Fonsecaea pugnacius, a Novel Agent of Disseminated Chromoblastomycosis

Abstract

fWe 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.

Molecular Epidemiology of Agents of Human Chromoblastomycosis in Brazil with the Description of Two Novel Species

“…monophora and F . pugnacius show some degree of neurotropism eventually leading to dissemination to the brain and other organs [14, 27]. …”

Chromoblastomycosis

“…1). Uncommon, recently described agents in this clade are F. nubica and F. pugnacius (38,39). Other fungi in the bantiana clade are Cladophialophora species related to C. bantiana, the main agent of primary brain infection, and several species isolated from disseminated infections but also some saprobes that are not known to be involved in human disease (40).…”

“…Earlier literature reports referred to an involvement of deep organic sites such as brain and lungs as CBM, but such cases should be considered PHM (241)(242)(243). CBM affects mainly the skin and the subcutaneous tissue; dissemination to deeper organs is extremely rare (39,244). Several species of the Herpotrichiellaceae are related to the etiology of CBM, but no link with a specific type of lesion or mild to severe grades of this disease has been associated with any etiological agent.…”

“…The taxonomy of Fonsecaea was revised previously by de Hoog et al (41) and Najafzadeh et al (57). New species such as F. nubica and F. pugnacius were identified with sequences of the ITS and cdc42, BT2, and ACT1 genes, eventually supplemented with amplified fragment length polymorphism (AFLP) profiles (38,39). Pathogenic species of Fonsecaea present optimum development at 33°C, with a thermotolerance of growth at 37°C.…”

“…Fonsecaea monophora and F. pugnacius show significant neurotropism, eventually leading to dissemination to the brain and other organs (38,39,41) or causing primary brain infection without skin lesions, which are clinical forms of PHM, because no muriform cells are seen in tissues (40,67). All species of Fonsecaea have felt-like, gray-olivaceous colonies.…”