Search

The 2009 World Health Organization (WHO) Guidelines on hand hygiene in health care recommend alcohol-based hand rubs for both hygienic and pre-surgical hand treatment. Two formulations based on ethanol 80% v/v and 2-propanol 75% v/v are proposed for local preparation in healthcare settings where commercial products are not available or too expensive. Both formulations and our suggested modifications (using mass rather than volume percent concentrations) were evaluated for their conformity with the efficacy requirements of the forthcoming amendment of the European Norm (EN) 12791, i.e. non-inferiority of a product when compared with a reference procedure (1-propanol 60% v/v for 3 min) immediately and 3 h after antisepsis. In this study, the WHO-recommended formulations were tested for 3 min and 5 min. Neither formulation met the efficacy requirements of EN 12791 with 3 min application. Increasing the respective concentrations to 80 w/w (85% v/v) and 75 w/w (80% v/v), together with a prolonged application of 5 min, rendered the immediate effect of both formulations non-inferior to the reference antisepsis procedure. This was not the case with the 3h effect, which remained significantly inferior to the reference. Although the original formulations do not meet the efficacy requirements of EN 12791, the clinical significance of this finding deserves further clinical trials. To comply with the requirement of EN 12791, an amendment to the formulations is possible by increasing the alcohol concentrations through changing volume into mass percent and prolonging the duration of application from 3 min to 5 min., (Copyright © 2011 World Health Organization. Published by Elsevier Ltd on behalf of the Healthcare Infection Society. Published by Elsevier Ltd.. All rights reserved.)

In the area of hand hygiene, European Norms exist, or are under development, with regard to protective gloves and for assessing the antimicrobial efficacy of hand disinfectants. Important norms for gloves are EN 420 (General requirements), EN 374 (Protective gloves against chemicals and microorganisms) and EN 455 (Medical gloves for single use). A suspension test for the demonstration of bactericidal activity (prEN 12054) is obligatory for hand disinfectants in all fields of application; a test to prove activity against yeasts applies only to hygienic hand rub. (Optional) Claims for virucidal activities can be substantiated by prEN 1476 and, in future, for mycobactericidal capacity by a test which is still under development. In vivo tests exist for post-contamination treatments, hygienic hand wash and hygienic hand rub (EN 1499 and EN 1500 respectively), and for the preoperative surgical hand rub/wash (prEN 12791). The two former tests employ artificially contaminated hands, the latter test is done with clean hands. All in vivo tests use reference hand treatments (with unmedicated soap or 2-propanol 60% (vol.) or 1-propanol 60% (vol.), respectively) against the results of which are compared with those achieved with the product under test and with the same volunteers. An antiseptic soap needs to be significantly more efficacious than unmedicated soap, a product for hygienic hand rub must not be inferior to the reference treatment with 2-propanol, and a surgical hand disinfectant must not cause a smaller bacterial reduction than the reference preparation with 1-propanol, immediately, and after 3 h. An (optional) claim for sustained activity of a surgical disinfectant needs to be demonstrated by achieving a significantly stronger bacterial reduction after 3 h than the reference preparation.

The non-aqueous use of ethanol or propanols offers various advantages over washing hands with either unmedicated or medicated soap in both hygienic and surgical hand disinfection. Alcohols exert the strongest and fastest activity against a wide spectrum of bacteria and fungi (but not bacterial spores) as well as enveloped (but less so against non-enveloped) viruses, being little influenced by interfering substances. They are of low toxicity and offer acceptable skin tolerability when made up with suitable emollients. The mode of their application is simple and three to four times more economical of time than wash procedures, features which help to increase the compliance with the rules of hand hygiene.

Treatment of skin with chlorine generates 'chlorine covers' which, in a previous study, exerted significant sustained bactericidal effects against transient skin flora on the upper arm and forearm. In this investigation, this effect was studied on both the transient and resident flora of the hands using test models for the evaluation of hand disinfectants as agreed upon in Austria and Germany. Chlorine covers were generated by bathing hands in a solution of 2% sodium tosylchloramide for 1 min. Subsequently, this cover was destroyed on one, randomly selected, hand by bathing it in a solution of 0.5% sodium thiosulphate for 15 s. The amount of chlorine on the fingertips of chlorinated hands was 2.2 +/- 0.4 micrograms/cm2; that on subsequently dechlorinated hands was 0.2 +/- 0.1 microgram/cm2. In experiments with artificially contaminated hands (Escherichia coli), the kinetics of bacterial die-off were the same on both hands. Also, in experiments with resident flora, the kinetics of bacterial die-off did not suggest bacterial reductions that increase with the duration of contact with the chlorine cover. It was concluded that with the test models used, a significant sustained antimicrobial effect of the chlorine cover could not be demonstrated on hands.

Two methods for artificial contamination of hands and two sampling techniques to recover the test organisms were compared for their effects on the results of two post-contamination hand treatments: a handrub with two portions of 3 ml of 2-propanol 60% v/v for 1 min, and a handwash with liquid soap 20% w/v for 1 min followed by a 15 s rinse. The two contamination methods involved a short immersion of the hands (up to the middle of the mid-hand) in a suspension of the test organism followed by either air-drying (3 min) or drying by rubbing the hands' vigorously against each other (3 min) in a standardized way. The two sampling techniques consisted of rubbing the fingertips in either 10 ml trypticase soy broth (TSB) against the bottom of a Petri dish; or 100 ml TSB against glass beads contained in a bowl. Sixteen volunteers were randomly allotted to four blocks of four. They carried out the four possible combinations of two treatments and two contamination methods in a series of four tests arranged in a Latin-square design. In addition, the two sampling techniques were compared with each other concurrently by sampling of the right and left hand each with a different one of the two techniques. The alcoholic handrub reduced the release of test organisms significantly (2P less than 0.005) more effectively, by 1.1-1.3 x log10, than did the handwash with liquid soap, regardless of the contamination or sampling method. Whereas the two recovery techniques yielded virtually identical results in corresponding situations, the method of artificial contamination affected the mean reduction factors, strongly.(ABSTRACT TRUNCATED AT 250 WORDS)

A prospective, randomized double-blind study with intra-individual comparison of the results was undertaken with 20 volunteers to assess the influence of cosmetic additives on the acceptability of a mixture of n-propanol (50% v/v) and isopropanol (30% v/v) for hand disinfection. Three to 5 ml of antiseptic was rubbed into the hands until dry 15 times a day, 5 days a week and for 2 weeks per preparation. For self-assessment the parameters 'appearance', 'intactness', 'turgor' and 'sensation' were evaluated weekly by visual analogue; for assessment by a dermatologist the same parameters except 'sensation' were used. Each score was compared before and after treatment. The antimicrobial efficacy of the alcoholic mixture was equivalent to or better than the standard (isopropanol 60% v/v, 1 min). The frequent application of these antiseptic preparations caused a slight but significant deterioration of the skin condition as judged by both self-assessment and dermatologist; however, this was significantly less when the antiseptic contained cosmetic additives. It is concluded that the addition of suitable emollients can significantly increase the acceptability of alcoholic disinfectants.

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.

In handwashing experiments with Salmonella typhimurium the effect of chlorhexidine (CHX) on the pathogenicity of surviving bacteria was assessed with and without a neutralizer in a mouse model of infection. Without neutralizer the LD50 of CHX handwash fluids was raised. Neutralizer in suspensions of untreated bacteria caused a reduction of LD50 up to 1.2 logs. Thus, in contrast to soap or alcohol, CHX without neutralizer exerted a slight 'depathogenizing' action and neutralizer a slight 'pathogenizing' effect in the experimental model used. However, in comparison to the efficiency of handwashing procedures which reduce the number of bacteria available for transfer by at least 3.0 to 4.2 logs, the size of these effects seems to be negligibly small and unpredictable. Therefore, the single most important parameter in assessing the potency of disinfectants remains the reduction of viable counts with time.

In a prospective, randomized, double-blind, placebo-controlled study involving 27 surgical units in six European countries, the effect of preoperative whole-body bathing on two occasions with a detergent containing chlorhexidine (CHX+) on the incidence of wound infection in elective, clean surgery was compared with two bathings with a detergent without chlorhexidine (CHX-). In the CHX+ group 2.62% of 1413 patients and in the CHX- group 2.36% of 1400 patients subsequently became infected. The infection rate in the CHX+ group was 1.11 times that in the CHX- group with 95% confidence limits ranging between 0.69 and 1.82. Consequently, bathing patients twice preoperatively with chlorhexidine-detergent did not reduce the incidence of infection of clean wounds.