Clostridium

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Clostridium
Photomicrograph of "Clostridium botulinum" bacteria stained with crystal violet
Photomicrograph of Clostridium botulinum bacteria stained with crystal violet
Scientific classification Edit this classification
Domain: Bacteria
Phylum: Bacillota
Class: Clostridia
Order: Eubacteriales
Family: Lachnospiraceae
Genus: Clostridium
Prazmowski 1880
Species

164 Species
See List of Clostridium species for complete taxonomy.

Clostridium is a

Clostridioides difficile, which was reclassified into the Clostridioides genus in 2016.[2]

History

In the late 1700s, Germany experienced several outbreaks of an illness connected to eating specific sausages. In 1817, the German neurologist

Emile van Ermengem published his finding of an endospore-forming organism he isolated from spoiled ham. Biologists classified van Ermengem's discovery along with other known gram-positive spore formers in the genus Bacillus. This classification presented problems, however, because the isolate grew only in anaerobic conditions, but Bacillus grew well in oxygen.[1]

Circa 1880, in the course of studying fermentation and butyric acid synthesis, a scientist surnamed Prazmowski first assigned a binomial name to Clostridium butyricum.[3] The mechanisms of anaerobic respiration were still not yet well elucidated at that time, so taxonomy of anaerobes was still developing.[3]

In 1924, Ida A. Bengtson separated van Ermengem's microorganisms from the Bacillus group and assigned them to the genus Clostridium. By Bengtson's classification scheme, Clostridium contained all of the anaerobic endospore-forming rod-shaped bacteria, except the genus Desulfotomaculum.[1]

Taxonomy

Main article: List of Clostridium species

As of October 2022, there are 164 validly published species in Clostridium.[4]

The genus, as traditionally defined, contains many organisms not closely related to its

rRNA phylogeny from Collins 1994, which split the traditional genus (now corresponding to a large slice of Clostridia) into twenty clusters, with cluster I containing the type species and its close relatives.[5] Over the years, this has resulted in many new genera being split out, with the ultimate goal of constraining Clostridium to cluster I.[6]

"Clostridium" cluster XIVa (now

Ruminococcaceae)[7] efficiently ferment plant polysaccharide composing dietary fiber,[8] making them important and abundant taxa in the rumen and the human large intestine.[9] As mentioned before, these clusters are not part of current Clostridium,[5][10] and use of these terms should be avoided due to ambiguous or inconsistent usage.[7]

Biochemistry

Species of Clostridium are obligate anaerobe and capable of producing endospores. They generally stain gram-positive, but as well as Bacillus, are often described as Gram-variable, because they show an increasing number of gram-negative cells as the culture ages.[11] The normal, reproducing cells of Clostridium, called the vegetative form, are

Greek κλωστήρ or spindle. Clostridium endospores have a distinct bowling pin or bottle shape, distinguishing them from other bacterial endospores, which are usually ovoid in shape.[citation needed] The Schaeffer–Fulton stain (0.5% malachite green in water) can be used to distinguish endospores of Bacillus and Clostridium from other microorganisms.[12]

Clostridium can be differentiated from the also endospore forming genus Bacillus by its obligate anaerobic growth, the shape of endospores and the lack of catalase. Species of Desulfotomaculum form similar endospores and can be distinguished by their requirement for sulfur.[1]

isopropanol, and carbon dioxide.[11]

There is a commercially available polymerase chain reaction (PCR) test kit (Bactotype) for the detection of C. perfringens and other pathogenic bacteria.[13]

Biology and pathogenesis

Clostridium species are readily found inhabiting soils and intestinal tracts. Clostridium species are also a normal inhabitant of the healthy lower reproductive tract of females.[14]

The main species responsible for disease in humans are:[15]

Treatment

In general, the treatment of clostridial infection is high-dose

Clostridium welchii and Clostridium tetani respond to sulfonamides.[20] Clostridia are also susceptible to tetracyclines, carbapenems (imipenem), metronidazole, vancomycin, and chloramphenicol.[21]

The vegetative cells of clostridia are heat-labile and are killed by short heating at temperatures above 72–75 °C (162–167 °F). The thermal destruction of Clostridium spores requires higher temperatures (above 121.1 °C (250.0 °F), for example in an

irradiated foods for general use in the retail market.[22] The addition of lysozyme, nitrate, nitrite and propionic acid salts inhibits clostridia in various foods.[23][24][25]

fusobacteria, and Bacteroides.[26]

Use

References

  1. ^
    ISBN 978-0-8160-7364-1
  2. PMID 30238983
    .
  3. ^
    ISBN 9781345750270
    .
  4. Deutsche Sammlung von Mikroorganismen und Zellkulturen
    . Retrieved 2022-10-03.
  5. ^
    PMID 7981107
    .
  6. PMID 26643615
    .
  7. ^ a b c Oh, Hyunseok (September 18, 2018). "Taxonomy Of Clostridium Clusters XIVa And IV". eMedicine. EzBioCloud. Retrieved 2021-06-04.
  8. PMID 25393313
    .
  9. PMID 23941657
    .
  10. PMID 23941657
    .
  11. ^
    ISBN 978-0-321-55007-1
  12. ISBN 978-0-8160-7364-1
  13. S2CID 86159965
  14. ISBN 978-0071716727
    .
  15. PMID 21413315
    .
  16. PMID 30082713
    .
  17. PMID 32021965
    .
  18. PMID 20879895
    .
  19. ISBN 978-1-4200-4479-9
  20. ISBN 978-3527306732
  21. ISBN 978-1-4511-1314-3
  22. ISBN 978-3527306732
  23. ISBN 978-3527306732
  24. ISBN 978-3527306732
  25. ISBN 978-3527306732
  26. ISBN 978-3527306732
  27. S2CID 46954613
    .
  28. ISBN 978-0-07-159087-7
  29. ^ "Providing for a Sustainable Energy Future". Bioengineering Resources, inc. Retrieved 21 May 2007.
  30. S2CID 2896050
    .
  31. ISBN 978-1-904455-38-7
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  32. doi:10.1016/j.ijhydene.2011.03.067
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Clostridium&oldid=1203370431"