{ "schema_version": "1.0", "level": "genus", "genus": "Comamonas", "overview": { "short": "Comamonas species are Gram-negative, aerobic, non-fermentative rods commonly found in soil and water, occasionally implicated in opportunistic human infections.", "clinical_context": "Rarely isolated in clinical microbiology but reported in bloodstream, intra-abdominal, and wound infections, often in immunocompromised hosts." }, "expected_fields": { "Gram Stain": "Negative", "Shape": "Rods", "Motility": "Positive", "Capsule": "Negative", "Spore Formation": "Negative", "Haemolysis": "Negative", "Haemolysis Type": "None", "Media Grown On": [ "Blood Agar", "Nutrient Agar" ], "Colony Morphology": [ "Smooth", "Grey", "Non-pigmented" ], "Oxygen Requirement": "Aerobic", "Growth Temperature": "15//42", "Catalase": "Positive", "Oxidase": "Positive", "Indole": "Negative", "Urease": "Negative", "Citrate": "Variable", "Methyl Red": "Negative", "VP": "Negative", "H2S": "Negative", "DNase": "Negative", "ONPG": "Negative", "Coagulase": "Negative", "Gelatin Hydrolysis": "Variable", "Esculin Hydrolysis": "Negative", "Nitrate Reduction": "Variable", "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": "Negative", "Gas Production": "Negative", "TSI Pattern": "Unknown", "Colony Pattern": "Unknown", "Pigment": "None", "Motility Type": "Polar" }, "field_notes": { "Oxidase": "Oxidase positivity supports differentiation from Enterobacterales.", "Glucose Fermentation": "Non-fermentative metabolism is genus-defining.", "Motility": "Motile by polar flagella." }, "key_differentiators": [ { "field": "Oxidase", "expected": "Positive", "distinguishes_from": ["Enterobacter", "Escherichia"], "notes": "Separates Comamonas from oxidase-negative Gram-negative rods." }, { "field": "Glucose Fermentation", "expected": "Negative", "distinguishes_from": ["Aeromonas", "Vibrio"], "notes": "Non-fermentative profile excludes common oxidase-positive fermenters." }, { "field": "Oxygen Requirement", "expected": "Aerobic", "distinguishes_from": ["Bacteroides", "Clostridium"], "notes": "Strict aerobic growth pattern." } ], "common_confusions": [ { "genus": "Alcaligenes", "reason": "Shared oxidase positivity and non-fermentative metabolism." }, { "genus": "Achromobacter", "reason": "Environmental origin and overlapping biochemical reactions." } ], "when_to_question_identification": [ "Glucose fermentation suggests Aeromonas or Vibrio.", "Oxidase negativity is inconsistent with Comamonas.", "Anaerobic growth argues against identification." ], "recommended_next_tests": [ { "test": "Oxidative-fermentative (OF) glucose test", "reason": "Confirms non-fermentative metabolism.", "api_kit": "API 20NE" }, { "test": "MALDI-TOF MS", "reason": "Accurate genus-level and species-level identification.", "api_kit": "Not applicable" }, { "test": "Molecular identification", "reason": "Useful for rare or clinically significant isolates.", "api_kit": "Not applicable" } ], "supported_species": [ "kerstersii", "testosteroni" ] }