Dermkielia cavawata sp. nov. gen. nov., Isolated From Plantar Eczema

Human skin is naturally exposed to diverse fungi. New taxa, including species with unknown pathogenic potential, continue to be isolated from human skin.

To characterize a hitherto unknown hyphomycete isolated from human eczema and to assess its habitat and pathogenic abilities.

A broad panel of culture conditions was used for morphological examination and physiological testing. Nucleotide ribosomal ITS and LSU sequences were analyzed separately by BLASTn to identify the closest relatives, and a combined ITS-LSU dataset was used for phylogenetic inference.

The isolate grew well on common mycological agars at 26°C and was not inhibited by 0.4 g/L cycloheximide. Colonies were flat, with a beige obverse and sparse aerial mycelium. Intercalary, round to subglobose spores developed within the hyphae, and submerged hyphae in cultures older than 4 weeks transformed into chains of spores consistent with chlamydospores. Neither microconidia, macroconidia, nor ascomata were observed. The isolate showed urease, keratinolytic, proteolytic, lipolytic and cellulolytic activity. It grew at 5°C and tolerated up to 6% NaCl; susceptibility to terbinafine was reduced. Phylogenetically, the isolate formed a distinct lineage branching basally to Pseudogeomyces, separated from related taxa by a distance comparable to that between Geomyces and Solomyces.

Dermkielia gen. nov. (IF 905143) is introduced with Dermkielia cavawata sp. nov. (IF 905164) as the type species. Related ITS sequences in NCBI GenBank suggest that additional species of Dermkielia may be discovered. Dermkielia cavawata is presumably geophilic and possibly linked to forest ecosystems, but it possesses traits that may facilitate opportunistic colonization of human keratinized tissue.