Streptococcus equinus / bovis
Cultural characteristics
Biochemical characters
Phylum Firmicutes, Class Bacilli, Order Lactobacillales, Family Streptococcaceae, Genus Streptococcus, Streptococcus equinus  
Andrewes and Horder 1906. Lancefield group D.

Streptococcus bovis  Orla-Jensen 1919. Poyart et al. 2002 proposed  to designate Streptococcus bovis (later heterotypic
synonym) as
Streptococcus equinus.
Gram-positive cocci, nonmotile, grouped in moderately long chains.
Small, alpha-hemolytic, nonpigmented colonies. Grow at 37 and 45 ºC, but not at 10 ºC.
Aerobic, facultatively anaerobic. Grow on complex media: Trypticase soy agar with
defibrinated sheep blood, L-asparagine enriched medium. No growth occurs in 6.5%
NaCl, 0.1% methylene blue milk, or at pH 9.6. Growth occurs in 40% bile.
Isolated from the intestinal tract of humans & animals (horse, cows, sheep).
Uncertain. Possible cause of human endocarditis, meningitis or septicemia (rarely).
In bovines  proliferation of
S. bovis in the rumen is enhanced by the high quantities fermentable carbohydrates diet. Lactic acid in
excess may lead to ruminal acidosis.
  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. Orla-Jensen S. (ed.): The lactic acid bacteria. Host, Copenhagen, 1919, pp. 1-196.
  4. Poyart C., Quesne G. & Trieu-Cuot P.: Taxonomic dissection of the Streptococcus bovis group by analysis of manganese-
    dependent superoxide dismutase gene (sodA) sequences: reclassification of 'Streptococcus infantarius subsp. coli' as
    Streptococcus lutetiensis sp. nov. and of Streptococcus bovis biotype II.2 as Streptococcus pasteurianus sp. nov. Int. J. Syst. Evol.
    Microbiol., 2002, 52, 1247-1255.
  5. Skerman VB et al. Approved lists of bacterial names. Int. J. Syst. Bacteriol. 30: 225-420, 1980.
  6. "Subacute Ruminal Acidosis". The Merck Veterinary Manual.
Lactic acid bacteria. Chemo-organotroph: metabolism fermentative.

Positive results for esculin hydrolysis, leucine arylamidase, Voges-Proskauer reaction, acid production from: amygdalin, arbutin,
cellobiose, fructose, glucose, galactose, D-mannose, maltose, N-acetylglucosamine, salicin & sucrose.

Negative results for arginine hydrolysis, hippurate hydrolysis, gelatin hydrolysis, alkaline phosphatase, pyrrolidonyl arylamidase,
beta-galactosidase, beta-glucuronidase, urease, acid production from: D- or L-arabinose, D- or L-arabitol, 2- or 5-ketogluconate,
dulcitol, erythritol, D- or L-fucose, glycerol, gluconate, inositol, D-lyxose, mannitol, methyl beta-xyloside, melezitose, ribose, rhamnose,
L-sorbose, sorbitol, D-turanose, D-tagatose, D- or L-xylose & xylitol.

Variable results for acid production from: glycogen, inulin, lactose, melibiose, D-raffinose, starch & trehalose.

Differences (if considering 2 different species):
S. equinus: mannitol, sorbitol, lactose - negative. Inulin, raffinose, salicin - variable.
S. bovis: lactose, raffinose, salicin - positive. Mannitol, sorbitol, trehalose, inulin - variable.
(c) Costin Stoica
Culture media
Biochemical tests
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