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BACKGROUND: Worldwide, the emergence of multidrug-resistant gram-negative bacteria is a clinical problem. Surface disinfectant cleaners (SDCs) that are effective against these bacteria are needed for use in high risk areas around patients and on multi-touch surfaces. We determined the efficacy of several SDCs against clinically relevant bacterial species with and without common types of multidrug resistance. METHODS: Bacteria species used were ATCC strains; clinical isolates classified as antibiotic-susceptible; and multi-resistant clinical isolates from Klebsiella oxytoca, Klebsiella pneumoniae, and Serratia marcescens (all OXA-48 and KPC-2); Acinetobacter baumannii (OXA-23); Pseudomonas aeruginosa (VIM-1); and Achromobacter xylosoxidans (ATCC strain). Experiments were carried out according to EN 13727:2012 in quadruplicate under dirty conditions. The five evaluated SDCs were based on alcohol and an amphoteric substance (AAS), an oxygen-releaser (OR), surface-active substances (SAS), or surface-active-substances plus aldehydes (SASA; two formulations). Bactericidal concentrations of SDCs were determined at two different contact times. Efficacy was defined as a log10 ≥ 5 reduction in bacterial cell count. RESULTS: SDCs based on AAS, OR, and SAS were effective against all six species irrespective of the degree of multi-resistance. The SASA formulations were effective against the bacteria irrespective of degree of multi-resistance except for one of the four P. aeruginosa isolates (VIM-1). We found no general correlation between SDC efficacy and degree of antibiotic resistance. CONCLUSIONS: SDCs were generally effective against gram-negative bacteria with and without multidrug resistance. SDCs are therefore suitable for surface disinfection in the immediate proximity of patients. Single bacterial isolates, however, might have reduced susceptibility to selected biocidal agents.

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BACKGROUND: There is a trend in some countries to recommend the use of surgical hand disinfectants at volumes as low as 4 ml per application. AIM: To determine whether the volume applied and hand size influence the efficacy of surgical hand disinfection. METHODS: Thirteen experiments, according to EN 12791, resulting in 269 datasets from 75 subjects were analyzed. Hands were first washed for one minute with soap. The pre-values were obtained by rubbing the finger tips in tryptic soy broth for one minute. Each subject treated his/her hands with n-propanol (60%, v/v), with as many portions as necessary to keep the hands wet for three minutes (6-12 ml). Bacterial post-values were taken from one hand (immediate effect); the other hand was gloved for three hours (sizes 7-9). The second post-value was taken when the glove was removed (3 h effect). RESULTS: The mean immediate log10 reduction of CFU was 2.56 ± 1.12. The glove size had no significant effect on the efficacy of disinfection (p = 0.182; ANOVA). However, a volume of 6 ml was significantly less effective than 9 ml for glove sizes of 7.5-8 (p < 0.05; Tukey post hoc analysis). The mean log10 reduction after 3 h was 2.12 ± 1.24. A volume of 6 ml was again significantly less effective than 12 ml for glove size 7 and than 9 ml for glove sizes 7.5-8 (p < 0.05). CONCLUSIONS: The application of small volumes of surgical hand disinfectant when using the EN 12791 reference procedure is likely to yield poor efficacy results, regardless of hand size.

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BACKGROUND: It has recently been reported that reusable dispensers for surface disinfection tissues may be contaminated, especially with adapted Achromobacter species 3, when products based on surface-active ingredients are used. Fresh solution may quickly become recontaminated if dispensers are not processed adequately. METHODS: We evaluated the abilities of six manual and three automatic processes for processing contaminated dispensers to prevent recolonisation of a freshly-prepared disinfectant solution (Mikrobac forte 0.5%). Dispensers were left at room temperature for 28 days. Samples of the disinfectant solution were taken every 7 days and assessed quantitatively for bacterial contamination. RESULTS: All automatic procedures prevented recolonisation of the disinfectant solution when a temperature of 60-70°C was ensured for at least 5 min, with or without the addition of chemical cleaning agents. Manual procedures prevented recontamination of the disinfectant solution when rinsing with hot water or a thorough cleaning step was performed before treating all surfaces with an alcohol-based disinfectant or an oxygen-releaser. Other cleaning and disinfection procedures, including the use of an alcohol-based disinfectant, did not prevent recolonisation. CONCLUSIONS: These results indicate that not all processes are effective for processing reusable dispensers for surface-disinfectant tissues, and that a high temperature during the cleaning step or use of a biofilm-active cleaning agent are essential.

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BACKGROUND: Reusable surface disinfectant tissue dispensers are used in hospitals in many countries because they allow immediate access to pre-soaked tissues for targeted surface decontamination. On the other hand disinfectant solutions with some active ingredients may get contaminated and cause outbreaks. We determined the frequency of contaminated surface disinfectant solutions in reusable dispensers and the ability of isolates to multiply in different formulations. METHODS: Reusable tissue dispensers with different surface disinfectants were randomly collected from healthcare facilities. Solutions were investigated for bacterial contamination. The efficacy of two surface disinfectants was determined in suspension tests against two isolated species directly from a contaminated solution or after 5 passages without selection pressure in triplicate. Freshly prepared use solutions were contaminated to determine survival of isolates. RESULTS: 66 dispensers containing disinfectant solutions with surface-active ingredients were collected in 15 healthcare facilities. 28 dispensers from nine healthcare facilities were contaminated with approximately 107 cells per mL of Achromobacter species 3 (9 hospitals), Achromobacter xylosoxidans or Serratia marcescens (1 hospital each). In none of the hospitals dispenser processing had been adequately performed. Isolates regained susceptibility to the disinfectants after five passages without selection pressure but were still able to multiply in different formulations from different manufacturers at room temperature within 7 days. CONCLUSIONS: Neglecting adequate processing of surface disinfectant dispensers has contributed to frequent and heavy contamination of use-solutions based on surface active ingredients. Tissue dispenser processing should be taken seriously in clinical practice.

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PURPOSE: The aim of this study was to evaluate the overall risk of hand disinfectants and skin antiseptics to become contaminated with bacterial spores throughout the production process and the subsequent in-use period, hence posing a public health risk. METHODS: Microbiological assessment of primary packaging material was carried out and long-term survival of bacterial spores in alcohol was assessed using sporulated B. subtilis ATCC 6633 as a standard. In-use contamination of alcohol-based formulations was tested by repeated use over 12 months under practical conditions and microbiological and physico-chemical data were determined. RESULTS: Among 625 containers analyzed, 542 did not yield any microbial growth. Median colony count for aerobic spore-forming bacteria was 0.2 cfu/10 ml container content. No anaerobic spore-forming bacteria were detected. Additionally, long-term survival of bacterial spores in aliphatic C2-C3 alcohols revealed 1-propanol to reduce the number of spores most effectively, with 2-propanol and ethanol having a somewhat less pronounced impact. In-use tests did not detect any microbial contamination or change in the physicochemical properties of the tested products over 12 months. CONCLUSIONS: Our data reveals that state-of-the-art production processes of alcohol-based hand rubs and antiseptics can be regarded safe. Primary packaging material and use were not found to pose a significant contamination risk as far as bacterial spores are concerned. Based on the data from this study, a microbial limit of <1 cfu/10 ml can be suggested as a quality-control threshold for finished goods to ensure high quality and safe products.

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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.

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BACKGROUND: Foams containing 62% ethanol are used for hand decontamination in many countries. A long drying time may reduce the compliance of healthcare workers in applying the recommended amount of foam. Therefore, we have investigated the correlation between the applied amount and drying time, and the bactericidal efficacy of ethanol foams. METHODS: In a first part of tests, four foams (Alcare plus, Avagard Foam, Bode test foam, Purell Instant Hand Sanitizer) containing 62% ethanol, which is commonly used in U.S. hospitals, were applied to 14 volunteers in a total of seven variations, to measure drying times. In a second part of tests, the efficacy of the established amount of foam for a 30 s application time of two foams (Alcare plus, Purell Instant Hand Sanitizer) and water was compared to the EN 1500 standard of 2 x 3 mL applications of 2-propanol 60% (v/v), on hands artificially contaminated with Escherichia coli. Each application used a cross-over design against the reference alcohol with 15 volunteers. RESULTS: The mean weight of the applied foam varied between 1.78 and 3.09 g, and the mean duration to dryness was between 37 s and 103 s. The correlation between the amount of foam applied and time until hands felt dry was highly significant (p < 0.001; Pearson's correlation coefficient: 0.724; 95% confidence interval: 0.52-0.93). By linear correlation, 1.6 g gave an intercept of a 30 s application time. Application of 1.6 g of Purell Instant Hand Sanitizer (mean log10-reduction: 3.05 +/- 0.45) and Alcare plus (3.58 +/- 0.71) was significantly less effective than the reference disinfection (4.83 +/- 0.89 and 4.60 +/- 0.59, respectively; p < 0.001). Application of 1.6 g of water gave a mean log10-reduction of 2.39 +/- 0.57. CONCLUSIONS: When using 62% ethanol foams, the time required for dryness often exceeds the recommended 30 s. Therefore, only a small volume is likely to be applied in clinical practice. Small amounts, however, failed to meet the efficacy requirements of EN 1500 and were only somewhat more effective than water.

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BACKGROUND: Although consecutive surgical hand disinfections is common clinical practice, the effect on the bacterial density on hands has not been studied for all commonly used hand rubs. We studied the effect of 2 consecutive applications of hand rubs on resident bacterial hand flora. METHODS: A propanol-based hand rub (PBHR; Sterillium) and the reference alcohol (60% n-propanol) were tested in a Latin-square design according to EN 12791. The first application of the PBHR was always for 1.5 minutes; the second application was for 1.5, 1, or 0.5 minutes. The reference alcohol was always applied for 3 minutes. Pre-values and post-values were obtained in accordance with EN 12791. RESULTS: The first reference disinfection reduced the bacterial density by 2.87 log(10) (immediate efficacy) and 2.27 log(10) (after 3 hours). The PBHR yielded a similar reduction. Immediately after the second reference disinfection, bacterial density was reduced by 0.45 log(10). Application of the PBHR yielded greater reductions of 0.71 log(10) (after 0.5 minute), 0.79 log(10) (after 1 minute), and 1.12 log(10) (after 1.5 minutes). The difference between all treatments was not significant (P = .089; Friedman test). After 3 hours, bacterial density was further decreased by 1.11 log(10) (reference disinfection), 1.89 log(10) (PBHR, 1 minute), 1.67 log(10) (PBHR, 1.5 minutes), and 1.08 log(10) (PBHR, 0.5 minute). The difference between all treatments was significant (P = .005), but none of the short treatments with the PBHR was significantly less effective than the reference treatment (P > .05; Wilcoxon-Wilcox test). CONCLUSIONS: Overall, a simple 1.5-minute application of a well-formulated PBHR for surgical hand disinfection keeps the bacterial density as low as possible ("irreducible minimum") even in 2 consecutive surgical procedures of 3 hours.

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OBJECTIVES: To evaluate the reproducibility and workability of the in vivo test model of the European test standard EN 12791 regarding the effectiveness of surgical hand antiseptics and, as a secondary objective, to evaluate the power of the model to discriminate between the effectiveness of various formulations of surgical hand antiseptics. DESIGN: Prospective, randomized, multicenter study with a Latin square design. SETTING: Five laboratories at 2 universities, 2 disinfectant manufacturers, and 1 private testing institution. PARTICIPANTS: Twenty healthy adults in each laboratory. INTERVENTION: Surgical hand antisepsis was performed by scrubbing with chlorhexidine gluconate 4% detergent (CHG) or by rubbing the hands with propan-2-OL (70% by volume; Iso 70) or ethanol 85% (E 85); rubbing the hands and forearms for 3 minutes with propan-1-OL (N 60) was used as the reference disinfection procedure. We deliberately chose to use these antiseptics at the given concentrations because they were intended to cover the range of typical antiseptics submitted for approval according to EN 12791. METHODS: In once-weekly tests, the immediate effects of the 4 antiseptics were established according to the method laid down in EN 12791 by assessing the release of skin flora from the fingertips as viable bacteria counts per milliliter of sampling fluids before treatment and viable bacteria counts immediately after treatment, separately for both hands, such that after 4 weeks each volunteer had used every formulation once. RESULTS: The mean log reduction factor (RF) for the release of bacterial skin flora (the log RF was calculated as the log count before treatment minus the log count after treatment) and corresponding standard deviations for the 4 hand antisepsis formulations were as follows: for CHG, 1.1+/-0.3 colony-forming units (cfu) per milliliter of sampled fluid; for Iso 70, 1.7+/-0.3 cfu/mL; for E 85, 2.1+/-0.3 cfu/mL; and for N 60, 2.4+/-0.4 cfu/mL. The differences between these values proved significant (P<.001) by analysis of variance and in Tukey's "honestly significantly different" (HSD) post hoc test. Although, with regard to their immediate antibacterial activity, the same ranking of these antiseptics was found at all laboratories, the levels of efficacy were significantly different across laboratories (P<.001); no statistical difference was found between left and right hands (P>.01). Relating the log RF values of the other 3 formulations to those of the reference formulation (N 60) abolished differences between laboratories (P=.16); in addition, the interclass correlation coefficient decreased from 9.1% to 4.5%. With 20 volunteers, a minimum difference of 0.47 log between the mean log RFs of the reference formulation and an inferior test formulation will be detected as significant at an alpha of .05 (1-sided) and a 1- beta value of .8. CONCLUSION: The test method described in EN 12791 yielded the same conclusion on the effectiveness of the tested formulations in every laboratory and proved, therefore, reproducible and workable.

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The antimicrobial efficacies of preparations for surgical hand antisepsis can be determined according to a European standard (prEN 12791 [EN]) and a U.S. standard (tentative final monograph for health care antiseptic drug products [TFM]). The U.S. method differs in the product application mode (hands and lower forearms, versus hands only in EN), the number of applications (11 over 5 days, versus a single application in EN), the sampling times (0, 3, and 6 h after application, versus 0 and 3 h in EN), the sampling methods (glove juice versus fingertip sampling in EN), and the outcome requirements (absolute bacterial reduction factor [RF], versus noninferiority to reference treatment in EN). We have studied the efficacies of two hand rubs according to both methods. One hand rub was based on 80% ethanol and applied for 2 min, and the other one was based on 45% propan-2-ol, 30% propan-1-ol, and 0.2% mecetronium etilsulfate and applied for 1.5 min. The ethanol-based hand rub was equally effective as the 3-min reference disinfection of prEN 12791 in both the immediate (RFs, 2.97 +/- 0.89 versus 2.92 +/- 1.03, respectively) and sustained (RFs, 2.20 +/- 1.07 versus 2.47 +/- 1.25, respectively) effects. According to TFM, the immediate effects were 2.99 log10 (day 1), 3.00 log10 (day 2), and 3.43 log10 (day 5), and bacterial counts were still below baseline after 6 h. The propanol-based hand rub was even more effective than the reference disinfection of prEN 12791 in both the immediate (RFs, 2.35 +/- 0.99 versus 1.86 +/- 0.87, respectively) and sustained (RFs, 2.17 +/- 1.00 versus 1.50 +/- 1.26, respectively) effects. According to TFM, the immediate effects were 2.82 log10 (day 1), 3.29 log10 (day 2), and 3.25 log10 (day 5), and bacterial counts were still below baseline after 6 h. Some formulations have been reported to meet the efficacy requirements of one of the methods but not those of the other. That is why we conclude that, despite our results, meeting the efficacy requirements of one test method does not allow the claim that the requirements of the other test method are also met.

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BACKGROUND: Aim of the study was to determine the efficacy of two distinct ethanol-based hand rubs for surgical hand disinfection in a controlled cross-over trial according to prEN 12791. METHODS: 20 subjects were included. Hands were washed for 1 min with soap. The bacterial prevalue was obtained by rubbing finger tips in TSB for 1 min. Then, each subject treated the hands with the reference procedure (n-propanol, 60% v/v) or the product (Sterillium Rub, based on 80% ethanol; Avagard, based on 61% ethanol and 1% chlorhexidine gluconate) which were all applied in 3 to 4 portions each of 3 ml for a total of 3 min. Bacterial postvalues (immediate effect) were taken from one hand, the other hand was gloved for 3 h. After gloves were taken off the second postvalue was taken for the assessment of a sustained effect. RESULTS: Bacterial pre-values were between 4.38 +/- 0.66 and 4.46 +/- 0.71. Sterillium Rub achieved the required immediate (mean log10-reduction of 2.59 +/- 1.19) and sustained effect (1.73 +/- 1.08) compared with the reference treatment (immediate effect: 2.58 +/- 1.16; sustained effect: 1.67 +/- 0.96). Avagard, however, did not achieve the required immediate (1.82 +/- 1.40) and sustained effect (1.41 +/- 1.08) in comparison to the reference disinfection (immediate effect: 2.98 +/- 0.90; sustained effect: 2.56 +/- 1.17; p < 0.01; Wilcoxon test). CONCLUSION: Based on our data, Sterillium Rub can be regarded to be effective for surgical hand disinfection, but Avagard can not. The addition of 1% chlorhexidine gluconate to 61% ethanol (w/w) did not outweigh an ethanol concentration of 80% (w/w).

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For assessment of the efficacy of surgical hand disinfection, European reference method prEN 12791 prescribes that the hands must be kept wet with the reference alcohol for 3 min regardless of the applied volume. The aim of this study was to determine whether the applied volume of the reference disinfectant n-propanol (60%, vol/vol) influences the effect on the resident hand flora. Ten experiments with 200 reference disinfections were analyzed. Hands were washed for 1 min with soap. The bacterial prevalue was obtained by rubbing fingertips in tryptic soy broth for 1 min. After this, each subject treated the hands with n-propanol (60%, vol/vol) by using as many portions as necessary to keep hands wet for a total of 3 min. Bacterial postvalues (immediate effect) were obtained for one hand, and the other hand was gloved for 3 h. After the gloves were taken off, a second postvalue was obtained (sustained effect). Most surgical reference disinfections (73%) were achieved with 9 ml of the reference alcohol, followed by 12 ml (24%) and 6 ml (3%). There was no significant difference between the mean log10 reduction values for the three treatment groups, both in terms of the immediate effect (P = 0.333, as determined by analysis of variance) and in terms of the sustained effect (P = 0.442). A higher number of portions did not correlate with a higher reduction factor (for immediate effect, Pearson's correlation coefficient = -0.028 [P = 0.689]; for sustained effect, Pearson's correlation coefficient = 0.059 [P = 0.404]). If the hands were kept wet with the reference alcohol for the total application time, the applied volume could vary, but this did not alter the efficacy.

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