Candida is a
genusIn biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of
yeastYeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...
s. Many species are harmless
commensalsIn ecology, commensalism is a class of relationship between two organisms where one organism benefits but the other is neutral...
or
endosymbiontAn endosymbiont is any organism that lives within the body or cells of another organism, i.e. forming an endosymbiosis...
s of animal hosts including humans, but other species, or harmless species in the wrong location, can cause disease.
Candida albicansCandida albicans is a diploid fungus that grows both as yeast and filamentous cells and a causal agent of opportunistic oral and genital infections in humans. Systemic fungal infections including those by C...
can cause infections (
candidiasisThrush redirects here. For the hoof infection see Thrush .Candidiasis or thrush is a fungal infection of any of the Candida species , of which Candida albicans is the most common...
or thrush) in
humanHumans are the only living species in the Homo genus...
s and other animals, especially in immunocompromised patients. Many species are found in
gut floraGut flora consists of microorganisms that live in the digestive tracts of animals and is the largest reservoir of human flora. In this context, gut is synonymous with intestinal, and flora with microbiota and microflora....
, including
C. albicans in mammalian hosts, whereas others live as endosymbionts in insect hosts.
Systemic infections of the bloodstream and major organs, particularly in immunocompromised patients, affect over 90,000 people a year in the U.S., with a 40-50% mortality.
The DNA of several
Candida species have been sequenced.
Antibiotics promote yeast infections, including gastrointestinal
Candida overgrowth, and penetration of the GI mucosa.Many people are under the impression that only women get genital yeast infections. Regardless of gender, prolonged antibiotic use increases your risk of a yeast infection. Also, men and women with diabetes or impaired immune systems, such as those with HIV, are more susceptible to yeast infections.
Some practitioners of
alternative medicineAlternative medicine is any healing practice, "that does not fall within the realm of conventional medicine." It is based on historical or cultural traditions, rather than on scientific evidence....
claim that
Candida overgrowth can cause many health problems, including fatigue to weight gain, but most traditional doctors reject this.
Candida antarctica is a source of industrially important
lipaseA lipase is an enzyme that catalyzes the formation or cleavage of fats . Lipases are a subclass of the esterases.Lipases perform essential roles in the digestion, transport and processing of dietary lipids in most, if not all, living organisms...
s.
Laboratory characteristics
Grown in the
laboratoryA medical laboratory or clinical laboratory is a laboratory where tests are done on clinical specimens in order to get information about the health of a patient as pertaining to the diagnosis, treatment, and prevention of disease.-Departments:...
,
Candida appears as large, round, white or cream (
albicans is from
LatinLatin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
meaning 'whitish') colonies with a yeasty odor on
agar plateAn agar plate is a Petri dish that contains a growth medium used to culture microorganisms or small plants like the moss Physcomitrella patens.Selective growth compounds may also be added to the media, such as antibiotics....
s at room temperature.
C. albicans ferments
glucoseGlucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
and
maltoseMaltose , or malt sugar, is a disaccharide formed from two units of glucose joined with an αbond, formed from a condensation reaction. The isomer "isomaltose" has two glucose molecules linked through an α bond. Maltose is the second member of an important biochemical series of glucose chains....
to acid and gas,
sucroseSucrose is the organic compound commonly known as table sugar and sometimes called saccharose. A white, odorless, crystalline powder with a sweet taste, it is best known for its role in human nutrition. The molecule is a disaccharide composed of glucose and fructose with the molecular formula...
to acid, and does not ferment
lactoseLactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2~8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from or , the Latin word for milk,...
, which help to distinguish it from other
Candida species.
Clinical characteristics
Candida are almost universal on normal adult skin and
albicans is part of the normal flora of the mucous membranes of the respiratory, gastrointestinal, and female genital tracts which cause no disease.
But overgrowth of several species including
albicans can cause superficial infections such as oropharyngeal
candidiasisThrush redirects here. For the hoof infection see Thrush .Candidiasis or thrush is a fungal infection of any of the Candida species , of which Candida albicans is the most common...
(thrush) and vulvovaginal candidiasis (vaginal candidiasis). Oral candidiasis is common in elderly denture wearers. In otherwise healthy individuals, these infections can be cured with topical or systemic antifungal medications (commonly over-the-counter treatments like miconazole or clotrimazole). In debilitated or immunocompromised patients, or if introduced intravenously, candidiasis may become a systemic disease producing abscess, thrombophlebitis, endocarditis, or infections of the eyes or other organs.
Colonization of the
gastrointestinal tractThe human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
by
C. albicansCandida albicans is a diploid fungus that grows both as yeast and filamentous cells and a causal agent of opportunistic oral and genital infections in humans. Systemic fungal infections including those by C...
after antibiotic therapy usually causes no symptoms and may also result from taking antacids or antihyperacidity drugs.
Species
Among
Candida species,
C. albicans, which is a 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 and
C. rugosa, which could be because they are frequently less susceptible to the currently used
azoleAn azole is a class of five-membered nitrogen heterocyclic ring compounds containing at least one other non-carbon atom of either nitrogen, sulfur, or oxygen. The parent compounds are aromatic and have two double bonds; there are successively reduced analogs with fewer...
antifungals. Other medically important
Candida species include
C. parapsilosis,
C. tropicalis, and
C. dubliniensis.
Other
Candida species, such as
C. oleophilaCandida oleophila is a species of yeast in the genus Candida.-External links:*...
have been used as biological control agents in fruit.
Alternative medicine therapies
Many practitioners of
alternative medicineAlternative medicine is any healing practice, "that does not fall within the realm of conventional medicine." It is based on historical or cultural traditions, rather than on scientific evidence....
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 hay fever, as vague as "
brain fogCognitive dysfunction is defined as unusually poor mental function, associated with confusion, forgetfulness and difficulty concentrating...
" and as common as weight gain or flatulence. These symptoms are attributed by some 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 digestive tract and bloodstream.
Use of the term
Candida in alternative medicine to describe this complex is unassociated with its use in clinical medicine to refer to the fungus that causes vaginal yeast infections and thrush. This can be confusing for patients. No studies have proven that having intestinal candidiasis causes any symptoms of illness.
To treat what they refer to as
Candida, some alternative medicine practitioners have recommended avoiding antibiotics, birth control pills, and foods that are high in sugar or yeast, ostensibly to "eliminate excess yeast" in the body. However, there is little clinically valid evidence that these "
Candida cleanse" treatments treat intestinal candidiasis effectively, or cure any of the symptoms claimed by the proponents of the hypothesis.
The probiotic
Saccharomyces boulardiiSaccharomyces boulardii is a tropical strain of yeast first isolated from lychee and mangosteen fruit in 1923 by French scientist Henri Boulard. It is related to, but distinct from, Saccharomyces cerevisiae in several taxonomic, metabolic, and genetic properties. S...
has been shown to diminish levels of intestinal
Candida in mice. This is therefore one of the specific probiotic strains often recommended by alternative medicine practitioners alongside a more general probiotic, for anyone on a "
Candida cleanse" or "
Candida diet".