Research for infection protection
  • germs
  • Adenovirus
  • Aspergillus niger
  • Bovine virus diarrhea
  • Clostridium difficile
  • Candida albicans
  • Candida albicans
  • Coronavirus
  • Corynebacterium
  • Escherichia coli
  • Helicobacter pylori

Author: Suchomel M et al. (2012) Source: Am J Infect Control. 2012; 40(4): 328-31.


Suchomel M et al. (2012)

Testing of the World Health Organization recommended formulations in their application as hygienic hand rubs and proposals for increased efficacy.

Background: Alcohol-based hand disinfectants have become world standard in hand hygiene. These alcohol-based preparations are more expensive, but possess superior antimicrobial activity and good skin tolerability. Hence, there is a worldwide trend towards alcohol-based hand disinfectants. In its guidelines, WHO recommends two alcohol-based formulations for local, comparatively inexpensive production in countries with limited resources (WHO I and WHO II). In this study, the authors investigated the bactericidal activity of WHO I (ethanol 80 % v/v) and WHO II (isopropanol 75 % v/v) in hygienic hand disinfection.

Methods: The prospective, randomised, crossover in-vivo laboratory study was conducted at the Institute for Hygiene and Applied Immunology, Medical University Vienna, Austria with 20 test persons. Evaluation of the preparations’ efficacy was carried out in accordance with EN 1500. As the WHO Guidelines do not define exact application times, the study examined the application of both 1 x 3 ml/30 seconds and 2 x 3 ml/2 x 30 seconds. The bactericidal efficacy on hands artificially contaminated with Escherichia coli K12 was compared with the efficacy of the reference procedure (isopropanol 60 % v/v, 2 × 3 ml). Additionally, for the exposure time of 30 seconds, it was tested which effect increased alcohol concentrations (weight instead of volume percent) have.

Results: With the short application (30 seconds), the reduction of microbial contamination yielded by either preparation recommended by WHO was significantly inferior (WHO I: 3.59 ± 0.89; WHO II: 3.57 ± 0.82) to the reference procedure (4.29 ± 1.00; 4.11 ± 1.10). Within 30 seconds, test products with increased alcohol content produced log10 reductions similar to the reference procedure. Application of 2 x 3 ml for 60 seconds also yielded reduction factors that meet the EN 1500 efficacy criteria.

Conclusions: Application time and alcohol content influence the efficacy of alcohol-based hand disinfectants. For the two formulations recommended by WHO for countries with limited resources to achieve adequate efficacy, the application time needs to be 60 seconds, which, however, lacks in practical relevance. Hence, the authors recommend increasing the alcohol content of both formulations.

Am J Infect Control. 2012; 40(4): 328-31.

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