Psoriasis, a common cutaneous disease of unknown etiology, may be triggered by infections, including those due to fungi. Since the fungal community of human skin is poorly characterized, we aimed to analyze the mycological microbiota in healthy skin and psoriatic lesions. Twenty-five skin samples from five healthy subjects (flexor forearm) and three patients with psoriasis were analyzed using broad-range 18S ribosomal DNA (rDNA) and 5.8S rDNA/internal transcribed spacer 2 (ITS2) Malassezia-specific PCR primers. Broadrange PCR analysis indicated that most organisms resembled Malassezia. Malassezia-specific 5.8S/ITS2 analysis of 1,374 clones identified five species and four unknown phylotypes, potentially representing new species. The species distribution appears largely host specific and conserved in different sites of healthy skin. In three subjects, the Malassezia microbiota composition appeared relatively stable over time. Samples of Malassezia microbiota from healthy skin and psoriatic lesions were similar in one patient but substantially different in two others. These data indicate the predominance of Malassezia organisms in healthy human skin, host-specific variation, stability over time, and as yet, no consistent patterns differentiating psoriatic skin from healthy skin.Human skin is colonized by diverse microbiota, including bacteria and fungi, that can be pathogenic under particular circumstances (14, 16). Traditionally, microorganisms have been identified by culture-dependent methods; however, many species are fastidious and underrepresented in cultures from mixed microbial communities (13), whereas others cannot be cultivated under known conditions (2). Therefore, culture-independent molecular techniques have been used for the identification of microbial species within ecosystems (2, 9, 27, 42).Such methods, particularly the analysis of rRNA genes, have been employed to characterize bacterial and fungal communities associated with diverse human body sites, including intestine (11), gingiva (28,33,43), esophagus (45), vagina (65), and outer ear canal (13). As predicted, these studies revealed greater diversity, including previously undescribed organisms, than did previous analyses based on culture-dependent techniques.The application of molecular techniques has been advocated to characterize the microbiota in both healthy and diseased skin (14). To date, rRNA data have been used to identify species associated with fungal dermatoses (21,29,38,39) and PCR-based diagnostic tests have been developed (15,26,62). Psoriasis, a common dermatosis affecting about 3% of the population in industrialized countries (3), is characterized by erythrosquamous cutaneous lesions associated with abnormal patterns of keratinocyte growth and differentiation (35). Although of unknown etiology, trigger factors, including physical trauma and streptococcal infections, may provoke clinical manifestations (51). Fungal organisms, including Candida albicans (63) and Malassezia furfur (3), have also been associated with the developmen...

Author contributions MGDB, PCD and RK conceived and designed the study. MGDB, JFRC, HSP, JH, RR, OLB, MJB, LCP, AN, HC collected the samples and metadata. AB acquired LC-MS data. LIM led LC-MS data analysis. CC led taxonomy and metadata analysis. QZ led DNA data and multi-omics analysis. JJM performed qPCR. SJS, ME, HC, AN, AB, JJM provided additional contributions to data analysis. LIM

Oral biofilms in those with denture stomatitis are different from those who are healthy. Using a cultural-independent method (polymerase chain reaction amplifi cation and sequences compared to the GeneBank database), pooled denture biofi lm samples were characterised from ten subjects who wore dentures with no stomatitis and ten others with Newton stage II denture stomatitis. Of those phylotypes that could be represented, the proportions of the genera Streptococ-cus, Veillonella, Atopobium and Prevotella differed between those subjects who were healthy and those with stomatitis. In contrast to a previously reported cultural study, there was greater fungus diversity (Candida albicans, Candida glabrata and Candida tropicalis) in the biofi lms of those who were healthy. The authors were not able to establish 'a direct cause and effect relationship between this fungus (C. albicans) and denture stomatitis'. Implant planning and placement using optical scanning and cone beam CT technology van der Zel J M. J Prosthodont 2008; 17: 476-481 Another surgical guide to ensure predictable implant placement. A surgical guide should 1) guarantee that an implant is idealy positioned, 2) take into account the soft tissues that overlie the recipient bed, and 3) ensure that there is suffi cient vertical space to accommodate the reconstruction. The surgical guide that is described in this paper fulfi ls these criteria. The method of fabrication involves forming, on a gypsum cast, a polyvi-nylacetate template containing radio opaque markers, which is used in both the scanning and imaging procedures. The cast is then optically scanned in order to map the mucosal surface, and a replica of the opposing teeth to establish the amount of vertical space. The recipient site, is imaged using a cone-beam CT scanner. A virtual implant is then selected by reference to the bone scan, the mucosal surface and opposing teeth, all combined in one 3D view. Finally, customised guides, are fabricated to accommodate the surgical drills.

Home microbes track space-use and reflect a decreasing exposure to environmental microbes due to urbanization.

Yeasts from the genus Malassezia are members of the normal biota of human skin, and may play a role in dermatopathology. Our previous study of the fungal microbiota from healthy subjects and from patients with psoriasis using clone library analysis revealed the presence of five Malassezia species and four uncharacterized phylotypes. We now compared the Malassezia microbiota from six healthy body locations and two psoriatic lesions, and evaluated its stability over time using multiplex real-time PCR. Samples from each body location were obtained monthly, for 4 months. Dual-labeled probes were designed to recognize four Malassezia sp. and two uncharacterized groups, and a genus-specific probe was also developed. A good correspondence was obtained between real-time PCR data and clone library analyses. Malassezia restricta was the most abundant species in the majority of samples, and high amounts of Malassezia globosa were also detected. The uncharacterized phylotype 1 was usually detected in lower proportions, nevertheless it was present in most samples. The microbiota was host-specific and relatively stable over time. In accordance with our previous observations, no significant dichotomy between samples from healthy skin and from psoriatic lesions was found; the samples clustered according to the subject, rather than health status.