albicans

Candida albicans is a dimorphic yeast in the family Saccharomycetaceae. It is a common member of the human microbiota, colonizing the oral cavity, gastrointestinal tract, and female genitourinary tract. In healthy individuals it typically resides as a commensal organism without causing disease, but disruption of the microbial balance or immune suppression can enable it to become pathogenic.

C. albicans can grow as oval yeast cells or as filamentous hyphae and pseudohyphae. The ability to switch between yeast and hyphal forms (dimorphism) is linked to tissue invasion and biofilm development and is influenced by factors such as temperature, pH, and CO2 levels.

As an opportunistic pathogen, C. albicans causes mucosal infections such as thrush (oral candidiasis) and vulvovaginitis, as well as esophagitis. In compromised patients, it can invade the bloodstream and organs, leading to candidemia, endocarditis, and intra-abdominal infections.

Virulence is aided by adhesins (notably the Als protein family), secreted hydrolytic enzymes including SAPs and lipases, and the capacity to form robust biofilms on medical devices. White-opaque phenotypic switching can influence mating and pathogenic traits in some conditions.

Diagnosis relies on culture of clinical specimens, germ tube testing, and, increasingly, MALDI-TOF mass spectrometry or molecular methods. Antifungal therapy includes azoles (e.g., fluconazole), echinocandins (e.g., caspofungin), and amphotericin B for severe disease, with treatment choices guided by location and patient risk factors.

C. albicans is a frequent cause of healthcare-associated fungal infections and is part of the normal microbiota in many people. Risk factors include neutropenia, immunosuppression, broad-spectrum antibiotics, indwelling catheters, and extensive hospitalization. Prevention focuses on infection control and device management.