Phylum Firmicutes, Class Clostridia, Order Clostridiales, Family Clostridiaceae, Genus Clostridium, Cluster I (Clostridium sensu
stricto), Clostridium tyrobutyricum van Beynum and Pette 1935.
Gram-positive, slender or slightly curved rods, 1.1-1.6 x 1.9-13.3 µm, occuring singly
or in pairs. Motility is variable (peritrichous flagella). Spores are elliptical, subterminal,
swelling the cell. Sporulation occurs most readily on chopped-meat agar slants or in
old PYG cultures. The cell wall is susceptible to dissolution by lysozyme.
Colonies on the surface of blood agar are circular, 0.5 mm in diameter, convex with
an entire margin, gray, translucent, have a glossy surface, and are often beta-
Optimum temperature for growth is 30-37 ºC. Can grow at 45 ºC (weak) and 25 ºC.
Cultures in PYG broth are turbid with a smooth sediment and have a pH of 5.0–5.4
after incubation for 1 week. Fermentable carbohydrates stimulate growth. Growth in
broth is inhibited by 6.5% NaCl or 20% bile. Abundant gas is proproduced in PYG
deep agar cultures. Products of fermentation in PYG broth are large amounts of
butyric and acetic acids; abundant hydrogen is produced.
Isolated from gley soil, dairy products (cheese), silage, feces of beagle dogs, bovine feces, human adult and infant feces.
One strain tested is susceptible to chloramphenicol, clindamycin, erythromycin, penicillin G, and tetracycline.
Toxin is not produced. Culture supernatants are not toxic to mice. Non-pathogenic for humans and other animals.
- 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 and meat digestion are negative.
Positive results for hydrogen production, neutral red reduction, substrate utilization and/or acid production from: fructose & glucose.
Negative results for casein hydrolysis, catalase, DNase, esculin hydrolysis, gelatin hydrolysis, H2S production, indole production,
lecithinase, lipase, starch hydrolysis, urease, Voges-Proskauer reaction, substrate utilization and/or acid production from: amygdalin,
adonitol, arabinose, cellobiose, cellulose, dulcitol, erythritol, esculin, galactose, glycogen, glycerol, inositol, inulin, lactose, maltose,
melezitose, melibiose, raffinose, rhamnose, ribose, salicin, sorbitol, sorbose, starch, sucrose & trehalose.
Variable results for ammonia, nitrate reduction, substrate utilization and/or acid production from: mannitol, mannose & xylose.
(c) Costin Stoica