Temporal study of staphylococcal species on the skin of human subjects in isolation and clonal analysis of Staphylococcus capitis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

The staphylococcal skin floras of an isolated group of subjects were studied for 1 year. A wide variation in isolation patterns was found for different species. Staphylococcus intermedius, previously thought to be of veterinary origin, was found to be part of the resident flora of some subjects, and this may indicate a wider role for it in clinical infection. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of S. capitis isolates indicated persistent skin colonization at some sites; each region was colonized by only one clone of that species, although an adjacent area could be inhabited by a separate clone. Nine clonal groups were identified by SDS-PAGE; there was a degree of specialization between the groups with regard to the sites which they colonized. The interaction between species at a single site was less well defined. Noncolonizing isolates often exhibited phenotypic similarities that were lower than expected when compared with their presumed source. The results of SDS-PAGE analysis were compared with immunoblotting, antibiograms, and biotyping, and SDS-PAGE analysis was found to be a useful and practical tool for epidemiological work.