1007. How Do Alcohol-Based Handrubs Fare Against the Semmelweis Hand Disinfection Procedure? An In Vivo study using the Standard Test Method ASTM E2755
Session: Poster Abstract Session: Hand Hygiene 2012
Friday, October 19, 2012
Room: SDCC Poster Hall F-H
Background: The standard test method ASTM E2755 was recently approved for evaluating the in vivoefficacy of alcohol-based handrubs (ABHR). This method was specifically designed to evaluate ABHR under conditions which are more reflective of in use conditions. To further validate E2755 for the evaluation of ABHR, we compared the efficacy of 70% alcoholic solutions to both the EN1500 internal reference standard and the original hand disinfection procedure introduced by Ignaz Semmelweis.

Methods: Fifteen test subjects evaluated 5 test substances according to ASTM E2755 in a crossover design. Hands were contaminated with 200 µl of a highly concentrated suspension of Serratia marcescens to obtain initial “baseline” contamination and prior to each test substance application. Test substances were 60% 2-propanol, 70% 2-propanol, 70% ethanol, 70% 1-propanol, and 4% chlorinated lime. The 60% 2-propanol solution was applied according to the reference procedure described in EN1500. The 70% alcoholic solutions were applied as single 3 ml portions and rubbed until completely dry. For the Semmelweis procedure, hands were submerged in a basin containing 2 L of chlorinated lime solution and rubbed for a total of 5 minutes. Surviving bacteria were recovered using the “glove juice” procedure and log10reductions were calculated by subtracting post-wash values from baseline values.

Results: Mean log10 reductions were as follows: 60% 2-propanol reference procedure = 2.23±0.63; 70% 2-propanol = 3.00±1.02; 70% ethanol = 3.07±0.91; 70% 1-propanol = 4.76±1.02; and 4% chlorinated lime = 5.81±0.30. The statistical ranking according to repeated measures ANOVA (P<0.05) was 60% 2-propanol reference procedure < 70% 2-propanol = 70% ethanol < 70% 1-propanol < 4% chlorinated lime.

Conclusion: These results demonstrate that ASTM E2755 is capable of effectively identifying ABHR performance differences. Furthermore, these results demonstrate that 70% alcoholic solutions are highly efficacious and confirm previous findings that 1-propanol is the most effective alcohol against transient bacteria. Although the Semmelweis procedure was the most effective, it is both impractical from a timing perspective and damaging to the skin, making it inappropriate for use in modern healthcare environments.

David Macinga, PhD, Research and Development, GOJO Industries, Inc., Akron, OH, Sarah Edmonds, MS, GOJO Industries, Inc, Akron, OH and Collette Duley, BS, BioScience Laboratories, Inc., Bozeman, MT

Disclosures:

D. Macinga, GOJO Industries, Inc: Employee, Salary

S. Edmonds, GOJO Industries: Employee, Salary

C. Duley, None

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