Updated: 11/13/2019

Clostridium perfringens

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  • A 45-year-old man presents to the emergency room after stepping on a nail resulting in a puncture wound on his right foot. He was given a tetanus booster and he left against medical advice refusing antibiotics. Two days later, he returned to the emergency room for increasing pain in his right foot. Physical exam reveals dark purple and black discoloration of the right sole with multiple ruptured bullae oozing serous drainage. On palpation, there is soft tissue crepitus. A wound culture is sent, which shows gram-positive bacilli. He is started on the appropriate antibiotics immediately.
  • Classification
    • Clostridium perfringens
      • anaerobic, spore-forming gram-positive bacillus
      • produces gas, exotoxin (alpha toxin), and enterotoxin
      • clinical syndromes
        • gas gangrene (exotoxin-mediated) 
          • necrotizing soft tissue infection
        • food poisoning (enterotoxin-mediated)
  • Epidemiology
    • incidence
      • low
    • risk factors
      • gas gangrene
        • traumatic open wounds
        • previous surgery
        • diabetes mellitus
        • peripheral vascular disease
        • alcoholism
        • frostbite
        • immunosuppression
      • food poisoning
        • reheated meat (spores that produce enterotoxin)
  • Pathogenesis 
    • forms spores, which lack metabolic activity and are highly resistant to both chemicals and heat
    • produces exotoxin alpha toxin 
      • a phospholipase or lecithinase that lyses cell membranes and tissues
      • causes myonecrosis or gas gangrene
    • when spores are ingested, bacteria release heat-labile enterotoxin and cause food poisoning
  • Prognosis
    • mortality up to 30% if treated
    • fatal if untreated
  • Food poisoning
    • watery diarrhea
    • nausea
  • Gas gangrene 
    • erythema with purple-black discoloration of affected limb
      • soft tissue crepitus
        • indicates gas
      • bullae with serous drainage
    • increasing pain
  • Computed tomography (CT)
    • indication
      • if diagnosis is unclear
    • findings
      • gas bubbles within soft tissues
  • Wound culture and Gram stain
    • gram-positive bacilli without polymorphonuclear cells
    • “stormy fermentation” in milk media
    • double zone of hemolysis on blood agar
  • Clostridium assay
    • detects neuraminidase produced by the bacteria
  • Making the diagnosis
    • based on clinical presentation
  • Cellulitis
    • distinguishing factor
      • typically does not present with dark colored skin, bullae, and crepitus
  • Management approach
    • gas gangrene requires early treatment as it is a surgical emergency
    • food poisoning is typically self-limited and can be treated supportively
  • Medical
    • penicillin
      • indication
        • gas gangrene
        • first-line
    • clindamycin
      • indication
        • gas gangrene
        • patients allergic to penicillin
  • Operative
    • debridement
      • indication
        • gas gangrene
  • Gas gangrene
    • amputation
    • permanent disability

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Questions (4)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2

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(M1.MC.14.1) A microbiology student was given a swab containing an unknown bacteria taken from the wound of a soldier and asked to identify the causative agent. She determined that the bacteria was a gram-positive, spore-forming bacili, but had difficulty narrowing it down to the specific bacteria. The next test she performed was the Nagler's test, in which she grew the bacteria on a plate made from egg yolk, which would demonstrate the ability of the bacteria to hydrolyze phospholipids and produce an area of opacity. Half the plate contained a specific antitoxin which prevented hydrolysis of phospholipids while the other half did not contain any antitoxin. The bacteria produced an area of opacity only on half of the plate containing no antitoxin. Which of the following toxins was the antitoxin targeting? Review Topic | Tested Concept

QID: 106316

Alpha toxin




Tetanus toxin




Botulinum toxin




Exotoxin A




Diphtheria toxin



L 2 D

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