Publikationsdatum:
2013-06-18
Beschreibung:
Candida tropicalis is an emerging virulent species. The aim of this study is to determine the biofilm-forming ability of 29 strains of C. tropicalis isolated from in-patients, and to examine its relation with other virulence factors such as cellular surface hydrophobicity (CSH), immediate (15 min, IA) and late (24 h, LA) plastic adherence and filamentation ability. The study was performed in parallel using two incubation temperatures, 37 º and 22º C, to determine the effect of growth temperature variations on these pathogenic attributes of C. tropicalis . Biofilm formation (BF) was measured by Optical Density (OD) and by XTT-reduction (XTT); Slime Index (SI), which includes growth as a correction factor in BF, was calculated in both methods. All strains were hydrophobic and adherent - at 15 min and 24 h - at both temperatures, with higher values for 22 °C; the adhered basal yeast layer appears to be necessary to achieve subsequent development of biofilm. Filamentation ability varied from 76.2% of strains at 37 °C to 26.6% at 22 °C. All C. tropicalis strains were biofilm-producers, with similar results obtained using OD determination and XTT measurement as evaluation methods; SI is useful when good growth is not presented. BF at 37 °C was similar at 24 h and 96 h incubation; conversely, at 22 °C, the highest number of biofilm-producing strains was detected at 96 h. CSH is an important pathogenic factor which is involved in adherence, is influenced by the filamentation of yeast, and plays a critical role in BF. This article is protected by copyright. All rights reserved.
Print ISSN:
0749-503X
Digitale ISSN:
1097-0061
Thema:
Biologie
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