data/rag/knowledge_base/Brucella/melitensis.json

{
  "schema_version": "1.0",
  "level": "species",
  "genus": "Brucella",
  "species": "melitensis",

  "overview": {
    "short": "Brucella melitensis is a Gram-negative, non-motile coccobacillus considered the most virulent Brucella species for humans.",
    "clinical_context": "Primarily infects goats and sheep, causing caprine brucellosis, and is a leading cause of human brucellosis worldwide."
  },

  "expected_fields": {
    "Gram Stain": "Negative",
    "Shape": "Short Rods",
    "Motility": "Negative",
    "Capsule": "Negative",
    "Spore Formation": "Negative",
    "Haemolysis": "Negative",
    "Haemolysis Type": "None",
    "Media Grown On": [
      "Blood Agar",
      "Chocolate Agar"
    ],
    "Colony Morphology": [
      "Small",
      "Smooth",
      "Translucent"
    ],
    "Oxygen Requirement": "Aerobic",
    "Growth Temperature": "35//37",
    "Catalase": "Positive",
    "Oxidase": "Positive",
    "Indole": "Negative",
    "Urease": "Positive",
    "Citrate": "Negative",
    "Methyl Red": "Negative",
    "VP": "Negative",
    "H2S": "Negative",
    "DNase": "Negative",
    "ONPG": "Negative",
    "Coagulase": "Negative",
    "Gelatin Hydrolysis": "Negative",
    "Esculin Hydrolysis": "Negative",
    "Nitrate Reduction": "Positive",
    "NaCl Tolerant (>=6%)": "Negative",
    "Lipase Test": "Negative",
    "Glucose Fermentation": "Negative",
    "Gas Production": "Negative",
    "Pigment": "None",
    "Motility Type": "None"
  },

  "species_markers": [
    {
      "field": "H2S",
      "value": "Negative",
      "importance": "high",
      "notes": "Absence of H₂S differentiates B. melitensis from B. abortus."
    },
    {
      "field": "CO₂ Requirement",
      "value": "None",
      "importance": "medium",
      "notes": "Does not require added CO₂ for growth, unlike some B. abortus strains."
    },
    {
      "field": "Host Association",
      "value": "Goats and sheep",
      "importance": "medium",
      "notes": "Strong correlation with small ruminants in endemic regions."
    }
  ],

  "common_confusions": [
    {
      "species": "Brucella abortus",
      "reason": "Shared biochemical results aside from H₂S production."
    },
    {
      "genus": "Ochrobactrum",
      "reason": "Phylogenetic similarity may lead to misidentification."
    }
  ],

  "when_to_question_identification": [
    "H₂S positivity suggests B. abortus.",
    "Failure to grow aerobically or absence of urease suggests misidentification.",
    "Rapid growth or fermentation reactions inconsistent with Brucella."
  ],

  "recommended_next_tests": [
    {
      "test": "H₂S production",
      "reason": "Confirms distinction from B. abortus and B. suis."
    },
    {
      "test": "PCR or molecular typing",
      "reason": "Definitive confirmation due to biosafety concerns."
    },
    {
      "test": "Serological agglutination test",
      "reason": "Supports diagnosis in clinical or veterinary contexts."
    }
  ]
}