Effect of a 1 min hand wash on the bactericidal efficacy of consecutive surgical hand disinfection with standard alcohols and on skin hydration

Abstract

Background In most surgical theatres, a 1 min or even longer hand wash is routine as part of the pre-operative hand disinfection. But its benefit has recently been seen critically. Methods We have therefore investigated the effect of a 1 min hand wash on skin hydration and on the efficacy of consecutive surgical hand rubbing with three standard alcohols (60% propan-1-ol, 60% propan-2-ol, 80% ethanol; all v/v) on the resident hand flora. Three types of treatment were performed: (i) a 1 min pre-wash before surgical hand disinfection, (ii) no pre-wash before surgical hand disinfection and (iii) no pre-wash but use of a brush for 1 min during disinfection procedure. The efficacy of the alcohols was determined according to prEN 12791 with the same 20 volunteers in paired groups. To assess the effect of the hand wash on skin hydration, 10 volunteers washed their hands with sapo kalinus for 1 min and dried hands with a paper towel. Skin hydration was measured with a corneometer before the hand wash and subsequently up to 10 min thereafter both on the palm and dorsum of hands. We also tested the reduction of bacterial spores by a 15 s hand wash according to EN 1499 after artificial contamination of hands of 14 volunteers with spores of B. stearothermophilus. Results Propan-1-ol (60%) was most effective with a mean log 10 reduction of 2.11, followed by ethanol (80%) with a mean log 10 reduction of 1.76 and propan-2-ol (60%) with a mean log 10 reduction of 0.57 (all immediate effect without hand wash). The efficacy of the alcohols was neither significantly improved nor impaired by a preceding 1 min hand wash, but there is a trend towards better efficacy on dry hands. Using a brush for 1 min during disinfection resulted in a better efficacy with all alcohols. An anaylsis of variance revealed that the immediate effect of ethanol ( p = 0.013 ) and propan-2-ol ( p = 0.001 ) is significantly influenced by the variation of treatments which is mainly explained by the effect of brushing during disinfection. But no significant difference between treatment variations was found in the sustained effect with any of the alcohols. Skin hydration increased significantly by a 1 min hand wash for up to 10 min despite drying hands with a paper towel. A 15 s hand wash reduced the number of bacterial spores significantly from log 10 3.84 to log 10 1.99 ( p = 0.001 ). Conclusions There is no benefit of a hand wash as part of surgical hand disinfection except that a short hand wash of 15 s can effectively reduce spores. The best time for this short hand wash is at the beginning of work in hospital, but at the latest in the sluice of the operating theatre about 10 min before applying an alcohol-based hand rub to give the skin enough time to dry.