Poster (Painel)
285-1Optimization of growth culture conditions for hemolytic factor production by clinical isolates of Candida parapsilosis
Autores:Helena Peggau de Góes (UEL - Universidade Estadual de Londrina) ; Emanuele Julio Galvão de França (UEL - Universidade Estadual de Londrina) ; Márcia Regina Terra (UEL - Universidade Estadual de Londrina) ; Luciana Furlaneto-maia (UTFPR - Universidade Federal Tecnológica do Paraná) ; Márcia Cristina Furlaneto (UEL - Universidade Estadual de Londrina)


Although the frequency of infections caused by Candida parapsilosis has increased significantly in recent years, little is known about virulence attributes associated with this species. In this context, the production of hemolytic factor is considered a putative virulence factor related to C. parapsilosis, however, according to literature, the ability of C. parapsilosis to promote hemolysis is controversial. The production of hemolysis by strains cultivated in solidified growth medium is revealed by a translucent ring and/or greenish around the colony. The goal of this study was to evaluate the influence of growth conditions in hemolysis production by clinical isolates of C. parapsilosis. To this end, we employed 12 isolates and the reference strain ATCC 22019 and a total of twenty one growth medium composed of glucose, peptone and yeast extract at different concentrations and supplemented with 7% fresh sheep blood. The culture plates were inoculated with 2μL (1,0x107 cells/mL) of C. parapsilosis isolates and then incubated under normal and increased CO2 atmosphere at 37 °C for 48 and 72 hours. Following incubation, the presence and absence of the halo of hemolysis was assessed. Of the total of the growth media tested, in eleven of them (52.38%) hemolysis was observed, while in ten (47.62%) of the growth medium tested none hemolysis was detected, even after 72 hours of incubation. The atmosphere of incubation did not influence the production of hemolytic factor by isolates tested. Among the growth medium in which hemolysis was observed, the medium that consisted of glucose (60 g/L) and yeast extract (2.5 g/L) showed a significant difference in promoting hemolysis compared to the others defining it as the optimal condition among the tested to produce of hemolysis. On the other hand, the growth medium where the smallest hemolysis was observed consisted of 60 g/L glucose, 20 g/L peptone and 5.0 g/L of yeast extract. There was no significant difference in hemolysis production among the isolates tested. The results obtained in this study confirm that for C. parapsilosis the components and concentrations of the growth medium directly influence the promotion of in vitro hemolysis.

Palavras-chave:  Candida parapsilosis, Growth culture conditions, Hemolytic factor