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{
"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"
}
]
} |