Dermatophytosis caused by Trichophyton raubitschekii. Report of the first case in São Paulo, Brazil

The authors report the first case of dermatophytosis caused by Trichophyton raubitschekii in a patient from the State of São Paulo with Tinea corporis lesions localized on the buttocks. Culture on Sabouraud-agar with cycloheximide permitted the isolation and identification of the fungus, and the diagnosis was confirmed by Dr. Lynne Sigler, University of Alberta, Canada. Systemic treatment with fluconazole, 150 mg/week for 4 weeks, in combination with topical treatment with isoconazole initially yielded favorable results, with recurrence of the lesions after the medication was discontinued. This is the fifth case of this dermatophytosis published in the Brazilian medical literature.

Transcriptional profiling reveals the expression of novel genes in response to various stimuli in the human dermatophyte Trichophyton rubrum

Background: Cutaneous mycoses are common human infections among healthy and immunocompromised hosts, and the anthropophilic fungus Trichophyton rubrum is the most prevalent microorganism isolated from such clinical cases worldwide. The aim of this study was to determine the transcriptional profile of T. rubrum exposed to various stimuli in order to obtain insights into the responses of this pathogen to different environmental challenges. Therefore, we generated an expressed sequence tag (EST) collection by constructing one cDNA library and nine suppression subtractive hybridization libraries. Results: The 1388 unigenes identified in this study were functionally classified based on the Munich Information Center for Protein Sequences (MIPS) categories. The identified proteins were involved in transcriptional regulation, cellular defense and stress, protein degradation, signaling, transport, and secretion, among other functions. Analysis of these unigenes revealed 575 T. rubrum sequences that had not been previously deposited in public databases. Conclusion: In this study, we identified novel T. rubrum genes that will be useful for ORF prediction in genome sequencing and facilitating functional genome analysis. Annotation of these expressed genes revealed metabolic adaptations of T. rubrum to carbon sources, ambient pH shifts, and various antifungal drugs used in medical practice. Furthermore, challenging T. rubrum with cytotoxic drugs and ambient pH shifts extended our understanding of the molecular events possibly involved in the infectious process and resistance to antifungal drugs.

Membrane transporter proteins are involved in Trichophyton rubrum pathogenesis

Trichophyton rubrum is a dermatophyte responsible for the majority of human superficial mycoses. The functional expression of proteins important for the initial step and the maintenance of the infection process were identified previously in T. rubrum by subtraction suppression hybridization after growth in the presence of keratin. In this study, sequences similar to genes encoding the multidrug-resistance ATP-binding cassette (ABC) transporter, copper ATPase, the major facilitator superfamily and a permease were isolated, and used in Northern blots to monitor the expression of the genes, which were upregulated in the presence of keratin. A sequence identical to the TruMDR2 gene, encoding an ABC transporter in T rubrum, was isolated in these experiments, and examination of a T rubrum Delta TruMDR2 mutant showed a reduction in infecting activity, characterized by low growth on human nails compared with the wild-type strain. The high expression levels of transporter genes by T. rubrum in mimetic infection and the reduction in virulence of the Delta TruMDR2 mutant in a disease model in vitro suggest that transporters are involved in T. rubrum pathogenicity.

In vitro susceptibility to antimycotic drug undecanoic acid, a medium-chain fatty acid, is nutrient-dependent in the dermatophyte Trichophyton rubrum

The antimycotic activity of fatty acids has long been known, and their presence in human skin and sweat appears to protect the host against superficial mycoses. Undecanoic acid is a medium-chain fatty acid that has been used in the treatment of dermatophytoses in humans. In this study, we selected one Trichophyton rubrum undecanoic acid-resistant strain that showed a marked reduction in its capacity to grow on human nail fragments, which correlated with the reduced activity of secreted keratinolytic proteases. Moreover, the susceptibility of T. rubrum to undecanoic acid is also dependent on the carbon source utilized by both control and resistant strains. The growth of the control strain was strongly inhibited by undecanoic acid in Sabouraud medium or in cultures supplemented with low-fat milk, whereas it was ineffective when the cultures were supplemented with Tween 20 or keratin as the carbon source, suggesting that nutrient conditions are crucial in establishing a susceptibility to antifungal drugs, which is helpful for the isolation and characterization of resistant strains, and in the screening for new antifungal drugs.

Isolation of transcripts overexpressed in the human pathogen Trichophyton rubrum grown in lipid as carbon source

Trichophyton rubrum is the most common etiological agent of human dermatophytosis. Despite the incidence and medical importance of this dermatophyte, little is known about the mechanisms of host invasion and pathogenicity. Host invasion depends on the adaptive cellular responses of the pathogen that allow it to penetrate the skin layers, which are mainly composed of proteins and lipids. In this study, we used suppression subtractive hybridization to identify transcripts over-expressed in T rubrum cultured in lipid as carbon source. Among the subtractive cDNA clones isolated, 85 clones were positively screened by cDNA array dot blotting and were sequenced. The putative proteins encoded by the isolated transcripts showed similarities to fungal proteins involved in metabolism, signaling, defense, and virulence, such as the MDR/ABC transporter, glucan 1,3-beta-glucosidase, chitin synthase B, copper-sulfate-regulated protein, and serine/threonine phosphatase (calcineurin A). These results provide the first molecular insight into the genes differentially expressed during the adaptation of T. rubrum to a lipidic carbon source.

Transcriptional profiling reveals genes in the human pathogen Trichophyton rubrum that are expressed in response to pH signaling

Trichophyton rubrum is a dermatophyte that infects human skin and nails. Its growth on keratin as its carbon source shifts the ambient pH from acidic to alkaline, which may be an efficient strategy for its successful infection and maintenance in the host. In this study, we used suppression subtractive hybridization to identify genes preferentially expressed in T rubrum incubated at either pH 5.0 or pH 8.0. The functional grouping of the 341 overexpressed unigenes indicated proteins putatively involved in diverse cellular processes, such as membrane remodeling, cellular transport, metabolism, cellular protection, fungal pathogenesis, gene regulation, interaction with the environment, and iron uptake. Although the basic metabolic machinery identified under both growth conditions seems to be functionally similar, distinct genes are upregulated at acidic or alkaline pHs. We also isolated a large number of genes of unknown function, probably unique to T rubrum or dermatophytes. Interestingly, the transcriptional profiling of several genes in a pacC mutant suggests that, in T rubrum, the transcription factor PacC has a diversity of metabolic functions, in response to either acidic or alkaline ambient pH. (C) 2009 Elsevier Ltd. All rights reserved.

Outbreak of Tinea capitis by Trichophyton tonsurans and Microsporum canis in Niterói, RJ, Brazil

18 girls from an orphanage (Orfanato Santo Antônio) in Niterói presented tinea capitis due to Trichophyton tonsurans (15 cases - 83.3%) and Microsporum canis (3 cases - 26.7%). Comments are made about clinical, mycological and therapeutic aspects of this microepidemy

First case of human infection by Trichophyton vanbreuseghemii in Brazil

This paper reports the first case of human infection caused by Ttrichophyton vanbreuseghemii in Brazil.

A FOCUS OF FAVUS DUE TO TRICHOPHYTON SCHOENLEINII IN RIO GRANDE DO SUL

This paper reports the ocurrence of a focus of favus due to Trichophyton schoenleinii affecting seven members of a family, 29 years after the last register of the disease in Rio Grande do Sul

Experimental dermatophytosis in hamsters inoculated with Trichophyton mentagrophytes in the cheek pouch

This study presents the results of T. mentagrophytes inoculation in the cheek pouch of the hamster, an immunologically privileged site. Forty two animals were used: 21 inoculated with 10(6) fungi in the cheek pouch (group 1) and 21 inoculated initially with 10(6) fungi in the foot pad and 15 days later in the cheek pouch, with the same amount of fungi (group 2). Animals were sacrificed at 20 hours, 3, 7, 14, 30, 60, and 120 days; samples from inoculated cheek pouch, and foot pads submitted to the foot pad test (FPT), were collected. Independent of group and time of evolution of infection, animals did not develop delayed hypersensitivity evaluated through the FPT. The pre-inoculation of fungi in the foot pad did not change the morphology of lesions induced in the cheek pouch. Therefore, in animals of group 1 and 2, the introduction of the fungus in the cheek pouch resulted in focal lesion composed of a sterile acute inflammatory infiltrate, with abscess formation that evolved to a macrophagic reaction, and later to resolution even in the absence of immune response detectable by FPT. Our results indicate that in spite of the important role of the immune response in the spontaneous regression of dermatophytosis, other factors are also an integral part in the defense against this fungal infection.

Strain differentiation of Trichophyton rubrum by random amplification of polymorphic DNA (RAPD)

Trichophyton rubrum is an important cause of dermatomycoses. Molecular strain typing methods have recently been developed to address questions about epidemiology and source of relapse following treatment. This report describes the application of RAPD for molecular strain differentiation of this fungus utilizing the primers 1- (5'-d[GGTGCGGGAA]-3') and 6- (5'-d[CCCGTCAGCA]-3'). A total of five RAPD patterns were observed among 10 strains of T. rubrum, with each of the primers used. We conclude that RAPD analysis using primers 1 and 6 can be used in epidemiological studies.

Dois Casos de Quérion por Trichophyton Mentagrophytes

Introdução: O Quérion é uma forma rara e infl amatória de tinea capitis causada por fungos dermatófi tos. O diagnóstico é difi cultado pela demora no exame cultural e possibilidade de várias etiologias no diagnóstico diferencial. O tratamento é prolongado e implica o recurso a antifúngicos sistémicos. Novos fármacos têm sido considerados após a descontinuação da griseofulvina em Portugal. Casos clínicos: Apresentamos duas crianças com lesões dolorosas do couro cabeludo com reação infl amatória exuberante, exsudativa e alopécia local acompanhadas de febre. O exame bacteriológico foi negativo e o micológico revelou Trichophyton mentagrophytes. Foram medicados com fl ucloxacilina endovenosa, antifúngicos orais (griseofulvina e itraconazol), corticoide e antifúngico tópicos. A resposta foi favorável com evolução lenta para a cura com área de alopécia residual. Conclusão: Estes casos destacam -se pela sua raridade e ilustram a exuberância das manifestações clínicas desta entidade. O diagnóstico precoce, a identificação e tratamento da fonte de contágio e as medidas de higiene e vigilância sanitária são primordiais para o controlo da infecção.

Epidemiologia e ecologia das dermatofitoses na cidade de Fortaleza: o Trichophyton tonsurans como importante patógeno emergente da Tinea capitis

As dermatofitoses são os distúrbios infecciosos de pele mais comuns do mundo. Na presente pesquisa foram avaliados 2.297 pacientes com lesões clínicas sugestivas de dermatofitoses das quais, 534 (23,2%) mostraram-se positivas para dermatófitos. Destes, o T. rubrum foi a espécie mais prevalente (49,6%; p <= 0,05), seguido por T. tonsurans (34,4%; p <= 0,05), M. canis (7%) e T. mentagrophytes (6,2%). Ao correlacionar-se as espécies isoladas com os respectivos sítios anatômicos, observou-se que o T. tonsurans foi o isolado mais freqüente nas lesões do couro cabeludo (73,9%; p <= 0.01). Por outro lado, o T. rubrum foi o principal envolvido nas lesões do corpo (72,8%; p <= 0,05). Portanto, nas infecções do couro cabeludo, observou-se o predomínio absoluto do T. tonsurans, dado este que se contrapõem, as estatísticas dos estados brasileiros da região Sudeste e Sul, bem como de outras regiões do mundo que correlacionam, ainda, o M. canis como sendo o microrganismo mais freqüentemente isolado nas Tinea capitis.

Pseudomicetoma dermatofítico: relato de um caso devido a Trichophyton tonsurans

É descrito um caso de pseudomicetoma dermatofítico, recidivante, em paciente com lesões no couro cabeludo. O exame histopatológico de uma das lesões mostrou, nos tecidos, os agregados micelianos ou pseudogrânulos, característicos da enfermidade. Dos tecidos frescos de outras lesões foi isolado o dermatófito Trichophyton tonsurans. Exames micológicos adicionais falharam em demonstrar a existência de tinea capitis, possível fonte do pseudomicetoma. A raridade dessa forma de dermatofitose profunda justifica a presente publicação.