Identificação das espécies de Candida, avaliação da ultraestrutura e perfil de suscetibilidade de biofilmes aos antifúngicos
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Data
2014-05-08
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Universidade Federal de Goiás
Resumo
The increase in the number of fungal infections by Candida species, as a result of the
significant increase of immunocompromised patients emphasizes the importance of
studies associated to this genre. The resistance of these strains to antifungal drugs is
observe in specific isolates, as well as infections associated with biofilm formation
(BF). The aim of this study was to compare the susceptibility profile of sessile and
planktonic cells of different Candida isolates, differentiating species by multiplex
qPCR and scanning electron microscopy. The sample consisted of 10 C. albicans, 10
C. parapsilosis and 1 C. tropicalis. The genetic material was extracted by phenolchloroform
extraction of the sample C. tropicalis, ATCC 28367 (C. albicans) and
ATCC 22019 (C. parapsilosis) for use in a species-specific multiplex qPCR assay with
analysis of differences in the curve fusion. Microdilution plate test and reduction of the
tetrazolium salt for 21 isolates were performed for the susceptibility of sessile and free
cells, respectively. The evaluation of the ultrastructure of the biofilm was performed
on strips of polyurethane with visualization by scanning electron microscopy. The
amplified products from C. albicans obtained three melting peaks with values of 75,2
°C, 76,8 °C and 79,8 °C, while C. tropicalis and C. parapsilosis showed one peak with
values 73,5 °C and 78,5 °C, respectively. The identification test showed to be reliable
for the identification of the most common species in the study. All of Candida yeasts
were able to form biofilm with own organization of each specie. The in vitro
susceptibility test of planktonic cells demonstrated that amphotericin B and
caspofungin showed better activity compared to fluconazole and voriconazole who
obtained 19% of resistant strains, all C. albicans. In assessing of the CIMs50% and
CIMs80% of sessile cells, we observed an increase of at least 60 times the values of
planktonic cells. It was observed a high percentage of BF that demonstrates the need
for diagnosis and combat against this biomass formed by Candida species. The BF
is a virulence factor determinant for decrease of susceptibility to antifungal agents
thus compromising antifungal therapy.
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Citação
MARRETO, L. C. N. L. Identificação das espécies de Candida, avaliação da ultraestrutura e perfil de suscetibilidade de biofilmes aos antifúngicos. 2014. 83 f. Dissertação (Mestrado em Biologia das Relações Parasito-Hospedeiro)–Universidade Federal de Goiás, Goiânia, 2014.