|823-2||Hemolytic factor production is variable among Candida species isolated from blood cultures|
|Autores:||Daniel Favero (UEL - Universidade Estadual de Londrina) ; Emanuele Julio Galvão de França (UEL - Universidade Estadual de Londrina) ; Luciana Furlaneto-maia (UTFPR - Universidade Tecnológica Federal do Paraná) ; Marcia Cristina Furlaneto (UEL - Universidade Estadual de Londrina) |
Yeasts belonging to the genus Candida are responsible for the majority of fungal bloodstream infections. Most cases of these infections have been attributed to C. albicans, but recently, non-albicans species have been identified as common pathogens. Although hemolytic factor is known to be putative virulence factor contributing to pathogenicity in Candida species, its production still poor evaluated. The present study was undertaken to analyze the production of hemolytic factor by C. albicans (10), C. tropicalis (13) and C. parapsilosis (08) isolates associated with bloodstream infections. Hemolytic activity was evaluated on both plate assay and from cell free broth. In the former analysis the hemolytic activity was revealed as a translucent and/or a greenish halo circumscribing the inoculum site in a sugar-enriched sheep blood agar medium. Hemolytic activity from culture supernatant was expressed as efficiency (hemolysis (%)/ 107 cells). Data of hemolysis zones on plate assay revealed that the majority of C. albicans isolates produced mild hemolytic activity whereas the majority of C. tropicalis produced strong activity. On the other hand, none of the tested C. parapsilosis isolates exhibited hemolysis. We also analyzed the production of hemolytic factor released in the culture supernatant. Different degrees of hemolysis were promoted by Candida isolates, where C. tropicalis isolates exhibited the highest production of hemolytic factor (P<0.05) followed by C. albicans and C. parapsilosis isolates. Furthermore, there were no significant intra-species differences (P>0.05) in the hemolytic activity among Candida species isolates. To the best of our knowledge, this is the first report of species-specific differences in hemolytic factor production by Candida isolates associated with bloodstream infections. We have further showed for the first time the secretion of a hemolytic factor by isolates of C. parapsilosis.
Palavras-chave: Blood cultures, Candida albicans, Candida parapsilosis, Candida tropicalis, Hemolytic factor