ABSTRACT
Candida species are normal colonizers of the oral cavity, gastrointestinal tract, and vagina of healthy humans and, as a component of the resident microbiota, inflict little to no damage to the host. Primarily in C. albicans, various host-related phenotypes including morphogenesis, adhesion and biofilm formation, interactions with phagocytes, stress tolerance, and nutrient utilization correlate with virulence. Among non-albicans Candida species, whose prevalence surpasses that of C. albicans in bloodstream infections, C. parapsilosis is the most heterogeneous. Overexpression of drug pumps in Candida biofilm cells promotes the development of antifungal resistance in the early phase of the biofilm formation, while in the maturation process, changes in sterol composition seem to be more relevant. Fungal biofilms confer complete or partial resistance to most drug classes, and represent an important factor in the pathogenesis of Candida species, as well as a diagnostic challenge.
