MORFOLOGIA: levedura, suas células tem caraerísticas esféricas e alongadas com ou sem blastoconídios, com capacdade limitada de formar hifas com clamidiosporos.
PATOGIA: raros casos de infecção pulmonar ou cutânea tem sido reportado. Também pode ser ocasionalmente recuperado como saprofitas de pele.
HABITAT:
C. laurentii é a levedura mais freqüentemente encontradas na tundra, da Antártida e os solos de pradaria, bem como nas superficies de folhas de muitos ecossistemas. As matérias fecais de aves saudáveis tem sido apontada como um importante repositório de fungos criptocócica.
http://www.mycology.adelaide.edu.au/Fungal_Descriptions/Yeasts/Cryptococcus/C_laurentii.html 20/04/11
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http://ddr.nal.usda.gov/bitstream/10113/32139/1/CAIN739173668.pdfCryptococcus laurentii Submitted by amh10 on 7 February, 2008 - 01:11 MRCPath Part2MycologyTraining Cryptococcus laurentii is an extremely rare human pathogen. This fungus was previously considered saprophytic and nonpathogenic to humans, but it has been isolated as the etiologic agent of skin infection, keratitis, endophthalmitis, lung abscess, peritonitis,meningitis and fungaemia. Ecology C. laurentii is the most frequently encountered yeast in tundra, Antarctic and prairie soils as well as the phyllosphere of numerous ecosystems. The faecal matter of healthy birds has been identified as an important repository for cryptococcal fungi. Although the related species C. neoformans has been identified as an important human pathogen, infections with C. laurentii occur almost exclusively in immuno-compromised individuals and rarely result in clinically significant outcomes. C. laurentii is psychrophillic and grows poorly above 30°C temperatures. While optimal growth temperatures of 15°C have been reported for this species, it is cryotolerant and can be successfully cultured at near freezing conditions. C. laurentii has been described as a facultative alkaliphile. On Sabouraud's dextrose agar colonies are cream colored, often becoming a deeper orange-yellow with age, with a smooth mucoid texture. Microscopic morphology : Spherical and elongated budding yeast-like cells or blastoconidia, 2.0-5.5 x 3.0-7.0 μm in size. No pseudohyphae present. India Ink Preparation: Positive - narrow but distinct capsules surrounding the yeast cells are present. Dalmau Plate Culture on Cornmeal and Tween 80 Agar: Budding yeast cells only. No pseudohyphae present. Physiological Tests: Germ Tube test is Negative Hydrolysis of Urea is Positive Growth on Cycloheximide medium is Variable Growth at 37C is Negative (weak growth in some strains) Fermentation Reactions: Where fermentation means the production of gas and is independent of pH changes. Negative: Glucose; Sucrose; Lactose; Galactose; Maltose; Trehalose. Susceptibility: •Can be fluconazole resistant •Usually treated with amphotericin REF: http://microblog.me.uk/332 Accessed: 20/04/11 Cryptococcus laurentii On Sabouraud's dextrose agar colonies are cream colored, often becoming a deeper orange-yellow with age, with a smooth mucoid texture. Microscopic morphology : Spherical and elongated budding yeast-like cells or blastoconidia, 2.0-5.5 x 3.0-7.0 um in size. No pseudohyphae present India Ink Preparation: Positive - narrow but distinct capsules surrounding the yeast cells are present. Dalmau Plate Culture on Cornmeal and Tween 80 Agar: Budding yeast cells only. No pseudohyphae present. Physiological Tests: Germ Tube test is Negative Hydrolysis of Urea is Positive Growth on Cycloheximide medium is Variable Growth at 37C is Negative (weak growth in some strains) Fermentation Reactions: Where fermentation means the production of gas and is independent of pH changes. Negative: Glucose; Sucrose; Lactose; Galactose; Maltose; Trehalose. Assimilation Tests: Positive: Glucose; Glucose; Galactose; Maltose; Sucrose; Trehalose; D-Xylose (weak); Melezitose; Lactose; Raffinose; Cellobiose; Melibiose; Inositol (delayed); L-Rhamnose; D-Arabinose; L-Arabinose; D-Mannitol; Ribitol; D-Ribose (delayed); Galactitol; Salicin. Variable: Erythritol; Soluble Starch; D-Glucitol; Glycerol; Citric acid; DL-Lactic acid; Succinic acid. Negative: Potassium nitrate; L-Sorbose (some positive). Clinical significance: Cryptococcus laurentii has been reported as a rare cause of pulmonary and cutaneous infection and CAPD associated peritonitis in humans. It may also be occasionally recovered as a saprophyte from skin. REF: http://www.mycology.adelaide.edu.au/Fungal_Descriptions/Yeasts/Cryptococcus/C_laurentii.html Accessed: 20/04/11 Look at this site: http://labmed.ucsf.edu/education/residency/fung_morph/fungal_site/yeastpage.html
