Melanized fungi and black yeasts in the family Herpotrichiellaceae (order chaetothyriales) are important agents of human and animal infectious diseases such as chromoblastomycosis and phaeohyphomycosis. the oligotrophic nature of these fungi enables them to survive in adverse environments where common saprobes are absent. Due to their slow growth, they lose competition with common saprobes, and therefore isolation studies yielded low frequencies of clinically relevant species in environmental habitats from which humans are thought to be infected. this problem can be solved with metagenomic techniques which allow recognition of microorganisms independent from culture. the present study aimed to identify species of the family Herpotrichiellaceae that are known to occur in Brazil by the use of molecular markers to screen public environmental metagenomic datasets from Brazil available in the Sequence Read Archive (SRA). Species characterization was performed with the BLASt comparison of previously described barcodes and padlock probe sequences. A total of 18,329 sequences was collected comprising the genera Cladophialophora, Exophiala, Fonsecaea, Rhinocladiella and Veronaea, with a focus on species related to the chromoblastomycosis. the data obtained in this study demonstrated presence of these opportunists in the investigated datasets. the used techniques contribute to our understanding of environmental occurrence and epidemiology of black fungi. A large number of species of black yeast-like fungi that belong to the ascomycetous order Chaetothyriales in the family Herpotrichiellaceae are renowned as opportunistic pathogens in immunocompetent vertebrate hosts 1,2. Agents are particularly involved in subcutaneous, and systemic or disseminated infections, known as chromoblastomycosis and phaeohyphomycosis, respectively 2-4. These infections are invariably chronic and can be severely mutilating or even fatal. Chromoblastomycosis is a relatively common disease in rural tropical climate zones around the world. This implantation disorder is characterized by the presence of a specialized tissue form of the fungus known as the muriform cell 2,5,6. Infection is hypothesized to take place via traumatic inoculation of environmental material such as plant thorns and/or wood fragments 7,8. Epidemiological data confirmed by studies using selective

The black yeast-like fungus Arthrocladium fulminans is known from strains that cause severe and eventually fatal disseminated infections in immunocompromised patients. Given the dramatic outcome of this clinical case, it is essential to understand the virulence potential of this species. The fungus is a member of the family Trichomeriaceae, at some phylogenetic distance from the Herpotrichiellaceae where most infectious fungi in the order Chaetothyriales are located. Main ecological preferences among Trichomeriaceae include colonization of exposed inert surfaces. Currently, black yeasts genomes that are available in public databases cover members of the families Herpotrichiellaceae and Cyphellophoraceae. In the present report, we sequenced the genome of the first member and only clinical representative of the family Trichomeriaceae.

A draft genome sequence of type strain Fonsecaea multimorphosa CBS 980.96T was obtained. This species was first isolated from a cat with cerebral phaeohyphomycosis in Queensland, Australia.

Chromoblastomycosis is a chronic, cutaneous or subcutaneous mycosis characterized by the presence of muriform cells in host tissue. Implantation disease is caused by melanized fungi related to black yeasts, which, in humid tropical climates, are mainly members of the genus Fonsecaea. In endemic areas of Brazil, F. pedrosoi and F. monophora are the prevalent species. The current hypothesis of infection is traumatic introduction via plant materials, especially by plant thorns. However, isolation studies have demonstrated a low frequency of the agents in environmental substrates. The present study aimed to detect F. pedrosoi and F. monophora in shells of babassu coconuts, soil, plant debris, and thorns from endemic areas of chromoblastomycosis in Maranhão state, northern Brazil, using Rolling Circle Amplification (RCA) with padlock probes as a new environmental screening tool for agents of chromoblastomycosis. In addition to molecular screening, the environmental samples were analyzed by fungal isolation using mineral oil flotation. The limit of detection of the RCA method was 2.88 × 107 copies of DNA per sample for the used padlock probes, indicating that this represents an efficient and sensitive molecular tool for the environmental screening of Fonsecaea agents. In contrast, with isolation from the same samples using several selective methods, no agents of chromoblastomycosis were recovered.

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