. RESULTS: Mixed-effects analysis confirmed that both the test organism and the contamination method impacted the pre-values, and all three factors influenced log10 reductions. Higher pre-values resulted in significantly higher log10 reductions, immersion contributed to significantly higher log10 reductions, and E. coli showed significantly lower log10 reductions. CONCLUSION: An efficacy evaluation against E. faecalis with a low-volume contamination method could be considered as an alternative to the EN 1500 standard. This could help to improve the clinical relevance of the test method by including a Gram-positive organism and reducing the soil load, allowing product application closer to reality.

Bactericidal efficacy of two modified WHO-recommended alcohol-based hand rubs using two types of rub-in techniques for 15 s.

We evaluated the bactericidal efficacy of two modified WHO-recommended alcohol-based hand rubs (3 mL) after a 15-s rubbing period using two different rub-in techniques (three vs six steps). The formulation based on 80% w/w ethanol and 0.5% v/v glycerol (modified WHO I) showed a mean log10-reduction of 3.63 ± 0.87 (six steps) and 3.80 ± 0.71 (three steps) which was inferior to the reference treatment (4.27 ± 0.98; six steps). The efficacy of the formulation based on 75% w/w isopropanol and 0.5% v/v glycerol (modified WHO II) was not inferior to the reference treatment for either rub-in technique.

Handrubbing with sprayed alcohol-based hand rub: an alternative method for effective hand hygiene.

BACKGROUND: Hand hygiene is crucial in infection prevention and control. It is unclear whether sprayed alcohol-based hand rub (ABHR) is non-inferior to the World Health Organization (WHO)-recommended method of handrubbing with poured ABHR. AIM: To test whether sprayed ABHR can be an alternative (non-inferior) method for effective hand hygiene with/without handrubbing. METHODS: A laboratory experiment was conducted with ABHR (isopropanol 60% v/v) according to European Norm 1500. Hand hygiene was performed by: (1) handrubbing with ABHR poured on to the palm of the hand; (2) handrubbing with sprayed ABHR; and (3) applying sprayed ABHR to hands without handrubbing. Hands were contaminated with Escherichia coli ATCC 10536, followed by hand hygiene and microbiological sampling. A generalized linear mixed model with a random intercept per subject was used to analyse the reduction in bacterial count following hand hygiene. FINDINGS: In total, 19 healthcare workers participated in the study. Handrubbing with sprayed ABHR was non-inferior [margin log10 0.6 colony-forming units (cfu)/mL] to the WHO-recommended method of handrubbing with poured ABHR; bacterial count reductions were log10 3.66 cfu/mL [95% confidence interval (CI) 1.68-5.64] and log10 3.46 cfu/mL (95% CI 1.27-5.65), respectively. Conversely, non-inferiority was not found for sprayed ABHR without handrubbing [bacterial count reduction log10 2.76 cfu/mL (95% CI 1.65-3.87)]. CONCLUSION: Handrubbing with sprayed ABHR was non-inferior to handrubbing with ABHR poured on to the palm of the hand to reduce bacterial counts on hands under experimental conditions. Handrubbing with sprayed ABHR may be an acceptable alternative hand hygiene method pending assessment in other settings and for other pathogens.

How long is enough? Identification of product dry-time as a primary driver of alcohol-based hand rub efficacy.

Background: The World Health Organization has called for the development of improved methodologies to evaluate alcohol-based handrub (ABHR) efficacy, including evaluation at "short application times and volumes that reflect actual use in healthcare facilities". The objective of this study was to investigate variables influencing ABHR efficacy, under test conditions reflective of clinical use. Methods: The test product (60% V/V 2-propanol) was evaluated according to a modified EN 1500 methodology, where application volumes of 1 mL, 2 mL, and 3 mL were rubbed until dry. Statistical analyses were performed to investigate the relative influences of product volume, hand size, and product dry-time on efficacy, and hand size and hand contamination on product dry-time. Results: Mean log10 reduction factors (SD) were 1.99 (0.66), 2.96 (0.84) and 3.28 (0.96); and mean dry-times (SD) were 24 s (7 s), 50 s (14 s), and 67 s (20 s) at application volumes of 1 mL, 2 mL, and 3 mL, respectively (p ≤ 0.030). When data were examined at the individual volunteer level, there was a statistically significant correlation between dry-time and log reduction factor (p < 0.0001), independent of application volume. There was also a statistically significant correlation between hand surface area and dry-times (p = 0.047), but no correlation between hand surface area and efficacy (p = 0.698). Conclusions: When keeping other variables such as alcohol type and concentration constant, product dry-time appears to be the primary driver of ABHR efficacy suggesting that dosing should be customized to each individual and focus on achieving a product dry-time delivering adequate efficacy.

Effect of hand lotion on the effectiveness of hygienic hand antisepsis: Implications for practicing hand hygiene.

BACKGROUND: Skin protection products should be used after washing hands with soap, during breaks, after work, and during leisure time. Aside from their beneficial effects, skin care products may also interact with alcohol-based hand disinfectants by reducing their efficacy. The aim of this study was to investigate the effect of a hand lotion on the effectiveness of hygienic hand antisepsis using an alcohol-based handrub. METHODS: The effect of a protective hand lotion against an isopropyl alcohol-based handrub was investigated in 20 healthy volunteers according to the European standard test procedure EN 1500 in the following combinations: handwashing and application of hand lotion, only application of hand lotion, and no washing and no hand lotion (control), each for 5 minutes or 1 hour before hand antisepsis. The difference in microbiologic before-and-after values were expressed as log reduction factor. RESULTS: The effectiveness of hand antisepsis was not significantly affected in any of the groups using the tested hand lotion. CONCLUSIONS: Hand antisepsis may be delayed for 5 minutes after hand lotion application. Shorter time intervals might be possible but were not tested.

Dose considerations for alcohol-based hand rubs.

BACKGROUND: Manufacturers' recommended dosages for alcohol-based hand rubs are typically determined by measuring product efficacy using a model protocol such as EN 1500; however, anecdotal reports and informal observation suggests that in many cases users self-titrate to much lower doses in real-world application. AIM: To examine the interdependence of alcohol-based hand-rub volume on in-vivo efficacy using the EN 1500 standard test method, on drying time on users' hands, and on their perceptions of acceptability. METHODS: Three formulations were studied using EN 1500 and a modification of this method. The modification used volumes ranging from 0.5 to 3.0 mL and 30 s application. Drying times were recorded and user acceptability was established using a three-point scale (too long, OK, or too short). Dying times were analysed in relation to hand surface area. FINDINGS: The drying time for all three products increased as a function of volume. The drying time displayed a positive association with volume and a negative association with hand surface area. The optimum volume for user acceptability was between 1.5 and 2 mL, yielding a drying time of between 20 and 30 s. CONCLUSION: Whereas EN 1500 is appropriate for establishing the efficacy of a hygienic hand-rub formulation compared to a benchmark, it does not reflect actual in-use conditions or the likely clinical effectiveness of the product. In particular, it fails to address the need to optimize the volume of application and user acceptability of the product.

Efficacy of hand rubs with a low alcohol concentration listed as effective by a national hospital hygiene society in Europe.

BACKGROUND: Some national hospital hygiene societies in Europe such as the French society for hospital hygiene (SFHH) have positive lists of disinfectants. Few hand disinfectants with a rather low concentration of ethanol are listed by one society as effective for hygienic hand disinfection with 3 mL in 30 s including a virucidal activity in 30 s or 60 s, but published data allow having doubts. We have therefore evaluated the efficacy of three commonly used hand disinfectants according to EN 1500 and EN 14476. METHODS: Products 1 (Aniosgel 85 NPC) and 2 (Aniosrub 85 NPC) were based on 70% ethanol, product 3 (ClinoGel derma+) on 60% ethanol and 15% isopropanol (all w/w). They were tested in 3 laboratories according to EN 1500. Three mL were applied for 30 s and compared to the reference treatment of 2 × 3 mL applications of isopropanol 60% (v/v), on hands artificially contaminated with Escherichia coli. Each laboratory used a cross-over design against the reference alcohol with 15 or 20 volunteers. The virucidal activity of the products was evaluated (EN 14476) in one laboratory against adenovirus and poliovirus in different concentrations (80%, 90%, 97%), with different organic loads (none; clean conditions; phosphate-buffered saline) for up to 3 min. RESULTS: Product 1 revealed a mean log10-reduction of 3.87 ± 0.79 (laboratory 1) and 4.38 ± 0.87 (laboratory 2) which was significantly lower compared to the reference procedure (4.62 ± 0.89 and 5.00 ± 0.87). In laboratory 3 product 1 was inferior to the reference disinfection (4.06 ± 0.86 versus 4.99 ± 0.90). Product 2 revealed similar results. Product 3 fulfilled the requirements in one laboratory but failed in the two other. None of the three products was able to reduce viral infectivity of both adenovirus and poliovirus by 4 log10 steps in 3 min according to EN 14476. CONCLUSIONS: Efficacy data mentioned in a positive list published by a society for hospital hygiene should still be regarded with caution if they quite obviously contradict published data on the same or similar products.

Higiene das mãos: comparação da eficácia antimicrobiana do álcool - formulação gel e liquida - nas mãos com matéria orgânica / Hand hygiene: antimicrobial activity comparison of three alcoholic produts - gel and liquid - in hands with organic material

Indiscutivelmente, higiene de mãos (HM)é uma das medidas mais importantes para prevenir as Infecções Hospitalares. Além da tradicional lavagem com água e sabão, o uso do álcool tem se destacado na HM, pois, possui boa atividade antimicrobiana, dispensa pia, reduz o tempo e previne ressecamento de mãos. Das evidências científicas sobre seu uso na HM, ainda há contradições quanto à sua efetividade na presença da matéria orgânica nas mãos. Esta pesquisa foi desenvolvida com intuito de elucidar esta questão avaliando a eficácia antimicrobiana de três formulações alcoólicas (duas em forma de gel e uma líquida) nas mãos com matéria orgânica. Os trabalhos laboratoriais foram realizados no Laboratório de Pesquisas do Instituto de Ensino e Pesquisas (coleta de amostras bacterianas) e no Laboratório de Microbiologia do Departamento de Patologia Clínica do Hospital Albert Einstein (contagem bacteriana), utilizando a metodologia oficial Européia - EN 1500 modificada. Quatorze voluntários - pessoas saudáveis, sem problemas de pele nas mãos e que assinaram o "Termo de Consentimento Livre e Esclarecido", foram aleatorizados em três grupos e cada grupo utilizou os produtos-testes e referência em sequências diferentes. Os produtos-teste foram: produto A - álcool etílico sob a forma de gel a 62% (p/p), produto B - álcool etílico sob a forma de gel a 70%(p/p) e produto C - álcool etílico a 70% (p/v) glicerinado sob a forma líquida e o produto D - álcool 2-propanolol ---------------------|a 60%, produto referência padronizado pela metodologia EN 1500. Para cada produto-teste e referência, foi realizada a seguinte sequência de procedimentos: lavagem de mãos por um minuto com água e sabão; aplicação de 1,2 ml de sangue estéril desfibrinado de carneiro; contaminação das mãos até metade dos matacarpos no caldo tríptico de soja (TSB) com o microrganismo-desafio S. macescens ATCC 14756; coleta de amostras pré HM, friccionando os dedos na placa de Petri contendo TSB (valor inicial); HM aplicando o(s) produto(s)-teste e referência; coleta de amostras para recuperação bacteriana (valor final), com a mesma técnica da fase pré HM e cálculo do fator de redução (FR) logarítmica (log10) de S. marcescens (valor inicial - valor final). Foram realizadas análises estatísticas (teste de Wilcoxon) para verificar a equivalência entre o(s) produto(s)-teste e referência, com o nível de significância estabelecido em P=0,10, unicaudal. Os FR (log10) foram: 3,29 para o produto A; 3,36 para o produto B e 3,56 para o produto C. O produto-referência, produto, produto D, promoveu FR log10 de 3,66. Os testes de Wilcoxon indicaram que há equivalência dos produtos B (P=0,198) e C (P=0,826) com o produto referência D, e que existe diferença do produto A (P=0,074) quando comparado ao produto D. Como conclusão, este estudo revelou que os produtos-teste, utilizados em mãos artificialmente sujas com matéria orgânica reduziram significativamente a colonização transitória das mãos - mais de 3 log10, redução acima de 99,9% podendo ser utilizados para HM. Estes valores são superiores aos valores de FR log10 encontrados após a lavagem de mãos com sabão não-antimicrobiano(2,7) e sabão antimicrobiano tricosan (2,8) e semelhantes aos valores de PVP-I (3,5) e clorexidina degermante (3,1). O produto A, apesar de reprovado pela metodologia oficial EN 1500, obteve o menor FR log10 (3,26), é superior aos sabões não-antimicrobianos e com triclosan e clorexidina degermante a 4%, o que indica a possibilidade de sua utilização como segunda opção.

Hand hygiene is considered the most important measure to reduce the transmission of nosocomial pathogens in health care settings. Because alcohol has excellent antimicrobial activity, requires less time, results in less skin irritation and does not require proximity to a sink, is the preferred agent for hand hygiene. In the face of scientific evidence, there's still contradiction concerning the effectiveness of alcohol in the hands with proteinaceous material. This research was developed in order to compare the antimicrobial activity of three alcoholic products commonly used (two alcohol-based gel and one liquid formulation) in the hands with organic material. It was conducted in the Research Laboratory (bacterial samples) and in the Microbiology Laboratory of the Clinical Pathology Department (bacterial counting) of the Hospital Albert Einstein, using modified European Standard EN 1500. The test products were: A - ethanol alcohol-based gel 62% (p/p), product B - ethanol alcohol-based gel 70% (p/p) and product C - ethanol alcohol-based liquid 70% (p/v) with glycerol 2% compared to reference product: D - alcohol 2-propanolol 60% (v/v) on artificially contaminated hands with S. marcescens ATCC 14756, using a cross-over design. Fourteen healthy volunteers, with no skin hand problems and who signed written consent form were randomized in 3 groups. For each reference and test products, the following sequence was carried through: hands were washed with soft soap, 1,2 ml of sterile sheep blood defibrinated was dispensed by sterile syringe into the hands, air-dried and immersed in the contamination fluid up to the mid-metacarpals. Bacterial sample were recovered for the inicial count by rubbing the fingertips of each hand for 1 min in the petri dish containing tryptone soya broth (TSB) . The hands were rubbed thoroughly over their entire surface (30 to 60 seconds) with 2 -3 ml of the test products. The reference product was used twice (total of 6 ml) and rubbed for 60 seconds. Both hands were rinsed in running water and excess water was drained off. Final bacterial count was obtained rubbing the fingertips of each hand for 1 min in the petri dish containing TSB. For both reference and test products, the mean log10 reduction factors (RF) were calculated (difference between the pre-value and post-value) and for testing the RF of the test products against that of reference product the Wilcoxon teste was used (level of significance was set at P=0,1, one sided) The RF log10 calculated were: 3,29 for the product A; 3,36 for the product B; 3,56 for the product C and 3,66 for the product D. The Wilcoxon test indicated that product A did not meet standard criteria (P = 0,074) and the products B (P = 0,198) and C (P = 0,826) met the EN 1500 requirement. As conclusion, this study indicated that the test products, used in hands with organic material, significantly reduced the transient flora, more than 3 log10 (99,9% of reduction), may be used for hand hygiene. These values are greater than the values of RF log10 after washing hands with plain soap (2,70) and triclosan (2,8) or similar or even exceeding when comparing with antimicrobial detergents used for hand washing, as PVP-I (3,5) or chlorhexidine 4% (3,1). Although the product A did not meet the EN 1500 criteria and had the lowest RF log10, its RF is superior to soaps (plain soap, triclosan and chlorhexidine 4%). This indicates a possibility of its usage as a second option.