Evaluation of the bactericidal effect of five products for surgical hand disinfection according to prEN 12054 and prEN 12791

Surgical hand disinfection (with an alcohol-based hand rub) and surgical handwash (with an antiseptic-based liquid soap) are accepted measures to reduce the risk for surgical site infections. The new European Standards allow a comparison of their antimicrobial efficacy. The bactericidal activity of surgical hand rubs [Sterillium and Softaman, (active ingredient=alcohols)] and handwashes [Derman plus (triclosan), Hibiscrub (chlorhexidine) and Betadine (PVP-iodine)] was tested according to the prEN 12054 suspension test using Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus hirae, and to prEN 12791 for the effect on resident skin flora in comparison with 1-propanol, 60% (v/v). All five products achieved a reduction of test bacteria within 3 min of >10(5)-fold so fulfilling prEN 12054. However, only Hibiscrub, Sterillium and Softa Man met the requirements of prEN 12791, giving a mean reduction of resident micro-organisms (immediate and sustained effect) which was not significantly lower than the reference alcohol (P>0.1; Wilcoxon matched-pairs signed-rank test). Sterillium was significantly more effective than the reference alcohol (immediate and sustained affect). Products for surgical hand disinfection may have equal antimicrobial activity in suspension tests but show large differences under practical conditions. Healthcare workers should not rely on results from suspension tests when deciding on a product for surgical hand disinfection.     

Povidone-iodine and chlorhexidine gluconate-containing detergents for disinfection of hands

The efficacy of a povidone-iodine and a chlorhexidine gluconate detergent was evaluated for ‘hygienic’ and ‘surgical’ hand disinfection. Rubbing 60 per cent iso-propanol on to the hands for 1 min was used as a standard for ‘hygienic’ disinfection, with Escherichia coli as the test organism. The mean log reduction obtained was 3.16 with povidone-iodine and 2.92 with chlorhexidine. These were considerably less than obtained with iso-propanol which produced a reduction of 4.23 and 4.30 orders of magnitude. In the ‘surgical’ hand disinfection tests, a 5 min wash with povidone-iodine and a 3 min wash with chlorhexidine detergent were compared with rubbing 60 per cent n-propanol or iso-propanol on to the hands for 5 min; n-propanol was taken as the standard preparation. Immediately after disinfection the log reduction in the resident flora was 0.92 with povidone-iodine and 0.78 with chlorhexidine, whereas n-propanol gave a log reduction of 3.43. After wearing a surgical glove for 3 h a log reduction of 0.24 was obtained with povidoneiodine, 0.75 with chlorhexidine and 2.94 with n-propanol. Treatment with iso-propanol gave a log reduction of 1.04. Thus, alcohols are shown by these tests to be far more effective than povidone-iodine or chlorhexidine detergent preparations in ‘hygienic’ as well as ‘surgical’ hand disinfection.     

Prevention of irritant contact dermatitis among health care workers by using evidence-based hand hygiene practices: a review

Irritant contact dermatitis is often found on the hands of healthcare workers and is generally caused by frequent hand washing, gloves, aggressive disinfectants or detergents. Alcohols have only a marginal irritation potential, although they may cause a burning sensation on pre-irritated skin. A burning sensation when using alcohols therefore, suggests that the skin barrier is already damaged. Two options for hand hygiene are generally available in clinical practice: (1) hand washing with some type of soap and water or (2) hand disinfection with alcohol-based hand rubs. Most clinical situations require the use of an alcohol-based hand rub for decontamination, which is especially useful for reducing the nosocomial transmission of various infectious agents. Washing one's hands should be the exception, to be performed only when they are visibly soiled or contaminated with proteinaceous material, or visibly soiled with blood or other body fluids. The overall compliance rate in hand hygiene is around 50%, which is far too low. In addition, healthcare workers quite often wash their hands with soap and water, when they should use an alcohol-based hand rub. This not only adds to the degree of skin irritation, but is also potentially dangerous for patients, due to the low efficacy of hand washing when compared to hand disinfection with alcohol rubs. Adhering to evidence-based hand hygiene protocols and following international guidelines on hand hygiene practices therefore, can help prevent irritant contact dermatitis among healthcare workers.     

Hand disinfection according to the European Standard EN 1500 (hygienic handrub): a study with gram-negative and gram-positive test organisms.

It was the aim of this study to compare the efficacy of alcohol-based hand disinfectants according to European Standard EN 1500 (hygienic handrub), using the routine test organism Escherichia coli and, additionally, Micrococcus luteus as a surrogate for Gram-positive pathogens. One ethanol-based hand disinfectant (product A) and one propanol-based hand disinfectant (product B) were used in all experiments. Product B (propanol-based) was significantly more effective against both test organisms than product A (ethanol-based) in quantitative suspension tests but not in tests simulating practical conditions. In the experiments according to EN 1500 germ reduction rates obtained with the ethanol-containing formulation A were identical for E. coli and M. luteus. Product B was slightly, but not significantly more effective against M. luteus. To conclude, using E. coli as the test organism for evaluating the antibacterial efficacy of alcoholic hand disinfectants under practical conditions even appears to be sufficient to permit the drawing of conclusions for Gram-positive pathogens. However, more alcohol-based hand disinfectants should be tested in further studies to verify the results obtained.     

Efficacy of alcohol-based gels compared with simple hand wash and hygienic hand disinfection

A recent research letter on the limited efficacy of alcohol-based hand gels has alerted the global infection control community and raised the question of the true significance of data obtained according to EN 1500. It has been described that a 1 min simple hand wash reduces artificial contamination of hands by a log(10) reduction factor of 2.8 and a 1 min reference hand disinfection with 2-propanol (60%, v/v) by a factor of 4.6 steps. The EN 1500 gel data show that the 30 s efficacy of most gels is closer to a simple hand wash than to the reference hand disinfection. The 30 s efficacy of most alcohol-based liquid products and one gel, however, is almost identical to the reference hand disinfection. In many European countries alcohol-based liquid products have been established as a standard practice in hygienic hand disinfection for decades. Replacement of these products with most available gels would be a step backward in terms of efficacy and has still to be seen critically from the efficacy point of view.     

Recommendations and requirements for soap and hand rub dispensers in healthcare facilities

Hand hygiene is one of the most important measures to prevent transmission of infectious agents and plays a major role in prevention of infection in any type of healthcare setting. While requirements for the efficacy of hand disinfectants are defined in European testing norms such as the EN 1500 for hygienic hand disinfection or EN 12791 for surgical hand preparation, no specific recommendations for hand rub dispensers and liquid soap dispensers have been given yet. Therefore, the intention of the present recommendation on soap and hand rub dispensers in healthcare facilities is to close this gap and to enhance future improvement of dispenser functionality and design. Regardless of manufacture and design of a hand rub or liquid soap dispensers the following requirements shall be met in healthcare facilities:Triggering the dispenser must be possible without using hands. Sensor- or elbow-operated dispensers both fulfill this requirement. Dispensers must be only refillable in a modality where the content, be it a hand rub or liquid soap, cannot be contaminated. This is achieved best by using replaceable cartridge systems. Refilling through "top-up" must not be possible. The disperser should allow usage of different types of cartridges made by different manufacturers. Dispensers must be operated and maintained such that a microbial contamination of the pump nozzle may easily be avoided. It must be possible to identify the products used in a dispenser easily and without any manipulation. Identifying the type of product, be it a hand rub or a liquid soap, as well as reading the product's name and critical manufacturers' warnings must be possible at any time. The disperser must allow identification of the level of the used product without any further manipulation at any time. The design of the dispenser must allow easy cleaning and disinfection the outside and inside of the dispenser. The manufacturer of the dispenser must provide the user with information on applicable chemicals and cleaning products. It must be possible to reprocess the dispenser and all of its permanent parts by applying machine based thermal disinfection at an A(0)-value of minimum 60 (e.g. 80°C/1 minute). Automatically portioning dispensers shall not fail during 200 hubs. The maximal allowed failure rate shall not exceed 1% (2 out of 200 consecutive hubs). A dispenser used for alcohol based hand rubs must allow keeping the alcohol concentration constant over a time period of 3 months. The maximum acceptable decrease in the concentration of the alcohol shall not exceed 5%. Liquid soap and hand rub dispensers with single-use pumps, ideally already mounted on the cartridge and to be discharged with the empty cartridge, are preferable. If pumps are used on the next consecutive cartridge, the manufacturer must provide the user with a detailed introduction for cleansing and reprocessing before further use. Because of forensic reasons it is recommended to place a good readable sign on the dispenser indicating e.g. "Apply alcohol based hand rubs only on the hand! Do not drink, avoid spraying into the eye or application on mucous membranes". It is regarded as an additional benefit, if the dispenser is able to document the consumption of hand rub or the frequency of hubs either mechanically or electronically.     

Improving adherence to surgical hand preparation

At present, no universal agreement on detailed practice for surgical hand preparation exists. In order to fill this gap, in 2002 a Franco-German recommendation for surgical hand preparation was published as a first step towards a generally accepted European recommendation. Based on an assessment of the actual literature, a protocol for surgical hand preparation is discussed with the aim to recommend evidence-based standard procedures including prerequisites, washing and disinfection phase, and its practical implementation. In contrast to hygienic hand disinfection, for surgical hand preparation compliance is not an issue, since it mostly is regarded as a ceremony which is carried out without exception. Nevertheless, the following factors influence acceptance and efficacy: skin tolerance, ease of use, duration of procedure, and recommended time), potential for impaired efficacy due to incorrect performance of the procedure, possibility of systemic risks and irritating potential by applied preparations, religious restrictions, ecological aspects, costs and safety. Here, we report our experience with the introduction of a new hand preparation regime in all surgical disciplines in our university hospital based on the above factors. The following statements were evaluated: 1) The immediate efficacy of an alcohol-based hand disinfectant is impaired by a preceding hand wash for up to 10 minutes. Therefore hands should not be routinely washed before the disinfection period unless there is a good reason for it such as visible soiling. 2) A shortened application time (1.5 minutes) is equal to 3 min in terms of efficacy. 3) Hands should be air dried before gloves are put on, otherwise the perforation rate of gloves will increase. 4) The efficacy of alcohol-based disinfectants is significantly higher when hands are allowed to dry for 1 minute after the washing phase and before the disinfection phase. To clarify the above questions before the establishment of the modified technique, the surgical team was invited to a meeting. As a result, the heads of surgical departments supported the new technique and decided to change their practice.     

Intra-laboratory reproducibility of the hand hygiene reference procedures of EN 1499 (hygienic handwash) and EN 1500 (hygienic hand disinfection)

The bactericidal efficacy of hand antiseptic products is determined in Europe using two norms--EN1499 (hygienic handwash), and EN 1500 (hygienic hand disinfection) based on reducing the counts of bacteria on artificially contaminated hands. Each requires 12-15 data sets per test and comparison with a reference procedure. Recent research using EN 1500 suggested that most alcohol-based hand gels are significantly less effective than the reference alcohol (2-propanol 60%), whereas liquid alcohol-based rubs are not. However concerns about the accuracy and reproducibility of the norm reference procedures have been raised. We therefore analysed 23 experiments carried out using EN 1500 representing 342 hand disinfection procedures, and 12 experiments using EN 1499 representing 178 handwashes, all performed in the same laboratory for reproducibility of the reference procedures. The reference alcohol gave a mean log(10) reduction factor (RF) of 4.64 +/- 0.93; only one data set gave a significantly higher result (5.14, P = 0.034), and one significantly lower (4.05; P = 0.034). Analysis of all 23 means revealed no significant difference (P = 0.188; ANOVA model). The reference soap gave a mean reduction of 2.82 +/- 0.49. Two data sets were significantly higher than this (3.35,P < 0.001; 3.12, P < 0.001) and two significantly lower (2.55, P = 0.031; 2.47,P = 0.004). Analysis of all the means did reveal a significant difference (P < 0.001, ANOVA model), which is probably explained by the smaller standard deviations of these results. Pre-values (bacteria recovered from fingers before a reference procedure) correlated significantly with RFs for both hand disinfection (correlation coefficient: 0.291;P = 0.01) and handwash (correlation coefficient: 0.372, P = 0.01). Overall both procedures gave accurate and reproducible results.     

Population kinetics of the skin flora on gloved hands following surgical hand disinfection with 3 propanol-based hand rubs: a prospective, randomized, double-blind trial.

OBJECTIVE: To study the bacterial population kinetics on gloved hands following hand treatment with 3 optically indistinguishable, alcohol-based surgical hand rubs, with and without supplements to delay bacterial regrowth. DESIGN: Prospective, randomized, double-blind, balanced quasi-Greco-Latin square design. SETTING: Microbiology laboratory of the Medical University Vienna, Austria. PARTICIPANTS: Twenty-four healthy adult volunteers without skin lesions.Surgical hand rubs. The following hand rubs, all stained blue, were applied to the hands for 3 minutes: 1-propanol 60% vol/vol (A); 2-propanol 70% m/m plus chlorhexidine gluconate 0.5% wt/wt (B); 2-propanol 45% wt/wt plus 1-propanol 30% wt/wt plus mecetronium etilsulfate 0.2% wt/wt (C). As a reference formulation (R), 1-propanol 60% vol/vol, unstained, was applied for the same amount of time. METHOD: In 8 once-weekly tests, 24 subjects randomly assigned to use the 4 hand rubs in groups of 6 persons each performed hand hygiene according to the method described in European Norm 12791. Every subject used one preparation at a time, the antimicrobial effect of which was evaluated at 2 sampling times. After week 8, each volunteer had tested every preparation at every preset sampling time. All preparations were tested in parallel. RESULTS: The mean pretreatment counts of viable bacteria (in colony-forming units per milliliter) in fluid samples were not significantly different between week 1 and week 8, nor between the right and left hands (analysis of variance [ANOVA], P>.1). Immediately after applying the formulation (t(0)), bactericidal effects of the blinded formulations A and C were equivalent to that of the reference formulation R, whereas the effect of B was questionable. The population kinetics of the flora on the hands proceeded from large and fast initial reductions of the skin flora by 2.7 log units (A), 3.1 log units (B), 3.3 log units (reference formulation), and 3.5 log units (C), to slow regrowth. However, even after 6 hours wearing gloves viable bacterial counts remained significantly (P<.01) below the baseline values (by 0.9 log [reference formulation], 1.1 log [A and B], and 1.5 log [C]). The slowest regrowth 1 and 3 hours after application (Delta from t(0), 0.1 log and 0.7 log respectively) was seen with formulation C, and the slowest regrowth after 6 hours was seen with formulation B (Delta from t(0), 1.6 log). These differences did, however, not reach statistical significance. CONCLUSIONS: With respect to the rapid and dramatic antibacterial action of suitable alcohols at high concentrations and with appropriate neutralizers, the contribution of supplements to the delay of bacterial regrowth on gloved hands appears rather minor, if a product only exerts an immediate effect equivalent to that of the reference disinfection procedure described in EN 12791.     

Surgical hand disinfection: effect of sequential use of two chlorhexidine preparations

The antimicrobial efficacy of three 'two-phase' surgical hand disinfection procedures was compared, in a volunteer study, to 60% n-propanol, applied for 5 min, which is the reference hand-disinfection procedure used in Austria and West Germany (FRG). The procedures involved sequential use of unmedicated soap or a disinfectant-detergent containing 4% chlorhexidine gluconate (CHX; 'Hibiscrub') followed by a handrub preparation containing 70% w/w isopropanol plus 0.5% CHX ('Hibisol'). The immediate and sustained effects (3 h) of washing with unmedicated soap (3 min) followed by rubbing on 'Hibisol' (4 min) were significantly smaller (log10 reductions of 1.72 and 1.12) than with each of the other procedures. Use of 'Hibiscrub' (3 min) and 'Hibisol' (4 min) produced log10 reductions of 2.50 and 1.71, equalling those of the reference procedure with n-propanol (2.49 and 1.78). When 'Hibisol' was used for 5 min rather than 4 min, a considerable, though not significant, increase in effect was achieved (log10 reductions of 2.90 and 2.07). Replacement of unmedicated soap by 'Hibiscrub' could significantly improve the effectiveness of the hand disinfection procedure commonly used by surgeons in German-speaking countries; namely to wash hands first with soap and then disinfect them with an alcoholic preparation. It may also be of additional advantage as this adds another 'layer' of CHX when 'Hibisol' rather than alcohol alone is used.     

Effect of a 1 min hand wash on the bactericidal efficacy of consecutive surgical hand disinfection with standard alcohols and on skin hydration

BACKGROUND: In most surgical theatres, a 1 min or even longer hand wash is routine as part of the pre-operative hand disinfection. But its benefit has recently been seen critically. METHODS: We have therefore investigated the effect of a 1 min hand wash on skin hydration and on the efficacy of consecutive surgical hand rubbing with three standard alcohols (60% propan-1-ol, 60% propan-2-ol, 80% ethanol; all v/v) on the resident hand flora. Three types of treatment were performed: (i) a 1 min pre-wash before surgical hand disinfection, (ii) no pre-wash before surgical hand disinfection and (iii) no pre-wash but use of a brush for 1 min during disinfection procedure. The efficacy of the alcohols was determined according to prEN 12791 with the same 20 volunteers in paired groups. To assess the effect of the hand wash on skin hydration, 10 volunteers washed their hands with sapo kalinus for 1 min and dried hands with a paper towel. Skin hydration was measured with a corneometer before the hand wash and subsequently up to 10 min thereafter both on the palm and dorsum of hands. We also tested the reduction of bacterial spores by a 15 s hand wash according to EN 1499 after artificial contamination of hands of 14 volunteers with spores of B. stearothermophilus. RESULTS: Propan-1-ol (60%) was most effective with a mean log10 reduction of 2.11, followed by ethanol (80%) with a mean log10 reduction of 1.76 and propan-2-ol (60%) with a mean log10 reduction of 0.57 (all immediate effect without hand wash). The efficacy of the alcohols was neither significantly improved nor impaired by a preceding 1 min hand wash, but there is a trend towards better efficacy on dry hands. Using a brush for 1 min during disinfection resulted in a better efficacy with all alcohols. An anaylsis of variance revealed that the immediate effect of ethanol (p = 0.013) and propan-2-ol (p = 0.001) is significantly influenced by the variation of treatments which is mainly explained by the effect of brushing during disinfection. But no significant difference between treatment variations was found in the sustained effect with any of the alcohols. Skin hydration increased significantly by a 1 min hand wash for up to 10 min despite drying hands with a paper towel. A 15 s hand wash reduced the number of bacterial spores significantly from log10 3.84 to log10 1.99 (p = 0.001). CONCLUSIONS: There is no benefit of a hand wash as part of surgical hand disinfection except that a short hand wash of 15 s can effectively reduce spores. The best time for this short hand wash is at the beginning of work in hospital, but at the latest in the sluice of the operating theatre about 10 min before applying an alcohol-based hand rub to give the skin enough time to dry.     

3种不同手卫生方法效果观察

目的 观察3种不同手卫生处置方法的效果,为医务人员提供便利、可靠的手卫生方法.方法 选择临床医护人员90名,随机分为3组,设肥皂洗手组30人,卫生手消毒组30人,先洗手后卫生手消毒组30人;洗手组使用肥皂,卫生手消毒组使用速干手消毒剂,先洗手后卫生手消毒组是先用肥皂再用速干手消毒剂洗手,干后立即用含相应中和剂的无菌洗脱液的无菌棉拭子采样双手标本送检,37℃培养48 h,观察3组人员手部细菌菌落数.结果 肥皂洗手、卫生手消毒、先洗手后卫生手消毒合格率分别为76.7％、93.3％、100.0％,均未检出致病菌;肥皂洗手与卫生手消毒比较、卫生手消毒与先洗手后卫生手消毒比较差异无统计学意义,肥皂洗手与先洗手后卫生手消毒比较差异有统计学意义(P＜0.05).结论 3种手卫生方法均可用于临床医务人员的手部清洗除菌,先洗手后卫生手消毒效果最佳,卫生手消毒效果优于肥皂洗手.     

Suitability of Sterillium Gel for surgical hand disinfection

In some countries, alcohol-based hand gels are used for hygienic hand disinfection but their efficacy and suitability for surgical hand disinfection has never been investigated. The efficacy of Sterillium Gel was investigated according to prEN 12791 in two separate experiments. Finger tips of 20 volunteers per experiment were sampled for resident skin bacteria before surgical hand disinfection. In a cross-over design, each volunteer carried out a surgical hand disinfection with the reference alcohol [n-propanol 60%, (v/v)] or Sterillium Gel [ethanol 85% (v/v)] for 3 min. After the product application, one hand was sampled for the immediate effect, the other hand was gloved for 3 h and then sampled for the sustained effect. Samples were analysed for remaining resident bacteria. The mean of the pre-value, the 0 h and 3 h values of the reference disinfection and the test product were calculated. With the reference alcohol, respective mean immediate log10-reduction factors of 2.06+/-0.76 and 2.23+/-1.13 were found in both experiments. The mean sustained effects with the reference alcohol were 2.03+/-1.14 and 1.44+/-0.81. Sterillium Gel achieved respective mean immediate effects of 2.48+/-1.06 and 2.13+/-0.81, the mean sustained effects were 2.77+/-0.95 and 2.18+/-0.72. They proved significantly larger than those obtained with the reference alcohol (P<0.05; pair-wise Wilcoxon test). Sterillium Gel, therefore, more than fulfils the efficacy requirements for surgical hand disinfection of prEN 12791. In addition, 25 of 26 operating theatre healthcare workers in an orthopaedic hospital found it suitable for surgical hand disinfection after a single use, which included putting on a pair of surgical gloves. Although none of them had ever used an alcohol-based gel before, they had rather been accustomed to alcohol-based liquid products for years. The main reasons given for the positive assessment were better skin feeling after use, smell and easier donning of the surgical gloves. No significant correlation was found between overall or dermal acceptance and years of professional experience, profession or number of gel portions used for surgical hand disinfection (Pearson's correlation; P>0.05).     

Effectiveness of hand washing and disinfection methods in removing transient bacteria after patient nursing

The effectiveness of various hand washing and disinfection methods in removing transient skin bacteria was studied in hospital after dry or moist contamination of the hands when nursing burn patients. The results were compared with those of laboratory tests with volunteers. A fairly good correlation of the bacterial reductions existed between hospital and laboratory tests. All other methods removed Staph. aureus from the hands more effectively than liquid soap. Gram-negative bacilli were more easily removed than staphylococci, even with soap wash alone. In hospital, none of the washing and disinfection methods always removed all patient-borne bacteria from the hands. After dry or moist contamination and subsequent washing with soap only, colonies of Staph. aureus were often detected in finger-print samples. Staphylococci were more often completely removed by a 4% chlorhexidine detergent scrub and alcoholic solutions (either with or without previous soap wash) than by liquid soap, hexachlorophene or iodophor preparations. Gram-negative bacilli were more easily removed by all the washing and disinfection methods. After moist contamination, Gram-negative bacilli were more often completely removed from the hands by ethanol than by other treatments. The results of the present study emphasize the importance of always using gloves when nursing a profuse spreader of bacteria or one who must be protected from infection.     

Surgical hand disinfection with a propanol-based hand rub: equivalence of shorter application times

The aim of this study was to determine the efficacy of a propanol-based hand rub at application times shorter than 3 min. The bacterial pre-value was obtained from the finger tips (prEN 12791). Subjects treated their hands with the reference procedure (n-propanol, 60%) for 3 min or the product (crossover design). Sterillium was applied for 3, 2, 1.5 and 1 min. Four other preparations were tested for 1 min. Post-values (immediate effect) were taken from one hand, and the other hand was gloved for 3h. After the gloves were removed, the second post-value was taken (sustained effect). Sterillium was more effective than the reference procedure at 3, 2 and 1.5 min (immediate and sustained effect). The immediate effect after 1 min was significantly lower [mean log(10) reduction factor (RF): 1.91+/-0.90 vs. 2.52+/-0.95; P=0.001], whereas the sustained effect was not (mean RF: 1.81+/-1.06 vs. 2.05+/-1.14; P=0.204). All other preparations failed the efficacy requirement at 1 min for both the immediate and sustained effect. Using 2 x 3 mL Sterillium for a total of 1.5 min for surgical hand disinfection was at least as effective as the 3-min reference disinfection.     

Effectiveness of hand washing and disinfection methods in removing transient bacteria after patient nursing.

The effectiveness of various hand washing and disinfection methods in removing transient skin bacteria was studied in hospital after dry or moist contamination of the hands when nursing burn patients. The results were compared with those of laboratory tests with volunteers. A fairly good correlation of the bacterial reductions existed between hospital and laboratory tests. All other methods removed Staph. aureus from the hands more effectively than liquid soap. Gram-negative bacilli were more easily removed than staphylococci, even with soap wash alone. In hospital, none of the washing and disinfection methods always removed all patient-borne bacteria from the hands. After dry or moist contamination and subsequent washing with soap only, colonies of Staph. aureus were often detected in finger-print samples. Staphylococci were more often completely removed by a 4% chlorhexidine detergent scrub and alcoholic solutions (either with or without previous soap wash) than by liquid soap, hexachlorophene or iodophor preparations. Gram-negative bacilli were more easily removed by all the washing and disinfection methods. After moist contamination, Gram-negative bacilli were more often completely removed from the hands by ethanol than by other treatments. The results of the present study emphasize the importance of always using gloves when nursing a profuse spreader of bacteria or one who must be protected from infection.     

Investigations into the efficacy of different procedures for surgical hand disinfection between consecutive operations.

In order to examine whether thorough surgical hand disinfection (handwashing plus hand disinfection) between consecutive operations is necessary, tests were carried out simulating normal clinical conditions. The tests were performed according to the guidelines for the evaluation of disinfection procedures of the German Society for Hygiene and Microbiology. Surgical hand disinfection was as follows: handwashing with soap without antimicrobial additives and subsequent 5-min disinfection with 60% n-propanol. This was followed by simulated operations of 30 or 120 min duration with a 30-min break between operations, during which half of the test group kept on the surgical gloves, while the other half removed them. The second surgical hand disinfection was done without prior handwashing by 50% of the test group. The disinfection time was reduced from 5 to 1 min by 50% of the test group. The results were evaluated by means of explorative data analysis and inductive statistical methods. Removing the surgical gloves during the interoperative break did not result in significantly higher numbers of colony forming units (cfu) compared with retaining the gloves. This was also the case after a subsequent handwashing. At the second surgical hand disinfection, after a simulated operation of 60 min duration (including break), there was no significant difference in the numbers of cfus between the test group who had washed their hands and those who had not. Reducing the disinfection time from 5 min to 1 min was not associated with a significant increase in the number of cfus. However, after a simulated operating time of 150 min (including the break), the second surgical hand disinfection with handwashing resulted in a significantly lower number of microorganisms than disinfection alone. In half the tests, the numbers of cfu were significantly lower when the test group disinfected their hands for 5 min rather than 1 min.     

Comparison of two test methods for the determination of sufficient antimicrobial activity of three commonly used alcohol-based hand rubs for hygienic hand disinfection

In Europe, the antimicrobial efficacy of alcohol-based hand rubs is determined with a quantitative suspension test (prEN 12054) and a test under practical conditions (EN 1500). Another test method has recently been published by the German Society for Hygiene and Microbiology (DGHM) with four differences to the European system in the in vitro tests: additional qualitative suspension tests with product dilutions to the ineffective range; a selection of the most resistant Gram-negative test strains in the qualitative suspension test, which should be used adjacent to Pseudomonas aeruginosa in the quantitative suspension test; a high organic load in the quantitative suspension tests (0.3% albumin and 0.3% sheep erythrocytes); and an aqueous control in the quantitative suspension test. According to DGHM, the in vitro tests should be followed by EN 1500. We have determined the antimicrobial efficacy of three commonly used alcohol-based hand rubs according to both methods. prEN 12054 was carried out without organic load. The qualitative suspension tests (DGHM) were carried out with P. aeruginosa, Escherichia coli, Proteus mirabilis, Staphylococcus aureus, Enterococcus hirae and Candida albicans. The quantitative suspension test (DGHM) was carried out with product dilutions of 75%, 50% and 25%, and a high organic load using the following test organisms: P. aeruginosa, P. mirabilis (one product only), S. aureus, E. hirae and C. albicans. All these suspension tests were carried out in quadruplicate with each product and exposure time. EN 1500 was carried out with 3 mL of each product and an application time of 30 s. All three products achieved the required bactericidal activity of prEN 12054 and the new DGHM method within 30 s, and were equally effective with the reference hand disinfection of EN 1500 within 30 s. In our study, the DGHM test method did not provide additional information for hand rubs which exhibit their bactericidal efficacy with 3 mL within 30 s (EN 1500).     

Evaluation of an alcohol-based surgical hand disinfectant containing a synergistic combination of farnesol and benzethonium chloride for immediate and persistent activity against resident hand flora of volunteers and with a novel in vitro pig skin model.

OBJECTIVE: To evaluate the immediate, persistent and sustained in vivo activity of an alcohol-based surgical hand disinfectant, consisting of a zinc gel and a preservative system containing a synergistic combination of farnesol and benzethonium chloride (ZBF disinfectant), and to develop a pig skin model for in vitro evaluation of the immediate and persistent efficacy of alcohol-based surgical hand disinfectants against resident hand flora. DESIGN: The in vivo immediate, persistent, and sustained activity of ZBF disinfectant was evaluated using human volunteers and the "glove-juice" method described in the US Food and Drug Administration's Tentative Final Monograph (FDA-TFM) for Healthcare Antiseptic Products. A novel in vitro pig skin model was developed to compare the immediate and persistent activity of alcohol-based surgical hand disinfectants against resident flora using Staphylococcus epidermidis as the test organism. Four alcohol-based surgical hand disinfectants were evaluated using this model. RESULTS: The results for the ZBF disinfectant exceed the FDA-TFM criteria for immediate, persistent, and sustained activity required for surgical hand disinfectants. The reduction factors for the 4 hand disinfectants obtained using the pig skin model show good agreement with the log(10) reductions in concentrations of hand flora obtained using human volunteers to test for immediate and persistent activity. CONCLUSION: The ZBF disinfectant we evaluated met the FDA-TFM criteria for surgical hand disinfectants. The immediate and persistent efficacy of the surgical hand disinfectants evaluated with the novel pig skin model described in this study shows good agreement with the results obtained in vivo.     

The permeability of surgical gloves to seven chemicals commonly used in hospitals

Disinfectants may cause adverse effects directly on the skin or systemically by permeating through the skin. In this study breakthrough times were measured for surgical gloves with chemicals which are commonly used in healthcare. Classical methods of analytical chemistry were tailored for the permeation tests, which were carried out according to the European standard EN 374 and the American standard ASTM F739. An exception to the EN 374 standard was made by using a 4 h testing time instead of 8 h. The gloves did not exhibit permeation of potassium hydroxide (45%), sodium hypochlorite (13%) or hydrogen peroxide (30%). Furthermore, neither glutaraldehyde (2%) nor chlorhexidine digluconate (4%) in the commercial disinfectant solutions studied exhibited permeation. Slight permeation of peracetic acid (0.35%) and acetic acid (4%) from a disinfectant agent was observed through single layered natural rubber materials. Clear evidence of formaldehyde permeation was detected through single layered natural rubber gloves, where the ASTM breakthrough times were 17-67 min, but the permeation rates were not high enough for breakthrough to have occurred according to the EN standard. The gloves in this study which offered most protection from chemical permeation were the chloroprene gloves and the thick double layered natural rubber gloves.