Diversity of opportunistic black fungi on babassu coconut shells, a rich source of esters and hydrocarbons.

The present study assessed the diversity of black yeast-like fungi present on babassu coconut shells, a substrate rich in lipids and several volatile organic compounds (VOCs) including aromatic hydrocarbons. Using different isolation methods, one-hundred-six isolates were obtained and were identified by ITS sequencing as members of the genera Exophiala, Cladophialophora, Veronaea, and Rhinocladiella. Two novel species were discovered. Eight strains were selected for assessing their ability to grow on toluene and phenyl acetate as the sole carbon and energy source. All strains tested were able to assimilate phenyl acetate, while two out of eight were able to use toluene. VOCs profiling in babassu samples was also investigated by GC-ToF MS, revealing that a complex mixture of VOCs was emitted, which included alkylbenzenes such as toluene. Assimilation of alkylbenzenes by the black yeasts might therefore be the result of evolutionary adaptation to symbiotic interactions with higher plants. The potential relationship between lipid/aromatic hydrocarbon metabolism and pathogenicity is also discussed.

Arthrocladium, an unexpected human opportunist in Trichomeriaceae (Chaetothyriales).

The family Trichomeriaceae (Chaetothyriales) mainly comprises epiphytic and epilithic organisms. In some species elaborate ascomata are formed, but for the great majority the species no asexual conidium formation is known other than simple fragmentation of the thallus. The present paper re-establishes the genus Arthrocladium with three non-sporulating species. One of these is described for a strain causing a fatal infection in a human patient with a rare genetic immune disorder.

Molecular identification of Histoplasma capsulatum using rolling circle amplification.

Histoplasmosis is a systemic fungal disease that occurs worldwide, causing symptomatic infection mostly in immunocompromised hosts. Etiological agent is the dimorphic fungus, Histoplasma capsulatum, which occurs in soil contaminated with bird or bat droppings. Major limitation in recognition of H. capsulatum infections is the low awareness, since other diseases may have similar symptomatology. The molecular methods have gained importance because of unambiguous diagnostic ability and efficiency. The aim of this study was to develop and evaluate a padlock probe in view of rolling circle amplification (RCA) detection method which targets ITS (Internal Transcribed Spacer) rDNA of H. capsulatum enabling rapid and specific detection of the fungus in clinical samples. Two padlock probes were designed and one of these (HcPL2) allowed specific amplification of H. capsulatum DNA while no cross-reactivity was observed with fungi used as negative controls. This method proved to be effective for H. capsulatum specific identification and demonstrated to be faster than the traditional method of microbiological identification.

Fonsecaea pugnacius, a Novel Agent of Disseminated Chromoblastomycosis.

We report a fatal case of a chromoblastomycosis-like infection caused by a novel species of Fonsecaea in a 52-year-old immunocompetent Caucasian male from an area of chromoblastomycosis endemicity in Brazil. The patient had a 30-year history of slowly evolving, verrucous lesions on the right upper arm which gradually affected the entire arm, the left hemifacial area, and the nose. Subsequent dissemination to the brain was observed, which led to death of the patient. The internal transcribed spacer (ITS) and partial large subunit (LSU), BT2, and CDC42 genes of the isolates recovered from skin and brain were sequenced, confirming the novelty of the species. The species is clinically unique in causing brain abscesses secondary to chromoblastomycosis lesions despite the apparent intact immunity of the patient. Histopathologic appearances were very different, showing muriform cells in skin and hyphae in brain.