Clostridium Botulinum – Basic microbiology, parasitology, and immunology; nature, reproduction, growth, and transmission of common microorganisms and parasites in Bangladesh; prevention including universal precaution and immunization, control, sterilization, and disinfection; and specimen collections and examination. Students will have an understanding of common organisms and parasites caused human diseases and acquire knowledge about the prevention and control of those organisms.
Clostridium Botulinum
Morphology of Clostridium Botulinum:
- Gram-positive bacilli.
- Anaerobic and spore forming.
- Spores are oval, sub-terminal and slightly bulging.
- Non-capsulated.
- Motile with peritrichous flagella.
- Produce toxins (protein in nature).
Botulism
Definition of Botulism:
Botulism is a rare and potentially fatal illness caused by a toxin produced by the bacterium Clostridium botulinum. The disease begins with weakness, blurred vision, feeling tired, and trouble speaking.
Causative agent: Clostridium botulinum
Source Of Infection:
- Canned/tinned /bottled food.
- Alkaline vegetables like green beans, peppers and mushrooms.
- Smoked fish.
Clinical Features:
- Descending weakness and paralysis, including diplopia, dysphagia, and respiratory 8 muscle failure are seen.
- No fever is present.
- Two special clinical forms occur:
✓ Wound botulism: Spores contaminate a wound, germinate and produce toxin at the site. In the United States, wound botulism is associated with drug abuse specially skin-popping with black tar heroin.
✓ Infant botulism: The organisms grow in the gut and produce toxins. Ingestion of honey containing the organism is implicated in transmission of infant botulism.
Pathogenesis of Botulism:
Ingestion of preformed toxin of Cl. botulinum in the food
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Absorption of the toxin (neurotoxin) from the intestine
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Neurotoxin in circulation
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Blocks release of acetylcholine in peripheral nerve synapse
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Prevention of muscle contraction
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Manifestation: Descending type of weakness and paralysis (flaccid type) including diplopia, to dysphagia and respiratory muscle.
Types of Botulism:
- Food borne botulism.
- Infant botulism.
- Wound botulism.
- Unclassified botulism
Lab. Diagnosis of Botulism:
Principle:
Diagnosis of botulism is based on demonstration of toxin by neutralization test with specific antitoxin.
Steps:
- Specimen collection: Left over food and patient’s serum.
- Culture: Isolation from left over food. (Culture is not usually done)
- Toxin identification: By animal pathogenicity test in mice (mouse protection test) Mice are inoculated with a sample of the clinical specimen and will die unless protected by antitoxin.
Treatment:
- Trivalent antitoxin (types A, B and E) administration.
- Respiratory support
- A bivalent antitoxin (types A, B) is also available for treatment of infant botulism.
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