Phylum Firmicutes, Class Clostridia, Order Clostridiales, Family Clostridiaceae, Genus Clostridium, Cluster XVIII (Clostridium non
sensu stricto), Clostridium cocleatum Kaneuchi, Miyazato, Shinjo and Mitsuoka 1979.
Gram-positive, semicircular, circular or spiral-shaped, 0.3-0.4 x 1.0-5.0 µm; may grow
in long chains, and be Gram-negative with filaments or swollen forms. Nonmotile.
Spores are round, terminal to subterminal, and swell the cell; spores are difficult to
demonstrate but can be found most reliably on medium 10 agar or on chopped-meat
agar slants incubated at 30 ºC.
Surface colonies on blood agar plates are pinpoint, 2 mm in diameter, circular, entire
to erose, low convex to pulvinate, semiopaque to opaque, smooth, shiny, grayish
white. Nonhemolytic. Obligately anaerobic. Cultures in PYG broth are turbid with a
smooth to mucoid sediment and have a pH of 4.9-5.4 after incubation for 4 days.
Growth is stimulated by fermentable carbohydrates and by rumen fluid. Growth is
inhibited by 6.5% NaCl, 20% bile and at a pH of 8.5. No growth at 15 ºC, weak growth
at 25 ºC ; optimum temperature 37-45 ºC. Products in PYG broth: acetic and formic
acids, abundant H2 . Abundant gas is detected in PYG deep agar cultures.
Isolated from feces of healthy humans, cecal contents of mice, rats, and chickens. Susceptible to chloramphenicol, penicillin G,
erythromycin and tetracycline. Resistant to clindamycin.
- 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., 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 is positive (curd production). Meat digestion is negative.
Positive results for hydrogen production (very abundantly), esculin hydrolysis, neutral red reduction, resazurin reduction, substrate
utilized and/or acid produced from: cellobiose, esculin, fructose, galactose, glucose, inulin, lactose, mannose & sucrose.
Negative results for ammonia production, catalase, gelatin hydrolysis, H2S production, indole production, lecithinase, lipase, nitrate
reduction, starch hydrolysis, urease, substrate utilized and/or acid produced from: arabinose, dulcitol, erythritol, glycogen, inositol,
mannitol, melezitose, melibiose, rhamnose, ribose, sorbitol, sorbose, starch, trehalose & xylose.
Variable results for Voges-Proskauer reaction, substrate utilized and/or acid produced from: amygdalin, maltose, raffinose & salicin.
(c) Costin Stoica