Search Results (16)

Dermatophytes are keratinophilic fungi that cause a wide range of superficial infections in humans and animals. The Trichophyton mentagrophytes species complex is one of the most clinically important groups due to its broad host range, widespread distribution, and increasing involvement in antifungal-resistant infections. Here, we described the epidemiology of T. mentagrophytes over a period of 4 years detected in the northeastern part of Italy and provided the genomic characterization of clinical isolates. ITS sequence analysis revealed that among the 13 strains studied, 11 belonged to the T. mentagrophytes complex. In detail, nine were classified as genotype I/II and two as genotype VII. Analysis of the SQLE gene revealed that nine strains harbored a wild-type gene, while two carried a Lys276Asn mutation. Genomic analysis was performed on three clinical T. mentagrophytes strains that belonged to genotype I/II, revealing the presence of different virulence factors including MEP-1, MEP-2, MEP-3, and MEP-5. Phylogenetic analysis based on core-genome SNPs demonstrated that the two genomes included in this study were clonally related to a T. mentagrophytes strain isolated in China in 2024. In conclusion, our study highlights the importance of genomic characterization in order to trace the epidemiology of dermatophytes worldwide and to characterize emerging strains. Full article

Equine skin mycoses are a significant concern in Kazakhstan’s livestock industry due to the country’s historical livestock farming practices, the development of equestrian sports, and food traditions. Skin infections are among the most common fungal infections in horses. Emerging pathogens of equine dermatophytosis include keratinophilic Chrysosporium spp., which can degrade and metabolize keratin found in superficial tissues. This, combined with their thermotolerance, contributes to their pathogenicity. In this study, we investigated the biological properties and pathogenicity of two Chrysosporium strains isolated from equine skin lesions in northern and central Kazakhstan. Our findings showed that the Chrysosporium isolates caused a variety of clinically expressed skin lesions and exhibited cultural and morphological similarities to Trichophyton mentagrophytes. Genetic identification using ribosomal gene sequencing revealed 98.9% identity with Chrysosporium kreiselii and Chrysosporium zonatum sequences in both cases. The C. kreiselii strain caused pronounced skin lesions typical of classic dermatomycoses, demonstrated both keratinophilic and keratinolytic properties, and showed resistance to antifungal drugs. In contrast, the C. zonatum strain, which caused atypical lesions such as dandruff and seborrhea, was more sensitive to antifungal agents and exhibited keratinophilic properties. Our results highlight the emergence of new pathogenic Chrysosporium strains responsible for skin pathology in horses in Kazakhstan. We recommend that the identification of Chrysosporium skin infections in horses in Kazakhstan be followed by a comprehensive retrospective analysis of newly identified pathogens, including a full characterization of their pathogenicity. Full article

Dermatophytes are widely distributed in the environment, with an estimated prevalence of 20–25% of the the global population yearly. These fungi are keratinophilic and keratinolytic and cause the infection of keratin-rich structures such as skin, hair, and nails. The pattern of this infectious disease covers a wide spectrum from exposed individuals without symptoms to those with acutely inflammatory or non-inflammatory, chronic to invasive, and even life-threatening symptoms. This review summarizes current information on the pathogenicity, virulence factors, and drug resistance mechanisms associated with dermatophytes. A greater number of virulence factors of these fungi are important for the occurrence of infection and the changes that occur, including those regarding adhesins, the sulfite efflux pump, and proteolytic enzymes. Other virulence factors include mechanisms of evading the host defense, while the development of resistance to antifungal drugs is increasing, resulting in treatment failure. The investigation of host-pathogen interactions is essential for developing a more complete understanding of the mechanisms underlying dermatophyte pathogenesis and host response to inform the use of diagnostics methods and antifungal therapeutics to minimize the high fungal burden caused by dermatophytes and to control the spread of resistance. Full article

Due to the falling water level in the Aral Sea and Muynak Lake, the content of salts dissolved in the water has gradually increased, and toxic elements have been deposited at the lake’s bottom and subsequently washed into the Aral region by the river. Bacteria, archaea and fungi are crucial for the cycling of several important inorganic nutrients in soils. From 15 genera and 31 species of recovered microscopic filamentous fungi, a big group was melanized, of which most of them were also phytopathogenic. The second group consisted of keratinophilic species. Isolated bacteria mainly included members of the genera Arthrobacter, Bacillus, Massilia, Rhodococcus and Nocardiopsis. High-throughput sequencing analysis permitted a better view of the mycobiome and prokaryotic communities (comprising archaea). The cultivation and sequencing approaches were shown to be complementary. The aim of the work was to identify soil microorganisms, including the order Halobacteriales, and to discover the differences in species diversity depending on soil salinity and the presence of PTEs in soil. Full article

In this study, we identified culturable microscopic fungi in soil from areas frequented by people (parks, allotments, and other green areas) in the city of Wrocław (Poland). In addition to general species analysis, attention was focused on keratin-degrading fungi. From 60 soil samples (12 study sites), we obtained 75 isolates of keratinophilic and keratinolytic fungi using the hair bait method, and 54 isolates of fungi were isolated on PDA (Potato Dextrose Agar) medium. Based on morphological and molecular analyses, a total of 37 strains were identified, classified into 2 phyla, 11 families, 17 genera, and 30 filamentous species. The mean values of the Shannon Diversity Index for both experimental variants ranged from 0.074 to 0.117. The most common species was the Penicillium genus, which accounted for 33.33% of all fungal species obtained in these studies. These fungi are common in both indoor and outdoor environments. However, particularly noteworthy in this study are the species belonging to the group of dermatophytes (Arthroderma uncinatum, Keratinophyton wagnerii, Nannizzia gypsea, and Paraphyton cookei), which may pose a real biological threat to humans and animals due to their well-known potential to cause dermatomycosis. Full article

Dermatophytes are the group of keratinophilic fungi that cause superficial cutaneous infection, which traditionally belong to the genera Trichophyton, Microsporum, and Epidermophyton. Dermatophyte infection is not only a threat to the health of small animals, but also an important zoonotic and public health issue because of the potential transmission from animals to humans. Rabbit dermatophytosis is often clinically identified; however, limited information was found in Asia. The aims of this study are to investigate the prevalence and to evaluate the risk factors of dermatophytosis in pet rabbits in Northern Taiwan. Between March 2016 and October 2018, dander samples of pet rabbits were collected for fungal infection examination by Wood’s lamp, microscopic examination (KOH preparation), fungal culture, and PCR assay (molecular identification). Z test and Fisher’s exact test were performed to evaluate the potential risk factors, and logistic regression analysis was then performed to build the model of risk factors related to dermatophyte infection. Of the collected 250 dander samples of pet rabbits, 29 (11.6%) samples were positive for dermatophytes by molecular identification. In those samples, 28 samples were identified as the T. mentagrophytes complex and 1 sample was identified as M. canis. Based on the results of the Firth’s bias reduction logistic analyses, animal source (rabbits purchased from pet shops) and number of rearing rabbits (three rabbits or more) were shown as the main risks for dermatophyte infection in the pet rabbits in Taiwan. The results of the present study elucidate the prevalence of rabbit dermatophyte infection, pathogens, and risk factors in Taiwan, and provide an important reference for the prevention and control of rabbit dermatophytosis. Full article

Fungi that decompose keratinized animal remains are an important component of the arable soil microbiome. The aim of the study is to characterize the communities of keratinophilic and co-inhabiting (non-keratinophilic) fungi in four cultivated soils that differ in physico-chemical properties, with particular emphasis on granulometric fractions, which have so far been omitted from studies concerning the ecology of these micromycetes. Fungi were isolated using the keratin-baiting method. Fungal species identification was carried out on the basis of their macro- and micromorphological features. The Simpson diversity index and Marczewski–Steinhaus similarity index were calculated for precise determination of the relationships between fungal communities. In the studied soils, Trichophyton ajelloi and Ctenomyces serratus dominated among keratinophilic fungi, while Purpureocillium lilacinum and Metacordyceps chlamydosporia, from the orders Eurotiales and Hypocreales, were dominant among non-keratinophilic fungi. The frequency of keratinophilic fungi was significantly positively correlated with pH and the content of two granulometric fractions, as opposed to non-keratinophilic fungi. This was reflected in the higher growth rates of keratinomycetes in loamy soil, chernozem, and rendzina, i.e., soils with a higher content of silt and clay fractions compared to sandy soil characterized by a high content of sand fractions. The species composition of both groups of fungi was most similar between loamy soil and chernozem, whereas the greatest differences were found for sandy soil and rendzina. Chernozem was characterized by the highest diversity of fungal species from both groups of fungi. The study, in addition to providing information about ecological factors, provided a collection of keratinomycete strains that can be used as a starting material for subsequent research stages regarding keratinolytic activity of these fungi and their potential use in agricultural practices. Full article

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. 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

Although keratinophilic fungi on avian feathers have been widely described, data from European literature are quite lacking regarding Mediterranean countries. The aim of the present study was therefore to evaluate the occurrence of fungal species on feathers of different avian species in Italy. A total of 378 feather samples from both aquatic (n = 254) and terrestrial birds (n = 124), for a total of 30 bird species, were cultured for keratinophilic fungi. Fungal isolates were recognized by their macro- and micro-scopical morphology, and results were corroborated by PCR and sequencing. Keratinophilic fungi belonging to 11 different species (Scopulariopsis brevicaulis, Chrysosporium keratinophilum, Trichophyton terrestre, Microsporum gypseum, Sepedonium sp., Chrysosporium pannorum, Myriodontium sp., Chrysosporium tropicum, Chrysosporium pruinosum, Chrysosporium luteum and Aphanoascus fulvescens) were isolated from 71 animals (18.8%). The frequency of isolation of keratinophilic species from terrestrial birds was significantly higher in waterfowl. Migratory birds in Italy have been proven to carry pathogenic fungi such as dermatophytes, (A. platyrhyncos, A. crecca, E. rubecula), besides saprophytic species. Full article

Off-leash dog parks are designated public spaces where dogs can move freely, under their owners’ supervision. These areas, allowing animals to socialize and move freely, are fundamental for dogs’ welfare. However, different pathogens, even zoonotic, may be excreted by the attending animals and contaminate the environment. The aim of the present study was to verify the occurrence of bacterial, fungal and parasitic pathogens in off-leash dog parks located in Florence (central Italy). Between March and May 2019, 83 fecal samples, 43 soil samples and 23 water samples (from fountains and puddles) collected from 26 off-leash fenced areas were examined. Fecal samples scored positive for Yersinia spp. (n = 7), Listeria innocua (n = 4), Toxocara canis eggs (n = 2) and Ancylostoma caninum/Uncinaria stenocephala eggs (n = 1). Keratinophilic geophilic fungi (mostly Microsporum gypseum /A. incurvatum) were recovered from 43 soil samples belonging to 23 out of 26 parks, along with Microsporum canis in a single case. Prototheca spp. was never isolated from water samples, while Trichosporon sp. was cultured in two cases, alone and in association with Geotrichum candidum. These results show that dogs did not act as important carriers for the investigated bacterial and parasitic pathogens, although examined areas may represent a risk for the spreading of some dermatophytoses to both pets and their owners. Periodical examinations to assess the main bacteriological, parasitological and mycological pathogens in different samples collected in off-leash dog parks should be carried out in a One-Health perspective. Full article

Dermatophytes are filamentous keratinophilic fungi which affect nails, skin, and hair. Their variable distribution in the world justifies local epidemiological studies. During recent decades, few studies have been published regarding the epidemiology and etiology of dermatophytosis in Romania. The aim of this study was to identify the dermatophytes isolated from superficial fungal infections. To the best of our knowledge, this is the first such study conducted in the area of North-Western Romania. Over the past four years, samples collected from outpatients with suggestive lesions for dermatophytoses (nails, skin, hair), who addressed several private practice dermatologists from Cluj-Napoca, Romania, were sent to a specialized laboratory and examined by microscopy and culture. A total of 350 samples from 322 patients were examined. One hundred samples (28.6%) collected from 90 patients (27.9%) were positive by direct microscopy and/or culture. Among the 63 positive cultures (18%), 44 dermatophytes (69.8%), 2 molds (3.2%), and 17 yeasts (27%) were isolated. The main dermatophyte species identified were Trichophyton rubrum (mostly from onychomycosis) and Microsporum canis (from tinea capitis and tinea corporis in children). Yeasts (Candida species) were isolated from nails, especially from women. Full article

Keratinolytic and keratinophilic fungi, such as dermatophytes, are frequently a cause of infections in humans and animals. Underground ecosystems are inhabited by various animals and are of interest for tourists. Therefore, the main goal of our research was the first evaluation of sediment and soil samples taken inside and outside the Harmanecká Cave in Slovakia for the occurrence of keratinolytic and keratinophilic fungi. Tests with Vanbreuseghema bait, as well as phenotyping and molecular methods, showed that all of the sampling sites contained ten isolates, all of the same species of keratinophilic fungi, belonging to the Microsporum cookei clade and with close affinities to Paraphyton cookei (Ajello) Y. Gräser, Dukik & de Hoog. Our research showed that, dependent on the medium, its mycelium varied in color and showed different growth rates. It also produced metabolites alkalizing DTM (dermatophyte test medium) medium. It dissolved keratin in in vitro hair perforation tests and was able to utilize most substrates in the API® 20C AUX, except for MDG (α-methyl-D-glucoside). In addition, the vegetative structures of mycelium were viable after storage at temperatures from −72 to −5 °C for 56 days, and actively grew after 28 days at a temperature range from 15 to 37 °C, with 25 °C being optimal. It showed weak, but active, growth at 5 and 10 °C after 56 days. We can assume that due to the low temperature in the caves, this fungus will not be able to actively grow rapidly on keratin substrates, but the contact with mammals, along with other favorable factors, might lead to an infection. Full article

Dermatophytes are keratinophilic fungi responsible for benign and common forms of infection worldwide. However, they can lead to rare and severe diseases in immunocompromised patients. Severe forms include extensive and/or invasive dermatophytosis, i.e., deep dermatophytosis and Majocchi’s granuloma. They are reported in immunocompromised hosts with primary (autosomal recessive CARD9 deficiency) or acquired (solid organ transplantation, autoimmune diseases requiring immunosuppressive treatments, HIV infection) immunodeficiencies. The clinical manifestations of the infection are not specific. Lymph node and organ involvement may also occur. Diagnosis requires both mycological and histological findings. There is no consensus on treatment. Systemic antifungal agents such as terbinafine and azoles (itraconazole or posaconazole) are effective. However, long-term outcome and treatment management depend on the site and extent of the infection and the nature of the underlying immunodeficiency. Full article

The parks of Mumbai are frequently visited by local residents every morning and evening. However, there are no reports on the occurrence of keratinophilic fungi in these areas. The purpose of this research was to study the occurrence of keratinophilic fungi in the public parks of Mumbai. One hundred soil samples were collected from five public parks: Kamla Nehru Park, Powai Garden, CD Deshmukh Garden, Five Gardens and Chota Kashmir. Keratinophilic fungi were isolated by the hair baiting technique using human hair as keratin bait. The cultures were identified using macroand micro-morphological features. Identification was also confirmed by the BLAST search of sequences of the ITS1-5.8S-ITS2 rDNA region against the NCBI/Genbank data and compared with deposited sequences. The ability of these fungi to use human hair was also evaluated by release of protein in liquid media. A total of 75 strains of keratinophilic fungi were recovered from 100 (75.0%) soil samples. The isolated fungi were composed of eleven species of eight genera: Arthrographis kalrae, Auxarthron conjugatum, Chrysosporium indicum, C. queenslandicum, C. zonatum, Gymnascella dankaliensis, G. hyalinospora, Microsporum gypseum (15.0%), Myriodontium keratinophilum, Trichophyton mentagrophytes and Uncinocarpus reesii. These fungi can release 148.8-307.6 μg/mL protein in liquid media when grown on human hair in shake flask culture and also decompose 16.2-38.6% of human hair after four weeks of incubation. Our study indicates that keratinophilic fungi are to be found in the soils of various public parks in Mumbai and that human hair can be a source of pathogenic fungi. Full article