Research for infection protection
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  • Adenovirus
  • Aspergillus niger
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  • Candida albicans
  • Candida albicans
  • Coronavirus
  • Corynebacterium
  • Escherichia coli
  • Helicobacter pylori

Author: Kampf et al. (2013) Source: BMC Infect Dis. 2013 Oct 10;13(1):472.


Kampf et al. (2013)

Less and less - influence of volume on hand coverage and bactericidal efficacy in hand disinfection

Background: Some companies recommend small volumes (e. g. 1.1 mL) of hand rubs based on efficacy data generated according to the American Society for Testing and Materials (ASTM). It is doubtful whether these volumes allow full hand coverage and fulfil the Food and Drug Administration (FDA) efficacy requirements, which apply in the US. Aim of the study was to investigate hand coverage and bactericidal efficacy of three hand rubs used at different volumes.

Methods: The following three products were tested: Purell Advanced Instant Hand Sanitizer (70 % v/v Ethanol, Gojo Industries), Purell Advanced Instant Hand Sanitizer Foam (70 % v/v Ethanol, Gojo Industries) and Sterillium Comfort Gel (85 % w/w Ethanol, Bode Chemie). Each product was supplemented with fluorescent dye and applied to hands of participants at volumes of 1.1 mL, 2 mL, 2.4 mL, 1 or 2 pump dispenser pushes. Participants applied the “responsible application technique” until hands felt dry. Hands were screened for coverage gaps by blinded investigators using UV light. Participants with one or more fluorescent gaps at any hands were classified as having leaks. Each type of application was blinded and tested on 15 participants.
Efficacy testing was performed with 12 participants per product as described in the test methods ASTM E 1174-6 or 2755-10, respectively. Briefly, hands were washed and rinsed followed by contamination with Serratia marcescens. Baseline population levels were determined. Hands were contaminated again followed by application of hand rubs at the manufacturer’s recommended volume (1.1 mL or 2 mL, respectively). Microbial samples were taken using glove juice technique, analysed and log10-reduction was calculated.

Results: 67 % ‒ 93 % of participants showed incomplete hand coverage when using hand rubs at volumes < 2 mL. Volumes ≥ 2 mL resulted in better coverage (leaks in 0 % – 53 %). Differences were significant between the five volumes for all handrubs but not between product types. Application of 1.1 mL 70 % ethanol hand rubs resulted in log10-reductions below 2. This failed to achieve the FDA’s efficacy requirement of an at least 2 log10-reduction. However application of 2 mL of the 85 % ethanol hand rub resulted in log10-reductions of 2.06 (ASTM E 1174-06) or 2.90 (ASTM E 2755-10), respectively thus fulfilling FDA efficacy requirements.

Conclusions: The 70 % ethanol hand rubs applied with 1.1 mL do not allow full hand coverage and do not fulfill FDA’s efficacy requirements. With regard to patient safety the use of small hand rub volumes is questionable.

BMC Infect Dis. 2013 Oct 10;13(1):472. [Epub ahead of print]

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