Experimental murine chromoblastomycosis obtained from Fonsecaea pedrosoi isolate cultured for a long periodt

Abstract

ABSTRACT:The present study aimed to describe F. pedrosoi propagules capable of causing chronic murine disease. Several changes in F. pedrosoi hyphae were identified in fungal cells cultured for a long period. Optical microscopy found many rounded cells with double-rigid melanin-rich walls. Terminal and intercalary chlamydoconidia were also frequently observed. Analyses of images from transmission electron microscopy (TEM) revealed several cells with walls composed of at least three layers and an outer layer enriched with melanin. Two groups of twenty BALB/c mice were subcutaneously infected in their footpads with F. pedrosoi cells at an inoculum concentration of approximately 1 x 10 4 cells/mL. In one group, long-term cultured F. pedrosoi cells were inoculated in one footpad, whereas in the other group, both footpads were infected. Active lesions were observed up to seven months post-infection, particularly in mice inoculated at two sites. After this period, animals were killed. Histological sections revealed characteristics bearing a strong resemblance to the human form of the disease such as tissue hyperplasia, granulomas with microabscesses and sclerotic cells. Based on this study, we identified fungal cells from old cultures capable of provoking chronic chromoblastomycosis under experimental conditions, especially when more than one site is infected.

Mycotic Rhinitis and Sinusitis in Florida Horses

“…11 C. bantiana is a common cause of cerebral phaeohyphomycosis in man and has been associated with infections in animals including endometritis in horses. 22 The pigmented chlamydoconidia in and surrounded by multinucleated macrophages resembled sclerotic bodies described in human chromoblastosis 3,17,23 except that only single-plane septation was found in the chlamydoconidia present in the equine rhinitis case.…”

“…For organisms for which PCR and DNA sequencing permitted identification of the genus or genus and species, specific structure names from the literature were used, including chlamydospores, chlamydoconidia, conidia, and conidial chains. 16,17,21,23,26,33…”

“…For organisms for which PCR and DNA sequencing permitted identification of the genus or genus and species, specific structure names from the literature were used, including chlamydospores, chlamydoconidia, conidia, and conidial chains. 16,17,21,23,26,33 PCR and DNA sequencing. Paraffin blocks were sectioned, and DNA was extracted from sections with a Qiagen formalin-fixed and paraffin-embedded (FFPE) QIAmp DNA extraction kit (Qiagen GmbH, Hilden, Germany) according to kit directions as described.…”

Reviewing the Etiologic Agents, Microbe-Host Relationship, Immune Response, Diagnosis, and Treatment in Chromoblastomycosis

“…However, some works standardized more stable experimental models of CBM that lasted at least six months. One of this study showed that F. pedrosoi cultured for a long period in vitro induced chronic lesions in BALB/c mice [214], although this study is important to the field, the production or standardization of an old colony may represent an obstacle to reproduce this experimental model. On the other hand, a progressive model of CBM was induced in athymic mice [215] and CD8 knockout mice [216]; although these models can be useful to depict the process of infection and differentiation of hyphae or conidia into muriform cells in vivo, as well as the development of new drugs, it may not be an interesting model to study the cellular immune response, as well as the potential of immunomodulatory drugs or vaccines in CBM.…”