For the keyboard study, we swabbed individual keys of
three personal computer keyboards (25–30 keys per keyboard) and the skin on
the ventral surface of the distal joint of each fingertip of the owner and nearly
exclusive userof each keyboard. All three individualswere healthy at the time of
sampling, had not taken antibiotics for at least 6 months, and were between 20
and 35 years of age. Two of these individuals shared the same office space.
Keyboards and fingertips were swabbed within 10 min of one another, but the
keyboards had not been touched for more than 30 min before sampling. To
compare the bacterial communities on these keyboards to other miscellaneous
keyboards, we swabbed space bar keys from 15 other private and public computerkeyboards
locatedontheUniversity ofColoradocampus. Skinsurfacesand
keyboard keys were sampled using autoclaved cotton-tipped swabs premoistened
with a sterile solution (8, 15). Swabbing has been shown to be a
suitable method for skin sample collection for microbial community analysis (7).
Theentireexposedsurface ofeachkeyboardkeywas swabbedlightly for 10s. All
swabs were stored at −80 °C for less than 1 week before DNA extraction.