First description of Candida nivariensis in Brazil: antifungal susceptibility profile and potential virulence attributes

This study evaluated the antifungal susceptibility profile and the production of potential virulence attributes in a clinical strain of Candida nivariensis for the first time in Brazil, as identified by sequencing the internal transcribed spacer (ITS)1-5.8S-ITS2 region and D1/D2 domains of the 28S of the rDNA. For comparative purposes, tests were also performed with reference strains. All strains presented low planktonic minimal inhibitory concentrations (PMICs) to amphotericin B (AMB), caspofungin (CAS), and voriconazole. However, our strain showed elevated planktonic MICs to posaconazole (POS) and itraconazole, in addition to fluconazole resistance. Adherence to inert surfaces was conducted onto glass and polystyrene. The biofilm formation and antifungal susceptibility on biofilm-growing cells were evaluated by crystal violet staining and a XTT reduction assay. All fungal strains were able to bind both tested surfaces and form biofilm, with a binding preference to polystyrene (p < 0.001). AMB promoted significant reductions (≈50%) in biofilm production by our C. nivariensis strain using both methodologies. This reduction was also observed for CAS and POS, but only in the XTT assay. All strains were excellent protease producers and moderate phytase producers, but lipases were not detected. This study reinforces the pathogenic potential of C. nivariensis and its possible resistance profile to the azolic drugs generally used for candidiasis management.     

Comparative Analysis of Putative Virulence-Associated Factors of Microsporum canis Isolates from Human and Animal Patients

Mycopathologia - Microsporum canis is a zoophilic dermatophyte and the most common fungus isolated from dogs and cats worldwide. To invade skin, this pathogen uses different enzymes, which may be...     

Production of Secreted Carbohydrates that Present Immunologic Similarities with the Cryptococcus Glucuronoxylomannan by Members of the Trichosporonaceae Family: A Comparative Study Among Species of Clinical Interest

Mycopathologia - Glucuronoxylomannan (GXM) participates in several immunoregulatory mechanisms, which makes it an important Cryptococcus virulence factor that is essential for the disease....     

Melanin biosynthesis in pathogenic species of Sporothrix

Melanins are dark polymers found in the cell wall of pathogenic fungi, including species from the genus Sporothrix that are causative agents of sporotrichosis. In vitro experiments strongly suggest that these pigments are important for fungal virulence and survival in the host. In S. schenckii, melanin biosynthesis occurs via three different common pathways, which generate dihydroxynaphthalene (DHN)-melanin, DOPA-melanin or pyomelanin. Moreover, melanin biosynthesis can be enhanced when the fungus is in contact with some bacteria, such as Pseudomonas aeruginosa and Klebsiella pneumoniae. Melanin pigments have protective effects against antifungals in this genus. New scanning transmission electron tomography data indicates the accumulation of dark pigments in membrane-bound cytoplasmic organelles (melanosomes) in S. schenckii yeasts. Here, we provide an up to date of review the biosynthesis and role of melanins and discuss its roles on the cell biology and pathogenesis of Sporothrix spp.     

Dietary Patterns and Their Associations with Obesity in the Brazilian City of Rio de Janeiro

Objective: To evaluate the dietary patterns of adults living in the city of Rio de Janeiro, Brazil and their associations with body mass index (BMI). Research Methods and Procedures: A survey was conducted in 1996 in a probabilistic sample of 2040 households. Weight and height were measured and food intake was based on an 80-item semi-quantitative food frequency questionnaire. Dietary patterns were identified through factor analysis. Results: More than one-third of the adult population (20 to 60 years old) was overweight (BMI = 25 to 29.9 kg/m²), and 12% were obese (BMI ≥ 30 kg/m²). Three major dietary patterns were identified: mixed pattern when all food groups and items had about the same factor loading, except for rice and beans; one pattern that relies mainly on rice and beans, which was called a traditional diet; and a third pattern, termed a Western diet, where fat (butter and margarine) and added sugar (sodas) showed the highest positive loading and rice and beans were strong negative components. Among men, the Western diet also included deep-fried snacks and milk products with high positive values. The traditional diet was associated with lower risk of overweight/obesity in logistic models adjusted for dieting, age, leisure physical activity, and occupation (13% reduction in men and 14% reduction in women comparing the traditional and Western diets). Discussion: Factors contributing to the effects of the Brazilian traditional diet may include low-energy density, high-dietary fiber content, incorporation of low glycemic index foods such as beans, or a relatively low food variety.     

Sequence Analysis of the Internal Transcribed Spacer 2 (ITS2) from Yeast Species Within the Genus Candida

Nucleotide sequences of the internal transcribed spacer 2 (ITS2) regions were determined for 13 species within the genus Candida, representing a collection of those species pathogenic for humans. No two species had identical sequences and the sizes of ITS2 varied fourfold, representing an apparent continuous gradient of nucleotides. When present, sequence homologies were observed in the 5′ end of ITS2, and many species exhibited more limited homologies within three known conserved domains found in other yeasts. Cluster analysis of primary sequence revealed a concordance with a known taxonomic subfamily and suggests that certain species within the genus form a similar grouping. A majority of species exhibited similar presumptive RNA secondary structures, consistent with the hypothesis that these spacer regions are essential for correct processing of the 5.8S and 28S subunits. Received: 14 April 1997 / Accepted: 22 July 1997