Streptococcus alactolyticus / intestinalis
Taxonomy
Morphology
Cultural characteristics
Biochemical characters
Ecology
Pathogenicity
References
Phylum Firmicutes, Class Bacilli, Order Lactobacillales, Family Streptococcaceae, Genus Streptococcus, Streptococcus alactolyticus
Farrow et al. 1985. Lancefield group D, occasionally strains belong to Lancefield group G (
S. intestinalis).
Possible synonym:
Streptococcus intestinalis Robinson et al. 1988 (proposed by Vandamme et al. 1999).
Gram-positive cocci, nonmotile, grouped in short chains or pairs.
Small (1 mm in diameter), alpha-hemolytic (sometimes nonhemolytic), nonpigmented
colonies.
S. intestinalis produce beta-hemolysis.
Grow at 37 ºC (30-45 ºC). Aerobic, facultatively anaerobic. Growth on complex media:
trypticase soy agar with defibrinated sheep blood, trypticase soy yeast extract medium.
No growth in 6.5% NaCl broth.
Isolated from  the intestinal tract & feces of birds and pigs.
Unknown (none). Normal inhabitant of the intestine (colon).
  1. Robert A. Whiley and Jeremy M. Hardie, 2009. Genus I. Streptococcus Rosenbach 1884, 22AL. 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, 655-711.
  2. Holt J.G., Krieg N.R., Sneath P.H.A., Staley J.T. and Williams S.T., 1994. Bergey's Manual of Determinative Bacteriology, Ninth
    Edition, Williams & Wilkins, A Waverly Company, Baltimore, pp 527-558.
  3. Farrow J.A.E., Kruze J., Phillips B.A., Bramley A.J. & Collins M.D.: Taxonomic studies on Streptococcus bovis and Streptococcus
    equinus: description of Streptococcus alactolyticus sp. nov. and Streptococcus saccharolyticus sp. nov. Syst. Appl. Microbiol., 1984,
    5, 467-482.
  4. Vandamme P., Devriese L.A., Haesebrouck F. & Kersters K.: Streptococcus intestinalis Robinson et al. 1988 and Streptococcus
    alactolyticus Farrow et al. 1984 are phenotypically indistinguishable. Int. J. Syst. Bacteriol., 1999, 49, 737-741
Streptococcus intestinalis strains are biochemically very similar to S. alactolyticus , but
S. intestinalis does not ferment mannitol and raffinose.

Positive results for alpha-galactosidase, esculin hydrolysis, leucine arylamidase, urea hydrolysis, Voges-Proskauer reaction, acid
production from: cellobiose,  galactose, fructose, D-glucose, maltose, mannose, N-acetylglucosamine, D-raffinose & saccharose.
Fermenting sugars results mainly in lactic acid production.

Negative results for arginine dehydrolase, beta-glucuronidase, alkaline phosphatase, beta-galactosidase, pyrrolidonyl arylamidase,
hippurate hydrolysis, acidification of adonitol, arabitol, arabinose, dulcitol, erythritol, fucose,  methyl-alpha-D-glucoside, 2- or
5-ketogluconate, gluconate, glycogen, glycerol, inositol, inulin, lactose,  melezitose, rhamnose, ribose, sorbitol, L-sorbose,
D-tagatose, xylitol & xylose.

Variable results for acid production from: amygdalin, arbutin, mannitol, methyl alpha-D-glucoside, starch, trehalose & D-turanose.
(c) Costin Stoica
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