Cultural characteristics
Biochemical characters
Phylum Firmicutes, Class Clostridia, Order Clostridiales, Family Clostridiaceae, Genus Clostridium, Cluster XVIII (non-Clostridium
sensu stricto),
Clostridium spiriforme Kaneuchi, Miyazato, Shinjo and Mitsuoka 1979.
Gram-positive, semicircular, circular or spiral-shaped, 0.3-0.5 x 2.0-10.0 µm; exhibit
various degrees of coiling and long chains of organisms forming tight coils often are
seen. After heating at 80 ºC for 10 minutes, cells may be nearly straight and
subsequent subcultures do not have coiled cells. Nonmotile. Spores are round,
terminal to subterminal, swelling the cell; most strains survive heating to 70 ºC for 10
minutes; survival after heating to 80 ºC for 10 min is variable. Spore demonstration is
sometimes difficult. Fresh isolates from humans may not form spores or survive
heating to 70 ºC for 10 min.
Surface colonies on Eggerth-Gagnon agar after 2 days incubation are 0.7-1.5 mm in
diameter, have an entire or slightly erose margin, circular, convex to slightly pulvinate,
smooth, shiny, semiopaque to opaque, and are whitish to brownish-gray.
Non-hemolytic on blood agar. Obligately anaerobic. Cultures in PYG broth are slightly
turbid with a smooth to flocculent sediment and have a pH of 4.9–5.2  after incubation
for 7 days. Growth is stimulated by fermentable
carbohydrates and by rumen fluid. Growth is inhibited by 6.5% NaCl and  20% bile.
Optimum temperature for growth is 30-37 ºC. No
growth at 15 ºC. Weak growth at 25 and 45 ºC. Products in PYG broth are acetic and formic acids, abundant hydrogen. Small to
moderate amounts of gas are produced in PYG deep agar cultures.
Isolated from feces of healthy humans, cecal contents of healthy rabbits and chickens and the ceca of rabbits with diarrhea.
Susceptible to chloramphenicol, clindamycin, penicillin G, erythromycin  and tetracycline.
A toxin produced in vitro is lethal to mice and causes dermonecrosis in guinea pigs, but toxin is not produced by all strains.
  1. 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,
    Springer, 738-828.
  2. Kaneuchi C., Miyazato T., Shinjo T. and Mitsuoka T., 1979. Taxonomic Study of Helically Coiled, Sporeforming Anaerobes Isolated
    from the Intestines of Humans and Other Animals: Clostridium cocleatum sp. nov. and Clostridium spiroforme sp. nov. IJSB 29, 1,
Milk reaction (curd production) is positive. Meat is not digested.

Positive results for hydrogen production, neutral red reduction, resazurin reduction, Voges-Proskauer reaction, substrate utilization
and/or acid production from: fructose, glucose, inulin, lactose, mannose & sucrose.

Negative results for ammonia production, catalase, gelatin hydrolysis, indole production, lecithinase, lipase, nitrate reduction, starch
hydrolysis, urease, substrate utilization and/or acid production from: arabinose, dulcitol, erythritol, galactose, glycogen, inositol,
maltose, mannitol, melezitose, melibiose, raffinose, rhamnose, ribose, sorbitol, sorbose, starch, trehalose & xylose.

Variable results for esculin hydrolysis, substrate utilization and/or acid production from: amygdalin (weak), cellobiose & salicin.
Clostridium spiriforme
(c) Costin Stoica
Culture media
Biochemical tests
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