Identification: Cryptococcus neoformans is identified by urease production and carbohydrate assimilation test, and confirmed by direct immunoflurorescence using a fluorescein-labeled anti- neoformans antibody. neoformans in Bird Seed Agar (source: The University of Adelaide) It is usually surrounded by a wide refractile capsule. Microscopy and stainingĬryptococcus neoformans appear as a spherical, single or multiple budding, thick-walled yeast that is 2-15 μm (wide variation in size) in diameter. Common specimens include spinal fluid (CSF), tissue, exudates, sputum, blood, and urine. Specimens: Specimens depends on clinical presentation and suspected disease conditions.
#India ink stain cryptococcus skin#
Skin and other infections: Sometimes skin, lymph nodes, bones are involved.Reactivation of old healed lesions may occur. Lung infections: Pulmonary disease is increasing nowadays, particularly in immunocompromised hosts.Blurry vision (and other cranial nerve deficits).Change in mental status (ranging from confusion to lethargy to coma).Signs and symptoms of cryptococcal meningitis.About 5-8% of patients with AIDS develop cryptococcal meningitis. All untreated cases of cryptococcal meningitis are ultimately fatal. Cryptococcal meningitis: Only in a small proportion of cases, hematogenous spread results in subacute or chronic meningitis or meningoencephalitis.People with immune-compromised status are likely to be affected more and have serious outcomes Infection occurs from the environment usually by inhalation, especially of dust containing excreta of pigeons but the infection is not transmitted from person to person. Cryptococcal infection occurs throughout the world sporadically. Important risk factors include AIDS, corticosteroid therapy, lymphoma, and T cell dysfunction. DiseasesĬryptococcosis is most often seen in immune-compromised patients with impaired T cell immunity. Phenoloxidase also protects the organism from oxidants released by phagocytic cells. It has been found that increased melanin production can decrease lymphocyte proliferation and tumor necrosis factor production. Melanin is might act as a virulence factor by making the organism resistant to leukocytes attack. Phenoloxidase: This enzyme is responsible for melanin production.Ideal size range for alveolar deposition: the cell size reduction, resulting from capsular collapse, places the yeast in the ideal size range for alveolar deposition.Protection under drying conditions: The capsule collapses and protects the yeast.Anti-phagocytic: Polysaccharide capsule contains compounds that are not recognized by phagocytes.Capsule: Cryptococcus neoformans is the only pathogenic yeast known to have a polysaccharide capsule.Virulence Factors of Cryptococcus neformans The inflammatory reaction is usually minimal or granulomatous. Other common sites of dissemination include the skin, adrenals, bone, eye and prostate gland. In immune-compromised patients with impaired T cell immunity, the yeasts may multiply and disseminate to other parts of the body but preferentially to the central nervous system (neurotropic), causing cryptococcal meningitis. The primary pulmonary infection may be asymptomatic or may mimic influenza-like respiratory infection often resolving spontaneously. Infection is initiated by inhalation of the yeast cells.
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