Living Organisms / Monera (Bacteria) /Bacteria with Gram positive staining cell-walls / Clostridium/ Species:
Clostridium botulinum
Summary Information
Morphology, Staining and Metabolism information at genera level (Clostridium)

(Classification of bacterial species is an evolving discipline. The information in Wildpro has been carefully referenced to the source material, as far as possible. Readers requiring further clarification should consult the source materials and more recent publications. Classification information in Wildpro will be altered when clear and scientifically endorsed new information regarding taxonomic divisions becomes available to us.

This section is currently predominantly used in Wildpro to link different data types and demonstrate inter-relationships. It does not contain detailed information on the bacteria species itself.)

Common synonyms Bacillus botulinus. The subgroup "type" of Clostridium botulinum producing Type G toxin was recently re-classified as Clostridium argentiniense.
  • There are six species "types" Clostridium botulinum of which each produce different Botulinum Toxins called: A, B, C, D, E, F. (B75)
  • This species is a strict anaerobe. It is commonly isolated from soil, marine and lake sediments, animal, bird and fish intestines and in food (particularly improperly preserved vegetables, meat and fish). Endospores are widely but sporadically distributed in soils and aquatic environments throughout the world and germination occurs in anaerobic situations such as contaminated tins of food, animal carcasses and baled silage. (B21) (B75) (B88) (B47)
  • The spores are highly resistant and may withstand boiling for 30 minutes to several hours. Most strains are killed by autoclaving at 120C for 20 minutes.(B47)
  • Clostridium botulinum and the ‘phage responsible for type C toxin production are widely available in the environment, with some places being heavily contaminated. Spores can survive in soil for many years. (J1.30.w4, J3.100.w1).
  • Optimal bacterial growth occurs at 25-40C (particularly 30-37C). Both shallow water and the presence of decaying organic matter may increase the risk of botulism outbreaks, by increasing the temperature of water and sediments, and decreasing dissolved oxygen (P15, B36.38.w38).
  • Bacterial growth also requires a nutrient source which provides certain essential amino acids which the bacterium cannot itself synthesize; this may be provided by the carcasses of invertebrates or vertebrates, also by raw sewage and rotting vegetation. Raw sewage, in addition to directly providing nutrients for bacterial growth may also precipitate a boom-and-bust- cycle of aquatic invertebrates and oxygen depletion, with resultant deaths of aquatic plants and animals (B36.38.w38).
  • The presence of protein source, usually decaying organic matter (vegetation, decaying aquatic invertebrates, decaying vertebrates), is required for bacterial growth and toxin production. (P17.50.w1, B48.12.w12) Wetland flooding and draining can kill aquatic life, as may pesticides and other agricultural pollutants, thereby providing more substrate for toxin production. Other potential sources of energy for bacterial growth include raw sewage and rotting vegetation.
  • Toxin production may continue in carcasses in relatively cold weather, as carcass temperature is often higher than air temperature; this may allow outbreaks to occur earlier than expected from the temperature in spring or later than expected in autumn (J1.19.w1, J1.20.w5, J1.24.w4, B36.38.w38) .
  • Artificially increased water temperature, e.g. due to power station outputs, (thermal pollution) may assist in providing favourable conditions even in cold weather (P17.50.w1, B15)
  • Specific microenvironmental features: The likelihood of botulism outbreaks is significantly influenced by pH, salinity, temperature, and oxidation-reduction potential in the sediments and water column. (B36.38.w38).
  • Shallow stagnant water, alkalinity, large numbers of aquatic invertebrates and oxygen depletion associated with rotting vegetation, have been thought to be contributory, also the provision of dead aquatic invertebrates or waterfowl as a 'particularly favourable growth medium and microenvironment (J3.100.w1, J7.27.w1).

B10.26.w9, B13.46.w1

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Associated Diseases linked in Wildpro
Toxins from all types are neurotoxic and pathogenic to laboratory animals. They have been recorded causing flaccid paralysis in a large variety of mammals, birds and fish. Death may occur due to respiratory failure. (B75) (B47)
Associated Waterfowl Diseases Avian Botulism (Limberneck, Western duck sickness, Duck disease, Alkali poisoning) Waterfowl Disease Summary
  • A paralytic, frequently fatal disease, caused by ingestion of toxin produced by the bacterium Clostridium botulinum. Death is usually from respiratory arrest, cardiac arrest or drowning.
  • Outbreaks affecting thousands and even millions of birds have been recorded. This is probably the most important disease of migratory birds, on a world-wide basis.
Waterfowl in which the disease has been recorded.

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Antibiotic Use and Resistance
Listed Antibiotics recorded as having efficacy
  • Chloramphenicol (B75)
  • Penicillin G (B75)
  • Tetracycline (B75)
  • Clindamycin (B75)
  • Erythromycin (B75)
  • Metronidazole (B75)
  • Rifampin (B75)
  • Clindamycin (B75)
  • Cefoxitin (B75)
  • Vancomycin (B75)
Listed Antibiotics recorded as RESISTANCE "One strain of Type B is resistant to Clindamycin and Erythromycin." (B75)

Types A and B are resistant to Cycloserine, sulfamethoxazole and Trimethoprim. (B75)

All types are resistant to:

  • Nalidixic Acid (B75)
  • Gentamycin (B75)

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References for Bacterial Species

Species Author

Suzanne Boardman
B47 John F Timoney, James H Gillespie, Fredric W Scott, Jeffrey E Barlough
Hagan and Bruner's Microbiology and Infectious Diseases of Domestic Animals - Eight Edition
B88 Dwight C Hirsh and Yuan Chuang Zee
Veterinary Microbiology
B21 P J Quinn, M E Carter, B Markey, G R Carter
Clinical Veterinary Microbiology
B75 Noel R Krieg and John G Holt
Bergey's Manual of Systematic Bacteriology - Volume 2

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