Atypical disseminated cutaneous histoplasmosis in an immunocompetent child, caused by an "aberrant" variant of Histoplasma capsulatum var. capsulatum

Laboratorio de Micologia Medica, Instituto de Medicina Tropical de Sao Paulo, Sao Paulo, SP, Brazil.
Revista do Instituto de Medicina Tropical de São Paulo (Impact Factor: 1.01). 05/1999; 41(3). DOI: 10.1590/S0036-46651999000300012
Source: DOAJ


A case of atypical disseminated cutaneous histoplasmosis in a five-year old, otherwise healthy child, native and resident in São Paulo metropolitan area is reported. Cutaneous lesions were clinically atypical. Histologic examination disclosed a granulomatous reaction but no fungal structures could be demonstrated by specific staining nor by immunohistochemical reaction. The fungus was isolated from biopsy material on two different occasions, confirming diagnosis of an unusual fungal infection. The fungus, originally thought to be a Sepedonium sp. due to the large sized, hyaline or brownish colored tuberculated macroconidia and to lack of dimorphism (yeast form at 37 °C) produce H and M antigens, visualized by the immunodiffusion with rabbit anti-Histoplasma capsulatum hyperimmune serum. Patient?s serum sample was non reactive with H. capsulatum antigen by immunodiffusion, counterimmunoelectrophoresis and complement fixation tests, and immunoenzymatic assay failed to detect the specific circulating antigen. This serum was tested negative by double immunodiffusion when antigen obtained from one of the isolated samples was used. Both cultures were sent to Dr. Leo Kaufman, Ph.D. (Mycoses Immunodiagnostic Laboratory, CDC-Atlanta/USA), who identified them as H. capsulatum by the exoantigen and gen-probe tests. Both clinic and mycologic characteristics of the present case were atypical, suggesting the fungus isolated is an ?aberrant variant? of H. capsulatum var. capsulatum, as described by SUTTON et al. in 199719. Treatment with itraconazole 100 mg/day led to cure within 90 days

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Available from: Gilda Maria Barbaro Del Negro, Aug 18, 2014
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    • "These cases might in all probability be properly diagnosed using modern molecular biology techniques. H. capsulatum and other dimorphic fungi can be identified using various commercially available assays, including exoantigen reagents (DiSalvo et al., 1980, 1981; Standard & Kaufman, 1982; Denys et al., 1983; Sekhon et al., 1984, 1986; Body et al., 1988; Wheat et al., 1989, 1991, 1992; Padhye et al., 1992; Sandin et al., 1993; Sutton et al., 1997; Lacaz et al., 1999) and acridinium esterlabelled chemiluminescent DNA probes (Accuprobe, Gen-Probe) (Hall et al., 1992; Padhye et al., 1992; Huffnagle & Gander, 1993; Sandin et al., 1993; Sutton et al., 1997; Chemaly et al., 2001; Brandt et al., 2005). These two methods are accurate and commonly used for H. capsulatum diagnosis (Wheat, 2003). "
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    ABSTRACT: The performance of fatty acid profiling for strain differentiation of Histoplasma capsulatum was assessed. Total fatty acids were isolated from the yeast-phase cells of seven stock and two previously unreported clinical strains of H. capsulatum var. capsulatum, as well as from one unreported clinical strain and one stock strain of H. capsulatum var. duboisii, and one strain of each of three other dimorphic zoopathogenic fungal species, Blastomyces dermatitidis, Paracoccidioides brasiliensis and Sporothrix schenckii. Different colony morphology and pigmentation types of the H. capsulatum strains were also included. The most frequently occurring fatty acids were oleic, palmitic, stearic and linoleic acids. There were variations in the relative percentage fatty acid contents of H. capsulatum strains that could be used for strain identification and discrimination. Differentiation between H. capsulatum strains was achieved by the comparison of detected fatty acids accompanied by principal component analysis using calculated Varimax-rotated principal component loadings. Statistical analysis yielded three major principal components that explained over 94 % of total variance in the data. All the strains of H. capsulatum var. capsulatum RFLP classes II and III were grouped into two distinct clusters: the heterogenic RFLP class I formed a large, but also well-defined group, whereas the outgroup strains of H. capsulatum var. duboisii, B. dermatitidis, P. brasiliensis and S. schenckii were shifted away. These data suggest that fatty acid profiling can be used in H. capsulatum strain classification and epidemiological studies that require strain differentiation at the intraspecies level.
    Full-text · Article · Jul 2007 · Journal of Medical Microbiology
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    ABSTRACT: For the first time in Argentina, we describe a strain of Histoplasma capsulatum var. capsulatum with an aberrant morphology that was isolated from a single patient with AIDS. Mycelial phase cultures on agar Sabouraud at 25-28 degrees C showed white, glabrous, umbilicated and centrally radiated colonies. Unusual microscopic findings were the absence of typical conidia, the presence of terminal/intercalary chlamydoconidia with a diameter of 4 pm and of thickened hyphae. Fungal identification was confirmed by the detection of bands H and M species specific antigens in mycelial culture supernatants and reversion to the typical yeast phase on agar brain-heart-cysteine at 37 degrees C. The genomic DNA profile obtained by RAPD-PCR with primers 1281-1283 coincided with the predominant profile of H. capsulatum among isolates from Argentine patients.
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