Candida albicans
Richard Campos

Candida albicans is a fungus that is from the genus Candida and can be found in small amounts in normal human intestine tracts can also grow out of control and infect areas such as the oral cavity, intestines, and gentiles.  There are several causes to this infection but one common cause is the use of antibiotics that destroy beneficial, as well as harmful, microorganisms in the body.

This organism is an endogenous organism and a diploid fungus capable of sexual reproduction but not meiosis.  C. albicans is normally unicellular however it can react to environmental cues and switches into an invasive, multicellular filamentous form.  Candida is a polymorphic yeast with yeast cells, hyphae, and pseudohyphae.  The yeast form is 10-12 microns in diameter, gram positive, and it grows overnight on most bacterial and fungal media.  Germ tubes and pseudohyphae may be formed from budding yeast cells that remain attached to each other.  The spores that are formed on the pseudomycelium are called chlamydospores and can be used to identify different species of Candida.

Whenever the C. albicans is found in the mouth it is referred to as thrush which appears as creamy-white or bluish-white patches on the tongue, which is inflamed and sometimes beefy red, and on the lining of the mouth or the throat.  When it appears on the vagina it is characterized by a white or yellow discharge, inflammation of the walls of the vagina, and causes burning and itching.  Although it is most frequently infects the skin and mucosae, it can also cause pneumonia, septicemia or endocarditis in immuno-compromised patients such as patients that have cancer or AIDS.  The immune system fights against C. Albicans by the involvement of the production of reactive oxygen species and nitrogen radicals such as nitric oxide, NO, that can damage the yeast or inhibit its growth.  However it is able to fight against NO by using enzymes, such as flavohemoglobin, an NO dioxygenase, to convert NO to less toxic molecules such as nitrate.  The gene that plays a central role in C. Albicans protection against NO is CaYHB1.

Complications with C. albicans can also arise from radiotherapy as described by a case report of a patient that had used such treaments.  A 46 year old male patient came into a clinic one week after radiotherapy, for esophageal carcinoma, with a fever and dyspnea.  The patient came in with white curdy lesions in the oral cavity.  Chest X-rays showed findings suggestive of enpyema.  The enpyema fluid was cultured on blood agar, Lownstein-Jensen medium and two tubes of Sabouraud’s dextrose agar, SDA, one incubated at 37°C and the other at 20°C.  The patient’s blood culture was done using brain-heart infusion broth which was subcultured on SDA.  After incubating for 48 hours typical creamy pasty colonies appeared on the blood agar and both tubes of SDA.

C. albicans was then isolated and identified by the germ tube test, growth on cornmeal agar.  Since there wasn’t anything else isolated antibacterial agents were stopped and the patient was started on intravenous Amphotericin B for 7 days followed by oral Fluconazole for 3 weeks.  From the oral cavity C. albicans can spill over into the blood and may cause bronchopulmory infection as was seen with this patient.

References

http://www.candidasupport.org/

http://www.medterms.com/script/main/art.asp?articlekey=11072

http://overcomingcandida.com/mycology/mycology-3.htm

http://en.wikipedia.org/wiki/Candida_albicans

http://www.healthscout.com/ency/68/312/main.html#cont

http://www.ijpmonline.org/article.asp?issn=0377-4929;year=2008;volume=51;issue=2;spage=286;epage=288;aulast=Baradkar#

http://ec.asm.org/cgi/reprint/3/3/715?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&searchid=1&FIRSTINDEX
=0&volume=3&firstpage=715&resourcetype=HWCIT

http://www.immunecliniclondon.com/phdi/p1.nsf/imgpages/2775_Candida-albicans-prep.jpg/$file/Candida-albicans-prep.jpg

http://www.consumerreports.org/health/resources//images/oral-thrush_default.jpg

*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.

 

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