|Species/Subspecies:||Clostridium botulinum, group IV|
|Categories:||Causes hemolysis; spore forming; motile; notifiable diseases and bacteria|
|Etymology:||Genus name: a small spindle. |
Species epithet: refers to sausage.
|Significance:||Has been found in Argentina and is of less importance in Europe.
[Of minor importance]
|Type Strain:||Reference strain: ATCC 27322|
|Macromorphology (smell):||Large greyish white colonies (5 mm in diameter) with very irregular edges. Gives β-hemolysis on blood agar.|
|Micromorphology:||Large motile, spore forming (1.3-1.9 x 1.6-9.4 µm) rods.|
|Gram +/Gram -:||
Type G: 1.3-1.9 x 1.6-9.4 µm.
|Other Enzymes:||Esculinase -, lecithinase -, tryptophanase -.|
|Biochemical Tests:||Hydrogen sulphide (H2S) +.|
|Fermentation of carbohydrates:||
|Spec. Char.:||C. botulinum type G strains are neither proteolytic nor saccharolytic. C.f. other C. botulinum groups.|
|Reservoir:||Soil and food contaminated by soil.|
|Disease:||Botulism or botulinus intoxication is a serious and potentially fatal disease in humans and animals. Botulism is usually an intoxication caused by intake of preformed toxin. It may also happen that spores of C. botulinum germinate in the intestine or in a deep wound and the bacteria may then start to produce toxin. This condition is termed a toxicoinfection.
|Hosts:||Or rather Animals that are sensitive to the toxin: Humans|
|Clinical Picture:||Flaccid muscular paralysis.|
|Virulence Factors:||C. botulinum strains within group III produce botulinum toxin type G
The different toxin types have the same basic structure and mechanism of action, but are serologically distinct. Botulinum toxin is a neurotoxin, which is similar to tetanospasmin in structure and mode of action, but they act on different parts of the nervous system. Botulinum toxin is (like tetanospasmin) composed of two protein subunits and one is a protease that destroys the fusion protein to which vesicles containing acetylcholine should bind. Thereby inhibiting the signal transduction between the efferent (= motoric) nerve and muscle cells by preventing vesicles from anchoring to the membrane to release acetylcholine. This results in a flaccid paralysis. C.f. Clostridium tetani.
Botulinum toxin is very potent, and the lethal dose for humans is approximately 1 ng/kg body weight.
|16S rRNA Seq.:|
||About 180 differens species have been descibed within genus Clostridium. C. botulinum can be classified into four different phenotypic groups: I-IV. C. botulinum-strains within group IV are most closely related to Clostridium subterminale as well as Clostridium argentinense and not to any strain within the other three phenotypic groups of C. botulinum.|
|Legislation:||In Sweden, botulism in animals and humans is notifiable to the Swedish Board of Agriculture and the Public Health Agency of Sweden, respectively. C. botulinum belongs to category A as a potential bioterrorism agent according to NIAID.|
|Comment:||C. botulinum actually represents four different species (phenotypic groups), all of which have at least one of the botulinum toxin genes. In the case of C. botulinum, you can really say that taxonomy is not consistent with phylogeny.
The type strain is of toxin type A.
In 1988 attempts were made to transfer C. botulinum, group IV, with the closely related species C. subterminale and C. hastiforme to the new species Clostridium argentinense. This proposal has not been accepted because it was previously determined that all species within the genus Clostridium, which produce botulinum toxin, should be named C. botulinum.
|Reference(s):||No. 4, 33|
|Link:||Botulinum + Tetanus Toxin Mechanism|
|New names of taxa within the classification category phylum|
During October 2021, an article was published by A. Oren och G.M. Garrity, in which new names are proposed for a number of taxa within the classification category phylum. This has resulted in many discussions in social media about whether it was really necessary to make these changes, which have created confusion among microbiologists and other professionals who come into contact with bacteriology.Published 2022-09-28. Read more...