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

First Report on the Occurence of Dermatophytes of Microsporum Cookei Clade and Close Affinities to Paraphyton Cookei in the Harmanecká Cave (Veľká Fatra Mts., Slovakia)

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