The cutaneous microbiology of haired and hairless mice.

The cutaneous microflora of the mid-dorsal area of hairless and haired mice was studied by processing skin biopsies. In both C3H and CBA hairless genotype animals the prevalence of colonization and the bacterial density were significantly greater than in the haired animals. The dominant bacteria were staphylococci and aerobic coryneforms. No propionibacteria were isolated. Temporal studies with C3H mice showed that from 0 to 9 days after birth the cutaneous microflora reduced and from then on the haired genotype animals maintained a low cutaneous microflora, whilst hairless genotype animals gradually lost hair from head to tail and the microflora density increased. Reciprocal skin grafting between haired and hairless animals showed that the donor skin acquired the microflora characteristics of the recipient animal after 15 d post-grafting even though the donor skin remained morphologically true to genotype.

A comparison of the in vivo antibacterial effects of 'OpSite', 'Tegaderm' and 'Ensure' dressings.

Three semi-permeable polyurethane dressings, 'Ensure', 'OpSite' and 'Tegaderm', were tested for their ability to prevent the increase in bacterial population under naturally hydrated, occluded volar forearm skin. Only 'OpSite' inhibited the bacterial multiplication in these tests. It is concluded that in the practical situation, 'OpSite' could well confer a greater margin of safety.

The follicular distribution and abundance of resident bacteria on human skin.

A cryostat sectioning procedure was used to determine quantitative viable counts of microorganisms both on the surface and in successive layers of human cadaver skin biopsies. Also, using a previously described xenograft model, we investigated the dependence of microorganisms on the presence of sebaceous glands by using full thickness (1.5-2.0 mm) and split thickness (0.6 mm, ensuring sebaceous gland exclusion) human skin. Our results show substantial variation in the distribution and abundance of skin bacteria, even amongst biopsies from the same cadaver. In general, propionibacteria were distributed within a narrow band at varying depths beneath the skin surface whereas staphylococci were more broadly distributed. The importance of this with respect to topically applied antiseptics and antimicrobial agents is indicated. The xenograft studies demonstrated that propionibacteria were dependent on the presence of sebaceous glands whereas staphylococci were not.