Molecular analysis of Malassezia microflora on the skin of atopic dermatitis patients and healthy subjects

Members of the genus Malassezia, lipophilic yeasts, are considered to be on e of the exacerbating factors in atopic dermatitis (AD). We examined variat ion in cutaneous colonization by Malassezia species in AD patients and comp ared it with variation in healthy subjects. Samples were collected by apply ing transparent dressings to the skin lesions of AD patients. DNA was extra cted directly from the dressings and amplified in a specific nested PCR ass ay. Malassezia-specific DNA was detected in all samples obtained from 32 AD patients. In particular, Malassezia globosa and M. restricta were detected in approximately 90% of the AD patients and M. furfur and M. sympodialis w ere detected in approximately 40% of the cases. The detection rate was not dependent on the type of skin lesion. In healthy subjects, Malassezia DNA w as detected in 78% of the samples, among which M. globosa, M. restricta, an d M. sympodialis were detected at frequencies ranging from 44 to 61%, with M.furfur at 11%. The diversity of Malassezia species found in AD patients w as greater (2.7 species detected in each individual) than that found in hea lthy subjects (1.8 species per individual). Our results suggest that M. fur fur, M. globosa, M. restricta, and M. sympodialis are common inhabitants of the skin of both AD patients and healthy subjects, while the skin microflo ra of AD patients shows more diversity than that of healthy subjects. To ou r knowledge, this is the first report of the use of a nested PCR as an alte rnative to fungal culture for analysis of the distribution of cutaneous Mal assezia spp.