Fungal biofilms in the hemodialysis environment

Hemodialysis, which is a kidney failure treatment that uses hemodialysis machine, dialyzer, dialysis solution, catheters, and needles, favors biofilm formation. This study evaluates whether Aspergillus, Candida, and Fusarium can form biofilm in dialysis fluids. Biofilms were grown in 96-well microplates containing solutions (acid and basic) consisting of dialysate, dialysate per se, or dialysate plus glucose as culture medium. The biofilms were incubated at 30 °C for 72 h, quantified by the violet crystal methodology, and visualized by transmission electron microscopy. All the fungi formed biomass in all the tested solutions. However, Bonferroni analysis revealed that the dialysate facilitated Aspergillus biomass development, whereas the dialysate and dialysate with glucose provided similar Fusarium oxysporum biomass development. Candida parapsilosis development was favored in biofilms grown in basic electrolytic solution. Electron micrographs of biofilms that grew on catheters after 72 h showed that Aspergillus formed abundant hyphae; the extracellular matrix was visible on the surface of some hyphae when Aspergillus was grown in the dialysate. A multilayered hyphal structure emerged when F. oxysporum biofilms were incubated in the dialysate with glucose. C. parapsilosis biofilm growth in basic solution elicited a dense network of yeasts and pseudohyphae as well as the extracellular matrix; the biofilm was attached across the catheter length. This study may contribute to the formulation of new strategies to monitor biofilm formation and to increase knowledge associated with fungal biofilms in the dialysis environment.