Candida (fungus)

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Candida
Candida albicans at 200X magnification.
Scientific classification
Kingdom:Fungi
Phylum:Ascomycota
Subphylum:Saccharomycotina
Class:Saccharomycetes
Order:Saccharomycetales
Family:Saccharomycetaceae
Genus:Candida
Berkh., 1923
Species

C. albicans
C. ascalaphidarum
C. amphixiae
C. antarctica
C. argentea
C. atlantica
C. atmosphaerica
C. blattae
C. carpophila
C. carvajalis[1]
C. cerambycidarum
C. chauliodes
C. corydali
C. dosseyi
C. dubliniensis
C. ergatensis
C. fructus
C. glabrata
C. fermentati
C. guilliermondii
C. haemulonii
C. insectamens
C. insectorum
C. intermedia
C. jeffresii
C. kefyr
C. krusei
C. lusitaniae
C. lyxosophila
C. maltosa
C. marina
C. membranifaciens
C. milleri
C. oleophila
C. oregonensis
C. parapsilosis
C. quercitrusa
C. rugosa
C. sake
C. shehatea
C. temnochilae
C. tenuis
C. theae[2]
C. tropicalis
C. tsuchiyae
C. sinolaborantium
C. sojae
C. subhashii
C. viswanathii
C. utilis

 
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Candida
Candida albicans at 200X magnification.
Scientific classification
Kingdom:Fungi
Phylum:Ascomycota
Subphylum:Saccharomycotina
Class:Saccharomycetes
Order:Saccharomycetales
Family:Saccharomycetaceae
Genus:Candida
Berkh., 1923
Species

C. albicans
C. ascalaphidarum
C. amphixiae
C. antarctica
C. argentea
C. atlantica
C. atmosphaerica
C. blattae
C. carpophila
C. carvajalis[1]
C. cerambycidarum
C. chauliodes
C. corydali
C. dosseyi
C. dubliniensis
C. ergatensis
C. fructus
C. glabrata
C. fermentati
C. guilliermondii
C. haemulonii
C. insectamens
C. insectorum
C. intermedia
C. jeffresii
C. kefyr
C. krusei
C. lusitaniae
C. lyxosophila
C. maltosa
C. marina
C. membranifaciens
C. milleri
C. oleophila
C. oregonensis
C. parapsilosis
C. quercitrusa
C. rugosa
C. sake
C. shehatea
C. temnochilae
C. tenuis
C. theae[2]
C. tropicalis
C. tsuchiyae
C. sinolaborantium
C. sojae
C. subhashii
C. viswanathii
C. utilis

Candida is a genus of yeasts. Many species are harmless commensals or endosymbionts of hosts including humans, but other species, or harmless species in the wrong location, can cause disease. Candida albicans can cause infections (candidiasis or thrush) in humans and other animals, especially in immunocompromised patients.[3] In winemaking, some species of Candida can create potential faults in wines.[4]

Many species are found in gut flora, including C. albicans in mammalian hosts, whereas others live as endosymbionts in insect hosts.[5][6]

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.[7][8]

The DNA of several Candida species have been sequenced.[8]

Antibiotics promote yeast infections, including gastrointestinal Candida overgrowth, and penetration of the GI mucosa.[9] While women are more susceptible to genital yeast infections, men can in fact get them as well. Certain factors, like prolonged antibiotic use, increase the risk for both men and women. Also, individuals with diabetes or impaired immune systems, such as those with HIV, are more susceptible to yeast infections.[10][11]

Some practitioners of alternative medicine say that Candida overgrowth can cause many health problems, including fatigue, headache, poor memory and weight gain, but most medical doctors state that there is currently little evidence to support this and that a yeast problem should not be diagnosed without definite clinical signs of an infection.[12][13]

Candida antarctica is a source of industrially important lipases.

Contents

Laboratory characteristics

Grown in the laboratory, Candida appears as large, round, white or cream (albicans is from Latin meaning 'whitish') colonies with a yeasty odor on agar plates at room temperature.[14] C. albicans ferments glucose and maltose to acid and gas, sucrose to acid, and does not ferment lactose, which help to distinguish it from other Candida species.[15]

Clinical characteristics

Candida are almost universal in low numbers on healthy adult skin[15] and albicans is part of the normal flora of the mucous membranes of the respiratory, gastrointestinal, and female genital tracts. In the case of skin, the dryness of skin compared to other tissues prevents the growth of the fungus, but damaged skin or skin in intertriginous regions is more amenable to rapid growth of fungi.[16]

But overgrowth of several species including albicans can cause superficial infections such as oropharyngeal candidiasis (thrush) and vulvovaginal candidiasis (vaginal candidiasis). Oral candidiasis is common in elderly denture wearers.[17] In otherwise healthy individuals, these infections can be cured with topical or systemic antifungal medications [18] (commonly over-the-counter antifungal 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.[8][15] Typically, relatively severe neutropenia is a prerequisite for the Candida to pass through the defenses of the skin and cause disease in deeper tissues; in such cases, mechanical disruption of the infected skin sites is typically a factor in the fungal invasion of the deeper tissues.[16]

Colonization of the gastrointestinal tract by C. albicans after antibiotic therapy may not cause symptoms[15] and may also result from taking antacids or antihyperacidity drugs.[citation needed]

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 azole antifungals.[19] Other medically important Candida species include C. parapsilosis, C. tropicalis, and C. dubliniensis.[8]

Other Candida species, such as C. oleophila have been used as biological control agents in fruit.[20]

Alternative therapies

Many practitioners of alternative medicine 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 fog" 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.[21]

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.[12][13] This can be confusing for patients. No studies have proven that having intestinal candidiasis causes any symptoms of illness.[12][13]

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. But, many people apparently suffering from candidiasis claim relief from these methods.[12][13]

The probiotic Saccharomyces boulardii has been shown to diminish levels of intestinal Candida in mice.[22] 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".

References

  1. ^ James, S. A.; Carvajal Barriga, E. J.; Bond, C. J.; Cross, K.; Nãºã±Ez, N. C.; Portero, P. B.; Roberts, I. N. (2009). "Candida carvajalissp. Nov., an ascomycetous yeast species from the Ecuadorian Amazon jungle". FEMS Yeast Research 9 (5): 784–788. doi:10.1111/j.1567-1364.2009.00518.x. PMID 19459983. edit
  2. ^ Chang, C. F.; Lin, Y. C.; Chen, S. F.; Carvaja Barriga, E. J.; Barahona, P. P.; James, S. A.; Bond, C. J.; Roberts, I. N. et al. (2012). "Candida theae sp. nov., a new anamorphic beverage-associated member of the Lodderomyces clade". International Journal of Food Microbiology 153 (1–2): 10–14. doi:10.1016/j.ijfoodmicro.2011.09.012. PMID 22088606. edit
  3. ^ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. ISBN 0-8385-8529-9.
  4. ^ K. Fugelsang, C. Edwards Wine Microbiology Second Edition, pp. 3–28 Springer Science and Business Media , New York (2010) ISBN 0387333495
  5. ^ Nguyen NH, Suh SO, Blackwell M (2007). "Five novel Candida species in insect-associated yeast clades isolated from Neuroptera and other insects". Mycologia 99 (6): 842–858. doi:10.3852/mycologia.99.6.842. PMID 18333508.
  6. ^ Suh SO, Nguyen NH, Blackwell M (2008). "Yeasts isolated from plant-associated beetles and other insects: seven novel Candida species near Candida albicans". FEMS Yeast Res 8 (1): 88–102. doi:10.1111/j.1567-1364.2007.00320.x. PMID 17986254.
  7. ^ Candidiasis in Emergency Medicine, Medscape Reference, Tarlan Hedayati, Rick Kulkarni, Updated Apr 15, 2010
  8. ^ a b c d dEnfert C; Hube B (editors) (2007). Candida: Comparative and Functional Genomics. Caister Academic Press. ISBN 978-1-904455-13-4.
  9. ^ Kennedy, MJ et al. "Mechanisms of association of Candida albicans with intestinal mucosa", Med Microbiol, volume-24, 333-341, 1987
  10. ^ http://www.mayoclinic.com/print/male-yeast-infection/HO00172/METHOD=print
  11. ^ http://www.nlm.nih.gov/medlineplus/yeastinfections.html#cat1
  12. ^ a b c d Mayoclinic.com. http://www.mayoclinic.com/health/candida-cleanse/AN01679.
  13. ^ a b c d Dubious "Yeast Allergies". http://www.quackwatch.org/01QuackeryRelatedTopics/candida.html.
  14. ^ "Candida species". DoctorFungus.org. Archived from the original on 2007-02-08. http://web.archive.org/web/20070208004957/http://www.doctorfungus.org/thefungi/Candida_spp.htm. Retrieved 2007-02-09.
  15. ^ a b c d Jawetz et al. (1978), "Medical Mycology", Review of Medical Microbiology (13th ed.), pp. 276–278
  16. ^ a b Goehring, Richard V. (2008). Mims' medical microbiology. (4th ed. ed.). Philadelphia, PA: Mosby Elsevier. pp. 656. ISBN 9780323044752.
  17. ^ Darwazeh A, Lamey P, Samaranayake L, MacFarlane T, Fisher B, Macrury S, MacCuish A (1990). "The relationship between colonisation, secretor status and in-vitro adhesion of Candida albicans to buccal epithelial cells from diabetics". J Med Microbiol 33 (1): 43–9. doi:10.1099/00222615-33-1-43. PMID 2231671.
  18. ^ http://www.webmd.com/skin-problems-and-treatments/candidiasis-yeast-infection?page=4
  19. ^ "Candida rugosa, an Emerging Fungal Pathogen with Resistance to Azoles: Geographic and Temporal Trends from the ARTEMIS DISK Antifungal Surveillance Program". J Clinical Microbiology 44: 3578–3582. 2006. http://jcm.asm.org/cgi/content/abstract/44/10/3578.
  20. ^ "Efficacy of Candida oleophila strain 128 in preventing Penicillium Expansum infection in apricot fruit". Acta Hort. (ISHS) 485: 141–148. 1999. http://www.actahort.org/books/485/485_18.htm.
  21. ^ What is Candida. http://www.chroniccandida.com/what-is-candida.html.[reference cited for viewpoint, not as reliable source]
  22. ^ Ducluzeau, D. and Bensaada, M. (1982).Comparative Effect of a Single or Continuous Administration of «Saccharomyces Boulardii» on the Establishment of Various Strains of «Candida» in the Digestive Tract of Gnotobiotic Mice

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