Infectious colitis

Clostridium botulinum

Last author update: 1 August 2015
Last staff update: 26 April 2022

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PubMed Search: Clostridium botulinum [title] colon

Elliot Weisenberg, M.D.
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Cite this page: Weisenberg E. Clostridium botulinum. website. Accessed February 22nd, 2024.
Definition / general
  • Botulism is a disease caused by botulinum toxin ("botox"), a potent neurotoxin produced by Clostridium botulinum or closely related microorganisms such as C. baratii or C. butyricum
  • Botulism is uncommon in the developed world
  • According to the CDC in the United States, about 145 cases are reported each year, 65% in infants, 20% wound related and 15% foodborne
  • Most cases are associated with eating raw or undercooked food containing botulinum toxin or C. botulinum spores
  • Clusters of disease associated with eating the same food are common
  • Canned (especially home canned alkaline foods), vacuum packed food and fermented or smoked foods are often implicated
  • Infant botulism is related to ingestion of spores which colonize and release toxin in the intestine; may be related to honey ingestion (MMWR 2003;52:21)
  • Wound botulism is caused by toxin released by C. botulinum that has contaminated a wound; may follow heroin injection (Euro Surveill 2013;18:20630, Anaerobe 2014;30:108)
  • Rare cases are associated with inhalation of spores, sometimes in a health care setting
  • Recently, iatrogenic botulism has been reported due to botulinum toxin for cosmetic or therapeutic purposes (Clin Neuropharmacol 2012;35:254, Clin Neuropharmacol 2010;33:158, Clin Neuropharmacol 2007;30:310, JAMA 2006;296:2476)
  • Clostridium are toxin producing, spore forming, anaerobic, gram positive bacilli found in soil and marine sediment
  • Botulinum toxin is one of the most dangerous substances known; one millionth of a gram is a lethal dose
    • It is a potent neurotoxin that blocks the presynaptic release of acetylcholine across the neuromuscular junction, leading to a toxic neuropathy
    • Eight toxins have been identified, A-H; A, B, E, and F have been associated with human disease
  • Foodborne botulism is associated with ingesting food containing botulinum toxin while infant botulism is associated with ingesting spores that colonize the intestines and produce toxin; disease in adults via a similar mechanism is rare, but may occur (adult intestinal colonization botulism)
  • Wound, inhalation and iatrogenic botulism are discussed above under Epidemiology
Clinical features
  • The incubation period for infant botulism is 2 to 4 weeks, with a peak incidence from 2 to 4 months
    • Infants usually present with constipation, occasionally hypoventilation, followed by hypotonia, drooling, weak cry, generalized muscular weakness ("floppy baby") and hypoventilation; half have upper airway obstruction and cranial nerve palsies (Pediatr Neurol 2005;32:193)
    • Has been associated with sudden infant death syndrome (Lancet 1985;1:237, Lancet 1978;1:1273)
  • Patients with foodborne botulism generally present with acute, bilateral, symmetric cranial neuropathies
    • Symptoms include lack of coordination of eye muscles, double vision, swallowing difficulties and dizziness
    • Subsequently there is descending progressive weakness of the extremities and respiratory muscles
    • Patients are generally afebrile, alert, and oriented
    • Physical exam demonstrates flaccid muscle weakness of tongue, laryngeal muscles, respiratory muscles and extremities
    • Without rapid intervention, patients may die of respiratory paralysis or cardiac arrest
  • A high index of suspicion is generally necessary for diagnosis
  • Diagnosis is largely clinical through electromyographic studies
  • PCR based assays for the bacteria in stool and gastric aspirates or culture are suggestive
  • Detection of toxin in stool, blood, contaminated food or the environment is more definitive
  • Testing should be performed in public health laboratories, not Level A Laboratories
  • These laboratories or the CDC should be contacted for information on specimen transport
  • Public health authorities should be notified as epidemiologic investigations are necessary; foodborne botulism is considered a public health emergency
  • Of note, infection does not lead to antibody production, and no serologic testing is available
Prognostic factors
  • With good supportive care, the death rate is currently < 5%; previously was > 50%
Case reports
  • Equine derived heptavalent antitoxin (available from CDC) for food borne and wound botulism
  • Debridement with antibiotics for wound botulism
  • Human Botulism Immune Globulin Intravenous (BabyBig) is administered for infant botulism; generally antibiotics are not given for infant botulism
  • Supportive care, especially respiratory support is critical
Diagrams / tables

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Binary toxin

Microscopic (histologic) images

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Chitin degradation

Electron microscopy images

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Electron micrograph

Differential diagnosis
  • Acute motor axonal neuropathy
  • Allergic reaction
  • Guillain-Barré syndrome
  • Miller Fisher syndrome
  • Mosquito borne encephalitis
  • Poliomyelitis
  • Tick paralysis
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