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

Molecular and phenotypic reidentification of Sporothrix schenckii clinical isolates preserved under mineral oil for 34 to 64 years in a culture collection in Brazil

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Impact of mineral oil as a method of preservation on clinical isolates of Sporothrix schenckii.

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Sporothrix spp sporulation induction using a culture medium supplemented with rose bush branches.

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Usefulness of polyphasic methodology in the re-identification of species of Sporothrix schenckii complex.

Sporotrichosis is a subcutaneous mycosis worldwide distributed reaching hyperendemic proportions in Brazil. Many isolates from patients with sporotrichosis are preserved in culture collections by different methods around the world. The preservation methods are used to maintain the viability and the morphophysiological and genetic characteristics of isolates for long periods. In this study, we evaluated 34 isolates, previously, identified as S. schenckii by a classical identification method, initially preserved by periodical subcultures and then under mineral oil at culture collection of Oswaldo Cruz Institute/Fiocruz, to re-identify them by polyphasic identification. Our results showed that seven isolates remained viable for 34 to 64 years under oil, one isolate lost the ability to sporulate which was reverted by using a medium culture supplemented with rosebush branches and all of them were identified as Sporothrix schenckii sensu stricto by morphological, physiological, partial β-tubulin gene sequencing and phylogenetic analysis.

Experimental Hyalohyphomycosis by Purpureocillium lilacinum: Outcome of the Infection in C57BL/6 Murine Models

Purpureocillium lilacinum is a filamentous, hyaline fungus considered an emerging pathogen in humans. The aim of our study was to evaluate the outcome of hyalohyphomycosis in C57BL/6 murine models inoculated with two clinical P. lilacinum isolates (S1 and S2). Each isolate was inoculated in mice randomly distributed in immunocompetent (CPT) and immunosuppressed (SPS) groups. Mice were evaluated at day 7, 21, and 45 after inoculation for histopathological analysis, recovery of fungal cells, and immunological studies. Histological analysis showed scarce conidia-like structures in lung tissue from CPT mice and a lot of fungal cells in SPS mice inoculated with S2 compared to mice inoculated with S1. The maximum recovery of fungal cells was seen in CPT mice inoculated with both isolates at day 7, but with mean significantly higher in those inoculated with S2 isolate. Phenotypical characterization of T cells showed TCD8⁺ lymphocytes predominance over TCD4⁺ in immunosuppressed mice infected and control groups. We also observed higher percentages of the central and effector memory/effector phenotype in CPT mice infected with S2 strain, especially in TCD8⁺ in the initial period of infection. Regulatory T cells showed higher percentages in immunosuppressed, predominantly after the acute phase. Our results showed that the P. lilacinum is a fungus capable to cause damages in competent and immunosuppressed experimental hosts. Furthermore, S2 isolate seems to cause more damage to the experimental host and it was possible to identify different cellular subsets involved in the mice immune response.

M2 macrophages and inflammatory cells in oral lesions of chronic paracoccidioidomycosis

BACKGROUND

Paracoccidioidomycosis (PCM) is a systemic fungal infection caused by Paracoccidioides brasiliensis (Pb) and associated with deficient cellular immune response, which is modulated by inflammatory cells, mainly macrophages, and cytokines. Recently, the comprehension of the macrophage polarization mediated by Th1 and Th2 cytokines has contributed to elucidate the immune response that takes part in some diseases. Thus, the aim of this study was to assess the presence of Th1- and Th2-immune response and also Pb counting in oral lesions of chronic PCM.

METHODS

Forty-eight cases of chronic PCM oral lesions were included. All cases were classified as loose or dense granulomas. S100 protein, IL-1β, IL-6, TNF-α, CD163 and CD68 immunoexpressions, and Pb localization were evaluated. The fungi present in the tissue were quantified by anti-Pb antibody.

RESULTS

Most patients were white men with mean age of 47 years old and showed higher incidence of multiple lesions. Loose granulomas were predominant and exhibited a great amount of M2 macrophages, which were visualized with anti-CD163 antibody. The expression for CD163 and CD68 was similar (P = 0.05), highlighting the predominance of M2 macrophages in PCM. IL-1β, IL-6, and TNF-α immunoexpression did not significantly change with CD163, CD68, and S100 protein. The number of fungi was significantly higher in cases with intense IL-1β immunoexpression (P = 0.003).

CONCLUSIONS

M2-activated macrophages were the majority among inflammatory cells in chronic PCM, characterizing the action of a Th2-immune response. Nevertheless, Th1 cytokines were also found; mainly IL-1β, which was associated with fungi counting in oral lesions.

Detection of antibody to Purpureocillium lilacinum by immunofluorescent assay and flow cytometry in serum of infected C57BL/6 mice

Purpureocillium lilacinum is an emerging pathogenic fungus that can cause different clinical manifestations ranging from cutaneous and sub-cutaneous infections to severe oculomycosis. In this study, using both conventional indirect immunofluorescence and non-conventional flow cytometry approaches, IgG antibodies were readily detected in both C57BL/6 immunocompetent and immunosuppressed mice after i.v. infection with P. lilacinum. The humoral immune response was specific, since virtually no antibodies were detected in the serum of control mice. Flow cytometry assays also showed both quantitative and qualitative differences in total IgG and its isotypes in sera of immunocompetent and immunosupressed infected mice. Although a good starting point, it is clear that the effectiveness of serological assays for P. lilacinum hyalohyphomycosis identification in clinical studies still requires further standardization. Upon further validation in humans, these techniques have the potential to be suitable to detect P. lilacinum infection in patients, thereby avoiding current laborious and time-consuming culture techniques.

Characteristics of Paecilomyces lilacinus infection comparing immunocompetent with immunosuppressed murine model

The characteristics of Paecilomyces lilacinus infection were evaluated using two murine experimental models: immunocompetent and immunosuppressed. The evaluation criteria for characteristics of infection were clinical signs, weight loss, survival rates, histopathological alterations and the number of viable fungal cells re-isolated from different organs; and those for immunological status were in vitro lymphoproliferative response, cell surface phenotyping and IFN-γ production. Morphological evaluation showed that P. lilacinus isolates presented morphological characteristics consistent with those described in the literature. The immunocompetent mice could be infected by the fungi, but they did not develop the disease, unlike the immunosuppressed mice, which showed clinical signs of mycosis in an environment of suppressed cellular immune response. The hypothesis of latent infection reactivation in mice was not confirmed. The difference observed in the infection rate of the two fungi isolates points to an intrinsic variation between strains of P. lilacinus and led us to hypothesise that even in the presence of immunosuppressed environment, the fungus virulence can play a role in the pathogenesis of hyalohyphomycosis.

First report on the diagnosis and treatment of encephalic and urinary paracoccidioidomycosis in a cat

A male Persian cat was presented with persistent fever, anorexia, weakness, hypopyon, nystagmus, and intention tremors. The hemogram showed severe neutropenia and laboratory analysis on cerebrospinal fluid (CSF) smears revealed abundant yeast cells compatible with Paracoccidioides brasiliensis. Urinalysis demonstrated persistent funguria and an increased urine protein-to-creatinine ratio (UPC) in addition to mild azotemia. Long-term therapy with oral fluconazole was effective in controlling the nervous system signs. Funguria was resolved with subcutaneous administration of diluted amphotericin B in a large volume of saline solution for a period of 12 weeks during the second year after initial diagnosis. Throughout 5 years of treatment, no adverse effects were observed and tolerance to the drugs was normal. Due to development of progressive uremic syndrome the animal was euthanased. To the best of our knowledge, this report is the first clinical case described of a nervous and urinary system infection caused by the P brasiliensis in a cat.

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.