The demonstration of bacteria on and within the stratum corneum using scanning electron microscopy

Using scanning electron microscopy it has been possible to demonstrate the location of bacteria on and within the stratum corneum of the human foot. Biopsies taken either by sectioning or by removing stratum corneum with cyanoacrylate ester adhesive were examined using a Jeol JSM-T20 scanning electron microscope. Bacteria could be seen easily on specimens from skin which had been occluded to increase the number of bacteria present. On the surface, bacteria were scattered widely in small colonies (usually containing less than ten bacteria). Although bacteria could be seen around the orifice of sweat ducts they did not preferentially favour these sites. Within the stratum corneum, bacteria could be found as relatively large colonies but these were usually associated with sweat ducts or the underside of the furrows in the skin surface. This study suggests that, in normal skin, bacteria are able to colonize both the surface and the depths of the stratum corneum.