title: Molecular analysis of Malassezia microflora in the lesional skin of psoriasis patients.
abstract: Systemic and focal infections by microorganisms have been known to induce or exacerbate psoriasis. To investigate the role of Malassezia species in the development of psoriasis, we analyzed the Malassezia microflora in psoriasis patients using a nested polymerase chain reaction (PCR) assay, and compared it with those in atopic dermatitis (AD) patients and healthy subjects. Fungal DNA was directly collected from the lesional and non-lesional skin of the trunk of 22 psoriasis patients by applying a transparent dressing. The extracted DNA was amplified by using specific primers designed for the PCR in the intergenic spacer or internal transcribed spacer area of the ribosomal RNA. All nine of the Malassezia species were detected at different rates from the 22 psoriasis patients. The overall detection rates in lesional and non-lesional skin of M. restricta, M. globosa and M. sympodialis were high (96%, 82% and 64%, respectively), whereas the detection rates of the other species were relatively low. However, there was no difference in the rates between lesional and non-lesional skin areas. The average number of Malassezia species detected in overall sites of the psoriasis patients was 3.7 +/- 1.6 species, although this fact showed no correlation with the severity of the symptoms. The number of Malassezia species detected was 4.1 +/- 1.9 in the AD patients, and 2.8 +/- 0.8 in the healthy subjects, suggesting that the skin microflora of psoriasis patients and AD patients show greater diversity than that of healthy subjects.
authors.affiliation: Department of Dermatology, Tokyo Medical University, Shinjuku-ku, Tokyo, Japan.
authors.forename: Misato
authors.initials: M
authors.lastname: Amaya
authors.forename: Mami
authors.initials: M
authors.lastname: Tajima
authors.forename: Yukari
authors.initials: Y
authors.lastname: Okubo
authors.forename: Takashi
authors.initials: T
authors.lastname: Sugita
authors.forename: Akemi
authors.initials: A
authors.lastname: Nishikawa
authors.forename: Ryoji
authors.initials: R
authors.lastname: Tsuboi
mesh_terms: D000328:Adult; D000368:Aged; D004271:DNA, Fungal / Q000032:analysis; D003876:Dermatitis, Atopic / Q000382:microbiology*; D005260:Female; D006801:Humans; D008290:Malassezia / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011565:Psoriasis / Q000382:microbiology*; D012867:Skin / Q000382:microbiology*
chemical_list: D004271:DNA, Fungal