Análise fenotípica e molecular de cepas de Cryptococcus spp. obtidas de fontes ambientais e clínicas. / Phenotypic and molecular analysis of strains of Cryptococcus spp. obtained from clinical and environmental sources.

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

16/11/2009

RESUMO

Cryptococcus is a capsulated yeast that presents capacity of infecting and causing disease in a great variety of hosts, including mammals, insects and birds, with C. neoformans and C. gattii as the main pathogenic species. Thus, during the first step of this research, 36 yeast strains, isolated from cloaca and stools of pigeons, which had previously been stocked in the mycoteca of Specialized Medical Mycology Center, were investigated in order to analyse phenotypic and genotypic Cryptococcus spp characteristic. In addition, vegetable material was collected from Psidium guajava (n = 11), Mangifera indica (n = 2), Eucalyptus sp. (n = 8), Cassia siamea (n = 5), Zizyphus joazeiro (n = 10) and Azadirachta indica (n = 14) trees, located near the areas where the analyzed yeasts were obtained. Besides, in vitro susceptibility to amphotericin B, azole derivatives and caspofungin against Cryptococcus spp. environmental strains was assessed. Out of the stocked isolates from stools, 27.8% were C. neoformans var. neoformans, 8.3% C. laurentii and 63.9% belonged to other yeast species. On the other hand, no Cryptococcus spp. isolates were obtained from cloaca and vegetable matter. From the latter, only one isolate of Candida glabrata was obtained. Azole resistance was observed in only one environmental strain of C. neoformans, which was resistant to itraconazole (MIC=1 μg/ml). Another goal of this study was to perform a comparative analysis between manual (morphological and biochemical characteristics), semi-automated (API 20C AUX), automated (VITEK 2) and molecular (PCR-REA) methods for the identification of Cryptococcus spp. obtained from environmental (n=13) and clinical (n=22) sources. Additionally, the variety and the serotype to which each strain belonged was determined. Considering the manual method as the gold standard for identification, PCR-REA was the fastest diagnostic method and was significantly related to manual methods. The last goal of this study was to characterize the mating-type profile of environmental and clinical Cryptococcus spp. strains. Through PCR, it was possible to verify that the evaluated strains belonged to α-mating-type. Finally, the importance of this research was the pursuit of new ecological niches for Cryptococcus spp. within vegetable sources, the investigation of occurrence of primary antifungal resistance phenomenon among fungal environmental strains, the evaluation of the most advantageous diagnostic method for the identification of Cryptococcus spp., including the determination of varieties and serotypes of the species C. neoformans and C. gattii and the determination of the mating-type profile of our isolates.

ASSUNTO(S)

resistência antifúngica cryptococcus spp pcr mating-type reproducao animal cryptococcus spp antifungal resistance pcr mating-type

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