Streptococcus oralis
Cultural characteristics
Biochemical characters
Phylum Firmicutes, Class Bacilli, Order Lactobacillales, Family Streptococcaceae, Genus Streptococcus, Streptococcus oralis  Bridge
and Sneath 1982.
- Streptococcus oralis subsp. oralis (Bridge and Sneath 1982) Jensen et al. 2016;
- Streptococcus oralis subsp. tigurinus (Zbinden et al. 2012) Jensen et al. 2016;
- Streptococcus oralis subsp. dentisani (Camelo-Castillo et al. 2014) Jensen et al. 2016.

Member of the "Mitis group".
Non-groupable by Lancefield antisera.
Gram-positive cocci, nonmotile, nonspore-forming,  arranged in long chains.
Alpha-hemolytic (on horse blood agar) colonies.
Facultatively anaerobic, optimal growth at 37.0 ºC. Growth at 10 & 45 ºC is variable.
Grow on: trypticase soy agar with defibrinated blood, BHI blood agar. Growth occurs in
the presence of 0.0004% crystal violet but not with 3% NaCl. Variable growth in
sodium azide. Dextran production is variable.
Isolated from human mouth. Is a dental plaque colonizer.
Oral opportunistic bacteria, may cause endocarditis and may be involved in dental caries production.
  1. Bridge P.D. & Sneath P.H.A.: Streptococcus gallinarum sp. nov. and Streptococcus oralis sp. nov. Int. J. Syst. Bacteriol., 1982, 32,
  2. Kilian M., Mikkelsen L. & Henrichsen J.: Taxonomic study of viridans streptococci: description of Streptococcus gordonii sp. nov. and
    emended descriptions of Streptococcus sanguis (White and Niven 1946), i (Bridge and Sneath 1982), and Streptococcus mitis
    (Andrewes and Horder 1906). Int. J. Syst. Bacteriol., 1989, 39, 471-484.
  3. J. A. Jacobs, J. L. N. Stappers & J. P. Sels: Endocarditis due to Streptococcus oralis in a patient with a colon tumour. European
    Journal of Clinical Microbiology & Infectious Diseases, Volume 14, Number 6 / June, 1995, 557-558.
  4. 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.
  5. 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.
  6. Jensen A, Scholz CF, Kilian M. Re-evaluation of the taxonomy of the Mitis group of the genus Streptococcus based on whole
    genome phylogenetic analyses, and proposed reclassification of Streptococcus dentisani as Streptococcus oralis subsp. dentisani
    comb. nov., Streptococcus tigurinus as Streptococcus oralis subsp. tigurinus comb. nov., and Streptococcus oligofermentans as a
    later synonym of Streptococcus cristatus. Int J Syst Evol Microbiol 2016; 66:4803-4820.
Description of S. oralis subsp. oralis (for subspecies tigurinus and dentisani see the pages Streptococcus tigurinus and
Streptococcus dentisani):
Positive results for alkaline phosphatase, acid phosphatase, leucine aminopeptidase, valine aminopeptidase, chymotrypsin,
alpha-D-glucosidase, sialidase (neuraminidase), N-acetyl-beta-D-glucosaminidase, N-acetyl-beta-D-galactosaminidase, glycyl
tryptophan arylamidase, beta-glucosaminidase, acid production from: fructose, galactose, glucose, N-acetylglucosamine, lactose,
maltose, pullulan and sucrose.

Negative results for acetoin production, arginine hydrolysis, catalase, esculin hydrolysis, hippurate hydrolysis, urease,
phospho-beta-galactosidase, alpha-arabinosidase, alaninephenylalanyl-proline arylamidase, alpha-L-fucosidase,
beta-D-fucosidase, beta-D-glucosidase, beta-maltosidase, beta-mannosidase, beta-glucuronidase, beta-lactosidase, alpha- or
beta-xylosidase, hyaluronidase, acid production from: amygdalin, arabinose, arabitol, arbutin, cellobiose, cyclodextrin, dulcitol,
esculin, glycogen, inulin, mannitol, melezitose, methyl D-glucoside, rhamnose, sorbitol, and sorbose.

Variable results for alpha-D-galactosidase, beta-D-galactosidase, methyl red reaction, acid production from: erythritold, glycerol,
melezitose, melibiose, ribose, salicin,  starch, raffinose, tagatose and trehalose.
(c) Costin Stoica
Culture media
Biochemical tests
Previous page