Streptococcus intermedius
Taxonomy
Morphology
Cultural characteristics
Biochemical characters
Ecology
Pathogenicity
References
Phylum Firmicutes, Class Bacilli, Order Lactobacillales, Family Streptococcaceae, Genus Streptococcus, Streptococcus intermedius
Prevot 1925.
Formerly was considered a later heterotypic synonym of
Streptococcus anginosus.
Usually ungroupable, but some strains may react with Lancefield group F & C antisera.
Gram-positive, 0.5-1.0 μm in diameter, coccoid cells, grouped in short chains.
Colonies on blood agar are 0.5-2.0 mm in diameter, white, translucent or matte,
convex and entire. On blood agar colonies are non-hemolytic or surrounded by zones
of alpha-hemolysis, occasionally beta-hemolytic. Always is beta-hemolytic on human
blood agar. Facultatively anaerobic. Growth is reduced aerobically, but enhanced by
incubation in 5% CO
2-supplemented atmosphere.
Habitats are the human oral cavity and upper respiratory tract. It has been reported to occur in feces.
Isolated from human purulent infections, liver and brain abscesses.
  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. Robert A. Whiley and David Beighton. Emended Descriptions and Recognition of Streptococcus constellatus, Streptococcus
    intermedius, and Streptococcus anginosus as Distinct Species. Int J Syst Bacteriol January 1991 41:1-5.
Positive results for alkaline phosphatase, arginine hydrolysis, esculin hydrolysis, beta-fucosidase, beta-galactosidase,
alpha-glucosidase, beta-N-acetylgalactosaminidase, beta-N-acetylglucosaminidase, hyaluronidase, leucine arylamidase,
neuraminidase, Voges-Proskauer reaction, acid production from: amygdalin (most strains), cellobiose (most strains), glucose,
lactose, maltose, salicin (most strains), sucrose & trehalose.

Negative results for catalase, alpha-galactosidase, beta-glucuronidase, hippurate hydrolysis, hydrogen peroxide production,
pyrrolidonyl arylamidase, urease, acid production from: arabinose, glycerol, glycogen, inulin, ribose & sorbitol. A few produce acid
from mannitol, melibiose, raffinose & sorbitol.

Variable results for beta-glucosidase.
(c) Costin Stoica
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