Glycerol significantly decreases the three hour efficacy of alcohol-based surgical hand rubs

Abstract

Glycerol in alcohol-based hand rubs has positive effects on skin condition and user acceptability, but, to the authors' knowledge, its effect on the bactericidal effect of alcohol-based pre-operative hand rubs has not been reported. To investigate the impact of glycerol on the reduction of resident hand flora by ethanol 80% (w/w), isopropanol 75% (w/w) and n-propanol 60% (V/V). In three series of in-vivo laboratory tests on volunteers hands, the efficacy of each of three alcohol-based formulations was tested concurrently with and without added glycerol 1.45% (V/V) according to European Norm EN 12791 for testing pre-operative hand rubs. Formulations were allotted at random to 24 volunteers to rub on to their hands for 3min. Viable counts from fingertip samples were compared with the respective pretreatment counts immediately after treatment and 3h later. The 3-h bactericidal effects of the three pure alcoholic formulations were significantly greater than those of formulations containing glycerol (P<0.01). With ethanol, this was also true for the immediate effect. Glycerol 1.45% (V/V) inhibits the bactericidal efficacy of alcohol-based surgical hand rubs, especially sustained efficacy.