{ "schema_version": "1.0", "level": "genus", "genus": "Cedecea", "overview": { "short": "Cedecea species are rare, Gram-negative, facultatively anaerobic rods within the Enterobacterales, infrequently isolated from clinical specimens.", "clinical_context": "Occasionally associated with opportunistic infections such as bacteremia, wound infections, and respiratory infections, particularly in immunocompromised patients." }, "expected_fields": { "Gram Stain": "Negative", "Shape": "Rods", "Motility": "Positive", "Capsule": "Variable", "Spore Formation": "Negative", "Haemolysis": "Negative", "Haemolysis Type": "None", "Media Grown On": [ "MacConkey Agar", "Blood Agar" ], "Colony Morphology": [ "Smooth", "Grey", "Moist" ], "Oxygen Requirement": "Facultative Anaerobe", "Growth Temperature": "30//37", "Catalase": "Positive", "Oxidase": "Negative", "Indole": "Negative", "Urease": "Negative", "Citrate": "Positive", "Methyl Red": "Negative", "VP": "Positive", "H2S": "Negative", "DNase": "Negative", "ONPG": "Positive", "Coagulase": "Negative", "Gelatin Hydrolysis": "Variable", "Esculin Hydrolysis": "Negative", "Nitrate Reduction": "Positive", "NaCl Tolerant (>=6%)": "Negative", "Lipase Test": "Negative", "Lysine Decarboxylase": "Negative", "Ornithine Decarboxylase": "Positive", "Ornitihine Decarboxylase": "Positive", "Arginine dihydrolase": "Negative", "Glucose Fermentation": "Positive", "Lactose Fermentation": "Negative", "Sucrose Fermentation": "Variable", "Maltose Fermentation": "Positive", "Mannitol Fermentation": "Positive", "Sorbitol Fermentation": "Variable", "Xylose Fermentation": "Positive", "Rhamnose Fermentation": "Negative", "Arabinose Fermentation": "Positive", "Raffinose Fermentation": "Negative", "Trehalose Fermentation": "Positive", "Inositol Fermentation": "Negative", "Gas Production": "Variable", "TSI Pattern": "A/A", "Colony Pattern": "Unknown", "Pigment": "None", "Motility Type": "Peritrichous" }, "field_notes": { "Lactose Fermentation": "Typically non-lactose fermenting on MacConkey Agar.", "Motility": "Motile by peritrichous flagella, helping distinguish from Klebsiella.", "ONPG": "Positive despite lactose non-fermentation, indicating beta-galactosidase activity." }, "key_differentiators": [ { "field": "ONPG", "expected": "Positive", "distinguishes_from": ["Salmonella", "Shigella"], "notes": "ONPG positivity helps separate Cedecea from non-ONPG Enterobacterales." }, { "field": "Ornithine Decarboxylase", "expected": "Positive", "distinguishes_from": ["Enterobacter"], "notes": "Ornithine positivity is useful in narrowing uncommon Enterobacterales." }, { "field": "Lactose Fermentation", "expected": "Negative", "distinguishes_from": ["Enterobacter", "Klebsiella"], "notes": "Non-lactose fermentation supports Cedecea over common lactose fermenters." } ], "common_confusions": [ { "genus": "Enterobacter", "reason": "Shared citrate positivity and VP positivity can overlap biochemically." }, { "genus": "Serratia", "reason": "ONPG positivity and motility may overlap in atypical isolates." } ], "when_to_question_identification": [ "Strong lactose fermentation on MacConkey Agar.", "Indole positivity (not typical for Cedecea).", "H2S production present." ], "recommended_next_tests": [ { "test": "ONPG test", "reason": "Supports identification among rare Enterobacterales.", "api_kit": "API 20E" }, { "test": "Ornithine decarboxylase", "reason": "Helpful discriminator for Cedecea species.", "api_kit": "API 20E" }, { "test": "MALDI-TOF MS", "reason": "Recommended due to rarity and biochemical overlap with other Enterobacterales." } ], "supported_species": [ "davisae", "lapagei" ] }