Candida yeast

Candida is a genus of yeasts and is the most common cause of fungal infections worldwide. Many species are harmless commensals or endosymbionts of hosts including humans; however, when mucosal barriers are disrupted or the immune system is compromised they can invade and cause disease, known as an opportunistic infection.

Characteristics

Candida species are small, oval, yeast cells that reproduce by a process called budding. Some species form a true hyphae or pseudohyphae, which are important in the disease process. Candida yeasts are generally present in healthy humans, particularly on the skin, but their growth is normally limited by the human immune system and by other microorganisms, such as bacteria occupying the same locations (microbiota). The genome of several Candida species has been sequenced.

Pathogenicity

Candida species can cause candidiasis, which includes infections ranging from superficial, such as oral thrush and vaginitis, to systemic and potentially life-threatening diseases. Candida albicans is the most commonly implicated species in human infections. However, with the increasing use of antibiotics and immunosuppressive drugs, other species of Candida, such as Candida glabrata, Candida tropicalis, and Candida parapsilosis, have also become pathogenic in humans.

Diagnosis and Treatment

Diagnosis of Candida infection is by microscopic examination and culture of body fluids. More recently, molecular techniques have been used. Treatment depends on the site of the infection and the patient's underlying health. Superficial infections are generally treated with topical antifungals. Systemic infections require oral or intravenous administration of antifungal drugs.

Epidemiology

Candida species are ubiquitous in the environment and can be isolated from objects and surfaces. Human-to-human transmission can occur, particularly in hospital settings. The incidence of candidiasis has increased in recent years, partly due to the growing population of immunocompromised individuals, including those with HIV/AIDS, cancer, transplant, and neonatal patients.

Prevention

Prevention of Candida infections involves measures to maintain normal flora, such as the use of probiotics, and to avoid unnecessary use of antibiotics and immunosuppressive drugs. Good personal hygiene and regular cleaning of surfaces can reduce the risk of transmission.