Cryptococcosis

Cryptococcosis is a chronic mycotic infection caused by Cryptococcus neoformans variation neoformans and Cryptococcus neoformans var. gattii, both considered opportunistic. Though the organism is usually harmless to humans, the yeast type fungus can severely affect those with severe immunosuppression, such as HIV and AIDS patients.

In 1894 Greifswal Medical Society was presented with a paper by a pathologist named Busse, stating that he managed to isolate yeast from a womanÐŽ¦s tibia. It was noted the resistance to sodium hydroxide. At the same time yet another physician, a surgeon noted an exact report of the same organism from the same patient; this condition was later named Busse-Buschke disease. Later reports of cryptococcal infections ranged from simple colonization of the airways and asymptomatic infections of laboratory employees to meningitis or circulated disease. The number one factor in whether a person may or may not become infected by a strain of cryptococci is the immune status of the host; because most of the serious infections occur in patients with some form of immunosuppression. In fact, cryptococcosis has now become a major life-threatening fugal infection in AIDS patients (King MD).

The most common variation of Cryptococcus in the United States, and other mild climate regions of the world is C. neoformans var. neoformans. This variation is usually found in the fecal droppings of pigeons. On the other hand C. neoformans var. gattii is found in the tropical regions of the world and grows in around some species of eucalyptus trees, not from birds. The rate of maturity of this organism is very fast each cell is expected to reach maturity in as little as 3 days (Larone 55). Though this infection is prevalent in immunosuppressed patients it is not limited to them, in fact C neoformans var. gattii does not commonly infect those patients with weakened immune systems but is more commonly found in those considered healthy and immunnocompetent. This is opposed to the fact that C neoformans var neoformans causes most of the world wide cryptococcal infections and targets immunosuppresed patients. This variation causes 85% of the cryptococcal infections in the United States amongst HIV patients (Cryptococcois).

This yeast buds and forms yeast like round cells, usually 3-6 Ñ"Эm in diameter. These cells have a polysaccharide capsule that surrounds each one, this capsule is composed of mannose, xylose, and glucuronic acid, and rarely psuedohyphae are formed (King MD). This fungus is identified by its appearance, biochemical tests, but mainly at its ability to grow at 37ÑžXC, because most nonpathogenic strains do not grow at that temperature. Also, majority of the strains of C neoformans use creatinine as a nitrogen source, which explains the growth in the pigeon feces; pigeon feces is rich in creatinine. Also, the pathogenic strains produce melanin, while the nonpathogenic stains do not (King MD).

This organismÐŽ¦s primary route of infection is through the respiratory tract, and does not usually transfer from human to human. This is contracted by the inhalation of the yeast spores and basidospores. Also, this organism has not been found to have an animal to human transmission. Because this yeast forms a capsule around each cell it makes it resistant to the immune-response. Once the bodyÐŽ¦s phagocytes located in the respiratory tract reach the infection, the encapsulated yeast cells block recognition of the yeast. This result is the lack of response by the bodyÐŽ¦s main defenses the leukocytes, white blood cells. The bodyÐŽ¦s production of antibodies is crucial in the defense of this infection. These antibodies increase the lymphocyte and macrophage response to the cryptococcal infection (King MD).

The bodyÐŽ¦s naturally inflammatory response does not apply to most cryptococcal infections. Actually, the lesions formed by C neoformans have no well-defined inflammatory response, only a cystic cluster of yeast. This organism lack identifiable endo- or exo- toxins resulting in the absence of necrosis, death of the surrounding tissue, in early infections. Though necrosis is not noticed in the early stages of infection, necrosis may occur late in the infection because of fugal burden and distortion. Since necrosis is not identified early on in the disease, one of the first indications of infection is the development of meningitis. The development of meningitis can cause such life long problems as neurological damage or even death, the approximate mortality rate is 12% with meningitis caused by a cryptococcal infection (Cryptococcosis). Of patients that have a diagnosed with a central nervous system infection 80% die within 2 years of discovery of the infection. Also lesions of the skin are apparent in 10-15% of patients leading to things such as papules, pustules, or ulcers. The formation of skin lesions in patients is another signature characteristic of this organism along with infections of the prostate and of the Medullary cavity of the bone. Because of the pulmonary invasion of the disease it is very likely that such problems like pneumonia, pulmonary nodules or even pleural effusion (King MD).

Though the organism enters through the respiratory tract majority of the patients with the infection primarily in their lungs are immunocompetent. The respiratory symptoms of those patients with intact immune systems usually are asymptomatic or so mild that the patient does not need to seek medical attention. All physical signs and symptoms are ultimately determined by the status of the patientÐŽ¦s immune response and capabilities (King MD).

Patients with cryptococcal infection generally have to undergo antifungal therapy, though pulmonary cryptococcosis is resolved with out medical treatment in immunocompetent patients. HIV patients with a C neofomans infection are usually controlled with