A laboratory model for testing agents for hygienic hand disinfection: handwashing and chlorhexidine for the removal of klebsiella.

A model for the laboratory assessment of hygienic hand disinfection is described which closely reproduces handwashing in a ward setting. The model uses a clinically relevant test organism and takes into account the natural antibacterial action of the skin. It also provides a means of measuring any residual antibacterial action after hand disinfection. Using an epidemic multiply-resistant strain of Klebsiella aerogenes K21, 0.5% chlorhexidine in iso-propyl alcohol yielded sterile post-disinfection finger washings more often than 4% chlorhexidine digluconate. Both preparations were more effective than soap and water, and with each residual action was demonstrable. The model is applicable to the laboratory evaluation of hygienic hand procedures and for agents of potential use in defined clinical settings.