Biochemical characters
Bacillus thuringiensis colonies on Sheep Blood Agar;
beta-hemolysis
Bacillus thuringiensis
Taxonomy
Morphology
Cultural characteristics
Ecology
Pathogenicity
References
Phylum Firmicutes, Class Bacilli, Order Bacillales, Family Bacillaceae, Genus Bacillus, Bacillus thuringiensis  Berliner (1915)
Synonym:
Bacillus cereus var. thuringiensis Smith, Gordon and Clarck (1952).
Hystorical synonyms:
B. cereus var. alesti  Toumanoff and Vago (1951), B. dendrolimus Talalaev (1956), B. entomocidus var.
entomocidus
Heimpel and Angus (1958), B. entomocidus var. subtoxicus Heimpel and Angus (1958), B. ephestiae ( Metalnikov and
Chorine ,1929) Steinhaus (1949),
B. finitimus Heimpel and Angus (1958), B. soto Metalnikov and Chorine (1927), B. bombycis
Macchiati (1891),
B. anagastae Heimpel (1967), B. tolworthi de Barjac and Bonnefoi (1968), B. darmstadiensis Krieg, de Barjac and
Bonnefoi (1968),
B. toumanoffii Krieg (1969), B. morrisoni de Barjac and Bonnefoi (1968), B. aizawai Hempel (1967), B. pacificus
Hempel (1967),
B. galleriae Hempel (1967), B. kenyae de Barjac and Bonnefoi (1967), B. amuscatoxicus Hempel (1967).

Phenotypically very close to other members of the Bacillus cereus group:
Bacillus anthracis, Bacillus mycoides, Bacillus
pseudomycoides, Bacillus cereus
and Bacillus weihenstephanensis. Genetic evidence supports the recognition of members of the
Bacillus cereus group as one species, but practical considerations (virulence characters) argue against such a move.
Bacillus
thuringiensis
is distinguished by its characteristic parasporal crystals. Smith et al. (1952) and Gordon et al. (1973) considered
Bacillus thuringiensis to be a variety of Bacillus cereus.
Bacillus thuringiensis has been divided on the basis of flagellar (H) antigens into 69 serotypes with 13 subantigenic groups, giving a
total of 82 serovars (Lecadet et al., 1999).
Gram positive, 1.1 -1.2 x 3.0-5.0 μm, motile rods. Ellipsoidal, central or paracentral
spore, not deforming the sporangia appreciably. Spores may be cylindrical and may
be positioned subterminally. Spores may lie obliquely in the sporangia. No capsule
present.
Parasporal bodies within the sporangia. These crystalline protein inclusions  may be
bipyramidal, cuboid, spherical to ovoid, flat-rectangular, or heteromorphic in shape.
They are formed outside the exosporium and readily separate from the liberated
spore. They are known as delta-endotoxins or insecticidal crystal proteins.
The bacilli tend to occur in chains. Cells grown on glucose agar produce large
amounts of storage material, giving a vacuolate or foamy appearance.
On agar, colonies are very variable in appearance. They are usually whitish to cream in color, large (2-7 mm in diameter), and vary in
shape from circular to irregular, with entire to undulate, crenate or fimbriate edges; they usually have matt or granular textures.
Sometimes smooth and moist colonies may appear.
Growth temperature  from  10-15 ºC  to  40-45 ºC. Grow in  0-7% NaCl and at pH 5,7 and 7. Allantoin or urate are not required.
Media: nutrient agar or nutrient broth.
Endospores are widespread in soil and many other environments. The organism has been isolated from all continents, including
Antarctica.
The ability to produce parasporal bodies has been transferred to strains of
B. cereus & B. pumilus and may be lost on subculture.
Grow in the presence of lysozyme 0.001%.
Insect larvae pathogen (mosquito, Lepidoptera etc.) by toxins synthesis. Used as bio-
pesticide. Some strains of
B. thuringiensis may produce the B. cereus diarrheal toxin.

Delta-endotoxins or insecticidal crystal proteins are protoxins which may be toxic for
certain insects and other invertebrates including flatworms, mites, nematodes and
protozoa. The ability to synthesize parasporal bodies is plasmid borne. There is little correlation between serotype and insecticidal
toxicity.
Although numerous strains are toxic to invertebrates, this property has not been demonstrated in many other strains. Natural
epizootics do not seem to occur, and it has been suggested that the natural habitat of this organism is soil.

B. thuringiensis has been implicated in cases of gastroenteritis and wound, burn & ocular infections.
  1. Gordon R.E., Haynes W.C., Pang C.H. (1973) – The genus Bacillus . Agriculture Handbook No. 427, U.S.D.A., Washington D.C.
  2. Buchanan R.E., Gibbons N.E., Cowan S.T., Holt J.G., Liston J., Murray R.G.E., Niven C.F., Ravin A.W., Stanier R.W. ( 1974) –  
    Bergey’s Manual of Determinative Bacteriology, Eight Edition, The Williams & Wilkins Company, Baltimore.
  3. Logan N. A., 2005. Bacillus anthracis, Bacillus cereus, and other aerobic endospore-forming bacteria. In: Topley & Wilson’s
    Microbiology & Microbial Infections, 10th Edition, Edited by Boriello S.P., Murray P.R., Funke G, Bacteriology, vol. 2, 922-952.
  4. N.A. Logan and P. De Vos, 2009. Genus I. Bacillus Cohn 1872. 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, 21-127.
Positive results for lysine decarboxylase, arginine dihydrolase, hydrolysis of esculin,
hydrolysis of casein, hydrolysis of gelatin, tyrosine decomposition, acid production
from: glycerol, starch, N-acetyl-D-glucosamine, arbutin, fructose, maltose, ribose &
trehalose.

Negative results for deamination of phenylalanine, beta-galactosidase, ornithine
decarboxylase, hydrolysis of urea, oxidase, acid production from: methyl
beta-xyloside, adonitol, amygdalin, D- or L-arabitol, dulcitol, erythritol, D- or L-fucose,
galactose, beta-gentiobiose, gluconate, meso-inositol, inulin, 2- or 5-ketogluconate,
lactose, lyxose, melezitose, melibiose, raffinose, rhamnose, sorbitol, sorbose & xylitol.

Variable results for acidification of salicin, cellobiose & sucrose.
(c) Costin Stoica
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