The capsular polysaccharides are long, unbranched polymers consisting of an α-1,3-linked polymannose backbone with β-linked monomeric branches of xylose and glucuronic acid.Their virulence is enhanced by the production of laccase and capsule, and the presence of the capsular polysaccharide.Pathogenesis and Clinical Features of Cryptococcus neoformans Infection Virulence Factors This produces the monokaryotic fruit which contributes to the fungal virulence. During this process of meiotic reproduction, they can also promote DNA repair from damages of oxidative and nitrosative stress.This mechanism is known as monokaryotic fruiting. Blastospores have the ability to undergo meiosis to form haploid basidiospores that are easily dispersed. The filaments of the mating types alpha have a haploid nucleus, which undergoes diploidization forming diploid cells called blastospores.They can also undergo sexual reproduction of meiosis by the alpha types of the fungi. The upper panel depicts the traditional bisexual mating involving partners of opposite mating types a and α, and the lower panel depicts unisexual mating that occurs between partners of the same mating-type or with itself. Image Source: Elsevier Inc. They then remain latent in the macrophages which have been associated with disease dissemination and resistance to antifungal drugs.įigure: The life cycle of Cryptococcus neoformans.the macrophages produce oxidative and nitrosative agents which normally kill microorganisms but Cryptococcus neoformans have the ability to escape killing by Oxidative reaction, by upregulation of expressing genes of oxidative stress. When it gains entry into the lungs, they get phagocytosed by the alveolar macrophages.They then disseminate into the Central nervous system where it causes meningoencephalitis.The yeast-like fungus gains entry into the human host via inhalation of aerosolized basidiospores.The fungus has the ability to colonize phagocytic cells and undergoes vomocytosis, hence it escapes phagocytosis without processing.Cryptococcus neoformans is a facultative intracellular pathogen, which uses human phagocytes to spread within the body.Cryptococcus neoformans affect immunocompetent persons but more often in patients with HIV/AIDS, tuberculosis, hematogenous malignancies, and hospitalized patients majorly those with invasive devices.
This infection is otherwise known as cryptococcosis, which is a systemic infection primarily involving the lungs and central nervous system.The yeast then migrates to the central nervous system causing meningoencephalitis. Its human pathogenicity is via inhalation of desiccated yeast cells or small basidiospores.Cryptococcus neorformans distinguishes from other fungal yeasts by the presence of a polysaccharide capsule, the formation of melanin, and urease activity, which all function as virulence determinants.laurentii and C.gittii are mildly pathogenic. albidus and C.laurentii are the most common species and C.neorformans is the most pathogenic of these species, for both humans and animals, while C. There are four known species of Cryptococcus:.They undergo sexual reproduction forming dikaryotic hyphae and basidiospores supported by a club-shaped basidium with hyphae that has a complex septate.Cryptococcus spp is a fungal group that belongs to the Phylum Basidiomycota (Basidiomycetes).
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