Although the micro-organisms forming the cutaneous microbiota are considered to play important roles in the modification and prevention of skin diseases, a comprehensive analysis of their composition has not yet been carried out because of difficulties in determining yet-to-be-cultured micro-organisms in the samples. Swab-scrubbed forehead skin samples of five healthy volunteers were analysed by profiling 16S rRNA genes, as well as by conventional culture methods, to provide a profile of the cutaneous microbiota that included yet-to-be-cultured bacteria from normal human skin. Cluster analyses of the 16S rRNA gene sequences indicated a marked increase in diversity compared with that derived from the culture methods. Nineteen previously recognized species and 13 novel phylotypes were obtained from the analysis of 416 clones. In addition to well-known bacteria such as Staphylococcus epidermidis and Propionibacterium acnes, phylotype A, the 16S rRNA gene of which is 97 % similar to that of Methylophilus methylotrophus, was detected in three of the five samples, in one of which it was the predominant clone. Culture-independent genetic profiling of 16S rRNA genes for detecting human cutaneous microbiota has allowed us to detect potentially novel components of the cutaneous microbiota in humans.

An immunofluorescent technique combined with tape-stripping was used to measure scTARC. The scTARC can be used as an indicator of the severity of local acute inflammation in patients with AD.

A previous study using bacterial 16S rRNA gene-based clone libraries revealed that the microbiota in healthy human skin included uncultured micro-organisms, although the micro-organisms in skin exposed to disease conditions remain to be examined. To compare the profiles of skin microbiota in 13 patients with atopic dermatitis (AD) and 10 healthy controls, terminal RFLP analysis of bacterial 16S rRNA genes was applied to 23 swab-scrubbed samples from facial skin. This culture-independent analysis successfully revealed the complex bacterial members of the microbiota as peak patterns following capillary electrophoresis of terminal restriction fragments (T-RFs). Each T-RF peak reflected a micro-organism, and the micro-organism to which each peak was assigned could be identified by computer simulation of T-RF length using the nucleotide sequence data of bacterial species residing in the skin. Among 18 species detected in the study, Stenotrophomonas maltophilia was detected significantly more commonly in AD patients (5/13 for AD patients vs 0/10 for controls), whilst Dietzia maris was detected significantly more commonly in normal controls (8/10 for controls vs 2/13 for AD patients). Moreover, Streptococcus species, which are considered to be uncommon in uninfected skin, were detected in seven patients and eight normal controls. Although further studies should be undertaken to investigate the roles of these micro-organisms in AD, the microbiota were presumed to include hitherto uninvestigated bacterial species in the major population of patients with AD and of healthy controls.