Cerebriform colonies of Paracoccidioides brasiliensis isolated from nine-banded armadillos (Dasypus novemcinctus) at room temperature

Paracoccin distribution supports its role in Paracoccidioides brasiliensis growth and dimorphic transformation

Paracoccidioides brasiliensis yeast was reported to express paracoccin, a GlcNAc-binding protein that displays N-acetyl-β-d-glucosaminidase (NAGase) activity. Highly specific anti-paracoccin antibodies have been previously used to examine the localization of paracoccin in yeast and inhibit its growth in vitro. In the present study, anti-paracoccin antibodies were used to characterize, by scanning confocal microscopy, the distribution of paracoccin in P. brasiliensis hyphae, transition forms from hyphae to yeast, and mature yeast. In the mycelial phase, paracoccin was detected mainly in the hyphae tips, where it demonstrated a punctate distribution, and was associated with the cell wall. During the first 48 hours after a temperature shift from 26°C to 37°C, paracoccin expression in the differentiating hyphae was mainly detected in the budding regions, i.e. lateral protrusions, and inside the new daughter cells. There was an increased number of chlamydoconidia that expressed a high concentration of paracoccin on their surfaces and/or in their interiors 72–96 hours after the temperature shift. After 120 hours, yeast cells were the predominant form and their cytoplasm stained extensively for paracoccin, whereas Wheat Germ Agglutinin (WGA) staining was predominant on their exterior walls. After 10 days at 37°C, the interior of both mother and daughter yeast cells, as well as the budding regions, stained intensely for paracoccin. The comparison of mRNA-expression in the different fungal forms showed that PCN transcripts, although detected in all evaluated morphological forms, were higher in hypha and yeast-to-hypha transition forms. In conclusion, the pattern of paracoccin distribution in all P. brasiliensis morphotypes supports prevalent beliefs that it plays important roles in fungal growth and dimorphic transformation.

Trichosporon asteroides Isolated from Cutaneous Lesions of a Suspected Case of "paracoccidioidomycosis ceti" in a Bottlenose Dolphin (Tursiops truncatus)

"Paracoccidioidomycosis ceti" is a rare zoonotic fungal infection affecting dolphins and is endemic worldwide. The causative agents are Paracoccidioides species; however, it is impossible to isolate the fungal species. We isolated Trichosporon asteroides from multifocal, irregularly raised skin lesions on a female bottlenose dolphin (Tursiops truncatus) captured off coast of Japan, which was suspected to have "paracoccidioidomycosis ceti." An abundance of round, yeast-like cells was detected in a potassium hydroxide direct-mount specimen of the skin samples; however, nested PCR targeting the partial sequence of 43-kDa glycoprotein-coding gene correspondent to Paracoccidioides sp. was negative. Biopsied tissue samples were cultured on brain heart infusion agar plates supplemented with chloramphenicol, 1% yeast extract, and 4% sodium chloride (4% NaCl-BHI), on Mycosel agar with 4% sodium chloride (4% NaCl-Mycosel), and on potato dextrose agar supplemented with chloramphenicol (CPDA) at 35 °C for 4 weeks. Cream-colored and wrinkled colonies consisting of hyphae and arthroconidia grew on 4% NaCl-BHI and CPDA, while film-like colonies composed of arthroconidia and round yeast-like cells developed on 4% NaCl-Mycosel. Although these primary cultures resembled fresh isolates of P. brasiliensis, they were identified as Trichosporon asteroides based on routine mycological studies and the internal transcribed spacer regions of ribosomal RNA sequences. The results suggested that trichosporonosis caused by T. asteroides might remain latent among cases of "paracoccidioidomycosis ceti" diagnosed without cultures and molecular biological analysis.

The ceja-1 sequence as a potential new molecular marker for Paracoccidioides brasiliensis infection

We have developed a two-step PCR assay that amplifies a region of the ceja-1 sequence that is specific for virulent strains of Paracoccidioides brasiliensis. An internal region of the ceja-1 sequence was chosen for designing primers that were utilised in a single tube heminested PCR protocol to amplify DNA from six virulent strains. PCR specificity was determined by the absence of amplified products with genomic DNA from four non-virulent strains of P. brasiliensis and from eight fungal pathogens, one bacterium, two protozoa, one worm and mouse and human genomic DNA (leucocytes). The fact that the PCR product was only obtained with the genetic material from virulent isolates of P. brasiliensis suggested that this partial amplified sequence might be a marker of virulence for this fungus. The diagnostic potential of this PCR was confirmed by the successful amplification of this fragment with genomic DNA obtained in lymph node aspirate from a patient with paracoccidioidomycosis.

Tropical dermatology: fungal tropical diseases

Fungal infections are common in tropical countries and can have an important impact on public health. Lobomycosis is a common fungal infection in the tropical rain forest of South America, and paracoccidioidomycosis (South American blastomycosis) is a widespread and sometimes severe illness. Penicilliosis marneffei is an opportunistic infection of AIDS patients in southeast Asia. Chromoblastomycosis and mycetomas are causes of morbidity around the world. Sporotrichosis is a worldwide subcutaneous mycosis with a high incidence in tropical countries and is an important illness in immunocompromised patients. Rhinosporidiosis was classed as a fungal infection but is now considered a protistan parasite that belongs to the class Mesomycetozoea. It is included in this review because of its historical classification. In the past, most of these mycoses were restricted to specific geographic areas and natural reservoirs. There are, however, situations in which people from other regions come in contact with the pathogen. A common situation involves an accidental contamination of a traveler or worker who has contact with a tropical mycosis. Even minor trauma to the skin surface or inhalation of the fungal conidia can infect the patient. Thus recognition of the clinical symptoms and the dermatologic findings of the diseases, as well as the geographic distribution of the pathogens, can be critical in diagnosis of the tropical mycoses. This review discusses some of the more common tropical subcutaneous and systemic mycoses, as well as their signs, symptoms, methods of diagnosis, and therapies.

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be able to recognize the clinical and histologic presentations of tropical fungal diseases with cutaneous manifestations and be familiar with the appropriate therapies.

Morphological, Biochemical and Molecular Approaches for Comparing Typical and Atypical Paracoccidioides brasiliensis Strains

We evaluated the morphology of typical and atypical Paracoccidioides brasiliensis strains and the expression of its 43 kDa glycoprotein (GP43). Strains of P. brasiliensis preserved under mineral oil for long periods of time presented different morphological patterns on peptone, yeast-extract and glucose (PYG) agar. The intravenous inoculation in BALB/c mice confirmed that a strain bearing morphological alterations was non-virulent. In contrast, another strain also maintained under mineral oil but which did not exhibit such morphological dysfunction was as virulent as the well characterized Pb 339 and Pb 18 strains. The expression of the main antigen expressed by P. brasiliensis, GP43, was assessed in culture filtrates by western immunoblots. Typical and atypical strains were capable of secreting the glycoprotein, except strain Pb IOC 1059. The identity of the atypical strains was confirmed by PCR using specific primers for gp43, though the single PCR-fragment varied in size for the atypical strains. The PCR fragments from an atypical strain, Pb IOC 1210, and the typical Pb 339 and Pb IOC 3698 strains were sequenced and blasted to the gp43 gene from the Pb 18 strain (GenBank AY005429). These results ensured the identity of the atypical strains as P. brasiliensis, and suggested a relationship between the alteration of morphological differentiation and the virulence factor following storage under mineral oil.

Analysis of the genetic polymorphism of Paracoccidioides brasiliensis and Paracoccidioides cerebriformis "Moore" by random amplified polymorphic DNA (RAPD) and 28S ribosomal DNA sequencing--Paracoccidioides cerebriformis revisited

Our purpose was to compare the genetic polymorphism of six samples of P. brasiliensis (113, 339, BAT, T1F1, T3B6, T5LN1), with four samples of P. cerebriformis (735, 741, 750, 361) from the Mycological Laboratory of the Instituto de Medicina Tropical de São Paulo, using Random Amplified Polymorphic DNA Analysis (RAPD). RAPD profiles clearly segregated P. brasiliensis and P. cerebriformis isolates. However, the variation on band patterns among P. cerebriformis isolates was high. Sequencing of the 28S rDNA gene showed nucleotide conservancy among P. cerebriformis isolates, providing basis for taxonomical grouping, and disclosing high divergence to P. brasiliensis supporting that they are in fact two distinct species. Moreover, DNA sequence suggests that P. cerebriformis belongs in fact to the Aspergillus genus.

Canine paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is a severe disease caused by the dimorphic fungus Paracoccidioides brasiliensis, which is characterized by granulomatous pulmonary and systemic lesions, affecting mainly men between 20 and 60 years of age. Reports of PCM disease in animals are rare, but the disease has been described in armadillos. On the other hand, PCM infection of domestic and wild animals detected by serological or cutaneous tests in the absence of apparent disease has been frequently reported. We present here the case of a female adult Doberman that developed cervical lymphadenomegaly. Histopathological examination of a cervical biopsy specimen revealed active PCM, with an epithelioid, granulomatous inflammation containing numerous yeast-like, multiple budding fungal forms. The diagnosis of PCM was confirmed by immunohistochemistry using a specific antibody anti-gp43 and by nested PCR using primers for the amplification of the gp43 gene region. This is the first report of PCM disease occurring in a dog, an animal that has been shown to play an important role in the natural history of North American blastomycosis.