Immunity to commensal skin fungi promotes psoriasiform skin inflammation.

Under steady-state conditions, the immune system is poised to sense and respond to the microbiota. As such, immunity to the microbiota, including T cell responses, is expected to precede any inflammatory trigger. How this pool of preformed microbiota-specific T cells contributes to tissue pathologies remains unclear. Here, using an experimental model of psoriasis, we show that recall responses to commensal skin fungi can significantly aggravate tissue inflammation. Enhanced pathology caused by fungi preexposure depends on Th17 responses and neutrophil extracellular traps and recapitulates features of the transcriptional landscape of human lesional psoriatic skin. Together, our results propose that recall responses directed to skin fungi can directly promote skin inflammation and that exploration of tissue inflammation should be assessed in the context of recall responses to the microbiota.

ame-miR-34 Modulates the Larval Body Weight and Immune Response of Apis mellifera Workers to Ascosphara apis Invasion.

MiRNAs are critical regulators of numerous physiological and pathological processes. Ascosphaera apis exclusively infects bee larvae and causes chalkbrood disease. However, the function and mechanism of miRNAs in the bee larval response to A. apis infection is poorly understood. Here, ame-miR-34, a previously predicted miRNA involved in the response of Apis mellifera larvae to A. apis invasion, was subjected to molecular validation, and overexpression and knockdown were then conducted to explore the regulatory functions of ame-miR-34 in larval body weight and immune response. Stem-loop RT-PCR and Sanger sequencing confirmed the authenticity of ame-miR-34 in the larval gut of A. mellifera. RT-qPCR results demonstrated that compared with that in the uninfected larval guts, the expression level of ame-miR-34 was significantly downregulated (p < 0.001) in the guts of A. apis-infected 4-, 5-, and 6-day-old larvae, indicative of the remarkable suppression of host ame-miR-34 due to A. apis infection. In comparison with the corresponding negative control (NC) groups, the expression level of ame-miR-34 in the larval guts in the mimic-miR-34 group was significantly upregulated (p < 0.001), while that in the inhibitor-miR-34 group was significantly downregulated (p < 0.01). Similarly, effective overexpression and knockdown of ame-miR-34 were achieved. In addition, the body weights of 5- and 6-day-old larvae were significantly increased compared with those in the mimic-NC group; the weights of 5-day-old larvae in the inhibitor-miR-34 group were significantly decreased in comparison with those in the inhibitor-NC group, while the weights of 4- and 6-day-old larvae in the inhibitor-miR-34 group were significantly increased, indicating the involvement of ame-miR-34 in modulating larval body weight. Furthermore, the expression levels of both hsp and abct in the guts of A. apis-infected 4-, 5-, and 6-day-old larvae were significantly upregulated after ame-miR-34 overexpression. In contrast, after ame-miR-34 knockdown, the expression levels of the aforementioned two key genes in the A. apis-infected 4-, 5-, and 6-day-old larval guts were significantly downregulated. Together, the results demonstrated that effective overexpression and knockdown of ame-miR-34 in both noninfected and A. apis-infected A. mellifera larval guts could be achieved by the feeding method, and ame-miR-34 exerted a regulatory function in the host immune response to A. apis invasion through positive regulation of the expression of hsp and abct. Our findings not only provide a valuable reference for the functional investigation of bee larval miRNAs but also reveal the regulatory role of ame-miR-34 in A. mellifera larval weight and immune response. Additionally, the results of this study may provide a promising molecular target for the treatment of chalkbrood disease.

Atypical chlamydoconidium-producing Trichophyton tonsurans strains from Ceará State, Northeast Brazil: investigation of taxonomy by phylogenetic analysis and biofilm susceptibility.

Chlamydoconidium-producing Trichophyton tonsurans strains isolated in Northeastern Brazil have morphological features different from the classic description of this dermatophyte species. This study investigated the phylogenetic relationship of chlamydoconidium-producing T. tonsurans strains isolated in Northeastern Brazil. Also, the effect of terbinafine and farnesol on mature biofilms of T. tonsurans strains was evaluated. The mass spectra of T. tonsurans strains were investigated by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The ITS and LSU loci regions of rDNA and the partial ß-tubulin gene were sequenced and the phylogenetic tree was analysed. The effects of terbinafine and farnesol on mature T. tonsurans biofilms were evaluated through the analysis of metabolic activity, quantification of biomass and observation by scanning electron microscopy. MALDI-TOF MS spectra of the chlamydoconidium-producing T. tonsurans strains differed from the spectrum of the control strain (ATCC 28942), presenting an intense ion peak at m/z 4155 Da. Phylogenetic tree analysis showed that the chlamydoconidium-producing strains isolated in Northeastern Brazil are allocated to a single cluster, differing from strains isolated from other countries. As for mature T. tonsurans biofilms, farnesol reduced biomass and metabolic activity by 64.4 and 65.9 %, respectively, while terbinafine reduced the biomass by 66.5 % and the metabolic activity by 69 %. Atypical morphological characteristics presented by chlamydoconidium-producing T. tonsurans strains result from phenotypic plasticity, possibly for adaptation to environmental stressors. Also, farnesol had inhibitory activity against T. tonsurans biofilms, demonstrating this substance can be explored for development of promising anti-biofilm drugs against dermatophytes.

Benzylpenicillin-producing Trichophyton erinacei and methicillin resistant Staphylococcus aureus carrying the mecC gene on European hedgehogs - A pilot-study.

BACKGROUND: A high carriage rate of methicillin-resistant Staphylococcus aureus with the mecC gene (mecC-MRSA) has been described among Wild European hedgehogs (Europeaus erineaus). Due to this frequent occurrence, it has been suggested that hedgehogs could be a natural reservoir for mecC-MRSA. However, the reason why hedgehogs carry mecC-MRSA remains unknown, but it has been hypothesized that mecC-MRSA could have evolved on the skin of hedgehogs due to the co-occurrence with antibiotic producing dermatophytes. The aim of this pilot-study was therefore to investigate if hedgehogs in Sweden carry Trichophyton spp. and to provide evidence that these dermatophytes are able to produce penicillin or similar substances. In addition, the study aimed to identify if dermatophytes co-occurred with mecC-MRSA. METHODS: Samples were collected from hedgehogs (Europeaus erineaus) that were euthanized or died of natural causes. All samples were screened for dermatophytes and mecC-MRSA using selective cultivation methods. Suspected isolates were characterized using PCR-based methods, genome sequencing and bioinformatic analyses. Identification of penicillin was performed by ultra-high-performance liquid chromatography-tandem mass spectrometry. RESULTS: In total 23 hedgehogs were investigated, and it was shown that two carried Trichophyton erinacei producing benzyl-penicillin, and that these hedgehogs also carried mecC-MRSA. The study also showed that 60% of the hedgehogs carried mecC-MRSA. CONCLUSION: The pilot-study demonstrated that Trichophyton erinacei, isolated from Swedish hedgehogs, can produce benzylpenicillin and that these benzylpenicillin-producing T. erinacei co-occurred with mecC-MRSA. The study also reconfirmed the high occurrence of mecC-MRSA among hedgehogs.

A review of recent research on antifungal agents against dermatophyte biofilms.

Dermatophytoses are inflammatory cutaneous mycoses caused by dermatophyte fungi of the genera Trichophyton, Microsporum, and Epidermophyton that affect both immunocompetent and immunocompromised individuals. With therapeutic failure, dermatophytoses can become chronic and recurrent. This is partly due to their ability to develop biofilms, microbial communities involved in a polymeric matrix attached to biotic or abiotic surfaces, contributing to fungal resistance. This review presents evidence accumulated in recent years on antidermatophyte biofilm activity. The following databases were used: Web of Science, Medline/PubMed (via the National Library of Medicine), Embase, and Scopus. Original articles published between 2011 and 2020, emphasizing the antifungal activity of conventional and new drugs against dermatophyte biofilms were eligible. A total of 11 articles met the inclusion criteria and were reviewed - the studies used in vitro and ex vivo (fragments of nails and hair) experimental models. The articles focused on reports of antibiofilm activity for conventional antifungals, natural drugs, and new therapeutic tools. The strains reported on were T. mentagrophytes, T. rubrum, T. tonsurans, M. canis, and M. gypseum. Between the studies, the wide variability of experimental conditions in vitro and ex vivo was observed. The data suggest the need for methodological standardization (at some minimum). This review systematically presents current studies involving agents that present antibiofilm activity against dermatophytes; and an overview of the ideal in vitro and ex vivo experimental conditions to guarantee biofilm formation that may assist future research. LAY ABSTRACT: This review presents the current studies on the antibiofilm activities of drugs against dermatophytes and ideal experimental conditions, which might guarantee in vitro and ex vivo biofilm formation. It can be useful to examine the efficacy of new antimicrobial drugs against dermatophytes.

Selection and validation of reference genes for qPCR in the human dermatophyte Trichophyton rubrum exposed to different carbon sources which promote adhesion-inducing conditions.

OBJECTIVE: The present study aimed to identify reference genes for qPCR analysis of T. rubrum growth in culture media which promote adhesion-inducing conditions to the host tissue. METHODS: We investigated the suitability of six candidate reference genes: ß-act, ß-tub, ef1-α, gapdh, sdha and rpl2 in reference strain of Trichophyton rubrum in response to different environmental stimuli. The stability of these genes was determined by NormFinder, geNorm and BestKeeper software. RESULTS: Our data obtained from the three algorithms revealed that mRNA expression levels of two candidate reference genes, ef1-α and ß-tub, remained the most stable in response to different carbon sources, while different sample sets had their own most stable reference genes, highlighting the importance of the choice of internal controls in qPCR experiments. We then checked the stability of ef1-α and ß-tub reference genes expression in different T. rubrum strains, suggesting that these two genes are reliable for normalisation of qPCR. Finally, we validated the suitability of selected reference genes as internal controls for target gene (SUB3) using the 2-ΔΔCt method. The best result indicating an increase of SUB3 transcript of T. rubrum was found when the two the most stable reference (ef1-α and ß-tub ) genes were used, as revealed by all three algorithms. CONCLUSIONS: We recommend the use of ef1-α and ß-tub as reference genes for qPCR analysis of target gene expression in T. rubrum exposed to different carbon sources which promote adhesion-inducing conditions.

The interplay among Th17 and T regulatory cells in the immune dysregulation of chronic dermatophytic infection.

The delineation of the pathogenic interaction between the host skin immune responses and dermatophytes has remained indigent. The obscure enigma in host-dermatophyte immunopathogenic interactions is the T regulatory (Treg) and T-helper (Th) 17  cell role in maintaining immune homeostasis. We attempted to understand the regulation and recognition of lineage-specific response in chronic dermatophytic skin infection patients. The percentages of Th17 (CD4+CD161+IL23R+) and Treg (CD4+CD25+FoxP3+) cell subpopulations in the peripheral circulation of thirty chronic dermatophytic skin infection patients and twenty healthy individuals was determined. The serum cytokine levels were estimated for disease correlation. The mean duration of the disease was 10.68 ± 8.72 months, with Trichophyton mentagrophytes complex as the major pathogen. Total serum IgE level of patients was significantly higher compared to healthy controls (305 ± 117 vs 98.53 ± 54.55 IU/ml; p < 0.01). Expression of Th17 and Treg cell markers on CD4+ T cells was significantly elevated in patients than controls (p < 0.05). Comparatively, serum interleukin (IL)-4 and interferon (IFN)-γ levels were increased, with low IL-10 levels in patients. Our data envisages a complex immune dysfunction in chronic dermatophytosis, arising either as a result of dermatophyte exposure or paradoxical precedence of disease establishment. Designing new treatment strategies and preventing recurrences are challenges for future research.

Acanthamoeba castellanii as an alternative interaction model for the dermatophyte Trichophyton rubrum.

BACKGROUND: Trichophyton rubrum (Tr) is the main aetiological agent of human dermatophytosis, being isolated from the environment and keratinised tissues. In the environment, Tr can interact with other organisms, such as free-living amoebas (FLA), which can act as an alternative host system to study the interaction between microbes and phagocytic cells. OBJECTIVES: To characterise the Acanthamoeba castellanii (ALX)-Tr interaction. METHODS: Interaction was characterised in three conditions: trophozoites (PYG), late (PYG/NES) and early (NES) encystation stimulus, evaluating encystation kinetics, phagocytosis, exocytosis and fungicidal activity dynamics. RESULTS: Tr was able to induce ALX encystation and be internalised by ALX. The number of internalised conidia was high at 1 hour, and ALX presented fungicidal activity with increased intracellular ROS production and exocytosis. In PYG/NES, phagocytosis and ROS production were reduced, with decreased ALX's fungicidal activity. However, in NES there was an increased fungal engulfment, and a reduced ROS production and higher fungal burden. Furthermore, exogenous mannose decreased phagocytosis of Tr conidia, and divalent cations induced ROS production and increased ALX's fungicidal activity. Interestingly, phagocytosis was reduced in the presence of cytoskeleton inhibitor, but exocytosis was increased, suggesting that Tr conidia may have alternative pathways to escape ALX's cells. CONCLUSION: A castellanii is a proper model for studying Tr-FLA interaction, since ALX can engulf, produce ROS and kill Tr, and all these parameters are influenced by an encystation stimulus and divalent cations. Moreover, this interaction is likely to occur in the environment implicating in the adaptation to environmental stressful conditions in both organisms.

Keratin Biomembranes as a Model for Studying Onychomycosis.

Difficulties in obtaining human nails that are large enough for examining the penetration of drug formulations led us to produce keratin films regenerated from human hair. We assume that these films can simulate human nail plates in drug penetration and permeation tests and can serve as a biological model for studying onychomycosis. The films were formed from keratin extracted from human hair using dithiothreitol, urea and thiourea. The obtained keratin extract was dispensed into Teflon rings and dried at 40 °C and then cured at 110 °C. The structure, surface morphology, chemical characterization and thermal stability of the films were characterized and were compared to those of human nail, hair and bovine hoof samples using SDS-electrophoresis, scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The structure of the obtained films was found to be closer to human nails than to hair or bovine hooves. The keratin films were infected with Trichophyton rubrum and were proven to be appropriate for serving as a model for studying onychomycosis.

Multiple-strain Trichophyton mentagrophytes infection in a silver fox (Vulpes vulpes) from a breeding farm.

Dermatophyte infections are extremely frequent worldwide, and their epidemiological features and distribution make them one of the most frequent infections all over the world. We identified and analysed multiform T. mentagrophytes strains isolated from a silver fox (Vulpes vulpes) kept on a breeding farm. Identification of dermatophyte strains was carried out traditionally by correlating both the clinical manifestations of the infection with a micro- and macroscopic examination. To confirm the species affiliation fully, molecular differentiation methods were used. DNA was isolated from the dermatophytes with the phenol-chloroform method. The reaction of chitin synthase 1 (chs1) amplification was carried out to confirm the dermatophytes. The phylogenetic analysis was based on the ITS sequences. The polymerase chain reaction melting profile (PCR-MP) procedure was used for differentiation of dermatophyte genomes. Direct analysis of the material sampled from the clinical lesions revealed the presence of arthrospores in the samples collected from all animals with skin lesions. The macromorphology of the colonies obtained from material sampled from the same individual was not homogeneous. The PCR-MP electrophoregram indicated high variability of their genomes. Although the dermatophytes were isolated from one infected fox, no two identical genomic profiles were obtained. The PCR-MP result corresponds with the phenotypic diversity of the isolates. The findings about the multiple dermatophyte infection in one individual complicate any future epidemiology work and other clinical investigation. Previously, using only morphological characteristics, it had been assumed that one fungal isolate per patient could be diagnosed. The novel findings encourage application of the newly developed molecular typing methods in the diagnosis of dermatophytosis.

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.

Invasive Infections Caused by Nannizziopsis spp. Molds in Immunocompromised Patients.

We report 2 new cases of invasive infections caused by Nannizziopsis spp. molds in France. Both patients had cerebral abscesses and were immunocompromised. Both patients had recently spent time in Africa.

The transcriptional regulators SteA and StuA contribute to keratin degradation and sexual reproduction of the dermatophyte Arthroderma benhamiae.

Most superficial fungal infections are caused by dermatophytes, a specialized group of filamentous fungi which exclusively infect keratinized host structures such as hair, skin and nails. Since little is known about the molecular basis of pathogenicity and sexual reproduction in dermatophytes, here we functionally addressed two central transcriptional regulators, SteA and StuA. In the zoophilic species Arthroderma benhamiae a strategy for targeted genetic manipulation was recently established, and moreover, the species is teleomorphic and thus allows performing assays based on mating. By comparative genome analysis homologs of the developmental regulators SteA and StuA were identified in A. benhamiae. Knock-out mutants of the corresponding genes as well as complemented strains were generated and phenotypically characterized. In contrast to A. benhamiae wild type and complemented strains, both mutants failed to produce sexual reproductive structures in mating experiments. Analysis of growth on keratin substrates indicated that loss of steA resulted in the inability of ΔsteA mutants to produce hair perforation organs, but did not affect mycelia formation during growth on hair and nails. By contrast, ΔstuA mutants displayed a severe growth defect on these substrates, but were still able to produce hair perforations. Hence, formation of hair perforation organs and fungal growth on hair per se are differentially regulated processes. Our findings on the major role of SteA and StuA during sexual development and keratin degradation in A. benhamiae provide insights into their role in dermatophytes and further enhance our knowledge of basic biology and pathogenicity of these fungi.

Genetic Manipulations in Dermatophytes.

Dermatophytes are a group of closely related fungi that nourish on keratinized materials for their survival. They infect stratum corneum, nails, and hair of human and animals, accounting the largest portion of fungi causing superficial mycoses. Huge populations are suffering from dermatophytoses, though the biology of these fungi is largely unknown yet. Reasons are partially attributed to the poor amenability of dermatophytes to genetic manipulation. However, advancements in this field over the last decade made it possible to conduct genetic studies to satisfying extents. These included genetic transformation methods, indispensable molecular tools, i.e., dominant selectable markers, inducible promoter, and marker recycling system, along with improving homologous recombination frequency and gene silencing. Furthermore, annotated genome sequences of several dermatophytic species have recently been available, ensuring an optimal recruitment of the molecular tools to expand our knowledge on these fungi. In conclusion, the establishment of basic molecular tools and the availability of genomic data will open a new era that might change our understanding on the biology and pathogenicity of this fungal group.

Pathogenic Dermatophytes Survive in Nail Lesions During Oral Terbinafine Treatment for Tinea Unguium.

Tinea unguium caused by dermatophyte species are usually treated with oral antimycotic, terbinafine (TBF). To understand the mechanisms of improvement and recalcitrance of tinea unguium by oral TBF treatment, a method of quantifying dermatophyte viability in the nail was developed, and the viability of dermatophytes was analyzed in toenail lesions of 14 patients with KOH-positive tinea unguium treated with oral TBF 125 mg/day for up to 16 weeks. Mycological tests, including KOH examination and fungal culture, and targeted quantitative real-time PCR for internal transcribed spacer (ITS) region, including rRNA, were demonstrated at the initial visit and after 8 and 16 weeks of treatment. Assays in eight patients showed that average ITS DNA amount significantly decreased, to 44% at 8 weeks and 36% at 16 weeks compared with 100% at initial visit. No significant difference was observed between at 8 and 16 weeks, despite the TBF concentration in the nail supposedly more than 10-fold higher than the minimum fungicidal concentration for dermatophytes. This finding suggests the pathogenic dermatophytes in nail lesions could survive in a dormant form, such as arthroconidia, during oral TBF treatment. Both antimycotic activity and nail growth are important factors in treatment of tinea unguium.

Epidemiology of onychomycosis in Crete, Greece: a 12-year study.

Onychomycosis is a chronic fungal nail infection caused by dermatophytes, yeasts or non-dermatophyte moulds (NDMs). It occurs worldwide and accounts for about 50% of all nail disorders. The incidence of the disease and the prevalence of pathogens involved vary in different geographical areas and change with time. This study was undertaken to determine the epidemiology of onychomycosis in Crete, Greece during a 12-year period. Mycologic nail investigation (direct microscopy and cultures) was performed in samples taken from 3317 patients with clinical suspicion of onychomycosis. Demographic characteristics, comorbidities and concurrent superficial fungal infections at other body sites were also recorded. Onychomycosis was mycologically confirmed in 547 (16.5%) patients. Fingernail onychomycosis was found in 274 (50.1%) patients, toenail onychomycosis in 271 (49.5%), and both toenail and fingernail onychomycosis in two (0.4%). Yeasts were the major causative agents, followed by dermatophytes and NDMs. Candida albicans was the most commonly isolated yeast species and Trichophyton rubrum the most common dermatophyte. Concomitant fungal skin infections were noted in 53 (19.6%) patients with toenail onychomycosis. Factors predisposing to onychomycosis were trauma, diabetes, psoriasis, peripheral circulatory insufficiency and immunosuppression. Mycological investigations are necessary to confirm clinical diagnosis and identify the pathogen, in order to select the most appropriate treatment.

Non-dermatophytic onychomycosis diagnostic criteria: an unresolved question.

Non-dermatophytic moulds (NDMs) have been increasingly recognised as causative agents of onychomycosis. The diagnosis of onychomycosis is most often obtained by microscopic observation of nail specimens where fungal elements can be detected and cultured by standard mycological techniques. Direct microscopic examination does not always result positive in NDM onychomycosis; therefore to perform a correct diagnosis, a proper mycological culture is often required. The purpose of our study was to evaluate the role of direct microscopic examination in the NDM onychomycosis diagnosis. The results show that only 57.2% of the specimens from onychomycosis patients could be properly diagnosed showing positivity to both direct microscopic examination and NDMs culture isolation in two or more subsequent inoculations, while 42.8% of analysed specimens with a negative direct microscopic examination, showed NDMs growth after three or more subsequent inoculations. The large proportion of false negatives (more than 42%) could be related to the duration of the infection and/or to the experience and skills of the personnel dedicated to specimen collection. We point out the need for thoroughly evaluating all specimens showing cultural growth in at least three subsequent medium inoculations, whatever the result of the microscopic examination, in order to reduce false-negative rates. This strategy would allow for more accurate diagnosis of this mycosis.

A randomised comparative study of 1064 nm Neodymium-doped yttrium aluminium garnet (Nd:YAG) laser and topical antifungal treatment of onychomycosis.

Conventional treatments for onychomycosis include oral and topical antifungal agents. Although Nd:YAG laser has been reported to be effective, controlled studies combined or compared with conventional treatments are needed. To evaluate the efficacy of 1064 nm Nd:YAG laser for onychomycosis and compare outcomes with those of topical antifungal treatment and combination therapy. Patients were randomly divided into three groups: Laser (L); laser with topical antifungal therapy (L + T); and topical antifungal treatment (T). Laser treatment consisted of three or four sessions at 4 week intervals. Outcomes were assessed clinically and mycologically. In 217 nails of 56 patients, 76% in the L group and 71.8% in the L + T group experienced clinical responses, and 15.2% and 22.5%, respectively, were cured at 24 weeks. The clinical and cure rates of both groups were significantly greater than those of the T group. Six patients of the L group developed new infections, as did one patient in the L + T group and two patients in the T group. 1064 nm Nd:YAG laser shows clinically good responses in onychomycosis. Addition of topical antifungal agent did not appear to improve efficacy, but may have protected against new infection.

[Arthroderma benhamiae strains in Germany : Morphological and physiological characteristics of the anamorphs]. / Arthroderma-benhamiae-Stämme aus Deutschland : Morphologische und physiologische Merkmale der anamorphen Formen.

BACKGROUND: Anamorphs of Arthroderma (A.) benhamiae, which can cause inflammatory tinea lesions in humans, have been progressively spreading in Germany. OBJECTIVES: Identification of A. benhamiae anamorphs by conventional methods. MATERIALS AND METHODS: Evaluation of our own results obtained with A. benhamiae anamorphs and from the relevant literature. RESULTS: Infections with A. benhamiae anamorphs are usually transferred by guinea pigs or other animals. A. benhamiae anamorphs can be cultured on growth media used for dermatophytes and can be characterized morphologically and physiologically. In Germany the yellow variant is seen most often but a white variant that equals Trichophyton (T.) interdigitale has also been observed. On Sabouraud agar the yellow variant develops markedly yellow thalli, whereas the white variant produces white aerial mycelium. Microconidia are formed by the yellow variant-if at all-only scarcely and delayed; they are small, roundish, and arranged in a grape-like order. The white variant produces peg-shaped microconidia alongside hyphae as well as roundish ones in grape-like clusters, and subsequently some macroconidia, chlamydospores, and spiral hyphae. In microcultures with both variants circuit-like hyphal structures can consistently be demonstrated. On Trichophyton agars only the yellow variant is clearly dependent on thiamine. The urease test is negative with the yellow variant and positive with the white variant. Most strains of both variants are negative in the hair perforation test. CONCLUSIONS: The characteristics described allow reliable identification of the yellow variant of the A. benhamiae anamorph by conventional methods; a distinction between the white variant and T. interdigitale can be more difficult. Dermatologists should be able to identify this agent in clinical routine.

In vitro and in vivo antidermatophytic activities of some Iranian medicinal plants.

In the last decades, the number of people suffering from dermatophytoses has seriously increased, which may be due to the development of resistant strains to a range of antifungal drugs. The present study was aimed to evaluate the antidermatophytic properties of eight extracts from the selected spices and herbs, which were ethno-medicinally used in Iran against Trichophyton mentagrophytes, Trichophyton interdigitale, Microsporum canis, and Microsporum gypseum (10 strain of each). The in vitro antifungal activities of the extracts from four spices and four plants were evaluated by the broth macro dilution method against four dermatophyte strains. In addition, the in vivo therapeutic effects of Myrtus communis L. and Cinnamomum zeylanicum Blume extracts (the most active extracts) on dermatophytosis induced by M. canis and T. mentagrophytes in guinea pigs were evaluated. Results of in vitro antifungal assay revealed that all the tested extracts demonstrated both fungistatic and fungicidal activities with the geometric mean (GM) MIC ranging from 0.058 to 3.73 mg/ml and GM (MFC) ranging from 0.058 to 7.46 mg/ml, respectively. Two extracts (M. communis and C. zeylanicum) significantly inhibited the growth of all the tested dermatophytes, while other extracts demonstrated weak (MICs of >0.625 mg/ml) to moderate (MICs ranging from 100 to 0.625 mg/ml) activities. In vivo antidermatophytic assay demonstrated that clotrimazole cured T. mentagrophytes and M. canis infection on days 21 and 17, respectively, whereas M. communis and C. zeylanicum extracts significantly (p < 0.05) cured T. mentagrophytes and M. canis infection on days 9 and 13 as well as 9, 11, respectively. Phytochemical screening showed the presence of flavonoids, tannins, phenols, and alkaloids in M. communis and alkaloids, flavonoids, and tannins in C. zeylanicum. Findings of the present study also provided the scientific evidence that natural plants could be used in traditional medicine for the prevention and treatment of dermatophytic infections.