Methods
Sample Collection. 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 user of each keyboard. All three individuals were 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 computer keyboards located on the University of Colorado campus. Skin surfaces and 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). The entire exposed surface of each keyboard key was swabbed lightly for 10 s. All swabs were stored at −80 °C for less than 1 week before DNA extraction.