Study questions antimicrobial efficiency of foam hand sanitisers
The way 62% ethanol foam hand sanitisers are used means they do not provide any more bacterial reduction than simply washing with the same quantity of water, a study by researchers at Bode Chemie in Hamburg, Germany has found.
The study, Efficacy of ethanol-based hand foams using clinically relevant amounts: a cross-over controlled study among healthy volunteers, was performed according to EN1500 standards and found that the applied volume of 62% alcohol foam used by healthcare workers so that their hands would dry in 30sec was only 1.6g. Compared with published data, even a simple hand wash using 1.6g of water alone has similar or better antimicrobial efficacy than the same amount of 62% alcohol foam sanitiser.
Furthermore, to reach desirable bactericidal levels would require approximately twice the practical amount of product, extending evaporation times to 90–120sec per application, which would not be practical in a clinical setting.
“The data suggests we have a false sense of security with regard to the level of bacterial reduction provided when using 62% foam hand sanitisers,” said author Dr Günter Kampf, who is a member of the German Association for Infection Control and a lecturer at the Ernst Moritz University in Germany. He has worked in the department of scientific affairs at Bode Chemie since 1998.
“Practically, it is very difficult to use these appropriately, so we may be fooling ourselves a bit with regard to hand hygiene efforts when using such products. This should be a wake up call to the infection prevention community.”
A healthcare worker has at least 20 opportunities to clean his/her hands in every hour of patient care, but would not apply sanitising products to their hands for more than 30sec per opportunity, as they simply do not have time to go beyond that and still provide quality patient care.
“It is more than in-vitro science – it is real life in a practical setting that we must consider,” said Kampf. “How much time do healthcare workers have? More effective hand hygiene agents are needed if reducing hospital-acquired infections is our objective.”
The lack of clear application instructions for foam products, with some suggesting the use of a “golf-ball sized” amount of foam and others suggesting simply to “apply product and rub hands until dry”, were regarded by the study authors as unhelpful.
“The subjects in our study all had a rather different understanding of how large a golf ball might be,” said Kampf. “Based on our data, the amount of foam recommended on product labels should be more precise and address both the efficacy and a clinically acceptable time for drying after application.”
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