Streptococcus pyogenes
Beta-haemolytic S. pyogenes colonies on Sheep
Blood Agar
S. pyogenes cells, Gram staining
Cultural characteristics
Biochemical characters
Phylum Firmicutes, Class Bacilli, Order Lactobacillales, Family Streptococcaceae, Genus Streptococcus, Streptococcus pyogenes  
Rosenbach 1884, type species of the genus.
Old synonyms:
Streptococcus erysipelatos Rosenbach 1884, Micrococcus scarlatinae Klein 1884, Streptococcus scarlatinae Klein 1887,
Streptococcus hemolyticus Rolly 1911.
Lancefield group A.
Gram-positive, spherical or ovoid cells, 0.5-1 µm in diameter. Grouped in pairs or
short to moderate chains in clinical materials; long chains in broth cultures. Some
strains form a capsule of hyaluronic acid.
Colonies may look mucoid, glossy or matt. Beta-hemolytic on blood agar (streptolysin
O). Facultative anaerobes, optimal temperature 37.0 ºC, no growth at 10 or 45 ºC.
Nutritionally fastidious, especially upon primary isolation. C, No growth in the
presence of 6.5% NaCl, at pH 9.6, or in the presence of 40% bile.
Isolated from human mouth, throat, respiratory tract, blood, various lesions and
inflammatory exudates. Rarely isolated from animals.
May be harboured as normal flora of the human upper respiratory tract. Can cause
pharyngitis, erysipelas, necrotizing fasciitis, glomerulonephritis, rheumatic fever,
scarlet fever, puerperal fever and streptococcal toxic shock syndrome.
Virulence factors: streptolysin O & S, pyrogenic exotoxin A & C, streptokinase,
hyaluronidase, streptodornase, C5a peptidase, chemokine protease.
Septicemia followed by death in guinea pigs was reported.
Virulence factors: hyaluronic acid capsule, M proteins, plasminogen-binding proteins,
pyrogenic exotoxins A, B, C, and F, streptococcal superantigen, Streptolysin O (SLO)
and streptolysin S (SLS)
  1. 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.
  2. 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.
  3. P. A. Okewole, P. S. Odeyemi, M. A. OlandunmadeiI, B. O. Ajagbonnai, J. Onaui & T. Spencer: An outbreak of Streptococcus
    pyogenes infection associated with calcium oxalate urolithiasis in guineapigs (Cavia porcellus).
Fermentative metabolism, the final pH in glucose broth is 4.8–6.0.
Positive results for alkaline phosphatase, arginine hydrolysis, pyrrolidonyl
arylamidase, acid production from: N-acetylglucosamine, fructose, glucose,
galactose, lactose, maltose, salicin, sucrose, methyl D-glucoside & trehalose.

Negative results for alpha- or beta-galactosidase, beta-glucosidase, N-acetyl-beta-
glucosaminidase, glycyl-tryptophan arylamidase, hippurate hydrolysis, Voges-
Proskauer reaction, acid production from: adonitol, amygdalin, arbutin, arabinose,
arabitol, dulcitol, cyclodextrin, erythritol, gluconate, inulin, melibiose, methyl D-
mannoside, mannitol, melezitose, raffinose, ribose, sorbitol, sorbose, tagatose,
methyl D-xyloside & xylose.

Variable results for esculin hydrolysis and beta-glucuronidase.
(c) Costin Stoica
Culture media
Biochemical tests
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