Taxonomy
Morphology
Cultural characteristics
Biochemical characters
Ecology
Pathogenicity
References
Phylum Firmicutes, Class Clostridia, Order Clostridiales, Family Clostridiaceae, Genus Clostridium, Cluster XIVa (Clostridium
non-sensu stricto
), Clostridium nexile  Holdeman and Moore 1974.
Gram-positive, ovals or straight rods, 0.8-1.7 x 0.8-6.3 µm, occuring in pairs or chains.
Nonmotile. Spores are round / oval, subterminal, but are rarely seen, even in cultures
that resist heating at 80 ºC for 10 min. Spores have been seen in 6-days-old cultures
of PYG broth.
Surface colonies on blood agar plates are 0.5-1 mm in diameter, circular, convex to
raised, semiopaque or with opaque centers and translucent edges, smooth, shiny,
white to yellowish, nonhemolytic, and with entire margins.
Cultures in PYG broth have a smooth or ropy sediment, often with no turbidity, and a
pH of 4.9
-5.3 after incubation for 5 days.
Obligately anaerobic. Growth is stimulated by fermentable carbohydrates.
Optimum temperature for growth is 30-37 ºC. Grow at 25 ºC (weak) and at 45 ºC.
Growth is inhibited by 6.5% NaCl and 20% bile. Abundant gas is detected in PYG
deep agar cultures. Products in PYG broth are  formic and acetic acids and ethanol;
abundant H
2 is detected.
Isolated from human feces as part of normal flora. Susceptible to chloramphenicol and clindamycin.
Considered normal flora in human feces.
  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. Holdeman L.V. and Moore W.E.C., 1974. New genus, Coprococcus, twelve new species, and emended descriptions of four
    previously described species of bacteria from human feces. IJSB vol. 24, No.2, 260-277.
Milk reaction is variable.  Meat is not digested.

Positive results for esculin hydrolysis, neutral red reduction, resazurin reduction, substrate utilization and/or acid production from:
fructose, galactose, lactose, sucrose & xylose (weak reactions).

Negative results for ammonia, catalase, gelatin hydrolysis, indole production, lecithinase, lipase, nitrate reduction, orotic acid
hydrolysis, starch hydrolysis, urease, Voges-Proskauer, substrate utilization and/or acid production from: adonitol, arabinose,
cellobiose, dulcitol, erythritol, glycogen, glycerol, inositol, maltose, mannitol, melezitose, rhamnose, ribose, sorbitol & sorbose.

Variable or weak results for H
2S production, substrate utilization and/or acid production from: amygdalin, esculin, inulin, mannose,
melibiose, raffinose, salicin, starch & trehalose.
Clostridium nexile
(c) Costin Stoica
Antibiogram
Encyclopedia
Culture media
Biochemical tests
Stainings
Images
Movies
Articles
Identification
Software
R E G N U M
PROKARYOTAE
Previous page
Back