Candida (genus)

Candida is a genus of yeasts. Many species of this genus are endosymbionts of animal hosts including humans. While usually living as commensals, some Candida species have the potential to cause disease. Clinically, the most significant member of the genus is Candida albicans, which can cause infections (called candidiasis or thrush) in humans and other animals, especially in immunocompromised patients. Many Candida species are members of gut flora in animals, including C. albicans in mammalian hosts, whereas others live as endosymbionts in insect hosts.

The last decade has seen the sustained medical importance of opportunistic infections due to different Candida species mainly due to the worldwide increase in the number of immunocompromised patients, who are highly susceptible to opportunistic infections. Meanwhile, the genome sequence of several Candida species has been completed, enabling the detailed investigation of some aspects of their biology with the aid of post-genomic approaches. The basic knowledge gained from these investigations of pathogenic Candida, and related yeasts, can translate into innovations in the development of novel antifungal therapies, original approaches for targeted immuno-interventions, or highly sensitive diagnosis of fungal infections.

Candida antarctica is a source of industrially relevant lipases.

Laboratory characteristics

Grown in the laboratory, Candida appears as large, round, white or cream (albicans is from Latin meaning 'whitish') colonies on agar plates.

Clinical characteristics

Some Candida species are responsible for superficial infections such as oropharyngeal candidiasis (thrush) and vulvovaginal candidiasis (vaginal Candidiasis). In otherwise healthy individuals, these infections can be cured with antifungal medications. However, persistent and deep-seated yeast infections can be lethal in, e.g., AIDS patients.

Candida are also responsible for a number of life-threatening opportunistic infections in AIDS patients and other immunocompromised persons - including patients treated in intensive care units (ICUs), cancer patients receiving chemotherapy, and organ transplant patients.

Another common Candida infection is oral candidiasis caused by acrylic dentures, especially in elderly denture wearers. Colonization of the gastrointestinal tract by C. albicans may result from taking antacids or antihyperacidity drugs. This colonization may interfere with absorption of Coenzyme Q10.

Species

Among Candida species, C. albicans, which is normal constituent of the human flora, a commensal of the skin and the gastrointestinal and genitourinary tracts, is responsible for the majority of Candida bloodstream infections (candidemia). Yet, there is an increasing incidence of infections caused by C. glabrata, which could be because it is frequently less susceptible to the currently used azole antifungals. Other medically important Candida species include C. parapsilosis, C. tropicalis, and C. dubliniensis.

Other Candida species, such as C. oleophila have been used as biological control agents in fruit.

Other

Alternative medicine practitioners use the term Candida to refer to a complex with broad spectrum of symptoms, the majority of which center around gastrointestinal distress, rashes, sore gums and other miscellaneous symptoms. Candida is accorded responsibility for symptoms as specific as hayfever, as vague as "foggy brain" and as common as weight gain or flatulence. These symptoms are attributed by alternative medicine practitioners to the "overgrowth" of intestinal candida albicans, which they claim leads to the spread of the yeast to other parts of the body via the bloodstream.

Use of the term Candida by alternative medicine practitioners to describe this complex and its unassociated use in biomedicine to refer to the fungus that causes vaginal yeast infections and thrush can be confusing for patients. No studies have proved that having intestinal candidiasis causes any symptoms of illness.

To treat what they refer to as Candida, alternative medicine practitioners will often recommend avoiding antibiotics, birth control, and foods that are high in sugar or yeast, ostensibly to "eliminate excess yeast" in the body. However, there is no evidence that these "candida cleanse" treatments treat intestinal candidiasis effectively.

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