Phylum Firmicutes, Class Clostridia, Order Clostridiales, Family Clostridiaceae, Genus Clostridium, Cluster XIVa (non-Clostridium
sensu stricto), Clostridium clostridioforme corrig. (Burri and Ankersmit 1906) Kaneuchi, Watanabe, Terada, Benno and Mitsuoka 1976.
Historical synonyms: Bacterium clostridiiforme Burri and Ankersmit 1906, Eggerthella clostridiiformis (Burri and Ankersmit 1906)
Beerens et al. 1962, Ristella clostridiiformis (Burri and Ankersmit 1906) Prevot 1938, Bacteroides clostridiiformis (Burri and Ankersmit
1906) Holdeman and Moore 1970.
Gram-negative, straight rods with pointed ends, 0.3-0.9 x 1.4-9.0 µm, occur in pairs or
singly/short chains. Motility is variable; sluggishly motile peritrichous cells or cells
with a subpolar tuft of flagella can be detected.
Spores are oval, central or subterminal, swelling the cell; sporulation occurs most
reliably on chopped-meat agar slants incubated at 30 ºC for 2-3 weeks or in 3-week-
old chopped meat broth cultures.
Obligately anaerobic. Surface colonies on blood agar plates are nonhaemolytic, 0.5-
2.0 mm in diameter, slightly scalloped or erose, convex to slightly peaked, translucent
to opaque, gray-white, usually with a mottled or mosaic internal structure.
Cultures in PYG broth are turbid with a heavy, sometimes viscous or ropy sediment and
have a pH of 5.2-5.5 after incubation for 24 hours. Grows at 25-45 ºC (weak); optimum
temperature 30-37 ºC.
Growth is inhibited by 6.5% NaCl or a pH of 8.5; strains vary in their reaction to 20% bile. Abundant gas is detected in PYG deep agar
cultures. Fermentation products in PYG broth cultures are acetic acid, H2, usually formic and lactic acids, and ethanol.
Isolated from intestinal contents of birds, humans, and other animals; calf rumen contents; turkey liver lesions; abdominal, cervical,
scrotal, pleural, and other infections; septicemias, peritonitis, and appendicitis.
All strains resist heating at 70 ºC for 10 min, but many do not survive heating at 80 ºC. Susceptibility to antibiotics is variable.
Culture supernatants are nontoxic for mice.
Found in various infections: abdominal, cervical, scrotal, pleural, and other infections; septicemias, peritonitis, and appendicitis.
- N.A. Logan and P. De Vos, 2009. Genus I. Clostridium Prazmowski 1880. In: (Eds.) P.D. Vos, G. Garrity, D. Jones, N.R. Krieg, W.
Ludwig, F.A. Rainey, K.-H. Schleifer, W.B. Whitman. Bergey’s Manual of Systematic Bacteriology, Volume 3: The Firmicutes,
- Kaneuchi C., Watanabe K., Terada A., Benno Y. and Mitsuoka T., 1976. Taxonomic Study of Bacteroides clostridiiformis subsp.
clostridiiformis (Burri and Ankersmit) Holdeman and Moore and of Related Organisms: Proposal of Clostridium clostridiiformis
(Burri and Ankersmit) comb. nov. and Clostridium symbiosum (Stevens) comb. nov. IJSB 26, 2, 195-204.
- Holdeman L.V. and Moore W.E.C., 1974. Genus I. Bacteroides Castellani and Chalmers 1919. In: (Eds.) Buchanan R.E. and
Gibbons N.E., Bergey’s Manual of Determinative Bacteriology, Eighth Edition , The Williams & Wilkins Company, Baltimore, 385-
Biochemical tests are quite variable, even those of a strain tested at different times. Milk reaction is positive (curd). Meat is not
Positive results for hydrogen production (very abundantly), ammonia production, nitrate reduction, Voges-Proskauer (weak), substrate
utilized and/or acid produced from: fructose, galactose, glucose, maltose, mannose (weak), sucrose & xylose.
Negative results for casein hydrolysis, catalase, DNase, gelatin hydrolysis, lecithinase, lipase, neutral red reduction, urease,
substrate utilized and/or acid produced from: dulcitol, esculin, glycerol, inositol, inulin, mannitol & sorbitol.
Variable results for H2S production, indole production, esculin hydrolysis, starch hydrolysis (weak), resazurin reduction, substrate
utilized and/or acid produced from: adonitol (weak), amygdalin (weak), arabinose, cellobiose, glycogen, lactose, melezitose,
melibiose, raffinose, rhamnose, ribose, salicin, sorbose, starch (weak) & trehalose.
(c) Costin Stoica