data/rag/knowledge_base/Cronobacter/genus.json

{
  "schema_version": "1.0",
  "level": "genus",
  "genus": "Cronobacter",
  "overview": {
    "short": "Cronobacter species are Gram-negative, facultatively anaerobic Enterobacterales that are opportunistic pathogens, best known for association with powdered infant formula contamination and invasive neonatal infections.",
    "clinical_context": "Can cause neonatal meningitis, sepsis, and necrotizing enterocolitis; also opportunistic infections in immunocompromised adults."
  },
  "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": "6//45",
    "Catalase": "Positive",
    "Oxidase": "Negative",
    "Indole": "Negative",
    "Urease": "Variable",
    "Citrate": "Positive",
    "Methyl Red": "Variable",
    "VP": "Positive",
    "H2S": "Negative",
    "DNase": "Negative",
    "ONPG": "Positive",
    "Coagulase": "Negative",
    "Gelatin Hydrolysis": "Variable",
    "Esculin Hydrolysis": "Variable",
    "Nitrate Reduction": "Positive",
    "NaCl Tolerant (>=6%)": "Negative",
    "Lipase Test": "Negative",
    "Lysine Decarboxylase": "Positive",
    "Ornithine Decarboxylase": "Variable",
    "Ornitihine Decarboxylase": "Variable",
    "Arginine dihydrolase": "Negative",
    "Glucose Fermentation": "Positive",
    "Lactose Fermentation": "Variable",
    "Sucrose Fermentation": "Positive",
    "Maltose Fermentation": "Positive",
    "Mannitol Fermentation": "Variable",
    "Sorbitol Fermentation": "Variable",
    "Xylose Fermentation": "Positive",
    "Rhamnose Fermentation": "Variable",
    "Arabinose Fermentation": "Positive",
    "Raffinose Fermentation": "Variable",
    "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": "Often variable or delayed; some strains appear weakly lactose-positive on MacConkey Agar.",
    "Motility": "Typically motile with peritrichous flagella, but some isolates may appear weakly motile depending on conditions.",
    "Growth Temperature": "Many isolates grow at lower temperatures than typical Enterobacterales; growth at ~6–10°C is reported for some strains and may support food-associated persistence."
  },
  "key_differentiators": [
    {
      "field": "ONPG",
      "expected": "Positive",
      "distinguishes_from": [
        "Salmonella",
        "Shigella"
      ],
      "notes": "ONPG positivity supports a lactose-delayed/β-galactosidase-positive Enterobacterales rather than classic ONPG-negative genera."
    },
    {
      "field": "Oxidase",
      "expected": "Negative",
      "distinguishes_from": [
        "Aeromonas",
        "Vibrio"
      ],
      "notes": "Oxidase negativity supports Enterobacterales and helps exclude oxidase-positive Gram-negative rods."
    },
    {
      "field": "Citrate",
      "expected": "Positive",
      "distinguishes_from": [
        "Escherichia"
      ],
      "notes": "Citrate positivity supports Cronobacter/Enterobacter-like profiles rather than typical E. coli."
    }
  ],
  "common_confusions": [
    {
      "genus": "Enterobacter",
      "reason": "Strong overlap in citrate/VP positivity and broad sugar fermentation patterns within Enterobacterales."
    },
    {
      "genus": "Klebsiella",
      "reason": "Some isolates can appear lactose-positive and mucoid, overlapping with Klebsiella phenotypes."
    },
    {
      "genus": "Citrobacter",
      "reason": "Citrate positivity and variable sugar reactions can overlap; species-level resolution often requires panels or MALDI-TOF."
    }
  ],
  "when_to_question_identification": [
    "Oxidase positivity argues against Cronobacter (suggests Aeromonas/Vibrio/Pseudomonas-type organisms).",
    "H2S production argues against Cronobacter and suggests Salmonella/Citrobacter freundii complex possibilities.",
    "Non-motile isolate with strong capsule and consistent lactose positivity may suggest Klebsiella."
  ],
  "recommended_next_tests": [
    {
      "test": "API 20E",
      "reason": "Useful Enterobacterales biochemical panel to support genus/species identification.",
      "api_kit": "API 20E"
    },
    {
      "test": "MALDI-TOF MS",
      "reason": "Rapid and reliable identification within Enterobacterales when biochemical overlap is high.",
      "api_kit": "Not applicable"
    },
    {
      "test": "Chromogenic Cronobacter medium (if available)",
      "reason": "Selective/differential support for Cronobacter from food/infant formula contexts.",
      "api_kit": "Not applicable"
    }
  ],
  "supported_species": [
    "sakazakii",
    "malonaticus",
    "turicensis"
  ]
}