ENVIRONMENTAL ISOLATION OF Fonsecaea SPECIES.

Black yeasts are melanized ascomycetous fungi, predominantly yeast-like, present in many ecological niches and ecosystems. The species associated with human and animal species belong to the Chaetothyriales order, Herpotrichiellaceae family. Fonsecaea is an important genus involved with mycosis, such as phaeohyphomycosis and chromoblastomycosis. The phaeohyphomycosis is an infection characterized by the presence of hyphae in the host tissue, and the disease can be affected the nervous system. Chromoblastomycosis is a chronic subcutaneous mycosis characterized by the presence of muriform cells in the host tissue. The specie F. pedrosoi is the major etiological agent of human chromoblastomycosis. Other species are involved with infections in human host such as F. monophora and F. nubica and with host animal such as F. multimorphosa and F. brasiliensis. The current hypothesis of infection is that pathogenic black yeast are present in environment and the disease occur by implantation. Thus, the present study aims the isolation of Fonsecaea species in soil, decomposing plant material, leaf, stem and plant spines samples, from chromoblastomycosis endemic areas in Maranhão, northern Brazil by a selective method of flotation in mineral oil. For isolation, approximately 20g of each sample was incubated at room temperature for 30 min, in 100mL of saline solution supplemented with 200 μg/L streptomycin, 200 μg/L chloramphenicol and 500 μg/L cycloheximide. After incubation, 20 mL of sterile mineral oil was added to the solution, mixed by 5 min and followed by 20 min. in rest. The oil-water interface was collected, plated in Mycosel (Difco) and subsequently incubated for 4 weeks at 28 °C. A total of 87 samples (20 soil, 20 plant in decomposing, 20 leaf, 20 long, 7 spines) was analyzed from four regions studied, with 5 replicates per sample being used, totaling 435 replicates. The total of 175 black colonies were recovered, 5 were macro and micromorphologicaly similar to Fonsecaea-like and were identified by molecular methods as F. multimorphosa (n = 1) and F. brasiliensis (n = 4), isolated from decomposing plant material samples. The Fonsecaea species isolated in this study showed relationship with environment substrates. The fungus F. multimorphosa and F. brasiliensis are species involved with infections in animal hosts; however, no chromoblastomycosis agents were isolated in this study.