Clostridium oroticum
Cultural characteristics
Biochemical characters
Phylum Firmicutes, Class Clostridia, Order Clostridiales, Family Clostridiaceae, Genus Clostridium, Cluster XIVa (non-Clostridium
sensu stricto),
Clostridium oroticum (Wachsman and Barker 1954) Cato, Moore and Holdeman 1968.

Historical synonyms:
Zymobacterium oroticum Wachsman and Barker 1954.
Gram-positive, ovals or straight rods with rounded ends, 0.3-1.6 x 1.3-3.9 µm,
occuring in long tangled chains. Spores are round/oval, central  or subterminal, not
swelling the cell. Sporulation occurs most readily in PY broth cultures. Non-motile.
Surface colonies on blood agar plates are 1-2 mm in diameter, circular, convex,
opaque, smooth, shiny, white or buff-colored. A slight beta hemolysis is produced.
Cultures in PYG broth have a heavy, smooth to mucoid sediment, with no turbidity,
and a pH of 5.1 after incubation for 4 days.
Optimum temperature for growth is 30-37 ºC. Grows at 25 and 45 ºC. Growth is
inhibited by 6.5% NaCl . Abundant gas is detected in PYG deep agar cultures.
Characteristically, orotic acid is utilized with 90% of the substrate degraded in 4 days.
Products in PYG broth are  formic and acetic acids, CO
2 and ethanol; abundant H2 is
Isolated from black mud from San Francisco Bay, human feces, suprapubic bladder aspirates, and a rectal abscess.
Susceptible to chloramphenicol erythromycin, penicillin G, and tetracycline. Resistant to clindamycin.
Culture supernatants are nontoxic to mice. Nonpathogenic for laboratory animals. Toxin is not produced. Isolated from suprapubic
bladder aspirates, a rectal abscess.
  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. 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.
  3. Wachsman J.T. and Barker H.A., 1954. Characterization of an orotic acid fermenting bacterium, Zymobacterium oroticum, nov.
    gen. spec. J.Bacteriol. 68(4):400.
  4. Cato E.P., Moore W.E.C. and Holdeman L.V., 1968. Clostridium oroticum comb. nov. amended description. IJSB 17, 1, 9-13.
Milk reaction is positive (curd production). Meat is not digested.

Positive results for ammonia production, esculin hydrolysis, neutral red reduction, orotic acid hydrolysis, resazurin reduction,
substrate utilization and/or acid production from: arabinose, dulcitol, fructose, galactose, glucose, inositol, inulin, lactose, maltose,
raffinose, rhamnose, ribose, salicin, sucrose & xylose.

Negative results for casein hydrolysis, catalase, gelatin hydrolysis, H
2S production, hippurate hydrolysis, indole production, lipase,  
lecithinase, starch hydrolysis, urease, Voges-Proskauer reaction, substrate utilization and/or acid production from: amygdalin,
cellobiose, esculin, glycogen, glycerol, mannose, melibiose, sorbose & starch.

Variable or weak results for nitrate reduction, substrate utilization and/or acid production from: mannitol, melezitose, sorbitol (weak) &
(c) Costin Stoica
Culture media
Biochemical tests
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