Candida parapsilosis is a yeast fungus with a diploid chromosome set that can infect human mucous membranes and cause fungal infection. The fungus has a nearly ubiquitous distribution and usually occurs in humans as a heterotrophic commensal that feeds on dead cellular debris without causing harm. Candida parapsilosis becomes pathogenic mainly in individuals with weakened or artificially suppressed immune systems.
What is Candida parapsilosis?
Candida parapsilosis is one of the types of yeast fungi that can cause a Candida infection, candidiasis, in humans. The fungus is nearly ubiquitous and usually occurs as a low-interference commensal that feeds on dead tissue as a heterotroph. Thus, unlike other Candida species, Candida parapsilosis is not an obligate human pathogen. Candida parapsilosis can become distinctly pathogenic when it encounters an immune system weakened by disease or artificially suppressed. It is therefore classified as an opportunistic pathogen and also occurs as a hospital-acquired nosocomial pathogen. The fungus can cause mild to severe candidiasis on the mucous membranes in the mouth and throat, in the genital area or in the digestive tract. Of all Candida infections that occur, Candida parapsilosis infections account for about 15 percent. The fungus has a diploid chromosome set as a special characteristic, but reproduces exclusively asexually. Based on DNA that can be distinguished from one another, Candida parapsilosis can be divided into groups I, II, or III.
Occurrence, distribution, and characteristics
The yeast Candida parapsilosis, as a fungus not exclusively specialized for humans, is detectable almost everywhere as a commensal and opportunistic pathogen. A problem, especially for hospitals, is that the fungus adheres well to implants, catheters, and other medical equipment, allowing it to enter directly into the bloodstream or other organs where it can cause nosocomial infections. Eventual direct detection of the fungus on organs – as long as no symptoms are apparent – is difficult. Candida parapsilosis is also thought to be potentially carcinogenic. If a systemic infection is present, in the worst case muscles, heart and nervous system can be affected in addition to the skin, with a sometimes severe course. Overall, the fungus shows a preference for mucous membranes, for example in the mouth and throat area as well as in the intestine. Since colonization of the mucous membranes with Candida parapsilosis can be classified as rather normal, it is difficult to differentiate between a rather harmless colonization and a pathological candidiasis in many cases.
Significance and function
What positive significance Candida parapsilosis has for the body and for metabolism when it occurs as a commensal in the intestinal mucosa and in other mucous membranes has not been adequately researched. Obviously, the potential pathogenicity of the fungus is more in the focus of interest than its possible positive meanings. On several occasions, Candida parapsilosis has been associated with the elimination of toxic heavy metals from the body. The fungus is believed to have the ability to bind heavy metals present in certain tissues and eliminate them naturally through the intestines. Some authors hypothesize that increased accumulation of Candida fungi causing candidiasis often correlates with contamination with toxic heavy metals and is causally related. This would mean that candidiasis is not only promoted by a weakened immune system, but also by an accumulation of toxic heavy metals in the organism. Conversely, it can then be assumed that after the heavy metals have been removed from the body, the accumulation of candida fungi is also reduced to a non-pathogenic normal level. If the hypothesis proves to be true, combating Candida fungi in the presence of simultaneous heavy metal poisoning could even be counterproductive, as this could hinder the elimination of heavy metals.
Diseases and ailments
As an opportunistic pathogen, Candida parapsilosis basically has the potential to cause candidiasis with a mild to severe course.People with fully functional immune systems very rarely show pathological symptoms indicative of candidiasis, although their mucous membranes are frequently colonized with Candida parapsilosis. The risk of developing candidiasis increases significantly in people whose immune system is weakened by disease or malnutrition or whose immune system has been artificially suppressed, for example, to suppress rejection reactions after transplantation with tissue foreign to the body. The risk of fungal infection also increases with various cancer treatments accompanied by chemotherapy or radiotherapy. Typical diseases that correlate with an increased risk of candidiasis are immunodeficiency diseases such as AIDS and diabetes mellitus. Likewise, the risk of infection can increase as a result of taking certain medications in the form of undesirable side effects. This is particularly the case after treatment with antibiotics. A problem for clinicians is the ability of Candida parapsilosis to adhere to catheters and implants, such as heart valve replacements or similar objects, and thus be inserted directly into the heart or other organs, where the fungus can cause serious infection. For example, after insertion of a synthetic heart valve, there is a residual risk of developing endocarditis, an infection of the inner lining of the heart, caused by Candida parapsilosis. A similar postoperative risk exists after the insertion of an artificial eye lens. Adherent Candida fungi can cause endophthalmitis, an inflammation of the eyeball, to develop. Peritonitis has also been observed after peritoneal dialysis. In rare cases, Candida parapsilosis can cause pneumonia. In addition, newborns in whom the immune system is not yet fully developed show increased susceptibility to infection with Candida parapsilosis.
