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Luciana Campos Paulino - One of the best experts on this subject based on the ideXlab platform.
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Malassezia intra specific diversity and potentially new species in the skin microbiota from brazilian healthy subjects and seborrheic dermatitis patients
PLOS ONE, 2015Co-Authors: Renan Cardoso Soares, Marcelo Zani, Ana Carolina Belini Bazan Arruda, Lucia Helena Favaro De Arruda, Luciana Campos PaulinoAbstract:Malassezia yeasts are part of the resident cutaneous microbiota, and are also associated with skin diseases such as seborrheic dermatitis (SD). The role these fungi play in skin diseases and why they are pathogenic for only some individuals remain unclear. This study aimed to characterize Malassezia microbiota from different body sites in healthy and SD subjects from Brazil. Scalp and forehead samples from healthy, mild SD and severe SD subjects were collected. Non-scalp lesions from severe SD patients were also sampled. 5.8S rDNA/ITS2 amplicons from Malassezia sp. were analyzed by RFLP and sequencing. Results indicate that Malassezia microbiota did not group according to health condition or body area. Phylogenetic analysis revealed that three groups of sequences did not cluster together with any formally described species, suggesting that they might belong to potential new species. One of them was found in high proportions in scalp samples. A large variety of Malassezia subtypes were detected, indicating intra-specific diversity. Higher M. globosa proportions were found in non-scalp lesions from severe SD subjects compared with other areas, suggesting closer association of this species with SD lesions from areas other than scalp. Our results show the first panorama of Malassezia microbiota in Brazilian subjects using molecular techniques and provide new perspectives for further studies to elucidate the association between Malassezia microbiota and skin diseases.
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analysis of Malassezia microbiota in healthy superficial human skin and in psoriatic lesions by multiplex real time pcr
Fems Yeast Research, 2008Co-Authors: Luciana Campos Paulino, Chi-hong Tseng, Martin J. BlaserAbstract: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.
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research article analysis of Malassezia microbiota in healthy superficial human skin and in psoriatic lesions by multiplex real time pcr
Fems Yeast Research, 2008Co-Authors: Luciana Campos Paulino, Chi-hong Tseng, Martin J. BlaserAbstract: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.
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Molecular Analysis of Fungal Microbiota in Samples from Healthy Human Skin and Psoriatic Lesions
Journal of Clinical Microbiology, 2006Co-Authors: Luciana Campos Paulino, Bruce E Strober, Chi-hong Tseng, Martin J. BlaserAbstract: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. Broad-range 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.
Martin J. Blaser - One of the best experts on this subject based on the ideXlab platform.
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research article analysis of Malassezia microbiota in healthy superficial human skin and in psoriatic lesions by multiplex real time pcr
Fems Yeast Research, 2008Co-Authors: Luciana Campos Paulino, Chi-hong Tseng, Martin J. BlaserAbstract: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.
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analysis of Malassezia microbiota in healthy superficial human skin and in psoriatic lesions by multiplex real time pcr
Fems Yeast Research, 2008Co-Authors: Luciana Campos Paulino, Chi-hong Tseng, Martin J. BlaserAbstract: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.
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Molecular Analysis of Fungal Microbiota in Samples from Healthy Human Skin and Psoriatic Lesions
Journal of Clinical Microbiology, 2006Co-Authors: Luciana Campos Paulino, Bruce E Strober, Chi-hong Tseng, Martin J. BlaserAbstract: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. Broad-range 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.
Akemi Nishikawa - One of the best experts on this subject based on the ideXlab platform.
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molecular analysis of the cutaneous Malassezia microbiota from the skin of patients with atopic dermatitis of different severities
Mycoses, 2011Co-Authors: M Kaga, Masataro Hiruma, Takashi Sugita, Akemi Nishikawa, Y Wada, Shigaku IkedaAbstract:Summary Cutaneous Malassezia is an exacerbating factor in patients with atopic dermatitis. We analysed the Malassezia microbiota of adult patients with head and neck atopic dermatitis of different severities (mild, moderate and severe). Of the nine human-associated Malassezia species, the number detected was similar (3.5–4.2 species per case) among the members of all severity groups. However, the ratio of the two major Malassezia species, M. globosa and M. restricta, was different in the severe group.
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quantitative analysis of cutaneous Malassezia in atopic dermatitis patients using real time pcr
Microbiology and Immunology, 2006Co-Authors: Takashi Sugita, Mami Tajima, Ryoji Tsuboi, Hisae Tsubuku, Akemi NishikawaAbstract:We quantified the cutaneous Malassezia in patients with atopic dermatitis using a real-time PCR assay. Seven to 12 times more Malassezia colonized the head and neck compared to the trunk or limbs, and the species M. globosa and M. restricta accounted for approximately 80% of all Malassezia colonization at any body site.
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antifungal activities of tacrolimus and azole agents against the eleven currently accepted Malassezia species
Journal of Clinical Microbiology, 2005Co-Authors: Takashi Sugita, Mami Tajima, Masuyoshi Saito, Ryoji Tsuboi, Akemi NishikawaAbstract:The lipophilic yeast Malassezia is an exacerbating factor in atopic dermatitis (AD) and colonizes the skin surface of patients with AD. With the goal of reducing the number of Malassezia cells, we investigated the antifungal activities of a therapeutic agent for AD, tacrolimus, and the azole agents itraconazole and ketoconazole against Malassezia species in vitro. We examined 125 strains of the 11 currently accepted Malassezia species by using the agar dilution method. All strains of the 11 Malassezia species were very susceptible to both azole agents, with MICs ranging from 0.016 to 0.25 μg/ml. Tacrolimus had antifungal activities against half of the strains, with MICs ranging from 16 to 32 μg/ml. Two of the major cutaneous floras, Malassezia globosa and Malassezia restricta, have several genotypes in the intergenic spacer region of the rRNA gene; the azole agents had slightly higher MICs for specific genotype strains of both microorganisms. A combination of azole agents and tacrolimus had a synergistic effect against Malassezia isolates, based on a fractional inhibitory index of 0.245 to 0.378. Our results provide the basis for testing these agents in future clinical trials to reduce the number of Malassezia cells colonizing the skin surface in patients with AD.
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new yeast species Malassezia dermatis isolated from patients with atopic dermatitis
Journal of Clinical Microbiology, 2002Co-Authors: Takashi Sugita, Ryoji Tsuboi, Masako Takashima, Takako Shinoda, Hajime Suto, Tetsushi Unno, Hideoki Ogawa, Akemi NishikawaAbstract:Malassezia species are considered to be one of the exacerbating factors in atopic dermatitis (AD). During examination of the cutaneous colonization of Malassezia species in AD patients, we found a new species on the surface of the patients' skin. Analysis of ribosomal DNA sequences suggested that the isolates belonged to the genus Malassezia. They did not grow in Sabouraud dextrose agar but utilized specific concentrations of Tween 20, 40, 60, and 80 as a lipid source. Thus, we concluded that our isolates were new members of the genus Malassezia and propose the name Malassezia dermatis sp. nov. for these isolates.
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molecular analysis of Malassezia microflora on the skin of atopic dermatitis patients and healthy subjects
Nippon Ishinkin Gakkai Zasshi, 2001Co-Authors: Takashi Sugita, Ryoji Tsuboi, Takako Shinoda, Hajime Suto, Tetsushi Unno, Hideoki Ogawa, Akemi NishikawaAbstract:Members of the genus Malassezia, lipophilic yeasts, are considered to be one of the exacerbating factors in atopic dermatitis (AD). We examined variation in cutaneous colonization by Malassezia species in AD patients and compared it with variation in healthy subjects. Samples were collected by applying transparent dressings to the skin lesions of AD patients. DNA was extracted directly from the dressings and amplified in a specific nested PCR assay. 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 were detected in approximately 40% of the cases. The detection rate was not dependent on the type of skin lesion. In healthy subjects, Malassezia DNA was detected in 78% of the samples, among which M. globosa, M. restricta, and 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 was greater (2.7 species detected in each individual) than that found in healthy subjects (1.8 species per individual). Our results suggest that M. furfur, M. globosa, M. restricta, and M. sympodialis are common inhabitants of the skin of both AD patients and healthy subjects, while the skin microflora of AD patients shows more diversity than that of healthy subjects. To our knowledge, this is the first report of the use of a nested PCR as an alternative to fungal culture for analysis of the distribution of cutaneous Malassezia spp. Members of the genus Malassezia, lipophilic yeasts, colonize the skin of the head, neck, and shoulders of humans and are one of the causative factors in pityriasis versicolor and seborrheic dermatitis (3). Malassezia species are also considered to be one of the factors that exacerbate atopic dermatitis (AD), based on the finding that AD patients (but not healthy subjects) have specific serum immunoglobulin E (IgE) antibodies against Malassezia spp. (9, 22, 23). Application of topical antimycotic agents to AD patients decreases Malassezia colonization and the severity of eczematous lesions (2), suggesting that Malassezia species play a role in AD. In addition, several candidate Malassezia antigens have been implicated in the pathogenesis of AD (10, 11, 16, 17, 19, 24). The taxonomy of the genus Malassezia was recently revised, primarily by using rRNA gene sequences, into seven species: M. furfur, M. globosa, M. obtusa, M. restricta, M. pachydermatis, M. slooffiae, and M. sympodialis (4, 5, 6). M. globosa, M. obtusa, M. restricta, and M. slooffiae were formerly designated M. furfur. The frequency of isolation of each species and its correlation with the clinical manifestations of AD have not been well investigated. Studies examining colonization by Malassezia spp. may aid in the understanding of the mechanism of AD and the development of an effective treatment. Due to the difficulties inherent in culturing Malassezia spp., we analyzed the cutaneous Malassezia microflora directly from the skin lesions of AD patients by using a nested PCR.
Takashi Sugita - One of the best experts on this subject based on the ideXlab platform.
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Molecular epidemiology of Malassezia globosa and Malassezia restricta in Sudanese patients with pityriasis versicolor.
Mycopathologia, 2013Co-Authors: M. Saad, Takashi Sugita, H. Saeed, A. AhmedAbstract:Pityriasis versicolor is a superficial infection of the stratum corneum caused by Malassezia yeasts. The cutaneous Malassezia globosa and Malassezia restricta in Sudanese patients with pityriasis versicolor were elucidated using a molecular-based, culture-independent method and compared with that in healthy individuals. Scale samples were collected by applying an Opsite™ transparent dressing to lesional and non-lesional sites on 29 Sudanese patients with pityriasis versicolor and 54 healthy individuals. Malassezia DNA was extracted directly from the samples. The overall level of colonization by Malassezia globosa and Malassezia restricta was analyzed by real-time PCR using a TaqMan probe. The overall level of colonization by Malassezia at the lesional sites was higher than that at the non-lesional sites for all body sites, including the face, neck, cheeks, and trunk (2.7- to 6.0-fold increase). Both M. globosa and M. restricta were detected in patients and healthy individuals. However, M. globosa predominated at lesional sites, whereas the level of colonization by both species was similar in healthy individuals.
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Transmission of the major skin microbiota, Malassezia, from mother to neonate
Pediatrics International, 2012Co-Authors: Rie Nagata, Daiki Ogishima, Masataro Hiruma, Yasushi Nakamura, Hiroshi Nagano, Takashi SugitaAbstract:Background: Skin surface colonization starts after birth. It is thought that early microbial colonization affects the development of skin immune functions. Although Malassezia is the predominant fungus in the skin microbiota in healthy individuals, the microorganism is associated with atopic dermatitis and seborrheic dermatitis. In the present study, transmission of skin microbiota from mothers to their neonates was elucidated using the Malassezia microbiota as an indicator. Methods: Temporal changes in the level of Malassezia colonization of the skin from 27 neonates and mothers were investigated by real-time polymerase chain reaction assay. The genotypes of Malassezia colonizing the neonate and mother were also determined. Results: Malassezia was detected from 89% and 100% of neonate samples on days 0 and 1 after birth, respectively. Subsequently, the level of Malassezia colonization of the neonates increased with time, whereas that of the mothers did not change. The Malassezia diversity of neonates shifted to the adult type by day 30. The genotype of Malassezia colonizing the skin of neonates agreed well with that of Malassezia colonizing the skin of the mothers. Conclusion: Fungal microbiota colonization of neonates began on day 0, and the fungal microbiota of neonates had changed to the adult type by day 30. To our knowledge, this is the first report of a molecular analysis of the fungal microbiota of neonates.
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molecular analysis of the cutaneous Malassezia microbiota from the skin of patients with atopic dermatitis of different severities
Mycoses, 2011Co-Authors: M Kaga, Masataro Hiruma, Takashi Sugita, Akemi Nishikawa, Y Wada, Shigaku IkedaAbstract:Summary Cutaneous Malassezia is an exacerbating factor in patients with atopic dermatitis. We analysed the Malassezia microbiota of adult patients with head and neck atopic dermatitis of different severities (mild, moderate and severe). Of the nine human-associated Malassezia species, the number detected was similar (3.5–4.2 species per case) among the members of all severity groups. However, the ratio of the two major Malassezia species, M. globosa and M. restricta, was different in the severe group.
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epidemiology of Malassezia related skin diseases
Malassezia and the Skin, 2010Co-Authors: Takashi Sugita, Aristea Velegraki, Teun Boekhout, Jacques Guillot, Suzana Hađina, Javier F CabanesAbstract:This chapter deals with the range of molecular biology methods including PCR-based assays, high-throughput DNA sequence analysis, and the use of real-time PCR in performing studies of skin and environmental community structure and dynamics. It highlights the utility of each molecular biology method in yielding Malassezia epidemiological data, the limitations of culture-based methods, and the possible biases that may influence Malassezia epidemiological studies. As in any disease or health-impacting event, the frequency and patterns of Malassezia-related diseases is examined by descriptive epidemiology. Thus, the chapter includes assessment of patient-related factors such as age, immunological status and gender, and environmental factors such as the geographical area and time of the year that contribute to the analysis of risks from Malassezia-induced or Malassezia -exacerbated disease. Also, a comprehensive account is given on the Malassezia epidemiology in animals and the factors associated with the animal hosts and their skin microenvironment.
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quantitative analysis of cutaneous Malassezia in atopic dermatitis patients using real time pcr
Microbiology and Immunology, 2006Co-Authors: Takashi Sugita, Mami Tajima, Ryoji Tsuboi, Hisae Tsubuku, Akemi NishikawaAbstract:We quantified the cutaneous Malassezia in patients with atopic dermatitis using a real-time PCR assay. Seven to 12 times more Malassezia colonized the head and neck compared to the trunk or limbs, and the species M. globosa and M. restricta accounted for approximately 80% of all Malassezia colonization at any body site.
Thomas L Dawson - One of the best experts on this subject based on the ideXlab platform.
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Malassezia: The Forbidden Kingdom Opens.
Cell Host & Microbe, 2019Co-Authors: Thomas L DawsonAbstract:Malassezia yeast exist on all humans and have long been associated with healthy and diseased skin. In this issue of Cell Host & Microbe, Sparber et al. (2019) and Limon et al. (2019) present murine models for Malassezia/host interaction and describe a role for Malassezia in inflammatory skin and gut disease.
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three etiologic facets of dandruff and seborrheic dermatitis Malassezia fungi sebaceous lipids and individual sensitivity
Journal of Investigative Dermatology Symposium Proceedings, 2005Co-Authors: Yvonne M Deangelis, Christina Marie Gemmer, Joseph Robert Kaczvinsky, Dianna Kenneally, James Robert Schwartz, Thomas L DawsonAbstract:Application of new molecular and biochemical tools has greatly increased our understanding of the organisms, mechanisms, and treatments of dandruff and seborrheic dermatitis. Dandruff results from at least three etiologic factors: Malassezia fungi, sebaceous secretions, and individual sensitivity. While Malassezia (formerly P. ovale) has long been a suspected cause, implicated by its presence on skin and lipophylic nature, lack of correlation between Malassezia number and the presence and severity of dandruff has remained perplexing. We have previously identified the Malassezia species correlating to dandruff and seborrheic dermatitis. In this report, we show that dandruff is mediated by Malassezia metabolites, specifically irritating free fatty acids released from sebaceous triglycerides. Investigation of the toxic Malassezia free fatty acid metabolites (represented by oleic acid) reveals the component of individual susceptibility. Malassezia metabolism results in increased levels of scalp free fatty acids. Of the three etiologic factors implicated in dandruff, Malassezia, sebaceous triglycerides, and individual susceptibility, Malassezia are the easiest to control. Pyrithione zinc kills Malassezia and all other fungi, and is highly effective against the Malassezia species actually found on scalp. Reduction in fungi reduces free fatty acids, thereby reducing scalp flaking and itch.
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Malassezia baillon emerging clinical yeasts
Fems Yeast Research, 2005Co-Authors: Roma Batra, Thomas L Dawson, Teun Boekhout, Javier F Cabanes, E Gueho, Aditya K GuptaAbstract:The human and animal pathogenic yeast genus Malassezia has received considerable attention in recent years from dermatologists, other clinicians, veterinarians and mycologists. Some points highlighted in this review include recent advances in the technological developments related to detection, identification, and classification of Malassezia species. The clinical association of Malassezia species with a number of mammalian dermatological diseases including dandruff, seborrhoeic dermatitis, pityriasis versicolor, psoriasis, folliculitis and otitis is also discussed.
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skin diseases associated with Malassezia species
Journal of The American Academy of Dermatology, 2004Co-Authors: Aditya K Gupta, Teun Boekhout, Roma Batra, Robyn Bluhm, Thomas L DawsonAbstract:Abstract The yeasts of the genus Malassezia have been associated with a number of diseases affecting the human skin, such as pityriasis versicolor, Malassezia ( Pityrosporum ) folliculitis, seborrheic dermatitis and dandruff, atopic dermatitis, psoriasis, and—less commonly—with other dermatologic disorders such as confluent and reticulated papillomatosis, onychomycosis, and transient acantholytic dermatosis. Although Malassezia yeasts are a part of the normal microflora, under certain conditions they can cause superficial skin infection. The study of the clinical role of Malassezia species has been surrounded by controversy because of their fastidious nature in vitro, and relative difficulty in isolation, cultivation, and identification. Many studies have been published in the past few years after the taxonomic revision carried out in 1996 in which 7 species were recognized. Two new species have been recently described, one of which has been isolated from patients with atopic dermatitis. This review focuses on the clinical, mycologic, and immunologic aspects of the various skin diseases associated with Malassezia . It also highlights the importance of individual Malassezia species in the different dermatologic disorders related to these yeasts.
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fast noninvasive method for molecular detection and differentiation of Malassezia yeast species on human skin and application of the method to dandruff microbiology
Journal of Clinical Microbiology, 2002Co-Authors: Christina Marie Gemmer, Yvonne M Deangelis, Teun Boekhout, Bart Theelen, Thomas L DawsonAbstract:Malassezia fungi have been the suspected cause of dandruff for more than a century. Previously referred to as Pityrosporum ovale, Pityrosporum orbiculare, or Malassezia, these fungi are now known to consist of at least seven Malassezia species. Each species has a specific ecological niche, as well as specific biochemical and genetic characteristics. Malassezia yeasts have fastidious culture conditions and exceedingly different growth rates. Therefore, the results of surveys of Malassezia based on culture methods can be difficult to interpret. We developed a molecular technique, terminal fragment length polymorphism analysis, to more accurately survey the ecology of Malassezia yeasts without bias from culture. This technique involves fluorescent nested PCR of the intergenic transcribed spacer (ITS) ITS I and ITS II region ribosomal gene clusters. All known Malassezia species can be differentiated by unique ITS fragment lengths. We have used this technique to directly analyze scalp samples from subjects enrolled in a demographic scalp health study. Results for subjects assigned composite adherent scalp flaking scores (ASFS) 24. Malassezia restricta and M. globosa were found to be the predominant Malassezia species present in both groups. Importantly, we found no evidence of M. furfur in either group, indicating that M. furfur can be eliminated as the causal organism for dandruff. Both groups also showed the presence of non-Malassezia fungi. This method, particularly when it is used in combination with existing fungal ITS databases, is expected to be useful in the diagnosis of multiple other fungal infections.