Search Results (15)

Dermatophytes are commonly encountered pathogens in clinical practice causing superficial infections of the skin, hair, and nails. These pathogens are often found on animals such as livestock (e.g., cattle, rabbits) and pets (e.g., cats, hedgehogs) that can lead to spillover infections in human populations. Here, we reviewed published reports (2009–2024) of dermatophyte infections in animals and in humans with a history of animal contact. A literature search was completed in October 2024 using PubMed, Embase (Ovid), and Web of Science (Core Collection), which identified 250 articles. Generally, dermatophytes tend to infect younger animals with long hair and exhibit a species-specific host range. Microsporum canis was the most commonly reported species—linked to cats—that can cause tinea capitis, especially concerning the development of kerion in children. Trichophyton verrucosum is strongly associated with cattle. The Trichophyton mentagrophytes complex shows a diverse range of animal hosts, with rabbits being most frequently reported; however, T. mentagrophytes var. erinacei is almost exclusively isolated from hedgehogs, and T. mentagrophytes var. benhamiae is more commonly found on rodents (e.g., guinea pigs). Lastly, the geophilic Nannizia gypsea has been isolated from both dogs and cats. Managing dermatophyte zoonoses is an ongoing challenge, as healthcare providers may empirically treat with corticosteroids or antibacterial agents due to its atypical inflammatory appearance. Evidence of in vitro resistance against griseofulvin and fluconazole has been documented in multiple zoonotic dermatophyte species. Resistance development against terbinafine and itraconazole is also a possibility, although the number of reports is scarce. Under the principles of the One Health approach, research on human fungal diseases should take animal and environmental factors into account. A renewed call for increased testing efforts is warranted. Full article

Background: Trichophyton benhamiae, an anthropophilic dermatophyte, can cause dermatophytosis in humans and animals with rising zoonotic infections through pets, primarily in Europe. Dermatophytosis from T. benhamiae is often misdiagnosed due to its inflammatory symptoms. We report a case of tinea corporis from T. benhamiae var. luteum in a Japanese woman, contracted from pet Czech degus. Case: The 40-year-old patient developed neck papules resembling acne. Initial treatment with topical antibiotics and steroids exacerbated the rash. Fungal elements were not detected by direct potassium hydroxide examination. Skin biopsy confirmed fungal elements in the stratum corneum and hair follicles, and tinea corporis was diagnosed. Oral terbinafine 125 mg was initiated without topical agents. Erythematous papules appeared on her limbs, determined as a trichophytid reaction. After two months, her skin improved significantly. Fungal culture identified T. benhamiae var. luteum colonies with a yellowish hue. Mating tests classified the strain as Americano-European race (−) with MAT1-1 genotype. This was diagnosed as tinea corporis from T. benhamiae var. luteum, likely transmitted from pet Czech degus. Conclusions: The incidence rate of pet-transmitted cutaneous fungal infections may increase in Japan with the trend to keep exotic pets. Dermatologists must recognize dermatophytosis clinical features from anthropophilic dermatophytes to prevent misdiagnosis and understand evolving nomenclature and pathogenesis. Full article

Most inflammatory dermatophytoses in humans are caused by zoophilic and geophilic dermatophytes. Knowledge of the epidemiology of these fungi in animals facilitates the prevention of dermatophytosis of animal origin in humans. We studied the prevalence of dermatophyte species in domestic animals in Switzerland and examined the effectiveness of direct mycological examination (DME) for their detection compared to mycological cultures. In total, 3515 hair and skin samples, collected between 2008 and 2022 by practicing veterinarians, were subjected to direct fluorescence microscopy and fungal culture. Overall, 611 dermatophytes were isolated, of which 547 (89.5%) were from DME-positive samples. Cats and dogs were the main reservoirs of Trichophyton mentagrophytes and Microsporum canis, whereas Trichophyton benhamiae was predominantly found in guinea pigs. Cultures with M. canis significantly (p < 0.001) outnumbered those with T. mentagrophytes in DME-negative samples (19.3% versus 6.8%), possibly because M. canis can be asymptomatic in cats and dogs, unlike T. mentagrophytes, which is always infectious. Our data confirm DME as a reliable, quick, and easy method to identify the presence of dermatophytes in animals. A positive DME in an animal hair or skin sample should alert people in contact with the animal to the risk of contracting dermatophytosis. Full article

Terbinafine resistance in Trichophyton species has emerged and appears to be increasing. A new EUCAST susceptibility testing method and tentative ECOFFs were recently proposed for Trichophyton. Terbinafine resistance and target gene mutations were detected in 16 Danish isolates in 2013–2018. In this study, samples/isolates submitted for dermatophyte susceptibility testing 2019–2020 were examined. Species identification (ITS sequencing for T. mentagrophytes/T. interdigitale species complex (SC) isolates), EUCAST MICs and squalene epoxidase (SQLE) profiles were obtained. Sixty-three isolates from 59 patients were included. T. rubrum accounted for 81% and T. mentagrophytes/T. interdigitale SC for 19%. Approximately 60% of T. rubrum and T. mentagrophytes/interdigitale SC isolates were terbinafine non-wildtype and/or had known/novel SQLE mutations with possible implications for terbinafine MICs. All infections with terbinafine-resistant T. mentagrophytes/interdigitale SC isolates were caused by Trichophyton indotineae. Compared to 2013–2018, the number of patients with terbinafine-resistant Trichophyton isolates increased. For T. rubrum, this is partly explained by an increase in number of requests for susceptibility testing. Terbinafine-resistant T. indotineae was first detected in 2018, but accounted for 19% of resistance (4 of 21 patients) in 2020. In conclusion, terbinafine resistance is an emerging problem in Denmark. Population based studies are warranted and susceptibility testing is highly relevant in non-responding cases. Full article

Skin infections by keratinophilic fungi are commonly referred to as dermatophytosis and represent a major health burden worldwide. Although patient numbers are on the rise, data on virulence factors, their function and kinetics are scarce. We employed an ex vivo infection model based on guinea pig skin explants (GPSE) for the zoonotic dermatophyte Trichophyton (T.) benhamiae to investigate kinetics of the virulence factors subtilisin (sub) 3, sub 6, metallocarboxypeptidase A (mcpA) and isocitrate lyase (isol) at gene level for ten days. Fluorescence in situ hybridization (FISH) and quantitative polymerase chain reaction (qPCR) were used to detect and quantify the transcripts, respectively. Kingdom-spanning, species-specific and virulence factor-specific probes were successfully applied to isolated fungal elements showing inhomogeneous fluorescence signals along hyphae. Staining results for inoculated GPSE remained inconsistent despite thorough optimization. qPCR revealed a significant increase of sub 3- and mcpA-transcripts toward the end of culture, sub 6 and isol remained at a low level throughout the entire culture period. Sub 3 is tightly connected to the de novo formation of conidia during culture. Since sub 6 is considered an in vivo disease marker. However, the presented findings urgently call for further research on the role of certain virulence factors during infection and disease. Full article

For the successful treatment of dermatophytoses, especially tinea capitis, there is a need for accurate and rapid diagnostic methods. A lot of recent literature has focused on the detection of dermatophytes directly on sample material such as nails, hair and skin scrapings. Molecular tools offer the ability to rapidly diagnose dermatophytosis within 48 h. This study aimed to compare the results of a commercial real-time PCR (real-time PCR) assay DermaGenius^®(DG) 2.0 complete multiplex kit with those of conventional diagnostic methods (direct microscopy and culture). A total of 129 hair samples were collected in Dakar (Senegal) from patients suspected of dermatophytosis. DG was applied for the molecular detection of Candida albicans, Trichophyton rubrum/soudanense, T. interdigitale, T. tonsurans, T. mentagrophytes, T. violaceum, Microsporum canis, M. audouinii, Epidermophyton floccosum, T. benhamiae and T. verrucosum. Dermatophytes species and C. albicans were differentiated by melting curve analysis. The sensitivity and specificity of the PCR assay were 89.3% and 75.3%, respectively. DG PCR was significantly more sensitive than culture (p < 0.001). DG PCR is fast and robust to contamination. In this paper, the main questions discussed were the replacement of culture by a broad-spectrum fungal real-time PCR and the implementation of DG PCR into a routine laboratory in Senegal. Full article

Dermatophytoses are superficial infections of human and animal keratinized tissues caused by filamentous fungi named dermatophytes. Because of a high and increasing incidence, as well as the emergence of antifungal resistance, a better understanding of mechanisms involved in adhesion and invasion by dermatophytes is required for the further development of new therapeutic strategies. In the last years, several in vitro and in vivo models have emerged to study dermatophytosis pathogenesis. However, the procedures used for the growth of fungi are quite different, leading to a highly variable composition of inoculum for these models (microconidia, arthroconidia, hyphae), thus rendering difficult the global interpretation of observations. We hereby optimized growth conditions, including medium, temperature, atmosphere, and duration of culture, to improve the sporulation and viability and to favour the production of arthroconidia of several dermatophyte species, including Trichophyton rubrum and Trichophyton benhamiae. The resulting suspensions were then used as inoculum to infect reconstructed human epidermis in order to validate their ability to adhere to and to invade host tissues. By this way, this paper provides recommendations for dermatophytes culture and paves the way towards a standardized procedure for the production of infective spores usable in in vitro and in vivo experimental models. Full article

Following our previous study of the therapy of onychomycosis by non-thermal plasma (NTP) and nail hygiene and to obtain some prerequisite data of dermatophytes sensitivity, the dynamics of those inactivation by NTP plasma was monitored for various strains of Trichophyton iterdigitale, Trichophyton benhamiae, Trichophyton rubrum, and Microsporum canis. Three strains of each species on agar plates were exposed with plasma produced by a DC corona discharge in the point-to-ring arrangement in various time intervals. Although all strains were sufficiently sensitive to plasma action, significant differences were observed in their sensitivity and inactivation dynamics. These differences did not correlate with the species classification of individual strains, but could be assigned to four arbitrarily created types of strain response to NTP according to their sensitivity. These results indicate that the sensitivity to plasma is not an inherent property of the fungal species, but varies from strain to strain. Full article

The detection and identification of fungal DNA from clinical samples is one of the fundamental approaches in biomedicine. The incidence, distribution, and control of dermatophytes has progress significantly and the use of phylogenetic species concepts based on rRNA regions have enhanced the taxonomy of dermatophyte species; however, the use of 28S rDNA genes has certain limitations. This gene has been used in dermatophyte taxonomy with limited enumeration; we appraised the sequence disparity within and among groups of the species, the gene ranking in identification, phylogenetic analysis, and taxonomy of 32 strains of eight dermatophyte species. In this study, a set of primers was adopted to amplify the target followed by a partial sequencing of the rDNA. The utilization of a pairwise nucleotide differentiation, an affinity was observed among eight dermatophyte species, with disparity among species ranging from 0 to 197 base pair (bp). Intra-species bp differences were found within strains of Trichophyton eriotrephon, Trichophyton bullosum, Trichophyton simii (Trichophyton genus), Microsporum audouinii, and Trichophyton tonsurans (Microsporum and Trichophyton genus, respectively); however, only some strains of Trichophyton eriotrephon were found to be invariant having three genotypes. Trichophyton tonsurans exhibited most intra-species variability. The characterization and construction of a phylogenetic tree of 28S rDNA gene on dermatophyte species provide a bedrock of an additional finding of connections between species. However, 28S rRNA capture provides a novel method of effective and sensitive detection of dermatophytes lodged in human skin scale. We report for the first time the emergence of T. eriotrephon, T. bullosum, T. simii, T. benhamiae, and Ctenomyces serratus dermatophytes from Tinea capitis in Nigeria. Full article

In recent years, considerable advances have been made in clearing up the phylogenetic relationships within the Arthrodermataceae family. However, certain closely related taxa still contain poorly resolved species boundaries. Here, we tried to elucidate the species composition of the Trichophyton benhamiae species complex using a combined approach consisting of multi-gene phylogenetic analysis based on internal transcribed spacer (ITS) and beta-tubulin (BT) gene regions, morphological analysis, and spectral comparison using MALDI-ToF. We confirmed the existence of 11 different monophyletic clades within the complex representing either species or genetically distinct groups within species. MALDI-ToF spectrometry analysis revealed that most of these clades were readily distinguishable from one another; however, some closely related sister clades, such as T. europaeum and T. japonicum, were often misidentified as their counterpart. The distinct “yellow” and “white” phenotypes of T. benhamiae do not have a clear genetic basis and should thus be considered as different morphotypes of the same species. Strains traditionally considered T. benhamiae can be divided into three main clades: (i) T. benhamiae, (ii) T. europaeum/T. japonicum, and (iii) the phylogenetically distant T. africanum. While T. europaeum and T. japonicum are distinguishable based on their genotype, spectral and morphological analysis did not provide clear delimiting characteristics. Full article

A recently identified Trichophyton rubrum major facilitator superfamily (MFS)-type transporter (TruMFS1) has been shown to give resistance to azole compounds and cycloheximide (CYH) when overexpressed in Saccharomyces cerevisiae. We investigated the roles of MFS1 in the intrinsic resistance of dermatophytes to CYH and chloramphenicol (CHL), which are commonly used to isolate these fungi, and to what extent MFS1 affects the susceptibility to azole antifungals. Susceptibility to antibiotics and azoles was tested in S. cerevisiae overexpressing MFS1 and ΔMFS1 mutants of Trichophyton benhamiae, a dermatophyte that is closely related to T. rubrum. We found that TruMFS1 functions as an efflux pump for CHL in addition to CYH and azoles in S. cerevisiae. In contrast, the growth of T. benhamiae ΔMFS1 mutants was not reduced in the presence of CYH but was severely impaired in the presence of CHL and thiamphenicol, a CHL analog. The suppression of MFS1 in T. benhamiae also increased the sensitivity of the fungus to fluconazole and miconazole. Our experiments revealed a key role of MFS1 in the resistance of dermatophytes to CHL and their high minimum inhibitory concentration for fluconazole. Suppression of MFS1 did not affect the sensitivity to CYH, suggesting that another mechanism was involved in resistance to CYH in dermatophytes. Full article

Dermatophytes are filamentous fungi with the ability to digest and grow on keratinized substrates. The ongoing improvements in fungal detection techniques give new scope for clinical implementations in laboratories and veterinary clinics, including the monitoring of the disease and carrier status. The technologically advanced methods for dermatophyte detection include molecular methods based on PCR. In this context, the aim of this study was to carry out tests on the occurrence of dermatophytes in cattle herds using qPCR methods and a comparative analysis with conventional methods. Each sample collected from ringworm cases and from asymptomatic cattle was divided into three parts and subjected to the real-time PCR technique, direct light microscopy analysis, and culture-based methods. The use of the real-time PCR technique with pan-dermatophyte primers detected the presence of dermatophytes in the sample with a 10.84% (45% vs. 34.17%) higher efficiency than direct analysis with light microscopy. Moreover, a dermatophyte culture was obtained from all samples with a positive qPCR result. In conclusion, it seems that this method can be used with success to detect dermatophytes and monitor cowsheds in ringworm cases and carriers in cattle. Full article

For about 10 years, a new variant of the pathogen Trichophyton (T.) benhamiae has appeared in Germany, characterized by a previously unobserved culture phenotype with a strong yellow reverse. A few studies suggest that this new variety is now the most common zoophilic dermatophyte in Germany. The guinea pig is the main carrier. Exact prevalence measurements are not yet available. Thus, the aim of our ongoing study was to collect data on the frequency and geographic distribution of the pathogen and its phenotypes (white and yellow) in humans and guinea pigs throughout Germany. Our former studies have already shown that animals from large breeding farms are particularly heavily affected. In contrast to this, 21 small, private breedings were sampled and husbandry conditions recorded. This placed us in a position to identify propagation factors and to give recommendations for containment. For animals from private breedings, we detected T. benhamiae with a prevalence of 55.4%, which is a reduction of nearly 40% compared with animals from large breeding farms. As risk factors, we identified the type of husbandry and the contact to other breedings. Furthermore, certain animal races, like Rex guinea pigs and races with long hair in combination with curls were predestined for colonization with T. benhamiae due to their phenotypic coat characteristics. A prevalence for infections with T. benhamiae of 36.2% has been determined for symptomatic pet guinea pigs suspected of having dermatophytosis and is comparable to the study of Kraemer et al. showing a prevalence of 34.9% in 2009 in Germany. The prevalence in humans is stable with about 2–3% comparing the data of 2010–2013 and 2018 in Thuringia. The new type of T. benhamiae was by far the most frequent cause in all settings. Full article

Dermatophytes are the most common pathogenic agents of superficial mycoses in humans and animals. Knowledge of their epidemiology can facilitate the prevention of dermatophytosis and improve prophylactic measures. We sought to determine the incidence of the different dermatophyte species diagnosed in Lausanne (Switzerland) from 2001 to 2018. In total, 10,958 dermatophytes were isolated from patients and 459 from pets. Overall, 99% of tinea unguium and tinea pedis were caused by Trichophyton rubrum and Trichophyton interdigitale with a prevalence ratio of 3:1. Trichophyton violaceum and Trichophyton soudanense were mainly found in tinea capitis in patients of African and Mediterranean origin. Interestingly, while Epidermophyton floccosum and Trichophyton verrucosum were prevalent 50 years ago in an epidemiological analysis carried out in the same laboratory from 1967 to 1970, these two species were rarely detected from 2001 to 2018. Trichophyton mentagrophytes, Trichophyton benhamiae and Microsporum canis were the prevalent zoophilic pathogenic species in children and young adults. Our investigation of animal samples revealed the main reservoirs of these zoophilic species to be cats and dogs for T. mentagrophytes and M. canis, and Guinea pigs for T. benhamiae. This study provides an epidemiological overview of dermatophytoses in Switzerland to improve their surveillance. Full article

Twelve wild North American porcupines (Erethizon dorsatum) out of a total of 44 of this species examined in an 8-year period were diagnosed with dermatopathies while being cared for at two wildlife rehabilitation clinics. Biopsy and necropsy were performed on seven and five animals, respectively. Atypical dermatophytosis was diagnosed in all cases. Lesions consisted of diffuse severe epidermal hyperkeratosis and mild hyperplasia with mild lymphoplasmacytic dermatitis and no folliculitis. Dermatophytes were noted histologically as hyphae and spores in hair shafts, and follicular and epidermal keratin. Trichophyton sp. was grown in 5/6 animals where culture was performed, with a molecular diagnosis of Arthroderma benhamiae/Trichophyton mentagrophytes in these five cases. Metagenomic analysis of formalin-fixed paraffin-embedded tissue samples from three cases identified fungi from 17 orders in phyla Basidiomycota and Ascomycota. Alteration of therapy from ketaconazole, which was unsuccessful in four out of five early cases, to terbinafine or nitraconazole led to the resolution of disease and recovery to release in four subsequent animals. In all, six animals were euthanized or died due to dermatopathy, no cases resolved spontaneously, and six cases were resolved with therapy. The work we present demonstrates an atypical lesion and anatomical distribution due to dermatophytosis in a series of free-ranging wild porcupines and the successful development of novel techniques for extracting and sequencing nucleic acids from fungus in archival formalin-fixed paraffin-embedded animal tissue. Full article