Candida albicans recovered from persistent candidemia exhibit enhanced virulence traits.

Candida albicans catheter-related candidemia is largely driven by microbial adhesion and biofilm formation on central venous catheters. Cells that disperse from these biofilms can enter the bloodstream, spread to distant organs, and sustain the cycle of infection. In this study, we investigated the virulence potential of C. albicans isolates obtained from the blood of catheterized patients experiencing persistent candidemia, comparing them to isolates that were cleared from the bloodstream early in the infection. Our results show that isolates persisting in the bloodstream for four days or longer, despite antifungal treatment, exhibited enhanced adherence, filamentation, and biofilm formation in vitro, along with increased expression of key virulence-related genes. Notably, cells dispersed from second-generation biofilms formed by these persistent isolates displayed even more pronounced pathogenic characteristics, including improved immune evasion. Furthermore, in vivo experiments using Galleria mellonella revealed that persistent isolates were significantly more virulent than their non-persistent counterparts.