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

SummaryBackgroundGlycerol 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.AimTo 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).MethodsIn 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 3 min. Viable counts from fingertip samples were compared with the respective pretreatment counts immediately after treatment and 3 h later.FindingsThe 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.ConclusionGlycerol 1.45% (V/V) inhibits the bactericidal efficacy of alcohol-based surgical hand rubs, especially sustained efficacy.