Nonalbicans

Nonalbicans is a term used in medical microbiology to refer to species of the genus Candida other than Candida albicans. In clinical practice, non-albicans Candida (NAC) infections describe candidiasis caused by these other species and collectively represent a growing portion of fungal infections, especially in hospital settings. NAC species are part of the normal human microbiota on mucosal surfaces and skin but can cause disease when immunity is compromised, when mucosal barriers are breached, or when implanted devices and broad-spectrum antibiotics disrupt microbial balance.

The most frequently encountered non-albicans species are Candida glabrata, Candida tropicalis, Candida parapsilosis, Candida krusei, and, increasingly, Candida auris. They vary in virulence and tissue predilections and can differ markedly in antifungal susceptibility. Some NAC species have reduced susceptibility to azoles, and others have intrinsic or acquired resistance patterns that influence treatment choices. For example, C. krusei is intrinsically resistant to fluconazole, while C. glabrata shows variable azole susceptibility and may require alternative agents. C. auris is notable for multi-drug resistance and nosocomial transmission.

Clinically, NAC species cause a range of diseases from mucosal candidiasis to invasive candidiasis, including candidemia. Diagnosis relies on culture with species identification, often using MALDI-TOF mass spectrometry, and antifungal susceptibility testing in many settings.

Therapy is species- and case-dependent. Echinocandins are commonly used as initial therapy for invasive NAC infections, with step-down to azoles like fluconazole when susceptibility allows. Treatment duration depends on infection site and host factors. Ongoing surveillance and antifungal stewardship aim to curb resistance and transmission.