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Poster number: 09
Phenotypic investigation of virulence factors in Candida
species isolated from different clinical specimens
Alina Maria Holban 1 , Crina Maria Saviuc 1,5 , Alexandru Mihai Grumezescu 2 ,
Coralia Bleotu 1,4 , Otilia Banu 3 , Dan Mihaiescu 2 , Paul Balaure 2 , Mariana
Carmen Chifiriuc 1 , Veronica Lazar 1
1 University of Bucharest, Faculty of Biology, Microbiology University Department; 2 University
Politechnica of Bucharest, Faculty of Applied Chemistry and Materials Science, Organic
Chemistry Department; 3 Institute of Cardiovascular Diseases Prof. C.C. Iliescu, Bucharest;
4 S. Nicolau Institute of Virology, Bucharest; 5 S.C. Biotehnos S.A.
Introduction. The purpose of this study was to investigate the phenotypic expression
of the cell associated and soluble virulence factors in 30 fungal strains recently isolated
from different clinical specimens.
Materials and methods. Fungal strains belonging to Candida genus were isolated
from different clinical specimens (urinary tract isolates, plague secretions, upper airway
secretions) and identified using Vitek II automatic system. Susceptibility to currently
used antifungals was assessed by E-test. The phenotypic study of soluble virulence
factors was performed by specific enzymatic assays of haemolysins, lecithinase,
gelatinase, lipase, DNA-se, amylase and iron chelating agents production. Microbial
adherence capacity to the inert (plastic, catheter sections) and cellular substrata was
performed by microtiter method, Brun Buisson method and modified Cravioto method,
using HeLa cells. Fungal dimorphism was studied by filamentation assay. Statistics—
Data were compiled and analyzed using Microsoft Excel and GraphPad In Stat
software, using One-way Analysis of Variance ANOVA.
Results. All tested strains were susceptible to voriconazole, itraconazole, caspofungin
B, fluconazole, flucytosin and amphotericin B. The tested strains exhibited different
abilities to colonize the plastic/catheter sections as well as the cellular substrate, being
divided in non-adherent, moderately and highly adherent. Concerning the filamentation
assay, the strains were classified in the following descendant order: C. albicans, C.
tropicalis, C. glabrata, C. krusei, C. Famata. The profiles of the soluble virulence factors
have been statistically different, related to the species and clinical origin of the tested
strains. The tested strains abundantly secreted haemolysins, DNA-se, amylase and iron
chelating agents.
Conclusion. The phenotypic investigation of virulence factors production in Candida
strains revealed specific virulence profiles depending on the source of isolation and the
taxonomic affiliation of the tested strains, proving the usefulness of these assays in
predicting the clinical outcome of the fungal infections and in the adjustment of the
antifungal treatment.
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