{ "schema_version": "1.0", "level": "species", "genus": "Cryptococcus", "species": "neoformans", "overview": { "short": "Cryptococcus neoformans is an encapsulated yeast most strongly associated with opportunistic infection and cryptococcal meningoencephalitis.", "clinical_context": "Classically affects immunocompromised hosts (especially HIV/AIDS), causing pulmonary disease and CNS infection." }, "expected_fields": { "Gram Stain": "Variable", "Shape": "Yeast", "Motility": "Negative", "Capsule": "Positive", "Spore Formation": "Negative", "Haemolysis": "Negative", "Haemolysis Type": "None", "Media Grown On": [ "Sabouraud Dextrose Agar", "Blood Agar" ], "Colony Morphology": [ "Mucoid", "Cream", "Smooth" ], "Oxygen Requirement": "Aerobe", "Growth Temperature": "25//37", "Catalase": "Positive", "Oxidase": "Negative", "Indole": "Negative", "Urease": "Positive", "Citrate": "Negative", "Methyl Red": "Unknown", "VP": "Unknown", "H2S": "Negative", "DNase": "Negative", "ONPG": "Negative", "Coagulase": "Negative", "Gelatin Hydrolysis": "Negative", "Esculin Hydrolysis": "Negative", "Nitrate Reduction": "Negative", "NaCl Tolerant (>=6%)": "Negative", "Lipase Test": "Negative", "Lysine Decarboxylase": "Negative", "Ornithine Decarboxylase": "Negative", "Ornitihine Decarboxylase": "Negative", "Arginine dihydrolase": "Negative", "Glucose Fermentation": "Negative", "Lactose Fermentation": "Negative", "Sucrose Fermentation": "Negative", "Maltose Fermentation": "Negative", "Mannitol Fermentation": "Negative", "Sorbitol Fermentation": "Negative", "Xylose Fermentation": "Negative", "Rhamnose Fermentation": "Negative", "Arabinose Fermentation": "Negative", "Raffinose Fermentation": "Negative", "Trehalose Fermentation": "Negative", "Inositol Fermentation": "Positive", "Gas Production": "Negative", "TSI Pattern": "Unknown", "Colony Pattern": "Unknown", "Pigment": "None", "Motility Type": "None" }, "species_markers": [ { "field": "Growth Temperature", "value": "25//37", "importance": "high", "notes": "Consistent growth at 37°C supports pathogenic Cryptococcus species; helps separate from more environmental yeasts." }, { "field": "Capsule", "value": "Positive", "importance": "high", "notes": "Strong encapsulation is a key feature in clinical isolates." }, { "field": "Urease", "value": "Positive", "importance": "high", "notes": "Urease positivity is expected and supports Cryptococcus identification." } ], "common_confusions": [ { "species": "Cryptococcus gattii", "reason": "Closely related; both are encapsulated urease-positive yeasts with overlapping phenotypes." }, { "genus": "Candida", "reason": "Yeast morphology can confuse early screening, but Candida is typically capsule-negative and urease-negative." } ], "when_to_question_identification": [ "Capsule not demonstrated argues against Cryptococcus neoformans.", "Urease negativity suggests a different yeast genus.", "A strong sugar fermentation profile is inconsistent with Cryptococcus." ], "recommended_next_tests": [ { "test": "India ink preparation", "reason": "Demonstrates characteristic capsule.", "api_kit": "Not applicable" }, { "test": "Cryptococcal antigen (CrAg) test", "reason": "Highly useful in clinical context, especially suspected CNS infection.", "api_kit": "Not applicable" }, { "test": "MALDI-TOF MS", "reason": "Reliable species-level ID between neoformans vs gattii complex.", "api_kit": "Not applicable" } ] }