Quest for a realistic in vivo test method for antimicrobial hand-rub agents: introduction of a low-volume hand contamination procedure

Appl Environ Microbiol. 2011 Dec;77(24):8588-94. doi: 10.1128/AEM.06134-11. Epub 2011 Oct 14.

Abstract

A novel method has been developed for the evaluation of alcohol-based hand rubs (ABHR) that employs a hand contamination procedure that more closely simulates the in-use conditions of ABHR. Hands of human subjects were contaminated with 0.2 ml of a concentrated suspension of Serratia marcescens (ATCC 14756) to achieve baseline contamination between 8 and 9 log₁₀ CFU/hand while allowing product to be applied to dry hands with minimal soil load. Evaluation of 1.5 ml of an ABHR gel containing 62% ethanol produced log₁₀ reductions of 2.66 ± 0.96, 2.40 ± 0.50, 2.41 ± 0.61, and 2.33 ± 0.49 (means ± standard deviations) after 1, 3, 7, and 10 successive contamination/product application cycles. In a study comparing this low-volume contamination (LVC) method to ASTM E1174, product dry times were more realistic and log₁₀ reductions achieved by the ABHR were significantly greater when LVC was employed (P < 0.05). These results indicate that a novel low-volume hand contamination procedure, which more closely represents ABHR use conditions, provides more realistic estimates of in-use ABHR efficacies. Based on the LVC method, log₁₀ reductions produced by ABHR were strongly dependent on the test product application volume (P < 0.0001) but were not influenced by the alcohol concentration when it was within the range of 62 to 85% (P = 0.378).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Load*
  • Disinfectants / administration & dosage*
  • Dose-Response Relationship, Drug
  • Hand / microbiology*
  • Hand Disinfection / methods*
  • Hand Disinfection / standards*
  • Humans
  • Serratia marcescens / drug effects*
  • Serratia marcescens / isolation & purification*
  • Treatment Outcome

Substances

  • Disinfectants