Phylum Firmicutes, Class Bacilli, Order Lactobacillales, Family Streptococcaceae, Genus Streptococcus, Streptococcus suis (Elliot
1966) Kilpper-Balz and Schleifer 1987.
35 different antigenic carbohydrate types are described.
Lancefield group R, S, T or non-groupable. The most common strains identified are
Lancefield group R.
Gram-positive, small ovoid cocci, less than 2 μm in diameter, occur singly, in pairs, or
rarely in short chains. Nonmotile.
Alpha-hemolytic on sheep blood agar and many strains are beta-hemolytic on horse
blood agar. Optimal growth at 37.0 ºC, no growth at 10 or 45 ºC, in 6.5% NaCl or
0.04% tellurite. Resistant to optochin. Some strains are resistant to 40% bile. Strains
do not produce extracellular polysaccharide on sucrose-containing medium.
Isolated mainly from the upper respiratory tract of swine (tonsils, pharynx, nose), rarely from other animals (dogs, cats, birds ).
Isolated from slaughter and pig farm workers.
Pig pathogen (meningitis, bacteremia, septicemia, arthritis, pneumonia, endocarditis, poliserositis, abortus, abscesses) especially
in piglets. May be transmitted to humans from diseased animals (meningitis, septicemia, arthritis, endocarditis, pneumonia,
spondylodiscitis, endophthalmitis, uveitis, peritonitis).
Virulence is variable; may be a normal inhabitant of the upper respiratory tract of swine. Sometimes may be a secondary agent in
respiratory infections produced by other germs.
Mice are susceptible to experimental infection (oral or respiratory) and infected mice can transmit the germ to healthy animals.
- 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.
- 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.
- Killpper-Balz R. & Schleifer K.H.: Streptococcus suis sp. nov., nom. rev. Int. J. Syst. Bacteriol., 1987, 37, 160-162.
- Huang YT, Teng LJ, Ho SW, Hsueh PR.: Streptococcus suis infection. J Microbiol Immunol Infect. 2005 Oct;38(5):306-13.
Positive results for L-arginine hydrolysis, esculin hydrolysis, glycogen hydrolysis, salicin hydrolysis, starch hydrolysis, L-ornithine
decarboxylase, beta-acetylglucosaminidase, alpha-galactosidase, beta-glucuronidase, leucine arylamidase, acid production from:
D-glucose, inulin, lactose, maltose, salicin, trehalose & sucrose.
Negative results for acid- or alkaline phosphatases, catalase, hippurate hydrolysis, pyrrolidonyl arylamidase, Voges-Proskauer
reaction, acid production from: L-arabinose, glycerol, D-mannitol, melezitose, D-ribose & D-sorbitol.
Variable results for beta-galactosidase, hyaluronidase, fermentation of raffinose & melibiose.
(c) Costin Stoica