Clostridium novyi

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Clostridium novyi
Scientific classification Edit this classification
Domain: Bacteria
Phylum: Bacillota
Class: Clostridia
Order: Eubacteriales
Family: Lachnospiraceae
Genus: Clostridium
Species:
C. novyi
Binomial name
Clostridium novyi
(Migula 1894 [sic]) Bergey et al. 1923[1]

Clostridium novyi (oedematiens) a

pathogenic
, causing a wide variety of diseases in humans and animals.

Growth in culture proceeds through 3 stages: Initial growth wherein no toxin is produced; vigorous growth wherein toxin is produced; and spore formation wherein endospores are formed and toxin production decreases. It is suggested that type C may be type B that forms spores more readily so does not go through the toxin-production stage.

Isolating and identifying C novyi is difficult due to its extreme anaerobic nature. Commercial kits may not be adequate.[2][3]

It is also fastidious and difficult to culture, requiring the presence of

thiols.[4]

Taxonomy

Clostridium novyi is considered to be made up from three clades, labelled A, B and C, distinguished by the range of

toxins they produce.[citation needed] While strains of type C were not linked to disease to laboratory animals, presence and activity of toxins in C. novyi have been linked to infection with Bacteriophages.[5]
Based on toxin production, Clostridium haemolyticum has been suggested to be considered a part of C. novyi, forming a separate type D in the genus.[6] More recent 16S-rDNA studies however have suggested, that C. haemolyticus and types B and C of C. novyi may form a distinct species, closely related to Clostridium botulinum type C and D ("group III"), instead.[5]

Toxins

The toxins are designated by Greek letters.[7]

Toxins normally produced by the various types of C novyi[7]
C novyi type Toxins
A alpha, gamma, delta, epsilon
B alpha, beta, zeta
C gamma

The alpha-toxin of Clostridium botulinum types C and D, is similar to the C novyi beta-toxin.[citation needed] The A and B toxins of Clostridium difficile show homology with the alpha-toxin of C novyi as does the lethal toxin of clostridium sordellii.[8]

Alpha-toxin

The alpha-toxin is characterised as lethal and

necrotizing.[citation needed
]

The type A alpha-toxin is

capillaries
, leading to oedema. The threshold concentration for this action to occur is 5 ng/ml (5 parts per billion) with 50% of cells rounded at 50 ng/ml.

The duodenum is particularly sensitive to the toxin. Injection into dogs resulted in extreme oedema of the submucosal tissues of the duodenum while leaving the stomach uninjured. Injection into the eye resulted in lesions similar to flame haemorrhages found in diabetic retinopathy.[9]

The toxin is a large 250-k

UDP-glucose as a substrate.[16]

Beta-toxin

The beta-toxin is characterised as haemolytic, necrotizing lecithinase.[citation needed]

Gamma-toxin

The gamma-toxin is characterised as haemolytic, lecithinase.[citation needed]

Delta-toxin

The delta-toxin is characterised as oxygen labile haemolysin.[citation needed]

Epsilon-toxin

The epsilon-toxin is characterised as lecithino-vitelin[check spelling] and thought to be responsible for the pearly layer found in cultures.

Zeta-toxin

The zeta-toxin is characterised as haemolysin.[citation needed]

Human diseases

The type and severity of the disease caused depends on penetration of the tissues. The epithelium of the alimentary tract, in general, provides an effective barrier to penetration. However, spores may escape from the gut and lodge in any part of the body and result in spontaneous infection should local anaerobic conditions occur.[citation needed]

Tissue penetration

Wound infection by C novyi and many other clostridium species cause gas gangrene[17] Spontaneous infection is mostly associated with predisposing factors of hematologic or colorectal malignancies and with diabetes mellitus,[18] although Gram-negative organisms, including Escherichia coli, may lead to a gas gangrene-like syndrome in diabetic patients. This presents with cellulitis and crepitus, and may be mistaken for gas gangrene.[19] Spontaneous, nontraumatic, or intrinsic infections from a bowel source have been increasingly reported recently.[20]

Clostridium novyi has been implicated in mortality among injecting illegal drug users.[21][22]

Epithelial infections

Symptoms are often non-specific including, colitis[citation needed], oedematous duodenitis[citation needed], and fever with somnolence[citation needed].

Testing is problematical with figures presented by McLauchlin and Brazier [cited above] suggesting a false negative rate of about 40% under ideal conditions. Only positive results may be regarded as reliable. In the absence of a positive test, C. novyi type A may be inferred from characterisation by clinical observation, table 2.

Table 2
Observation Comment
Oedema Especially if extreme with rapid onset. In view of the sensitivity of the duodenum to the alpha-toxin, oedematous duodenum is always suspect.
Anaerobic Infection occurs at an anaerobic site such as the gut or salivary gland. It may also occur at a site temporarily made anaerobic by occlusion and maintained in this state by oedema.
Gram positive If penicillin causes remission of oedema then a Gram positive organism is the causative agent.

Chronic infection leading to leaky capillaries may also cause retinal haemorrhages and oedema in the lower extremities leading to necrosis and gangrene. Leaky

nephrons may compromise the ability of kidneys to concentrate urine leading to frequent urination and dehydration.[citation needed
]

Animal diseases

Gas gangrene: infectious necrotic hepatitis (black disease)[23]

See also

References

  1. LPSN
    .
  2. PMID 12448683
    .
  3. ^ "Identification of Clostridium species". National Standard Methods (PDF). BSOP ID8 Issue 3. Health Protection Agency. July 2008. Archived from the original (PDF) on 2009-11-05. Retrieved 2010-02-26.
  4. PMID 5721591
    .
  5. ^
    PMID 11411712
    .
  6. PMID 20238541
    .
  7. ^
    PMID 20238541
    .
  8. S2CID 10460632
    .
  9. ^
    PMID 2744858
    .
  10. S2CID 25746652
    .
  11. PMID 1612768
    .
  12. PMID 11035748
    .
  13. S2CID 31949189
    .
  14. S2CID 4334048
    .
  15. S2CID 38311133
    .
  16. S2CID 19531499
    .
  17. PMID 2404569
    .
  18. PMID 18256217
    .
  19. ^ "Necrotising infections". The British Society for Antimicrobial Chemotherapy. Archived from the original on 2003-11-26. Retrieved 2009-08-04.
  20. S2CID 25810277
    .
  21. PMID 14567722. Archived from the original
    on 2020-12-12. Retrieved 2020-11-29.
  22. PMID 12448684
    .
  23. OCLC 57355058
    .

Further reading

External links
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