Challenging the Morphology-Virulence Paradigm in Candida Species

Candida species represent a major cause of hospital-acquired bloodstream infections, particularly for immunocompromised individuals including cancer patients on chemotherapy, organ transplant recipients and HIV/AIDS patients. About 50% of infections can be attributed to Candida albicans, a major human fungal pathogen, while the remainder are caused by a variety of less pathogenic non-albicans Candida species. C. albicans possesses several important pathogenicity traits, including the ability to undergo a reversible morphological transition from single budding yeast cells to elongated filaments. However, very little is known about the relationship between morphology and pathogenicity in non-albicans Candida species. In this seminar, a variety of approaches are taken to address this relationship, including transcriptional and immune profiling as well as molecular genetic, phenotypic and pathogenicity studies. Our findings challenge conventional views and suggest that there are fundamental evolutionary differences in the morphology-virulence relationship among Candida species.