Metadata language
Title:
Evaluation of selected virulence factors of Rhodotorula fungi
Author:
Subject:
virulence factors ; drug susceptibility ; biotyping ; rhodotorula
Abstract:
In the recent years more and more cases of Rhodotorula infection are reported. Deep mycosis (fungaemia) is the most frequent form of rhodothorulosis and the most common aetiological agents is the species R. mucilaginosa. The aim of this study was to evaluate the prevalence of virulence factor of Rhodotorula strains in comparison to known human pathogen Candida albicans. For that purpose the ability to grow in body temperature, activity of selected enzymes, capsule production, change of the phenotype and the ability to form a biofilm were investigated. Moreover antifungal drug susceptibility test was performed and a trial to biotype the strains with API ZYM test was performed. The study was carried out on isolates from patients and environmental samples tested in the Department of Mycology. There was a wide diversity in the expression of virulence factors in Rhodotorula strains. It has been shown that most strains had the ability to grow in body temperature. R. mucilaginosa has a higher phospholipase activity of at 37°C than C. albicans. One-third of the strains of R. mucilaginosa has proteolytic activity. The aspartyl protease activity of these strains was comparable to the activity exhibited by the C. albicans strains. The lipase activity at 37°C was found in only 16.67% of R. mucilaginosa strains moreover this activity was also lower than the lipase activity in the compared C ; . albicans strains. Only some strains of R. mucilaginosa produce capsules and pseudohyphae in the serum. Most strains of R. mucilaginosa are able to produce the biofilm in serum at 37°C in polystyrene microplates, but the size of the biofilm after three days incubation is significantly lower than in the compared strains of C. albicans. This may explain the case studies of fungemia due to Rhodotorula during maintenance of long-term venous catheters. High MICs have been shown for strains of R. mucilaginosa to fluconazole and itraconazole. Biotyping on the base of enzymograms of API ZYM test are useless in differentiation of strains.