Analysis of virulence factors and in vivo biofilm-forming capacity of Yarrowia lipolytica isolated from patients with fungemia

Abstract

Yarrowia lipolytica is ubiquitous in the environment, opportunistic, and might be considered as one of the causative agents of catheter-related candidemia. Our work aimed to study some virulence factors of Y. lipolytica such as hydrolases production and biofilm formation with comparison to the most frequent Candida specie in human disease. In sum, 58 clinical isolates of Y. lipolytica, 16 C. glabrata, and 12 C. albicans were collected from Intensive care unit (ICU). All were tested for enzymatic production and biofilm formation. All tested isolates of C. albicans and C. glabrata were able to degrade casein, and 98.2% of Y. lipolytica showed caseinase activity but no gelatinase activity was detected in all isolates. Y. lipolytica strains showed significantly lower (3.4%) in vitro phospholipase activity than C. albicans and C. glabrata (P < .05). No significant differences of the hemolytic activity were detected between the three species (P > .05). Concerning biofilm formation, and unlike the results obtained on polystyrene plate, the number of adhered and biofilm cultivable cells obtained by Y. lipolytica after 168 hours of catheter subcutaneous implantation is significantly greater and tends to be more compact and structured hyphal layer. Although C. albicans remains the most pathogenic yeast, development of selective ability of Y. lipolytica to adhere, to form a biofilm on catheter medical devices, and to produce phospholipase and hemolytic enzyme is of particular interest, and it is strongly recommended to be vigilant in the use of medical implanted medical devices, particularly in ICU.

Keywords: Virulence factors; Yarrowia lipolytica; biofilm formation.