Candida

Candida is a genus of yeasts in the family Saccharomycetaceae that includes several species capable of living as harmless commensals or causing disease in humans. The most clinically important species is Candida albicans, though others such as C. glabrata, C. tropicalis, C. parapsilosis, C. krusei, and the emerging pathogen Candida auris also cause illness. Candida species are part of the normal microbiota of the mouth, skin, gastrointestinal tract, and female genital tract in many people, and infections typically arise when the host’s defenses are compromised or microbial balance is disrupted.

Candidiasis encompasses a range of conditions from mucosal infections to invasive disease. Mucosal candidiasis includes oral thrush and vulvovaginal candidiasis. Cutaneous candidiasis can affect skin folds and nails. Invasive candidiasis, including candidemia, can occur in patients with prolonged hospitalization, central venous catheters, surgery, or neutropenia and can affect multiple organs.

Pathogenesis involves dimorphic growth in some species (yeast and hyphae), biofilm formation, and expression of adhesins and hydrolytic enzymes that promote tissue invasion and immune evasion. Diagnosis combines culture from suspected sites, microscopy, and nonculture tests such as beta-D-glucan or species-specific assays in certain settings. Blood cultures are central for suspected invasive disease; molecular tests are increasingly used.

Treatment depends on species, site, and severity. Options include azoles (such as fluconazole), echinocandins (caspofungin, micafungin), and amphotericin B. Resistance is an emerging concern, particularly with C. glabrata and C. auris, guiding local empiric choices and stewardship efforts. Prevention focuses on infection-control practices, judicious antibiotic use, and antifungal stewardship to reduce colonization and transmission in healthcare settings.