Shedding of bacteria and skin squames after handwashing.

Particles released into the air by wringing the hands together were collected in a slit sampler before and after washing with bar soap, with three surgical scrubs, and after rubbing them with a spirit-based lotion. The particles were identified, their number estimated, those that bore bacteria counted, and the bacteria themselves classified. It was found that there was a significant increase, averaging 17-fold, in the number of particles carrying viable bacteria released after washing with soap. The increase in bacterial dissemination was suppressed if a surgical scrub was used in place of soap, or when the lotion was used without washing. The number of skin squames released increased by 18-fold or more after washing with soap or a surgical scrub, but not after using the lotion. This suggests that a surgical scrub should be used more widely in clinical practice, and that a spirit-based hand lotion might with advantage become a partial substitute for handwashing, particularly in areas where handwashing is frequent and iatrogenic coagulase-negative staphylococcal infection common.