Trichophyton eboreum sp. nov. isolated from human skin

Inopinatus corneliae sp. nov. gen. nov. isolated from human skin: A newly discovered keratinophilic hyphomycete, order Onygenales

BACKGROUND

Fungi clinically relevant to human skin comprise prevalent commensals and well-known pathogens. Only rarely human skin harbours fungi that evade identification.

OBJECTIVE

To characterise an enigmatic specimen isolated from a skin lesion.

METHODS

A comprehensive clinical and mycological workup including conventional methods for phenotypic characterisation and sequencing based on internal transcribed spacer (ITS) and large subunit (LSU) regions to infer a phylogenetic tree.

RESULTS

Cultures on common solid media were macroscopically inconspicuous initially until mycelial tufts developed on the surface, notably on potato dextrose agar. Polymorphous chlamydospores were detected but no aleurospores and ascomata. At 26°C, the isolate grew on standard agars, plant materials and garden soil and utilised peptone, keratins, lipids, inulin, erythrocytes and cellulose. It also grew at 5°C and at 37°C. Nucleotide sequences of its ITS region showed 93% similarity to sequences of different Malbranchea species. The closest matches among LSU rRNA sequences were obtained with the genera Amauroascus, Arthroderma, Auxarthronopsis and Malbranchea (93%-95%). A combined phylogenetic analysis placed the fungus in a sister clade to Neogymnomycetaceae, classified as incertae sedis in Onygenales, on a large distance to either Diploospora rosea or 'Amauroascus' aureus.

CONCLUSIONS

The genus Inopinatus gen. nov. (MB854685) with the species Inopinatus corneliae sp. nov. (MB854687) is introduced to accommodate our isolate (holotype: DSM 116806; isotypes: CBS 151104, IHEM 29063). Probably Inopinatus corneliae is a geophilic species that, although potentially harmful, was no relevant pathogen in our case. Its ecology, epidemiology and pathogenicity need to be further clarified.

Insights into Some Onygenalean Fungi from Freshwater Sediments in Spain and Description of Novel Taxa

During the course of a project investigating culturable Ascomycota diversity from freshwater sediments in Spain, we isolated 63 strains of cycloheximide-resistant fungi belonging to the order Onygenales. These well-known ascomycetes, able to infect both humans and animals, are commonly found in terrestrial habitats, colonizing keratin-rich soils or dung. Little is known about their diversity in aquatic environments. Combining morphological features and sequence analyses of the ITS and LSU regions of the nrDNA, we identified 14 species distributed in the genera Aphanoascus, Arachniotus, Arthroderma, Arthropsis, Emmonsiellopsis, Gymnoascoideus, Leucothecium, Malbranchea, and Myriodontium. Furthermore, three novel species for the genus Malbranchea are proposed as M. echinulata sp. nov., M. irregularis sp. nov., and M. sinuata sp. nov. The new genera Albidomyces and Neoarthropsis are introduced based on Arachniotus albicans and Arthropsis hispanica, respectively. Neoarthropsis sexualis sp. nov. is characterized and differentiated morphologically from its counterpart by the production of a sexual morph. The novel family Neoarthropsidaceae is proposed for the genera Albidomyes, Apinisia, Arachnotheca, Myriodontium, and Neoarthropsis, based on their phylogenetic relationships and phenotypic and ecological traits. Pseudoamaurascopsis gen. nov. is introduced to accommodate P. spiralis sp. nov., a fungus with unclear taxonomy related to Amaurascopsis and Polytolypa. We traced the ecology and global distribution of the novel fungi through ITS environmental sequences deposited in the GlobalFungi database. Studying the fungal diversity from freshwater sediments not only contributes to filling gaps in the relationships and taxonomy of the Ascomycota but also gives us insights into the fungal community that might represent a putative risk to the health of animals and humans inhabiting or transient in aquatic environments.

Wild rodents harbour high diversity of Arthroderma

Arthroderma is the most diverse genus of dermatophytes, and its natural reservoir is considered to be soil enriched by keratin sources. During a study on the diversity of dermatophytes in wild small rodents in the Czech Republic, we isolated several strains of Arthroderma. To explore the diversity and ecological significance of these isolates from rodents (n = 29), we characterised the strains genetically (i.e., sequenced ITS, tubb and tef1α), morphologically, physiologically, and by conducting mating experiments. We then compared the rodent-derived strains to existing ITS sequence data from GenBank and the GlobalFungi Database to further investigate biogeography and the association of Arthroderma species with different types of environments. In total, eight Arthroderma species were isolated from rodents, including four previously described species (A. crocatum, A. cuniculi, A. curreyi, A. quadrifidum) and four new species proposed herein, i.e., A. rodenticum, A. simile, A. zoogenum and A. psychrophilum. The geographical distribution of these newly described species was not restricted to the Czech Republic nor rodents. Additional isolates were obtained from bats and other mammals, reptiles, and soil from Europe, North America, and Asia. Data mining showed that the genus has a diverse ecology, with some lineages occurring relatively frequently in soil, whereas others appeared to be more closely associated with live animals, as we observed in A. rodenticum. Low numbers of sequence reads ascribed to Arthroderma in soil show that the genus is rare in this environment, which supports the hypothesis that Arthroderma spp. are not soil generalists but rather strongly associated with animals and keratin debris. This is the first study to utilise existing metabarcoding data to assess biogeographical, ecological, and diversity patterns in dermatophytes. Citation: Moulíková Š, Kolařík M, Lorch JM, et al. 2022. Wild rodents harbour high diversity of Arthroderma. Persoonia 50: 27- 47. https://doi.org/10.3767/persoonia.2023.50.02.

Phylogenetic and ecological reevaluation of the order Onygenales

The order Onygenales is classified in the class Eurotiomycetes of the subphylum Pezizomycotina. Families in this order have classically been isolated from soil and dung, and two lineages contain causative agents of superficial, cutaneous and systemic infections in mammals. The ecology and habitat choices of the species are driven mainly by the keratin and cellulose degradation abilities. The present study aimed to investigate whether the ecological trends of the members of Onygenales can be interpreted in an evolutionary sense, linking phylogenetic parameters with habitat preferences, to achieve polyphasic definitions of the main taxonomic groups. Evolutionary processes were estimated by multiple gene genealogies and divergence time analysis. Previously described families, namely, Arthrodermataceae, Ajellomycetaceae, Ascosphaeraceae, Eremascaceae, Gymnoascaceae, Onygenaceae and Spiromastigoidaceae, were accepted in Onygenales, and two new families, Malbrancheaceae and Neogymnomycetaceae, were introduced. A number of species could not be assigned to any of the defined families. Our study provides a revised overview of the main lines of taxonomy of Onygenales, supported by multilocus analyses of ITS, LSU, TUB, TEF1, TEF3, RPB1, RPB2, and ribosomal protein 60S L10 (L1) (RP60S) sequences, combined with available data on ecology, physiology, morphology, and genomics.

Potential of propolis antifungal activity for clinical applications

The high incidence of skin diseases of microbial origin along with the widespread increase of microbial resistance demand for therapeutic alternatives. Research on natural compounds has been opening new perspectives for the development of new therapies with health positive impacts. Propolis, a resinous mixture produced by honeybees from plant exudates, is widely used as a natural medicine since ancient times, mainly due to its antimicrobial properties. More recently, antioxidant, anti-tumor, anti-inflammatory, hepatoprotective and immunomodulatory activities were also reported for this natural product, highlighting its high potential pharmacological interest. In the present work, an extensive review of the main fungi causing skin diseases as well as the effects of natural compounds, particularly propolis, against such disease-causing microorganisms was organized and compiled in concise handy tables. This information allows to conclude that propolis is a highly effective antimicrobial agent suggesting that it could be used as an alternative skin treatment against pathogenic microorganisms and also as a cosmeceutic component or as a source of bioactive ingredients.

Keratinophilic and Keratinolytic Fungi in Cave Ecosystems: A Culture-Based Study of Brestovská Cave and Demänovská Ľadová and Slobody Caves (Slovakia)

Despite speleomycological research going back to the 1960s, the biodiversity of many specific groups of micromycetes in underground sites still remains unknown, including keratinolytic and keratinophilic fungi. These fungi are a frequent cause of infections in humans and animals. Since subterranean ecosystems are inhabited by various animals and are a great tourist attraction, the goal of our research was to provide the first report of keratinophilic and keratinolytic fungal species isolated from three caves in Tatra Mts., Slovakia (Brestovská, Demänovská Ľadová and Demänovská Slobody). Speleomycological investigation was carried out inside and outside the explored caves by combining culture-based techniques with genetic and phenotypic identifications. A total of 67 fungal isolates were isolated from 24 samples of soil and sediment using Vanbreuseghem hair bait and identified as 18 different fungal species. The study sites located inside the studied caves displayed much more fungal species (17 species) than outside the underground (3 species), and the highest values of the Shannon diversity index of keratinophilic and keratinolytic fungi were noted for the study sites inside the Demänovská Slobody Cave. Overall, Arthroderma quadrifidum was the most common fungal species in all soil and/or sediment samples. To the best of our knowledge, our research has allowed for the first detection of fungal species such as Arthroderma eboreum, Arthrodermainsingulare, Chrysosporiumeuropae, Chrysosporiumsiglerae, Keratinophytonwagneri, and Penicillium charlesii in underground sites. We also showed that the temperature of soil and sediments was negatively correlated with the number of isolated keratinophilic and keratinolytic fungal species in the investigated caves.

Discovery of New Trichophyton Members, T. persicum and T. spiraliforme spp. nov., as a Cause of Highly Inflammatory Tinea Cases in Iran and Czechia

Pathogens from the Trichophyton benhamiae complex are one of the most important causes of animal mycoses with significant zoonotic potential. In light of the recently revised taxonomy of this complex, we retrospectively identified 38 Trichophyton isolates that could not be resolved into any of the existing species. These strains were isolated from Iranian and Czech patients during molecular epidemiological surveys on dermatophytosis and were predominantly associated with highly inflammatory tinea corporis cases, suggesting possible zoonotic etiology. Subsequent phylogenetic (4 markers), population genetic (10 markers), and phenotypic analyses supported recognition of two novel species. The first species, Trichophyton persicum sp. nov., was identified in 36 cases of human dermatophytosis and one case of feline dermatophytosis, mainly in Southern and Western Iran. The second species, Trichophyton spiraliforme sp. nov., is only known from a single case of tinea corporis in a Czech patient who probably contracted the infection from a dog. Although the zoonotic sources of infections summarized in this study are very likely, little is known about the host spectrum of these pathogens. Awareness of these new pathogens among clinicians should refine our knowledge about their poorly explored geographic distribution. IMPORTANCE In this study, we describe two novel agents of dermatophytosis and summarize the clinical manifestation of infections. These new pathogens were discovered thanks to long-term molecular epidemiological studies conducted in Czechia and Iran. Zoonotic origins of the human infections are highly probable, but the animal hosts of these pathogens are poorly known. Further research is needed to refine our knowledge about these new dermatophytes.

A new lineage of mazaediate fungi in the Eurotiomycetes: Cryptocaliciomycetidae subclass. nov., based on the new species Cryptocalicium blascoi and the revision of the ascoma evolution

The class Eurotiomycetes (Ascomycota, Pezizomycotina) comprises important fungi used for medical, agricultural, industrial and scientific purposes. Eurotiomycetes is a morphologically and ecologically diverse monophyletic group. Within the Eurotiomycetes, different ascoma morphologies are found including cleistothecia and perithecia but also apothecia or stromatic forms. Mazaediate representatives (with a distinct structure in which loose masses of ascospores accumulate to be passively disseminated) have evolved independently several times. Here we describe a new mazaediate species belonging to the Eurotiomycetes. The multigene phylogeny produced (7 gene regions: nuLSU, nuSSU, 5.8S nuITS, mtSSU, RPB1, RPB2 and MCM7) placed the new species in a lineage sister to Eurotiomycetidae. Based on the evolutionary relationships and morphology, a new subclass, a new order, family and genus are described to place the new species: Cryptocalicium blascoi. This calicioid species occurs on the inner side of loose bark strips of Cupressaceae (Cupressus, Juniperus). Morphologically, C. blascoi is characterized by having minute apothecioid stalked ascomata producing mazaedia, clavate bitunicate asci with hemiamyloid reaction, presence of hamathecium and an apothecial external surface with dark violet granules that becomes turquoise green in KOH. The ancestral state reconstruction analyses support a common ancestor with open ascomata for all deep nodes in Eurotiomycetes and the evolution of closed ascomata (cleistothecioid in Eurotiomycetidae and perithecioid in Chaetothyriomycetidae) from apothecioid ancestors. The appropriateness of the description of a new subclass for this fungus is also discussed.

Three-gene phylogeny of the genus Arthroderma: Basis for future taxonomic studies

Arthroderma is the most diverse genus among dermatophytes encompassing species occurring in soil, caves, animal burrows, clinical material and other environments. In this study, we collected ex-type, reference and authentic strains of all currently accepted Arthroderma species and generated sequences of three highly variable loci (ITS rDNA, β-tubulin, and translation elongation factor 1-α). The number of accepted species was expanded to 27. One novel species, A. melbournense (ex-type strain CCF 6162T = CBS 145858T), is described. This species was isolated from toenail dust collected by a podiatrist in Melbourne, during an epidemiological study of four geographical regions of Eastern Australia. Trichophyton terrestre, Chrysosporium magnisporum, and Chrysosporium oceanitis are transferred to Arthroderma. Typification is provided for T. terrestre that is not conspecific with any of the supposed biological species from the former T. terrestre complex, that is, A. insingulare, A. lenticulare and A. quadrifidum. A multi-gene phylogeny and reference sequences provided in this study should serve as a basis for future phylogenetic studies and facilitate species identification in practice.

LAY ABSTRACT

The genus Arthroderma encompasses geophilic dermatophyte species that infrequently cause human and animal superficial infections. Reference sequences from three genetic loci were generated for all currently accepted Arthroderma species and phylogeny was constructed. Several taxonomic novelties are introduced. The newly provided data will facilitate species identification and future taxonomic studies.

A novel dermatophyte relative, Nannizzia perplicata sp. nov., isolated from a case of tinea corporis in the United Kingdom

A novel dermatophyte was isolated from skin scales of a female patient presenting with tinea corporis of the wrist and arm. Her principal risk factor was long-term corticosteroid use for underlying Lupus autoimmune syndrome. Microscopic examination of skin scales from lesions revealed hyphae consistent with dermatophyte infection, and a morphologically identical fungus grew in pure culture on all cultures of skin scales. Repeat isolation of the same organism from persistent lesions five months later confirmed the novel species as the causative agent. Microscopic examination revealed predominantly smooth, thin-walled macroconidia, with large numbers of unicellular aleuriospores of varied shapes and sizes. Since the isolate exhibited considerable microscopic pleomorphism, sharing morphological features consistent with several dermatophyte genera, it was subjected to multi-locus phylogenetic analyses employing a total of six different loci. Sequence analyses of all loci revealed that the isolate clustered with species within Nannizzia but diverged from all known members of the genus by 2 to 13% depending on locus analyzed. The isolate exhibited high minimum inhibitory concentrations for terbinafine in vitro, which might explain why the infection had failed to respond to two cycles of oral treatment with this antifungal agent. Interestingly, sequences in GenBank of an unnamed "Microsporum sp" isolated from leg skin of a patient in the Czech Republic showed greater than 99% identity across all of the loci analysed in common, indicating that this novel organism, which we describe here as Nannizzia perplicata sp. nov., is likely not restricted to the UK.

[Dynamic diversity of dermatophytes]

BACKGROUND

Many dermatologists do not understand the perpetual adjustments in the dermatophyte nomenclature.

OBJECTIVES

The aim is to explain the background and the development of methods that have led to previous and current changes of dermatophyte taxonomy and to the detection of new dermatophytes.

METHODS

In this article we evaluate the recent literature on this topic and our own results in the fields of dermatophyte identification, their detection, and of the associated taxonomic developments.

RESULTS

Today, the phylogenetic species concept is the basis of taxonomic classification, including that of dermatophytes. Genetic techniques have decisively advanced this and are state of the art nowadays. The detection of new dermatophyte species was often triggered by clinical observations and by morphologically conspicuous cultures that prompted their subsequent exact mycological characterization. Even today not all species of dermatophytes are unequivocally defined.

CONCLUSIONS

By exclusively using selected genetic characteristics for the construction of phylogenetic trees additional taxonomically relevant features are neglected. Therefore it is necessary to better integrate data derived from morphologic, physiologic, ecologic and pathophysiologic observations into phylogenetic analyses. Dermatologists are still asked to contribute such information.

Arthroderma chiloniense sp. nov. isolated from human stratum corneum: Description of a new Arthroderma species

A 68-year-old woman was submitted to our hospital because of erythematous and scaly skin lesions. To exclude tinea samples of stratum corneum were collected and used for mycological investigations. In this material, no fungal elements were detected microscopically, but inoculation on Sabouraud agar with cycloheximide yielded a presumptive dermatophyte fungus. Subsequent detailed investigations with conventional morphological and physiological methods and a phylogenetic analysis of the combined LSU rRNA gene (D1/D2 domains) and ITS region sequences suggested that the fungus represents a hitherto undescribed species of the genus Arthroderma. Here, we describe this species as Arthroderma chiloniense sp. nov., EMBL accession no. LT992885. This new species can be distinguished from phylogenetically related Arthroderma species using ribosomal ITS and LSU genes, and 60S L10 protein sequences; specific macroscopic, microscopic and physiological features are lacking. Our attempts to re-isolate this fungus from the patient's skin failed although her skin lesions persisted. Most likely A. chiloniense is a geophilic species that incidentally contaminated or transiently colonised the patient's skin. To avoid diagnostic misinterpretations, it is necessary to distinguish A. chiloniense from truly pathogenic dermatophytes like Trichophyton (T.) rubrum and T. interdigitale which can easily be confused with A. chiloniense based on similar mycelium morphology.

Unusual Species of Dermatophytes: Rarely Identified or New?

Dermatophytes are causing superficial mycosis in animals and humans. Depending on the geophilic, zoophilic or anthropophilic origin of the fungus but also on the immunological status of the patient, symptomatology can widely differ. Nevertheless, each species is currently associated with typical clinical manifestations, even if atypical localizations and/or clinical pictures are sometimes also reported. Diagnostic tools applied to species identification have been changing since the last two decades with the more frequent use of molecular methods currently considered nowadays as reference methods for species identification. It becomes obvious that the algorithm used for the distinction of closely related species needs to combine phenotypic and genomic methods. All these different points are discussed, and the most recent novel species causing or involved in human dermatophytosis are reported.

Cutaneous hyalohyphomycosis due to Parengyodontium album gen. et comb. nov

"Engyodontium album" is an environmental saprobic mould and an emerging opportunistic pathogen able to cause both superficial and systemic infections. In this study, we isolated a mould from the skin lesion biopsy specimen of the right shin in a patient who received renal transplantation for end-stage renal failure with prednisolone, tacrolimus, and azathioprine immunosuppressant therapy. Histology of the skin biopsy showed mild squamous hyperplasia and neutrophilic infiltrate in the epidermis, active chronic inflammation in the dermis, and fat necrosis in the subcutis, with numerous fungal elements within the serum crusts. On Sabouraud glucose agar, the fungus grew as white, cobweb-like, floccose colonies. Microscopically, conidiogenous cells were arranged in whorls of one to seven at wide angles, with zigzag-shaped terminal fertile regions and smooth, hyaline, oval, apiculate conidia. DNA sequencing showed the mould isolate belonged to "E. album" but matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF MS) failed to identify the isolate. Phylogenetic analyses based on the internal transcribed spacer region, 28S nuclear ribosomal DNA, and β-tubulin gene and MALDI-TOF MS coupled with hierarchical cluster analysis showed that "E. album" is distantly related to other Engyodontium species and should be transferred to a novel genus within the family Cordycipitaceae, for which the name Parengyodontium album gen. et comb. nov. is proposed. Three potential cryptic species within this species complex were also revealed. Antifungal susceptibility testing showed posaconazole and voriconazole had high activities against all clinical P. album isolates and may be better drug options for treating P. album infections.

The fungus Trichophyton redellii sp. Nov. Causes skin infections that resemble white-nose syndrome of hibernating bats

Before the discovery of white-nose syndrome (WNS), a fungal disease caused by Pseudogymnoascus destructans, there were no reports of fungal skin infections in bats during hibernation. In 2011, bats with grossly visible fungal skin infections similar in appearance to WNS were reported from multiple sites in Wisconsin, US, a state outside the known range of P. destructans and WNS at that time. Tape impressions or swab samples were collected from affected areas of skin from bats with these fungal infections in 2012 and analyzed by microscopy, culture, or direct DNA amplification and sequencing of the fungal internal transcribed spacer region (ITS). A psychrophilic species of Trichophyton was isolated in culture, detected by direct DNA amplification and sequencing, and observed on tape impressions. Deoxyribonucleic acid indicative of the same fungus was also detected on three of five bat carcasses collected in 2011 and 2012 from Wisconsin, Indiana, and Texas, US. Superficial fungal skin infections caused by Trichophyton sp. were observed in histopathology for all three bats. Sequencing of the ITS of Trichophyton sp., along with its inability to grow at 25 C, indicated that it represented a previously unknown species, described herein as Trichophyton redellii sp. nov. Genetic diversity present within T. redellii suggests it is native to North America but that it had been overlooked before enhanced efforts to study fungi associated with bats in response to the emergence of WNS.

Microsporum aenigmaticum sp. nov. from M. gypseum complex, isolated as a cause of tinea corporis

An undescribed Microsporum species was isolated from skin scales recovered from a 40-mm large, annular, scaling lesion on the wrist of a 46-year-old woman. The risk factors for dermatophyte infection in the patient were frequent work in the garden, hunting, and contact with dogs and horses. Direct microscopic examination of the scales revealed the presence of dermatophyte hyphae; when the samples were cultured, a morphologically similar fungus grew on all slants in pure culture. Both of these findings strongly suggested that the isolate was the true causal agent of infection. The possible geophilic nature of the species was based on phylogenetic analysis (internal transcribed spacer region of rDNA and β-tubulin gene) that placed it in between species of the M. gypseum complex. However, its divergencies from all other Microsporum species exceeded 4% base pairs. Based on β-tubulin phylogeny, the isolated species is a sister to M. gypseum. The species produces abundant chlamydospores and clumps of hyphae similar to those of ascomatal primordia but no conidia and ascospores. The species was unable to grow at 37°C and does not grow on T6 basal medium, which is unlike other Microsporum species; hair perforation and urease tests were positive. The addition of histidine to the T6 medium resulted in rapid growth of the fungus. The phylogenetic evidence, morphology, growth parameters, and physiology justified the proposal that the isolate is a new species, M. aenigmaticum, sp. nov.

[Taxonomy and biology of fungi causing human infection]

The advent of molecular techniques, mainly DNA sequencing, has led to important changes in the taxonomy of pathogenic fungi and a better understanding of the phylogenetic relationships among them. The number of fungal species potentially pathogenic for humans has increased dramatically. Most of them are cryptic species belonging to complex species that have replaced traditional single morphospecies. This has occurred in several genera of mucorales and particularly in different ascomycetous genera, such as Aspergillus, Fusarium, Sporothrix and Scedosporium, among others. The correct identification of these species is crucial for a better management of patients, since on many occasions those species show different virulence and different antifungal responses. This review summarises some of the most striking recent taxonomic changes produced in pathogenic fungi.

Molecular identification and phylogenesis of dermatophytes isolated from rabbit farms and rabbit farm workers

Little information is available on the molecular epidemiology of dermatophytoses in rabbit farms and farm workers. A total of 117 isolates belonging to the Trichophyton mentagrophytes complex and 21 isolates of Microsporum canis were collected from rabbits with or without skin lesions, air samples of farms known to harbour these pathogens, and from farm workers with skin lesions, and molecularly characterized. Sequencing of amplicons from the T. mentagrophytes complex and M. canis isolates revealed the presence of one sequence-type for both partial chitin synthase-1 gene (pchs-1) and ribosomal internal transcribed spacer (ITS+), respectively. On the basis of comparative sequence analyses, isolated representing the T. mentagrophytes complex were molecularly identified as Trichophyton interdigitale (zoophilic) Priestley. The M. canis and T. interdigitale pchs-1 sequences herein analysed were 100% homologous to known sequences from different hosts (i.e., cats, dogs, humans and rabbits). Conversely, the ITS+ sequences of T. interdigitale from dogs, pigs and mice were identical, but displayed up to 8.6% difference with those from humans, guinea pigs and rabbits. The results of this study suggest that environmental and clinical isolates of T. interdigitale (zoophilic) and M. canis might share a common origin. Interestingly, the close phylogenetic relationship between T. interdigitale (zoophilic) strains and isolates from dogs, pigs and mice might indicate that these animals represented a reservoir of dermatophyte infection in rabbit farms. These animal species should therefore be considered when setting up control protocols to prevent infections by dermatophytes and their zoonotic transmission.

Signature polymorphisms in the internal transcribed spacer region relevant for the differentiation of zoophilic and anthropophilic strains of Trichophyton interdigitale and other species of T. mentagrophytes sensu lato

BACKGROUND

Dermatophytes are the main cause of superficial mycoses in humans and animals. Molecular research has given useful insights into the phylogeny and taxonomy of the dermatophytes to overcome the difficulties with conventional diagnostics.

OBJECTIVES

The Trichophyton mentagrophytes complex consists of anthropophilic as well as zoophilic species. Although several molecular markers have been developed for the differentiation of strains belonging to T. mentagrophytes sensu lato, correct identification still remains problematic, especially concerning the delineation of anthropophilic and zoophilic strains of T. interdigitale. This differentiation is not academic but is essential for selection of the correct antimycotic therapy to treat infected patients.

METHODS

One hundred and thirty isolates identified by morphological characteristics as T. mentagrophytes sensu lato were investigated using restriction fragment length polymorphism (RFLP) and sequence analysis of the polymerase chain reaction-amplified internal transcribed spacer (ITS) region of the rDNA.

RESULTS

Species of this complex produced individual RFLP patterns obtained by the restriction enzyme MvaI. Subsequent sequence analysis of the ITS1, 5.8S and ITS2 region of all strains, but of T. interdigitale in particular, revealed single unique polymorphisms in anthropophilic and zoophilic strains.

CONCLUSIONS

Signature polymorphisms were observed to be useful for the differentiation of these strains and epidemiological data showed a host specificity among zoophilic strains of T. interdigitale/Arthroderma vanbreuseghemii compared with A. benhamiae as well as characteristic clinical pictures in humans when caused by zoophilic or anthropophilic strains. The delineation is relevant because it helps in determining the correct treatment and provides clues regarding the source of the infection.

Identification of dermatophyte species causing onychomycosis and tinea pedis by MALDI-TOF mass spectrometry

Identification of dermatophytes is currently performed based on morphological criteria and is increasingly supported by genomic sequence comparison. The present study evaluates an alternative based on the analysis of clinical fungal isolates by mass spectrometry. Samples originating from skin and nail were characterized morphologically and by sequencing the internal transcribed spacer 1 (ITS1), ITS2 and the 5.8S rDNA regions of the rDNA clusters. In a blind comparative study, samples were analyzed by matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF MS). The mass spectra were compared to a database comprising of the spectral data of reference strains by applying the saramis software package. All fungal isolates belonging to the taxa Trichophyton rubrum, T. interdigitale, T. tonsurans, Arthroderma benhamiae and Microsporum canis were correctly identified, irrespective of host origin and pathology. To test the robustness of the approach, four isolates were grown on five different media and analyzed. Although the resulting mass spectra varied in detail, a sufficient number of signals were conserved resulting in data sets exploitable for unequivocal species identification. Taken together, the usually widespread dermatophytes can be identified rapidly and reliably by mass spectrometry. Starting from pure cultures, MALDI-TOF MS analysis uses very simple sample preparation procedures, and a single analysis is performed within minutes. Costs for consumables as well as preparation time are considerably lower than for PCR analysis.

Dermatophytes: recognizing species of clonal fungi

Now that molecular data have forever changed our perspective on the anthropophilic and zoophilic dermatophyte species, the concepts of these species needs re-evaluation. In this paper, main concepts (morphological, biological (BSC), phylogenetic and genealogical concordance phylogenetic species recognition (GCPSR)) are compared. While in geophilic dermatophytes the application of the BSC works well for species distinction and is supported by molecular data, it is not applicable for the anthropophilic and zoophilic dermatophytes where the majority of species reproduce purely asexually. Also, the application of GCPSR (an operational method to define the limits of species using molecular, multi-locus data) is problematic. GCPSR can be applied in recombining fungi even when recombination is infrequent and fungi lack phenotypic sexuality. In truly clonal fungi, however, no incongruities in multi-locus data are found, and thus separation of species may be difficult. In fungi this problem is currently taken to be non-existent, since clonality is supposed to lead to extinction. In the medically relevant, host-associated dermatophytes, however, is reason to suggest that clonal dermatophyte lineages are able to maintain ongoing populations and to follow independent evolutionary trajectories. We distinguish seasonal, short-lived and long-lived clonal species. The final goal of a species concept, in the dermatophytes as well as in other fungi, is to provide a taxonomic system that reflects the evolution of the fungal species so that the underlying biological trends elucidated in this way may be brought forward to help to guide the clinician in applying optimal therapy and prophylaxis. The application of the different species concepts may have an enormous impact on the nomenclature of dermatophytes, directly affecting the quality of communications with care providers.

Trichophyton eboreum– A recently described dermatophyte

BACKGROUND

The distribution of distinct species of dermatophytes is continuously changing and different species of dermatophytes can cause the same type of tinea. Therefore, it is necessary to always identify the pathogenic agents in dermatophytoses.

PATIENTS AND METHODS

An unusual fungus was isolated from moccasin type tinea pedis in a HIV-positive immunocompromised patient from the Ivory Coast and characterized by morphological, physiological and genetic methods.

RESULTS

The strain under study showed typical characteristics of dermatophytes but considering all its morphologic, physiologic and genetic features it unambiguously differed from all previously described species.

CONCLUSION

The strain was recently described as a new dermatophyte species (Trichophyton eboreum). Distribution and pathogenicity of this species are as yet unknown.

Internal Transcribed Spacer (ITS) of rDNA of appendaged and non-appendaged strains of Microsporum gypseum reveals Microsporum appendiculatum as its synonym

Recently a new taxon of geophilic dermatophytes was established as Microsporum appendiculatum Bhat and Mariam, based on the presence of appendaged macroconidia. However, such appendages are already known in the related species Microsporum gypseum. We conducted a survey of soil in central India as a part of a microbial biodiversity project and obtained two strains of M. gypseum with appendaged macroconidia. Using phenotypical characterization in combination with sequencing and restriction fragment length polymorphism (RFLP) of the Internal Transcribed Spacer (ITS) region of rDNA, we found that all strains of appendaged species are identical. Therefore M. appendiculatum is regarded as a synonym of M. gypseum.

Arthroderma olidum, sp. nov. A new addition to theTrichophyton terrestrecomplex

In 1981, four fungal isolates from hair of the European badger (Meles meles) were examined by Dr Phyllis Stockdale at the Commonwealth Mycological Institute, Kew, and deposited in the UK National Collection of Pathogenic Fungi as an undescribed member of the Trichophyton terrestre complex. The present paper formalizes the complete description of a new ascomycete taxon, Arthroderma olidum following successful recent attempts to re-isolate the same fungus from the soil of Badger holes in South West England. Furthermore, using ribosomal RNA gene sequencing, we show that the asexual form of A. olidum is conspecific with the recently described Trichophyton eboreum1 isolated from a human skin specimen in Germany.