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.

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.

Overview of tight fit and infection prevention benefits of respirators (filtering face pieces).

Regulations for measures to protect against SARS-CoV-2 transmission vary widely around the world, with very strict regulations in Germany where respirators (filtering face piece FFP2 or comparable) are often mandatory. The efficiency of respirators, however, depends essentially on the tight facial fit avoiding the bypass of contaminated air via gaps between mask and wearer's face. The facial fit can be verified in a fit test. The aim of this review was to describe the quantitative fit test results depending on the respirator designs. A literature search revealed 29 suitable studies. Of all respirators with circumferential head straps, three-panel folded dome-shaped respirators showed the best fit (80.8% of 4625 fit tests passed), followed by rigid-dome-shaped respirators (72.4% of 8234 fit tests passed), duckbill-shaped respirators (31.6% of 2120 fit tests passed), and coffee-filter-shaped respirators (30.9% of 3392 fit tests passed). Respirators with ear loops showed very poor tight fit (3.6% of 222 fit tests passed). In four randomized control trials, single-use respirators were not shown to be superior to surgical masks for the prevention of laboratory-confirmed viral respiratory infections, even when adjusted with a fit test. Therefore, we consider the mandatory use of respirators to be disproportionate and not supported by evidence. Further evidence should be generated, in which scenarios respirators might provide an effective benefit as part of occupational health and safety. For situations with confirmed benefits, only high-quality disposable respirators with head straps or respiratory protective equipment of higher protective levels should be used.

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.

Efficacy of biocidal agents and disinfectants against the monkeypox virus and other orthopoxviruses.

The number of human monkeypox virus infections is increasing in many countries. The typical mode of transmission is by direct contact. As orthopoxviruses may stay infectious on inanimate surfaces under laboratory conditions for up to 42 days, disinfection may be relevant in the surroundings of confirmed cases. The aim of this review was to evaluate published data on the antiviral efficacy of biocidal agents and disinfectants against the monkeypox virus and other orthopoxviruses. A Medline search was carried out on 5th June 2022. The terms 'monkeypox virus', 'poxvirus' and 'orthopoxvirus' were used in combination with 'disinfection'. Publications were included and results were extracted where they provided original data on any orthopoxvirus regarding its inactivation by disinfectants. Vaccinia viruses could be inactivated by at least 4 log10 in suspension tests and on artificially contaminated surfaces by 70% ethanol (≤1 min), 0.2% peracetic acid (≤10 min) and 1-10% of a probiotic cleaner (1 h), mostly shown with different types of organic load. Hydrogen peroxide (14.4%) and iodine (0.04-1%) were effective in suspension tests, sodium hypochlorite (0.25-2.5%; 1 min), 2% glutaraldehyde (10 min) and 0.55% orthophthalaldehyde (5 min) were effective on artificially contaminated surfaces. Copper (99.9%) was equally effective against vaccinia virus and monkeypox virus in 3 min. Disinfectants with efficacy data obtained in suspension tests and under practical conditions with different types of organic load resembling compounds of the blood, the respiratory tract and skin lesions are preferred for the inactivation of the monkeypox virus.

Explosive COVID-19 outbreak in a German nursing home and the possible role of the air ventilation system.

BACKGROUND: Most COVID-19 outbreaks in nursing homes are explained by transmission of SARS-CoV-2 from nurses or visitors. METHODS AND RESULTS: We describe an outbreak with 64 of the 67 residents identified as COVID-19 cases within two weeks (34 in nursing block 1, 30 in nursing block 2), at least 32 of them had relevant symptoms of COVID-19. Thirteen of the residents' deaths were associated with COVID-19. In addition, 27 of approximately 60 staff members were identified as COVID-19 cases, 23 of them had relevant symptoms. In none of the samples from residents or staff was a mutation of SARS-CoV-2 detected. Quarantine of the residents was already in force at the beginning of the outbreak. A common source among the staff was considered to be unlikely because the two nursing home blocks had no staff rotation and the staff had to wear FFP2 masks during contact with residents. Three months after the outbreak the RNA of SARS-CoV-2 was detected on 14 of 39 sampled indoor surfaces of the air ventilation system with Ct values between 34.9 and 41.9, but only at the air supply in the corridor (11 of 24 samples) and the air overflow in the door between the corridor and the residents' rooms (three of 11 samples) but not at the air exhaust in the residents' bathrooms. CONCLUSIONS: The air ventilation system and an inversion weather situation three days before the first confirmed case may have enhanced viral spread inside the nursing home assuming that a common source with a high viral load had existed at the time of outbreak.

Efficacy of five 'sporicidal' surface disinfectants against Clostridioides difficile spores in suspension tests and 4-field tests.

BACKGROUND: A sporicidal surface disinfection is recommended both for the outbreak and the endemic setting but a comparative evaluation on the efficacy of 'sporicidal' surface disinfectants using suspension tests and 4-field tests has not been performed. AIM: To determine the efficacy of five 'sporicidal' surface disinfectants (three ready-to-use wipes (A, B, E), two concentrates (C, D) based on peroxides or aldehydes against C. difficile spores. METHODS: The efficacy was determined under clean conditions using a suspension test and the 4-field test. Each test was performed in duplicate in two separate laboratories. Wipes were wrung to collect the solution for the suspension tests. RESULTS: Product A (peracetic acid; 5 min), product C (peracetic acid; 2% solution in 15 min or 1% solution in 30 min) and product D (peracetic acid; only 2% solution in 15 min) were effective with at least a 4 log10-reduction of C. difficile spores in suspension and on surfaces. Product B (hydrogen peroxide) was not effective in suspension (0.9 log10 after 15 min; 3.2 log10 after 1 h) and on surfaces (2.8 log10 after 15 and 60 min). Product E based on glutaraldehyde, (ethylendioxy)dimethanol and DDAC demonstrated 0.9 log10 after 4 h in suspension and 4.5 log10 after 4 h on surfaces. CONCLUSIONS: Not all surface disinfectants with a sporicidal claim were effective against C. difficile spores in standardized suspension tests and in the 4-field test. In clinical practice preference should be given to products that reliably pass the efficacy criteria of both types of tests.

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.

Identifying drivers for user preference and acceptability of different hydro-alcoholic hand rub formulations.

BACKGROUND: In the current era, the importance of proper hand hygiene to reduce the transmission of infectious diseases has become difficult to debate. Yet, compliance rates remain low and are affected by many factors, amongst which is user acceptability of hand hygiene products. AIM: The present study aimed at investigating drivers of preference towards different hand hygiene formulations. METHODS: Three different formulations (liquid, foam and gel) of the same brand were randomly and blindly evaluated by 54 participants based on the WHO Protocol for Evaluation of Tolerability and Acceptability of Alcohol-based Handrubs. RESULTS: The majority (76%) of respondents indicated that the product formulation impacted their level of compliance with hand hygiene protocols. The preferred formulation was liquid, with 50% of participants ranking it as first choice. General product satisfaction, the product texture, the drying speed and the ease of application, were the statistically significant drivers for participants to rank a formulation as their first choice vs not ranking it as their first choice. CONCLUSIONS: When designing alcohol formulations and implementing hand hygiene protocols, understanding drivers of preference for formulations may enhance product user acceptability and therefore compliance with hand hygiene.

Skin bacteria after chlorhexidine exposure-is there a difference in response to human beta-Defensin-3?

We investigated whether exposure to sub-lethal concentrations of chlorhexidine digluconate (CHG) changed the response of five Staphylococcus spp. to human beta-Defensin-3 (hBD-3). The change in response for each strain was determined in vitro with time-kill experiments in suspension by comparing the mean log(10) reduction caused by hBD-3 at 1.5 and 3 h in exposed and non-exposed bacteria. The identity of staphylococcal species was verified by DNA sequence homology in the gyrA genes in comparison with reference strains. Baseline sub-lethal concentrations allowing visible bacterial growth were between 0.0625 and 0.25 microg/ml. Sub-lethal CHG concentrations increased within 3 days in two isolates. For S. capitis 19/2, CHG-exposed cells were less susceptible to 0.5 microg/ml hBD-3 (log(10) reduction 0.78 versus 2.06 at 1.5 h; p < 0.001; t-test). For S. aureus, however, CHG-exposed cells were more susceptible to 1 microg/ml hBD-3. The observed changes between CHG-exposed and non-exposed cells did not indicate a general trend in response to hBD-3. Overall, we found no consistent evidence that 3 days of exposure to CHG changed the response of five Staphylococcus spp. to hBD-3. The use of CHG for skin antisepsis is, based on our data, unlikely to change the natural defence activity of hBD-3.

Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents.

Currently, the emergence of a novel human coronavirus, SARS-CoV-2, has become a global health concern causing severe respiratory tract infections in humans. Human-to-human transmissions have been described with incubation times between 2-10 days, facilitating its spread via droplets, contaminated hands or surfaces. We therefore reviewed the literature on all available information about the persistence of human and veterinary coronaviruses on inanimate surfaces as well as inactivation strategies with biocidal agents used for chemical disinfection, e.g. in healthcare facilities. The analysis of 22 studies reveals that human coronaviruses such as Severe Acute Respiratory Syndrome (SARS) coronavirus, Middle East Respiratory Syndrome (MERS) coronavirus or endemic human coronaviruses (HCoV) can persist on inanimate surfaces like metal, glass or plastic for up to 9 days, but can be efficiently inactivated by surface disinfection procedures with 62-71% ethanol, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite within 1 minute. Other biocidal agents such as 0.05-0.2% benzalkonium chloride or 0.02% chlorhexidine digluconate are less effective. As no specific therapies are available for SARS-CoV-2, early containment and prevention of further spread will be crucial to stop the ongoing outbreak and to control this novel infectious thread.

Efficacies of the original and modified World Health Organization-recommended hand-rub formulations.

The World Health Organization (WHO) hand-rub formulations have been in use around the world for at least the past 10 years. The advent of coronavirus disease 2019 (COVID-19) has further enhanced their use. We reviewed published efficacy data for the original and modified formulations. Only efficacy data according to the European Norms (EN) were found. The bactericidal efficacy of the original formulations was, under practical conditions, partly insufficient (EN 1500, only effective in 60 s; EN 12791, efficacy too low in 5 min). The first modification with higher alcohol concentrations improves their efficacy as hygienic hand rub (effective in 30 s). The second (0.725% glycerol) and third (0.5% glycerol) modification improves their efficacy for surgical hand preparation (effective in 5 and 3 min). The original and second modified formulations were tested and demonstrate activity against enveloped viruses including severe acute resiratory syndrome coronavirus 2 (SARS-CoV-2) in 30 s. The ethanol-based formulation is also active against some non-enveloped test viruses in 60 s (suspension tests, EN 14476). In-vivo data on the formulations would provide a more reliable result on the virucidal efficacy on contaminated hands but are currently not available. Nevertheless, the most recent modifications should be adopted for use in healthcare.

COVID-19-associated shortage of alcohol-based hand rubs, face masks, medical gloves, and gowns: proposal for a risk-adapted approach to ensure patient and healthcare worker safety.

The coronavirus disease 2019 (COVID-19) pandemic has caused a huge demand for alcohol-based hand rubs, medical gloves, face masks, and gowns in healthcare and from the public. More and more hospitals face a serious shortage of these articles. We propose a risk-adapted approach to ensure adequate patient and healthcare worker safety for as long as possible.

Prion disease and recommended procedures for flexible endoscope reprocessing - a review of policies worldwide and proposal for a simplified approach.

Several guidelines recommend specific treatments for endoscopes, procedures of quarantine for endoscopes, or additional treatments for the endoscope washer disinfector (EWD) in suspected or confirmed cases of Creutzfeldt-Jakob disease (CJD) or variant CJD (vCJD) but vary in many details. This study therefore reviewed guidelines on reprocessing flexible endoscopes after use in patients with suspected or confirmed prion disease. In addition, a literature search was performed in Medline on prion, CJD, vCJD, chemical inactivation, transmission healthcare, epidemiology healthcare, concentration tissue human and endoscope. Thus far, no case of CJD or vCJD transmitted by flexible endoscope has been reported. In animals it has been shown that oral uptake of 0.1-5 g of bovine spongiform encephalopathy (BSE)-infected brain homogenate is necessary for transmission. The maximum prion concentration in other tissues (e.g., terminal ileum) is at least 100-fold lower. Automated cleaning of endoscopes alone results in very low total residual protein ≤5.6 mg per duodenoscopes. Recommendations vary between countries, sometimes with additional cleaning, use of alkaline cleaners, no use of cleaners with fixative properties, use of disinfectants without fixative properties or single-use disinfectants. Sodium hydroxide (1 M) and sodium hypochlorite (10,000 and 25,000 mg/L) are very effective in preventing transmission via contaminated wires implanted into animal brains, but their relevance for endoscopes is questionable. Based on circumstantial evidence, it is proposed to consider validated reprocessing as appropriate in the case of delayed suspected prion disease when immediate bedside cleaning, routine use of alkaline cleaners, no fixative agents anywhere prior to disinfection and single use brushes and cleaning solutions can be assured.

Potential sources, modes of transmission and effectiveness of prevention measures against SARS-CoV-2.

During the current SARS-CoV-2 pandemic new studies are emerging daily providing novel information about sources, transmission risks and possible prevention measures. In this review, we aimed to comprehensively summarize the current evidence on possible sources for SARS-CoV-2, including evaluation of transmission risks and effectiveness of applied prevention measures. Next to symptomatic patients, asymptomatic or pre-symptomatic carriers are a possible source with respiratory secretions as the most likely cause for viral transmission. Air and inanimate surfaces may be sources; however, viral RNA has been inconsistently detected. Similarly, even though SARS-CoV-2 RNA has been detected on or in personal protective equipment (PPE), blood, urine, eyes, the gastrointestinal tract and pets, these sources are currently thought to play a negligible role for transmission. Finally, various prevention measures such as handwashing, hand disinfection, face masks, gloves, surface disinfection or physical distancing for the healthcare setting and in public are analysed for their expected protective effect.

A 1-minute hand wash does not impair the efficacy of a propanol-based hand rub in two consecutive surgical hand disinfection procedures.

We studied the effect of a 1-min hand wash on the bacterial hand flora in two consecutive surgical hand disinfection procedures. A propanol-based hand rub (PBHR; Sterillium) and n-propanol (60%, v/v) were tested in a Latin-square design according to EN 12791 in four variations. The reference alcohol was always applied for 3 min after a 1-min hand wash (variation 1). The PBHR was applied for 1.5 min (first application) or 0.5 min (second application). Variation 2 included a 1-min hand wash before both applications, variation 3 included the hand wash before application 1, in variation 4 hands were not washed at all before application. Pre- and post-values were obtained according to EN 12791. The reference disinfection reduced bacteria by 2.99 log(10) (immediate efficacy) and 2.22 log(10) after 3 h. The second reference disinfection reduced bacteria by 0.95 log(10) (immediate efficacy) and 0.68 log(10) after 3 h. The PBHR always yielded an equivalent reduction with and without a preceding hand wash (p > 0.05; Friedman test). A 1-min hand wash before application of the PBHR did not significantly change its efficacy for surgical hand disinfection in two consecutive surgical procedures of 3 h.

Enterococcus hirae, Enterococcus faecium and Enterococcus faecalis show different sensitivities to typical biocidal agents used for disinfection.

BACKGROUND: Enterococcus faecium and E. faecalis are known nosocomial pathogens. The bactericidal activity of biocidal agents used for disinfection, however, is determined with E. hirae. AIM: To find out whether E. hirae is a suitable species to evaluate the efficacy of biocidal agents against the clinically relevant species E. faecalis and E. faecium. METHODS: The bactericidal activity was determined in suspension tests according to EN 13727 using E. faecium ATCC 6057, E. faecalis ATCC 47077 and E. hirae ATCC 10541. Glutaraldehyde, ethanol, benzalkonium chloride, peracetic acid and sodium hypochlorite were used with three exposure times per biocide. When major differences in the sensitivity of the three enterococcal species to the respective substance was found, two more replicates were performed. The number of colony-forming units (cfu) was transformed into decimal logarithms. Results from replicate experiments were described with means and standard deviations. FINDINGS: At a 5-min exposure time, E. hirae was found to be more tolerant to 0.2% glutaraldehyde and 0.0125% peracetic acid compared to E. faecium and E. faecalis, whereas it was more susceptible to 40% ethanol and 3% sodium hypochlorite. Only with 0.00125% benzalkoniumchloride (15 min) was the susceptibility of E. hirae between that of E. faecium and E. faecalis. CONCLUSIONS: E. hirae is a suitable species when a bactericidal activity should be determined against enterococci with glutaraldehyde and peracetic acid. E. hirae may not be a suitable species for ethanol or sodium hypochlorite if the bactericidal activity should include the clinical pathogens E. faecium and E. faecalis.

Isopropanol at 60% and at 70% are effective against 'isopropanol-tolerant' Enterococcus faecium.

The bactericidal activity of isopropanol was determined against Enterococcus faecium ATCC 6057, ST 796 (isopropanol-tolerant strain) and Enterococcus hirae ATCC 10541 (EN 13727). Isopropanol at 60% and 70% were effective (≥5.38 log10-reduction) in 15 s against all strains but 23% isopropanol was not (<0.99 log10-reduction in ≤15 min). Isopropanol at 70% was tested against E. faecium in the four-field test. Eight millilitres was not effective enough in 1 min (<5 log10-reduction), whilst 16 mL was effective (≥5.85 log10-reduction). Healthcare workers can be reassured that 60% and 70% isopropanol with an appropriate volume are effective against E. faecium.

Interlaboratory reproducibility of a test method following 4-field test methodology to evaluate the susceptibility of Clostridium difficile spores.

BACKGROUND: Sporicidal surface disinfection is recommended to control transmission of Clostridium difficile in healthcare facilities. EN 17126 provides a method to determine the sporicidal activity in suspension and has been approved as a European standard. In addition, a sporicidal surface test has been proposed. AIM: To determine the interlaboratory reproducibility of a test method for evaluating the susceptibility of a C. difficile spore preparation to a biocidal formulation following the 4-field test (EN 16615 methodology). METHODS: Nine laboratories participated. C. difficile NCTC 13366 spores were used. Glutaraldehyde (1% and 6%; 15 min) and peracetic acid (PAA; 0.01% and 0.04%; 15 min) were used to determine the spores' susceptibility in suspension in triplicate. FINDINGS: One-percent glutaraldehyde revealed a mean decimal log10 reduction of 1.03 with variable results in the nine laboratories (0.37-1.49) and a reproducibility of 0.38. The effect of 6% glutaraldehyde was stronger (mean: 2.05; range: 0.96-4.29; reproducibility: 0.86). PAA revealed similar results. An exemplary biocidal formulation based on 5% PAA was used at 0.5% (non-effective concentration) and 4% (effective concentration) to determine the sporicidal efficacy (4-field test) under clean conditions in triplicate with a contact time of 15 min. When used at 0.5% it demonstrated an overall log10 reduction of 2.68 (range: 2.35-3.57) and at 4% of 4.61 (range: 3.82-5.71). The residual contamination on the three primarily uncontaminated test fields was <50 cfu/25 cm2 in one out of nine laboratories (0.5%) and in seven out of nine laboratories (4%). CONCLUSION: The interlaboratory reproducibility seems to be robust.

Comparative review of the test design Tentative Final Monograph (TFM) and EN 12791 for surgical hand disinfectants.

Preoperative antiseptic treatment of the hands of the surgical team is a standard procedure used worldwide in order to reduce the risk of surgical site infection. Two different types of antiseptics are available: alcohol-based hand rubs and antimicrobial liquid detergents ("soaps"). Standards have been developed to determine the antimicrobial efficacy of such preparations: the European norm EN 12971, finally issued in 2005, and the Tentative Final Monograph (TFM) for health care antiseptic products from 1994, which is the corresponding document in the USA. Although both methods use the reduction of resident hand flora as a quantitative parameter for antimicrobial efficacy, there are major differences concerning the test design. Whereas the European method is carried out following a randomized, reference-controlled crossover design, the US method can be characterized as a randomized, blinded parallel arm design. While both standards aim at immediate as well as sustained efficacy of the procedure, according to the EN the test product must not be significantly less effective than the reference procedure, whereas the TFM requires absolute reduction of > or = 1, > or = 2, and > or = 3 log10 per hand on days 1, 2, and 5, respectively. Results from various studies demonstrated that meeting the criteria defined by both standards may happen, but meeting the specifications of one standard does not necessarily mean that the same product will pass the requirements of the other. Missing accordance may be due to a number of considerable differences between both test methods. For a number of reasons the European method seems to be closer to clinical practice and to provide higher patient safety than the US method. However, available study data do neither allow for evaluation of the clinical impact of surgical hand disinfection as such nor of the effect of a particular product on postoperative wound infection rates.