Produção de proteases e fator hemolítico e switching fenotípico em Candida spp

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

25/02/2010

RESUMO

Yeast species belonging to the genus Candida are responsible for the majority of fungal infections in humans. The aim of the present study was to determine haemolytic and protease activities of clinical isolates of Candida parapsilosis and Candida tropicalis obtained from anatomically distinct sites, and to determine the frequency of phenotypic switching in C. tropicalis. Analysis of haemolytic activity of C. parapsilosis and C. tropicalis isolates obtained from the same anatomic site revealed that C. tropicalis isolates from blood had statistically higher activity than C. parapsilosis. When compared haemolytic activities of Candida isolates obtained from different anatomic sites, C. parapsilosis isolates from tracheal secretion had higher activity than blood isolates. For C. tropicalis isolates no correlation was observed between hemolytic activity and site of isolation. Analysis of proteinase activity of C. parapsilosis and C. tropicalis isolates obtained from the same anatomic site revealed that C. parapsilosis isolates from tracheal secretion had statistically higher activity than C. tropicalis isolates. When compared proteinase activities of Candida isolates obtained from different anatomic sites, C. parapsilosis isolates from tracheal secretion had higher activity than blood and superficial lesions isolates. Furthermore, C. tropicalis isolates from superficial lesions had higher activity than tracheal secretion isolates. Our results show the potential of C. parapsilosis and C. tropicalis isolates, obtained from distinct anatomic sites, to produce haemolytic factor and proteinases at a distinct manner. In the present study it was also described a new system of switching for C. tropicalis. A total of four morphotypes was identified and denoted “smooth”, “bowl-shaped”, “ring” and “rough”. Colonies phenotypes “ring” and “rough” are structurally more complex than that observed for the other phenotypes. They present cavities with the presence of extracellular matrix. The colony structure development of the “ring” variant was evaluated. For this variant there was a correlation between the matrix content and colony development. Analyses of the biofilm production by the morphotypes revealed that the parental morphotype (“smooth”) produces less biofilm than others variants. For the former the biofilm comprised mostly yeast-like cells while for the variants a large proportion of hyphae and pseudohyphae were observed. Biofilm matrix was observed only for “ring” and “rough” variants.

ASSUNTO(S)

candida leveduras (fungos) enzimas proteolíticas hemólise e hemolisinas biofilme microbiologia médica yeast fungi proteolytic enzymes hemolysis and hemolysins

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