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f208415 bcd3612 f208415 bcd3612 f208415 bcd3612 f208415 bcd3612 f208415 bcd3612 f208415 bcd3612 f208415 bcd3612 f208415 bcd3612 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 | {
"schema_version": "1.0",
"level": "genus",
"genus": "Citrobacter",
"overview": {
"short": "Citrobacter species are Gram-negative, facultatively anaerobic rods within the Enterobacterales, commonly found in the intestinal tract and environment.",
"clinical_context": "Associated with opportunistic infections including urinary tract, bloodstream, neonatal meningitis, and intra-abdominal infections."
},
"expected_fields": {
"Gram Stain": "Negative",
"Shape": "Rods",
"Motility": "Variable",
"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": "10//45",
"Catalase": "Positive",
"Oxidase": "Negative",
"Indole": "Variable",
"Urease": "Variable",
"Citrate": "Positive",
"Methyl Red": "Positive",
"VP": "Negative",
"H2S": "Variable",
"DNase": "Negative",
"ONPG": "Positive",
"Coagulase": "Negative",
"Gelatin Hydrolysis": "Variable",
"Esculin Hydrolysis": "Variable",
"Nitrate Reduction": "Positive",
"NaCl Tolerant (>=6%)": "Negative",
"Lipase Test": "Negative",
"Lysine Decarboxylase": "Variable",
"Ornithine Decarboxylase": "Variable",
"Ornitihine Decarboxylase": "Variable",
"Arginine dihydrolase": "Negative",
"Glucose Fermentation": "Positive",
"Lactose Fermentation": "Variable",
"Sucrose Fermentation": "Variable",
"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 delayed or variable on MacConkey Agar.",
"H2S": "Some species produce H2S, which may cause confusion with Salmonella.",
"Indole": "Indole reactions vary by species and are useful at the species level."
},
"key_differentiators": [
{
"field": "Methyl Red",
"expected": "Positive",
"distinguishes_from": ["Enterobacter", "Klebsiella"],
"notes": "MR positivity helps separate Citrobacter from VP-positive Enterobacterales."
},
{
"field": "H2S",
"expected": "Variable",
"distinguishes_from": ["Escherichia"],
"notes": "Possible H2S production differentiates Citrobacter from E. coli."
},
{
"field": "Lactose Fermentation",
"expected": "Variable",
"distinguishes_from": ["Escherichia"],
"notes": "Delayed or absent lactose fermentation helps exclude E. coli."
}
],
"common_confusions": [
{
"genus": "Salmonella",
"reason": "Shared H2S production and Enterobacterales profile."
},
{
"genus": "Enterobacter",
"reason": "Overlapping sugar fermentation and citrate positivity."
}
],
"when_to_question_identification": [
"Strong VP positivity suggests Enterobacter or Klebsiella.",
"Consistent lactose fermentation suggests Escherichia.",
"Absence of nitrate reduction argues against Citrobacter."
],
"recommended_next_tests": [
{
"test": "Indole test",
"reason": "Critical for species-level differentiation."
},
{
"test": "H2S production assessment",
"reason": "Helps separate Citrobacter from related genera."
},
{
"test": "API 20E",
"reason": "Standard biochemical panel for Enterobacterales identification."
},
{
"test": "MALDI-TOF MS",
"reason": "Provides rapid and reliable species-level identification."
}
],
"supported_species": [
"braakii",
"freundii",
"koseri"
]
} |