Phylum Firmicutes, Class Clostridia, Order Clostridiales, Family Clostridiaceae, Genus Clostridium, Cluster XIVa (non-Clostridium
sensu stricto), Clostridium sphenoides (Douglas, Fleming & Colebrook 1919) Bergey, Harrison, Breed, Hammer & Huntoon 1923.
Historical synonyms: Bacillus sphenoides Douglas, Fleming and Colebrook in Bulloch, Bullock, Douglas, Henry, McIntoch, O’Brien,
Robertson and Wolf 1919; Douglasillus sphenoides Heller 1922; Plectridium sphenoides Prevot 1938.
Gram-positive/negative straight rods, 0.3-1.1 x 1.3-8.6 µm, occuring singly, in pairs, or
in short chains. Motile by peritrichous flagella. Spores are spherical / oval, swelling
the cell, located subterminally / terminally ; sporulation occurs most readily on blood
agar plates incubated 48 hours or on chopped-meat slants incubated at 30 ºC. The
cell wall is susceptible to dissolution by lysozyme.
Colonies on the surface of blood agar are 1-2 mm in diameter, nonhemolytic, circular
with an entire or erose margin, low convex, translucent, gray, with a glossy surface,
often with a mottled internal structure. Cultures in PYG broth are turbid with a smooth
or ropy sediment and have a pH of 4.9-5.4 after incubation for 5 days.
Optimum temperature for growth is 30-37 ºC; grows at 25 ºC. Weak growth at 45 ºC.
Moderate growth in nutrient broth, cooked meat broth. Growth is slightly stimulated by
the presence of a fermentable carbohydrates and is inhibited by 20% bile. Abundant
gas is produced in PYG deep agar cultures. No aero-tolerance.
Products of metabolism in PYG broth include large amounts of acetic and formic
acids; abundant hydrogen is produced.
Isolated from soil, marine sediment, dog feces, normal human appendices, feces of from 4 - 6.4% of adult humans, infections in
range animals, blood, bone, and soft tissue infections, intraperitoneal infections, war wounds, visceral gas gangrene and renal
Converts the insecticide hexachlorocyclohexane to tetrachlorocyclohexene.
Phage-like particles are produced by one strain tested.
Susceptible to erythromycin and tetracycline.
Culture supernatants are not toxic for mice. Toxin is not produced. Not pathogenic for laboratory animals.
Occasionally is recovered from polymicrobial infections in humans and animals; pathogenicity has not been reported.
- 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,
- Smith L.D.S. and Hobbs G., 1974. Genus III. Clostridium Prazmowski 1880. In: (Eds.) Buchanan R.E. and Gibbons N.E., Bergey’s
Manual of Determinative Bacteriology, Eighth Edition, The Williams & Wilkins Company, Baltimore, 551-572.
Milk reaction (curd) is variable. Meat is not digested.
Positive results for ammonia production, citrate utilization, DNase, esculin hydrolysis, H2S production, indole production, neutral red
reduction, substrate utilization and/or acid production from: cellobiose, fructose, glucose, maltose, mannitol, mannose, raffinose,
rhamnose & salicin.
Negative results for casein hydrolysis, gelatin hydrolysis, lecithinase, lipase, urease, substrate utilization and/or acid production from:
adonitol, amygdalin, cellulose, dulcitol, erythritol, inulin & sorbitol.
Variable results for nitrate reduction, resazurin reduction, starch hydrolysis, Voges-Proskauer reaction, substrate utilization and/or
acid production from: arabinose (weak), galactose, glycogen (weak), glycerol, inositol, lactose, melezitose (weak), melibiose, ribose
(weak), sorbose, starch (weak), sucrose (weak), trehalose & xylose.
(c) Costin Stoica