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Michel Monod - One of the best experts on this subject based on the ideXlab platform.
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Which Fungus Originally was Trichophyton mentagrophytes? Historical Review and Illustration by a Clinical Case
Mycopathologia, 2015Co-Authors: Annemay Chollet, Marina Fratti, Vincent Cattin, Bernard Mignon, Michel MonodAbstract:Several Dermatophytes producing numerous pyriform or round microconidia were called Trichophyton mentagrophytes . Among these Dermatophytes are the teleomorph species Arthroderma benhamiae , Arthroderma vanbreuseghemii and Arthroderma simii , and other species such as Trichophyton interdigitale , Trichophyton erinacei and Trichophyton quinckeanum for which only the anamorph is known. Confusion exists about which fungus should be really called T. mentagrophytes and about the rational use of this name in practice. We report a case of beard ringworm (tinea barbae) with A. vanbreuseghemii . According to both clinical signs and the type of hair parasitism, this case was exactly compatible to the first description of a non-favic dermatophytosis by Gruby under the name of “mentagrophyte” from which was derived the Dermatophyte epithet mentagrophytes . In addition, the phenotypic characters of the isolated fungus in cultures perfectly matched with those of the first description of a Dermatophyte under T. mentagrophytes by Blanchard (Parasites animaux et parasites végétaux à l’exclusion des Bactéries, Masson, Paris, 1896 ). In conclusion, T. mentagrophytes corresponds to the fungus later named A. vanbreuseghemii . However, because the neotype of T. mentagrophytes was not adequately designated in regard to the ancient literature, we would privilege the use of A. vanbreuseghemii and abandon the name of T. mentagrophytes .
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Which Fungus Originally was Trichophyton mentagrophytes? Historical Review and Illustration by a Clinical Case
Mycopathologia, 2015Co-Authors: Annemay Chollet, Marina Fratti, Vincent Cattin, Bernard Mignon, Michel MonodAbstract:Several Dermatophytes producing numerous pyriform or round microconidia were called Trichophyton mentagrophytes. Among these Dermatophytes are the teleomorph species Arthroderma benhamiae, Arthroderma vanbreuseghemii and Arthroderma simii, and other species such as Trichophyton interdigitale, Trichophyton erinacei and Trichophyton quinckeanum for which only the anamorph is known. Confusion exists about which fungus should be really called T. mentagrophytes and about the rational use of this name in practice. We report a case of beard ringworm (tinea barbae) with A. vanbreuseghemii. According to both clinical signs and the type of hair parasitism, this case was exactly compatible to the first description of a non-favic dermatophytosis by Gruby under the name of “mentagrophyte” from which was derived the Dermatophyte epithet mentagrophytes. In addition, the phenotypic characters of the isolated fungus in cultures perfectly matched with those of the first description of a Dermatophyte under T. mentagrophytes by Blanchard (Parasites animaux et parasites vegetaux a l’exclusion des Bacteries, Masson, Paris, 1896). In conclusion, T. mentagrophytes corresponds to the fungus later named A. vanbreuseghemii. However, because the neotype of T. mentagrophytes was not adequately designated in regard to the ancient literature, we would privilege the use of A. vanbreuseghemii and abandon the name of T. mentagrophytes.
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keratin degradation by Dermatophytes relies on cysteine dioxygenase and a sulfite efflux pump
Journal of Investigative Dermatology, 2013Co-Authors: Maria Grumbt, Michel Monod, Tsuyoshi Yamada, Christian Hertweck, Jiri Kunert, Peter StaibAbstract:Millions of people suffer from superficial infections caused by Dermatophytes. Intriguingly, these filamentous fungi exclusively infect keratin-rich host structures such as hair, nails, and skin. Keratin is a hard, compact protein, and its utilization by Dermatophytes for growth has long been discussed as a major virulence attribute. Here, we provide strong support for the hypothesis that keratin degradation is facilitated by the secretion of the reducing agent sulfite, which can cleave keratin-stabilizing cystine bonds. We discovered that sulfite is produced by Dermatophytes from environmental cysteine, which at elevated concentrations is toxic for microbes and humans. We found that sulfite formation from cysteine relies on the key enzyme cysteine dioxygenase Cdo1. Sulfite secretion is supported by the sulfite efflux pump Ssu1. Targeted mutagenesis proved that Dermatophyte mutants in either Cdo1 or Ssu1 were highly growth-sensitive to cysteine, and mutants in Ssu1 were specifically sensitive to sulfite. Most notably, Dermatophyte mutants in Cdo1 and Ssu1 were specifically growth-defective on hair and nails. As keratin is rich in cysteine, our identified mechanism of cysteine conversion and sulfite efflux supports both cysteine and sulfite tolerance per se and progression of keratin degradation. These in vitro findings have implications for Dermatophyte infection pathogenesis.
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Dermatophyte identification in skin and hair samples using a simple and reliable nested polymerase chain reaction assay
British Journal of Dermatology, 2013Co-Authors: Julie Verrier, Olympia Bontems, Marina Fratti, L Krahenbuhl, Karine Salamin, Michel MonodAbstract:Summary Background Dermatophyte identification in tinea capitis is essential for choosing the appropriate treatment and in tinea infections to identify the possible source. The failure of fungi to grow in cultures frequently occurs, especially in cases of previous antifungal therapy. Objectives To develop a rapid polymerase chain reaction (PCR) sequencing assay for Dermatophyte identification in tinea capitis and tinea corporis. Material and methods Fungal DNA was extracted from hair and skin samples that were confirmed to be positive by direct mycological examination. Dermatophytes were identified by the sequence of a 28S ribosomal DNA subunit amplicon generated by nested PCR. Results Nested PCR was found to be necessary to obtain amplicons in substantial amounts for Dermatophyte identification by sequencing. The results agreed with those of classical mycological identification in 14 of 23, 6 of 10, and 20 of 23 cases of tinea capitis, tinea corporis and tinea pedis, respectively, from which a Dermatophyte was obtained in culture. In seven of the 56 cases, another Dermatophyte was identified, revealing previous misidentification. A Dermatophyte was identified in 12 of 18, three of five, and four of nine cases of tinea capitis, tinea corporis and tinea pedis, respectively, in cases in which no Dermatophyte grew in culture. Conclusions Although the gold standard Dermatophyte identification from clinical samples remains fungal cultures, the assay developed in the present study is especially suitable for tinea capitis. Improved sensitivity for the identification of Dermatophyte species was obtained as it is possible to identify the Dermatophyte when the fungus fails to grow in cultures.
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comparative genome analysis of trichophyton rubrum and related Dermatophytes reveals candidate genes involved in infection
Mbio, 2012Co-Authors: Diego Martinez, Michel Monod, Brian G Oliver, Yvonne Graser, Jonathan M Goldberg, Nilce Maria Martinezrossi, Ekaterina Shelest, Richard C Barton, Elizabeth Birch, Axel A BrakhageAbstract:The major cause of athlete's foot is Trichophyton rubrum, a Dermatophyte or fungal pathogen of human skin. To facilitate molecular analyses of the Dermatophytes, we sequenced T. rubrum and four related species, Trichophyton tonsurans, Trichophyton equinum, Microsporum canis, and Microsporum gypseum. These species differ in host range, mating, and disease progression. The Dermatophyte genomes are highly colinear yet contain gene family expansions not found in other human-associated fungi. Dermatophyte genomes are enriched for gene families containing the LysM domain, which binds chitin and potentially related carbohydrates. These LysM domains differ in sequence from those in other species in regions of the peptide that could affect substrate binding. The Dermatophytes also encode novel sets of fungus-specific kinases with unknown specificity, including nonfunctional pseudokinases, which may inhibit phosphorylation by competing for kinase sites within substrates, acting as allosteric effectors, or acting as scaffolds for signaling. The Dermatophytes are also enriched for a large number of enzymes that synthesize secondary metabolites, including Dermatophyte-specific genes that could synthesize novel compounds. Finally, Dermatophytes are enriched in several classes of proteases that are necessary for fungal growth and nutrient acquisition on keratinized tissues. Despite differences in mating ability, genes involved in mating and meiosis are conserved across species, suggesting the possibility of cryptic mating in species where it has not been previously detected. These genome analyses identify gene families that are important to our understanding of how Dermatophytes cause chronic infections, how they interact with epithelial cells, and how they respond to the host immune response.
Nancy L Wengenack - One of the best experts on this subject based on the ideXlab platform.
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Dermatophyte identification using matrix assisted laser desorption ionization time of flight mass spectrometry
Journal of Clinical Microbiology, 2011Co-Authors: Elitza S Theel, Leslie Hall, Jayawant N Mandrekar, Nancy L WengenackAbstract:The performance of the Bruker Biotyper matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometer (MS) for the identification of Dermatophytes from clinical cultures was compared to that of Dermatophyte identification using 28S rRNA gene sequencing. The MALDI Biotyper library (MBL; version 3.0) was used alone and in combination with a supplemented library containing an additional 20 Dermatophyte spectra (S-MBL). Acquired spectra were interpreted using both the manufacturer-recommended scores (genus, ≥1.7; species, ≥2.0) and adjusted cutoff values established by this study (genus, ≥1.5; species, ≥1.7); identifications required a minimum 10% difference in scores between the top two different organisms to be considered correct. One hundred well-characterized, archived Dermatophyte isolates and 71 fresh Dermatophyte cultures were evaluated using both libraries and both sets of cutoff criteria. Collectively, the S-MBL significantly outperformed the MBL at both the genus (93% versus 37.4%; P < 0,0001) and species (59.6% versus 20.5%; P < 0.0001) levels when using the adjusted score criteria. Importantly, application of the lowered cutoff values significantly improved genus (P = 0.005)- and species (P < 0.0001)-level identification for the S-MBL, without leading to an increase in misidentifications. MALDI-TOF MS is a cost-effective and rapid alternative to traditional or molecular methods for Dermatophyte identification, provided that the reference library is supplemented to sufficiently encompass clinically relevant, intraspecies strain diversity.
Shigaku Ikeda - One of the best experts on this subject based on the ideXlab platform.
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cytokine secretion profiles of human keratinocytes during trichophyton tonsurans and arthroderma benhamiae infections
Journal of Medical Microbiology, 2006Co-Authors: Yumi Shiraki, Masataro Hiruma, Akemi Nishikawa, Yoshio Ishibashi, Shigaku IkedaAbstract:Dermatophytes cause intractable superficial infections in humans. Arthroderma benhamiae ,a zoophilic Dermatophyte, triggers severe inflammatory responses in humans, while Trichophyton tonsurans, an anthropophilic Dermatophyte, triggers minimal ones. Cytokines and other factors derived from keratinocytes play important roles in inflammatory and immune responses in the skin. The authors performed an in vitro investigation to determine the human keratinocyte cytokine profiles during Dermatophyte infection. The human keratinocyte cell line PHK16-0b was infected with A. benhamiae or T. tonsurans for 24 h, and the cytokines secreted were analysed using a human cytokine antibody array. Marked differences were observed in the cytokine profiles of the cells infected with the two Dermatophytes. A. benhamiae infection resulted in the secretion of a broad spectrum of cytokines, including proinflammatory cytokines, chemokines, and immunomodulatory cytokines. In contrast, T. tonsurans-infected keratinocytes secreted only limited cytokines, including eotaxin-2, interleukin (IL)-8 and IL-16. cDNA microarray analysis confirmed that A. benhamiae infection upregulated genes encoding IL-1b, IL-2, IL-4, IL-6, IL-10, IL-13, IL-15, IL-16, IL-17 and interferon (IFN)-c, while T. tonsurans infection upregulated only a few genes, such as those encoding IL-1b and IL-16. RT-PCR demonstrated that infection by both Dermatophytes enhanced IL-8 mRNA expression in keratinocytes. These results suggest that A. benhamiaeinduced secretion of several cytokines from keratinocytes may be involved in a severe inflammatory response, and that the limited cytokine secretion from keratinocytes in response to T. tonsurans infectionmayresultinaminimalinflammatoryresponseintheskin.Thesecytokineprofilesmayaidin proving the clinical features of dermatophytosis.
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cytokine secretion profiles of human keratinocytes during trichophyton tonsurans and arthroderma benhamiae infections
Journal of Medical Microbiology, 2006Co-Authors: Yumi Shiraki, Masataro Hiruma, Akemi Nishikawa, Yoshio Ishibashi, Shigaku IkedaAbstract:Dermatophytes cause intractable superficial infections in humans. Arthroderma benhamiae, a zoophilic Dermatophyte, triggers severe inflammatory responses in humans, while Trichophyton tonsurans, an anthropophilic Dermatophyte, triggers minimal ones. Cytokines and other factors derived from keratinocytes play important roles in inflammatory and immune responses in the skin. The authors performed an in vitro investigation to determine the human keratinocyte cytokine profiles during Dermatophyte infection. The human keratinocyte cell line PHK16-0b was infected with A. benhamiae or T. tonsurans for 24 h, and the cytokines secreted were analysed using a human cytokine antibody array. Marked differences were observed in the cytokine profiles of the cells infected with the two Dermatophytes. A. benhamiae infection resulted in the secretion of a broad spectrum of cytokines, including proinflammatory cytokines, chemokines, and immunomodulatory cytokines. In contrast, T. tonsurans-infected keratinocytes secreted only limited cytokines, including eotaxin-2, interleukin (IL)-8 and IL-16. cDNA microarray analysis confirmed that A. benhamiae infection upregulated genes encoding IL-1beta, IL-2, IL-4, IL-6, IL-10, IL-13, IL-15, IL-16, IL-17 and interferon (IFN)-gamma, while T. tonsurans infection upregulated only a few genes, such as those encoding IL-1beta and IL-16. RT-PCR demonstrated that infection by both Dermatophytes enhanced IL-8 mRNA expression in keratinocytes. These results suggest that A. benhamiae-induced secretion of several cytokines from keratinocytes may be involved in a severe inflammatory response, and that the limited cytokine secretion from keratinocytes in response to T. tonsurans infection may result in a minimal inflammatory response in the skin. These cytokine profiles may aid in proving the clinical features of dermatophytosis.
J Pedersen - One of the best experts on this subject based on the ideXlab platform.
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pcr identification of Dermatophyte fungi trichophyton rubrum t soudanense and t gourvilii
Journal of Medical Microbiology, 2002Co-Authors: D Liu, S Coloe, L Pearce, G Lilley, R Baird, J PedersenAbstract:Diagnosis of dermatophytosis employing conventional laboratory procedures has been complicated by the slow growth and varied morphological features shown by Dermatophytes. After analysis of the nucleotide base sequences of a 1.2-kb fragment amplified from a Dermatophyte fungus Trichophyton rubrum by arbitrarily primed PCR with random primer OPD18, a pair of primers (TR1F and TR1R) was designed and evaluated for specific identification of T. rubrum. The sensitivity of the primers TR1F and TR1R was high, as a specific PCR band of c. 600 bp was detected from as little as 7 pg of T. rubrum DNA. By examining 92 Dermatophyte strains and clinical isolates, it was found that this pair of primers reacted in PCR with T. rubrum, T. soudanense and T. gourvilii through formation of the specific fragment of 600 bp, but not with any other of the Dermatophyte species or varieties, fungi, yeasts or bacteria tested. As T. rubrum is one of the most frequently isolated Dermatophyte fungi, and T. soudanense and T. gourvilii are relatively uncommon in many parts of the world, these primers can be used for rapid, sensitive and specific identification and differentiation of T. rubrum from other fungi and micro-organisms.
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application of pcr to the identification of Dermatophyte fungi
Journal of Medical Microbiology, 2000Co-Authors: D Liu, S Coloe, Robert W Baird, J PedersenAbstract:Infection of the keratinised tissues (skin, hair and nails) in man and animals by keratinophilic fungi (Dermatophytes) results in dermatophytosis (also known as tinea or ringworm). As conventional laboratory procedures for the identification of Dermatophytes are either slow or lack specificity, improved diagnostic methods are required. The application of nucleic acid amplification technology has made rapid and precise identification of Dermatophytes possible. Recent studies have shown that when one of the four random primers (OPAA11, OPD18, OPAA17 and OPU15) was used in arbitrarily primed PCR (AP-PCR), up to 20 of the 25 Dermatophyte species or subspecies under investigation could be distinguished on the basis of characteristic band patterns detected in agarose gel electrophoresis. A combination of two random primers (OPD18 and OPAA17) used in separate reaction tubes identified 23 of the 25 Dermatophyte species or subspecies examined. AP-PCR provides a rapid and practical tool for identification of Dermatophyte isolates that is independent of morphological and biochemical characteristics and thus enhances laboratory diagnosis of dermatophytosis.
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molecular determination of Dermatophyte fungi using the arbitrarily primed polymerase chain reaction
British Journal of Dermatology, 1997Co-Authors: D Liu, S Coloe, Robert W Baird, J PedersenAbstract:Dermatophytes are keratinophilic fungi capable of causing dermatophytosis (commonly known as tinea or ringworm) in humans and animals. Previously, we reported the differentiation of the common Dermatophytes Trichophyton rubrum, T. mentagrophytes and T. tonsurans using a random primer 5'-ACCCGACCTG-3' (OPAA11) in the arbitrarily primed polymerase chain reaction (AP-PCR). In the present study, by examining additional Dermatophytes including eight Microsporum spp., 16 Trichophyton species/subspecies and Epidermophyton floccosum using both OPAA11 and a second random decamer 5'-GAGAGCCAAC-3' (OPD18) in AP-PCR, we show that except for T. rubrum and T. gourvilli, and three T. mentagrophytes varieties, most of the Dermatophyte fungi investigated formed distinct DNA band patterns on gel electrophoresis. The amplification of specific DNA bands in AP-PCR appeared to be independent of culture variations shown by Dermatophyte isolates. These results provide the basis for the rapid identification of Dermatophytes at the genetic level, supplementing existing laboratory methods and improving the diagnosis of human dermatophytosis.
Marieelisabeth Bougnoux - One of the best experts on this subject based on the ideXlab platform.
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successful identification of clinical Dermatophyte and neoscytalidium species by matrix assisted laser desorption ionization time of flight mass spectrometry
Journal of Clinical Microbiology, 2012Co-Authors: Kinda Alshawa, Jeanluc Beretti, C Lacroix, Martine Feuilhade, Brunhilde Dauphin, Gilles Quesne, N Hassouni, Xavier Nassif, Marieelisabeth BougnouxAbstract:ABSTRACT Dermatophytes are keratinolytic fungi responsible for a wide variety of diseases of glabrous skin, nails, and hair. Their identification, currently based on morphological criteria, is hindered by intraspecies morphological variability and the atypical morphology of some clinical isolates. The aim of this study was to evaluate matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) as a routine tool for identifying Dermatophyte and Neoscytalidium species, both of which cause dermatomycoses. We first developed a spectral database of 12 different species of common and unusual Dermatophytes and two molds responsible for dermatomycoses (Neoscytalidium dimidiatum and N. dimidiatum var. hyalinum). We then prospectively tested the performance of the database on 381 clinical Dermatophyte and Neoscytalidium isolates. Correct identification of the species was obtained for 331/360 Dermatophytes (91.9%) and 18/21 Neoscytalidium isolates (85.7%). The results of MALDI-TOF MS and standard identification disagreed for only 2 isolates. These results suggest that MALDI-TOF MS could be a useful tool for routine and fast identification of Dermatophytes and Neoscytalidium spp. in clinical mycology laboratories.