{ "schema_version": "1.0", "level": "species", "genus": "Erysipelothrix", "species": "tonsillarum", "overview": { "short": "Erysipelothrix tonsillarum is a Gram-positive, non-spore-forming, non-motile short rod most commonly associated with animals and environmental exposure rather than classic erysipeloid.", "clinical_context": "More often isolated from animals (e.g., tonsils/oropharynx) and may appear in mixed cultures; human disease is less commonly described than E. rhusiopathiae." }, "expected_fields": { "Gram Stain": "Positive", "Shape": "Short Rods", "Motility": "Negative", "Capsule": "Negative", "Spore Formation": "Negative", "Haemolysis": "Variable", "Haemolysis Type": "Variable", "Media Grown On": [ "Blood Agar" ], "Colony Morphology": [ "Small", "Grey", "Translucent", "Smooth" ], "Oxygen Requirement": "Facultative Anaerobe", "Growth Temperature": "20//42", "Catalase": "Negative", "Oxidase": "Negative", "Indole": "Negative", "Urease": "Negative", "Citrate": "Negative", "Methyl Red": "Positive", "VP": "Negative", "H2S": "Variable", "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": "Positive", "Lactose Fermentation": "Negative", "Sucrose Fermentation": "Variable", "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": "None" }, "species_markers": [ { "field": "H2S", "value": "Variable", "importance": "high", "notes": "Compared with E. rhusiopathiae, H2S may be less consistently observed; treat as supportive rather than definitive." }, { "field": "Clinical Context", "value": "Animal-associated / commensal-leaning", "importance": "medium", "notes": "Frequently associated with animal reservoirs; human clinical relevance may require correlation." } ], "common_confusions": [ { "species": "Erysipelothrix rhusiopathiae", "reason": "Very close overlap in routine phenotypic testing; separation often requires MALDI-TOF or molecular identification." }, { "genus": "Listeria", "reason": "Short rod appearance; motility and catalase help separate." } ], "when_to_question_identification": [ "Clear and reproducible H2S positivity plus classic erysipeloid context favors E. rhusiopathiae.", "Motility suggests non-Erysipelothrix short rods.", "Catalase positivity argues against Erysipelothrix." ], "recommended_next_tests": [ { "test": "MALDI-TOF MS", "reason": "Most practical method to separate E. tonsillarum from E. rhusiopathiae in routine workflows.", "api_kit": "Not applicable" }, { "test": "H2S detection on TSI or iron-containing media", "reason": "Use as a supportive feature; interpret cautiously due to variability.", "api_kit": "API Coryne" }, { "test": "Molecular identification (e.g., sequencing)", "reason": "Useful where MALDI libraries are limited or when clinical stakes are high.", "api_kit": "Not applicable" } ] }