Fusobacteria are obligately anaerobic non-sporeforming Gram-negative bacilli. Since the first reports in the late nineteenth century, various names have been applied to these organisms, sometimes with the same name being applied to different species. More recently, not only have there been changes to the nomenclature, but also attempts to differentiate between species which are believed to be either pathogenic or commensal or both. Because of their asaccharolytic nature, and a general paucity of positive results in routine biochemical tests, laboratory identification of the fusobacteria has been difficult. However, the application of novel molecular biological techniques to taxonomy has established a number of new species, together with the subspeciation of Fusobacterium necrophorum and F. nucleatum, and provided new methods for identification. The involvement of fusobacteria in a wide spectrum of human infections causing tissue necrosis and septicaemia has long been recognised, and, more recently, their importance in intra-amniotic infections, premature labour and tropical ulcers has been reported.

Since the first reports of fusobacteria in the late nineteenth century, the variety of species names has led to some confusion within the genera Fusobacterium and Leptotrichia. However, newer methods of investigation have led to a better understanding of the taxonomy, with the description of several new species of fusobacteria. Among the new species described are F. ulcerans from tropical ulcers, and several species from the oral cavity. Subspeciation of the important species F. necrophorum and F. nucleatum has also been possible. It is probable that the taxonomy of the fusobacteria may be further developed in the future.[2]

"Fusobacterium novum" in liquid culture
Fusobacterium novum in liquid culture
Scientific classification
Domain: Bacteria
Phylum: Fusobacteria
Garrity & Holt 2012
Class: Fusobacteriia
Staley & Whitman, 2012
Order: Fusobacteriales
Staley & Whitman, 2012
Families and genera[1]


The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LSPN)[3][4] and the phylogeny is based on 16S rRNA-based LTP release 123 by The All-Species Living Tree Project.[5]


S. hongkongensis Woo et al. 2014

S. moniliformis Levaditi et al. 1925

Sneathia sanguinegens Collins et al. 2002 (type sp.)

Sebaldella termitidis (Sebald 1962) Collins and Shah 1986


L. goodfellowii Eribe et al. 2004

L. hofstadii Eribe et al. 2004

L. buccalis (Robin 1853) Trevisan 1879 (type sp.)

L. wadei Eribe et al. 2004

L. shahii Eribe et al. 2004

L. hongkongensis Woo et al. 2011

L. trevisanii Tee et al. 2002


Psychrilyobacter atlanticus Zhao et al. 2009

Ilyobacter tartaricus Schink 1985

Ilyobacter polytropus Stieb and Schink 1985 (type sp.)

Propionigenium maris Janssen and Liesack 1996 emend. Watson et al. 2000

Ilyobacter insuetus Brune et al. 2002

Propionigenium modestum Schink and Pfennig 1983 (type sp.)


C. ceti Foster et al. 1996 (type sp.)

C. somerae Finegold et al. 2003


F. perfoetens (Tissier 1905) Moore and Holdeman 1973

F. necrogenes (Weinberg et al. 1937) Moore and Holdeman 1970

F. mortiferum (Harris 1901) Moore and Holdeman 1970

Clostridium rectum (Heller 1922) Holdeman and Moore 1972

F. ulcerans Adriaans and Shah 1988

F. varium (Eggerth and Gagnon 1933) Moore and Holdeman 1969

F. gonidiaformans (Tunnicliff and Jackson 1925) Moore and Holdeman 1970

F. equinum Dorsch et al. 2001

F. necrophorum

F. n. funduliforme (ex Hallé 1898) Shinjo et al. 1991

F. n. necrophorum (Flügge 1886) Shinjo et al. 1991

F. russii (Hauduroy et al. 1937) Moore and Holdeman 1970

F. nucleatum polymorphum (ex Knorr 1922) Dzink et al. 1990

F. periodonticum Slots et al. 1984

F. canifelinum Conrads et al. 2004

F. nucleatum fusiforme (ex Veillon and Zuber 1898) Gharbia and Shah 1992

F. nucleatum vincentii Dzink et al. 1990

F. nucleatum nucleatum (Knorr 1922) Dzink et al. 1990 (type sp.)

F. simiae Slots and Potts 1982

F. nucleatum animalis Gharbia and Shah 1992

Filifactor alocis (Cato et al. 1985) Jalava and Eerola 1999

Note 1: Species not used in the All-Species Living Tree Project

  • Leptotrichiaceae
    • Caviibacter abscessus Eisenberg et al. 2016
    • Oceanivirga salmonicida Eisenberg et al. 2016
    • Streptobacillus felis Eisenberg et al. 2015
    • Streptobacillus notomytis Eisenberg et al. 2015
    • Streptobacillus ratti Eisenberg et al. 2015
    • Sneathia amnioniiHarwich et al. 2012
  • Fusobacteriaceae
    • Ilyobacter delafieldii Janssen and Harfoot 1991
    • Ilyobacter psychrophilusQoura & Antranikian 2005a
    • Fusobacterium naviforme (Jungano 1909) Moore and Holdeman 1970
    • Fusobacterium plautii corrig. Séguin 1928
    • Fusobacterium polysaccharolyticum van Gylswyk 1981
    • Fusobacterium prausnitzii (Hauduroy et al. 1937) Moore & Holdeman 1970
    • Fusobacterium sulci Cato et al. 1985

Note 2:
♠ Strain found at the National Center for Biotechnology Information (NCBI) but not listed in the List of Prokaryotic names with Standing in Nomenclature (LPSN

New evidence is emerging that this bacteria may cause or be related to human colon cancer. In 2011 investigators reported the presence of fusobacteria in colon cancer tissue ( Genome Res 2012; 22:292 ) and a new multicenter study provides evidence that some cases-particularly right-sided might be caused by infection by Fusobacteria.(1)

1. Bullman S et al. Science 2017 Dec 15; 358:1443.

See also

  • Fusiform


  1. ^ "Fusobacteriales" (HTML). NCBI taxonomy. Bethesda, MD: National Center for Biotechnology Information. Retrieved 3 January 2019.
  2. ^ Bennett, K. W.; Eley, A. (1 October 1993). "Fusobacteria: New taxonomy and related diseases". Journal of Medical Microbiology. 39 (4): 246–254. doi:10.1099/00222615-39-4-246. PMID 8411084.
  3. ^ J.P. Euzéby. "Fusobacteria". List of Prokaryotic names with Standing in Nomenclature (LPSN). Retrieved 2016-03-20.
  4. ^ Sayers; et al. "Fusobacteria". National Center for Biotechnology Information (NCBI) taxonomy database. Retrieved 2016-03-20.
  5. ^ See the All-Species Living Tree Project [1]. Data extracted from the "16S rRNA-based LTP release 123 (full tree)" (PDF). Silva Comprehensive Ribosomal RNA Database. Retrieved 2016-03-20.

Cetobacterium is a Gram-negative, pleomorphic, non-spore-forming, rod-shaped and non-motile genus of bacteria from the family of Fusobacteriaceae.

Cetobacterium ceti

Cetobacterium ceti is a Gram-negative, and rod-shaped obligately anaerobic bacterium from the genus of Cetobacterium which has been isolated from sea mammals. Cetobacterium ceti represents a hitherto unknown line of descent peripherally associated to the fusobacteria and low G + C relatives.There is no growth of Cetobacterium ceti at 25°C or 45°C.

Cetobacterium somerae

Cetobacterium somerae is a Gram-negative, microaerotolerant, non-spore-forming and rod-shaped bacterium from the genus of Cetobacterium which has been isolated from human feces. Cetobacterium somerae occur in intestinal tracts of freshwater fish.

Cetobacterium somerae produces cobalamin.


Fusiform means having a spindle-like shape that is wide in the middle and tapers at both ends. It may refer to:

Fusiform, a body shape common to many aquatic animals, characterized by being tapered at both the head and the tail

Fusiform, a classification of aneurysm

Fusiform bacteria (spindled rods, that is, fusiform bacilli), such as the fusobacteria

Fusiform cell (biology)

Fusiform face area, a part of the human visual system which seems to specialize in facial recognition

Fusiform gyrus, part of the temporal lobe of the brain

Fusiform muscle, where the fibres run parallel along the length of the muscle

Fusiform neuron, a spindle-shaped neuron


Fusobacterium is a genus of anaerobic, Gram-negative, non-sporeforming bacteria, similar to Bacteroides. Individual cells are slender' rod-shaped bacilli with pointed ends.

Strains of Fusobacterium cause several human diseases, including periodontal diseases, Lemierre's syndrome, and topical skin ulcers.

Although older sources state that Fusobacterium is part of the normal flora of the human oropharynx, the current consensus is that Fusobacterium should always be treated as a pathogen. F. prausnitzii, a gut commensal associated with healthy patients, was moved out of Fusobacterium into its own genus, Faecalibacterium, in 2002.

Fusobacterium necrophorum

Fusobacterium necrophorum is a species of bacteria responsible for Lemierre's syndrome and other medical problems.

Ilyobacter delafieldii

Ilyobacter delafieldii is a motile, gram-negative, obligately anaerobic rod-shaped bacteria, with type strain 10cr1 (=DSM 5704). It is notable for metabolising beta-Hydroxybutyric acid.

Ilyobacter insuetus

Ilyobacter insuetus is a mesophilic and anaerobic bacterium from the genus of Ilyobacter which has been isolated from marine anoxic sediments from Venice in Italy.

Leptotrichia buccalis

Leptotrichia buccalis is an anaerobic, Gram-negative rod bacteria. It is a constituent of normal oral flora.

Leptotrichia buccalis can be clearly identified using live blood analysis in dark field. They have a distinct form, which separates them from other rod forms.

Leptotrichia goodfellowii

Leptotrichia goodfellowii is a Gram-negative, non-spore-forming and non-motile bacterium from the genus of Leptotrichia which has been isolated from human blood of an endocarditis patient.

Leptotrichia trevisanii

Leptotrichia trevisanii is an aerotolerant, filamentous and non-motile bacterium from the genus of Leptotrichia which has been isolated from human blood.

List of bacterial orders

This article lists the orders of the Bacteria.

Necrotizing periodontal diseases

Necrotizing periodontal diseases are a type of inflammatory periodontal (gum) disease caused by bacteria (notably fusobacteria and spirochaete species). The diseases appear to represent different severities or stages of the same disease process, although this is not completely certain. These diseases usually have a sudden onset, and so the term acute is often added to the diagnosis. The mildest on the spectrum is necrotizing ulcerative gingivitis (NUG), followed by the successively more severe conditions necrotizing ulcerative periodontitis (NUP), necrotizing stomatitis and finally cancrum oris (noma), which is frequently fatal.

Propionigenium modestum

Propionigenium modestum is a gram-negative, strictly anaerobic organism. It is rod-shaped and around 0.5-0.6 x 0.5-2.0μm in size. It is important in the elucidation of mechanism of ATP synthase.


Sneathia is a Gram-negative,rod-shaped, non-spore-forming and non-motile genus of bacteria from the family of Leptotrichiaceae. Sneathia is named of the microbiologist H. A. Snaeth.

Sneathia sanguinegens

Sneathia sanguinegens is a Gram-positive and anaerobic bacterium from the genus of Sneathia which has been isolated from humans.


The order Sphingobacteriales comprises four families of environmental bacteria.


Streptobacillus is a genus of aerobic, gram-negative facultative anaerobe bacteria, which grow in culture as rods in chains.

Species associated with infection - S. moniliformis

Reported susceptibilities and therapies - penicillin, erythromycin

Streptobacillus moniliformis

Streptobacillus moniliformis is a non-motile, Gram-negative rod-shaped bacterium that is a member of the family Leptotrichiaceae. The genome of S. moniliformis is one of two completed sequences of the order Fusobacteriales. Its name comes the Greek word streptos for "curved" or "twisted", and the Latin words bacillus meaning "small rod" and moniliformis for "necklace". S. moniliformis is microaerophilic, requiring less oxygen than is present in the atmosphere for its growth.

Prokaryotes: Bacteria classification (phyla and orders)
no OM
Extant Life phyla/divisions by domain
Taxon identifiers

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