Wristwatch use and hospital-acquired infection

The wrists and hands of hospital-based healthcare workers (HCWs) were sampled for bacterial contamination in two consecutive cross-sectional cohort studies of wristwatch wearers and non-wristwatch wearers. In the first study (N=100), wrists were sampled by skin swabs and hands by direct plate inoculation. In the second study (N=155) wrists were sampled after each HCW removed the watch immediately prior to sampling. Staphylococcus aureus was found on the hands of 25% of wristwatch wearers and 22.9% of non-wristwatch wearers in the first study. Watch wearers had higher counts of bacteria on their wrist (P<0.001) but not on their hands. In the second study, removal of the watch prior to sampling resulted in increased counts of bacteria on both hands as well as on the watch wrist compared with non-watch wearers (P<0.001). In conclusion, wearing a wristwatch results in an increase in bacterial contamination of the wrist but excess hand contamination does not occur unless the watch is manipulated.