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{
"schema_version": "1.0",
"level": "genus",
"genus": "Cryptococcus",
"overview": {
"short": "Cryptococcus species are encapsulated, yeast-form fungi primarily affecting immunocompromised hosts.",
"clinical_context": "Most commonly associated with pulmonary infections and meningoencephalitis, especially in HIV/AIDS and other immunosuppressed patients."
},
"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": "20//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"
},
"field_notes": {
"Capsule": "Prominent polysaccharide capsule is a defining feature and key virulence factor.",
"Urease": "Urease positivity is consistent across clinically relevant Cryptococcus species.",
"Inositol Fermentation": "Positive reaction is characteristic and aids differentiation from other yeasts."
},
"key_differentiators": [
{
"field": "Capsule",
"expected": "Positive",
"distinguishes_from": ["Candida"],
"notes": "Encapsulation separates Cryptococcus from most Candida species."
},
{
"field": "Urease",
"expected": "Positive",
"distinguishes_from": ["Candida"],
"notes": "Urease activity is a key screening test for Cryptococcus."
},
{
"field": "Inositol Fermentation",
"expected": "Positive",
"distinguishes_from": ["Candida"],
"notes": "Inositol utilization supports Cryptococcus identification."
}
],
"common_confusions": [
{
"genus": "Candida",
"reason": "Both are yeast-form fungi, but Candida lacks a capsule and is urease negative."
},
{
"genus": "Rhodotorula",
"reason": "Some species share urease positivity but differ in pigmentation and capsule presence."
}
],
"when_to_question_identification": [
"Absence of capsule argues against Cryptococcus.",
"Urease negativity suggests alternative yeast genera.",
"Strong carbohydrate fermentation profile is inconsistent with Cryptococcus."
],
"recommended_next_tests": [
{
"test": "India ink preparation",
"reason": "Demonstrates the characteristic polysaccharide capsule.",
"api_kit": "Not applicable"
},
{
"test": "Urease test",
"reason": "Rapid screening test for Cryptococcus.",
"api_kit": "Christensen Urea Agar"
},
{
"test": "MALDI-TOF MS",
"reason": "Accurate species-level identification.",
"api_kit": "Not applicable"
}
],
"supported_species": [
"neoformans",
"gattii",
"laurentii"
]
} |