title: Substantial alterations of the cutaneous bacterial biota in psoriatic lesions.
abstract: For psoriasis, an idiopathic inflammatory disorder of the skin, the microbial biota has not been defined using cultivation-independent methods. We used broad-range 16S rDNA PCR for archaea and bacteria to examine the microbiota of normal and psoriatic skin. From 6 patients, 19 cutaneous samples (13 from diseased skin and 6 from normal skin) were obtained. Extracted DNA was subjected to the broad range PCR, and 1,925 cloned products were compared with 2,038 products previously reported from healthy persons. Using 98% sequence identity as a species boundary, 1,841 (95.6%) clones were similar to known bacterial 16S rDNA, representing 6 phyla, 86 genera, or 189 species-level operational taxonomic unit (SLOTU); 84 (4.4%) clones with <98% identity probably represented novel species. The most abundant and diverse phylum populating the psoriatic lesions was Firmicutes (46.2%), significantly (P<0.001) overrepresented, compared to the samples from uninvolved skin of the patients (39.0%) and healthy persons (24.4%). In contrast, Actinobacteria, the most prevalent and diverse phylum in normal skin samples from both healthy persons (47.6%) and the patients (47.8%), was significantly (P<0.01) underrepresented in the psoriatic lesion samples (37.3%). Representation of Propionibacterium species were lower in the psoriatic lesions (2.9+/-5.5%) than from normal persons (21.1+/-18.2%; P<0.001), whereas normal skin from the psoriatic patients showed intermediate levels (12.3+/-21.6%). We conclude that psoriasis is associated with substantial alteration in the composition and representation of the cutaneous bacterial biota.
authors.affiliation: Department of Medicine, New York University School of Medicine, New York, New York, United States of America.
authors.forename: Zhan
authors.initials: Z
authors.lastname: Gao
authors.forename: Chi-hong
authors.initials: CH
authors.lastname: Tseng
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Strober
authors.forename: Zhiheng
authors.initials: Z
authors.lastname: Pei
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Blaser
mesh_terms: D000328:Adult; D000368:Aged; D001419:Bacteria / Q000378:metabolism*; D044822:Biodiversity; D004247:DNA / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism; D005260:Female; D006801:Humans; D007249:Inflammation; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D011565:Psoriasis / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000737:chemistry; D012867:Skin / Q000378:metabolism / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D004247:DNA