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    Caracterização genotípica e fenotípica de isolados clínicos e ambientais pertencentes a aspergillus seção flavi
    (Universidade Federal de São Paulo (UNIFESP), 2011-03-30) Goncalves, Sarah Santos [UNIFESP]; Colombo, Arnaldo Lopes [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The species of Aspergillus section Flavi have been extensively reported as causative agents of human infectious diseases, and have shown the ability to produce aflatoxins. There is no accurate method for identification of the genus Aspergillus at species level. Because of this inconsistence, the polyphasic approach for species discrimination has been proposed. The aim of the present study was to correctly identify 74 Aspergillus isolates (28 clinical and 46 environmental) deposited in the filamentous fungi bank of the Laboratório Especial de Micologia/Brazil and of the Facultat de Medicina i Ciències de la Salut de Reus/Spain, with previous identification suggested as species belonged to the Aspergillus section Flavi. This study was based on combination of several molecular, morphological, physiological, and ecological data in a polyphasic approach, comparing the isolates to type and/or neotype strains used as reference strains. Genetic markers were selected for phylogenetic inference of the 74 isolates, including the ITS region, structural and protein-coding genes. The phenotypic characterization was performed by macro and micromorphological analyses, aflatoxin production, carbon and nitrogen assimilation, evaluation of thermotolerance and of the in vitro susceptibility profile to ten antifungals. The genomic sequencing of the ITS region confirmed that the isolates belonged to section Flavi and revealed two main clades of clinical interest. Thus, we selected genetic markers (AMDS, OMTS, and others genes) with discriminatory potential to identify the species included in each clade. Phylogenetic analyses of those genes demonstrated eight species, two undescribed. The first new species was closely related to A. flavus and A. oryzae, and the second one was closely related to A. parasiticus. In addition to ability to cause invasive infection in humans, the two new species produce aflatoxins. Among 28 clinical isolates studied, A. flavus was the most prevalent species (42.8%). In relation to environmental isolates, A. oryzae was the most frequent (63%), being also prevalent in the nosocomial environment and responsible for 65.1% (15/23) of the isolates. Moreover, antifungal susceptibility testing showed heterogeneous patterns among the species of section Flavi. Terbinafine and echinocandins were the most active antifungal agents against the Aspergillus isolates. Posaconazole was the triazole with better in vitro activity against the fungal strains studied. In conclusion, this was the first Brazilian study showing the wide heterogeneity of the species in Aspergillus section Flavi isolated from clinical and environmental sources, with different antifungal susceptibility patterns. We found two new species causing human infection, thereby demonstrating the emergence of new fungal pathogens in immunocompromised patients.