The cutaneous microbiology of normal human feet.

A survey has been made of the bacterial and fungal populations carried at three different sites on the feet of 60 individuals. The bacteria found at the three sites were quantitatively similar and Micrococcaceae and aerobic coryneform bacteria predominated. The carriage of other bacterial groups was generally low. There was a quantitative variation between sites--mean total counts were 1.04 X 10(7) cfu/cm2 skin in the fourth toe cleft, 4.08 X 10(5) cfu/cm2 skin on the sole and 1.21 X 10(3) cfu/cm2 skin on the dorsal surface. Staphylococci were most often dominant on the sole and dorsal surface whereas aerobic coryneforms predominated in the majority of fourth toe clefts. The higher the total count at a given site the more likely it was that aerobic coryneform bacteria predominated. The skin surface pH was significantly higher on the sole (mean value 6.25) than on the dorsal surface (mean value 5.23). Factors controlling the microbial ecology of the foot are discussed.