Streptococcus iniae (S. shiloi)
Cultural characteristics
Biochemical characters
Phylum Firmicutes, Class Bacilli, Order Lactobacillales, Family Streptococcaceae, Genus Streptococcus, Streptococcus iniae  Pier
and Madin 1976.
Streptococcus shiloi  Eldar et al. 1995 is a later heterotypic synonym of Streptococcus iniae Pier and Madin 1976.

Nongroupable by Lancefield antisera.
Gram-positive, 1.5 μm in diameter, nonmotile, capsulated cocci. Grouped in long
Colonies are white, slightly mucoid, small (1-2 mm diameter colonies after 48 hours
of incubation). Beta-hemolytic, more visible when growth occurs anaerobically (partial
hemolysis noted on human or bovine blood medium).
Growth temperature 37.0 ºC, no growth at  45 ºC; can grow at 10 ºC. Aerobic,
facultatively anaerobic. Grow on complex media:Trypticase soy agar with defibrinated
sheep blood, Brain-hearth infusion agar / broth. No growth at pH 9.6 or in 40% bile.
Isolated from fish (diseased rainbow trout Onchorynchus mykiss & tilapia) and mammalians (skin lesions in an Amazon freshwater
Inia geoffrensis). Isolated from humans working with fish.
Septicaemia in fish (meningoencephalitis, ascitis in trout & tilapia), subcutaneous abscesses in dolphin - "golf ball disease".
Possible cause of endocarditis, osteomyelitis & arthritis in humans.
  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. Pier G.B. & Madin S.H.: Streptococcus iniae sp. nov., a beta hemolytic streptococcus isolated from an Amazon freshwater dolphin,
    Inia geoffrensis. International Journal of Systematic Bacteriology, 1976, 26, 545-553.
  4. Eldar A., Bejerano Y. & Bercovier H.: Streptococcus shiloi and Streptococcus difficile: two new streptococcal species causing a
    meningoencephalitis in fish. Curr. Microbiol., 1994, 28, 139-143.
  5. Eldar  A., Frelier P.F., Assenta L., Varner P.W., Lawhon S. & Bercovier H.: Streptococcus shiloi, the name for an agent causing
    septicemic infection in fish, is a junior synonym of Streptococcus iniae. Int. J. Syst. Bacteriol., 1995, 45, 840-842.
  6. Mitchell R. Weinstein et al.:Invasive Infections Due to a Fish Pathogen, Streptococcus iniae. NEJM Volume 337:589-594  August
    28, 1997  Number 9 .
  7. Jun-Ren Sun, Juh-Cheng Yan, Ching-Ying Yeh, Shih-Yi Lee and Jang-Jih Lu: Invasive infection with Streptococcus iniae in Taiwan.
    Med Microbiol 56 (2007), 1246-1249.
Positive results for alkaline phosphatase, arginine dehydrolase, esculin hydrolysis, leucine arylamidase, pyrrolidonylarylamidase,
starch hydrolysis, acid production from: N-acetylglucosamine, arbutin, cellobiose, esculin, D-fructose, D-glucose, glycogen,
gentiobiose, maltose, D-mannose, mannitol, methyl D-mannoside, melezitose, ribose, salicin, sucrose, starch & trehalose.

Negative results for hippurate hydrolysis, alpha & beta-galactosidase, urease, Voges-Proskauer reaction, acid production from:
adonitol, D- and L-arabinose, D- and L-arabitol, amygdalin, dulcitol, erythritol, D- and L-fucose, methyl D-glucoside, glycerol,
gluconate, 2- or 5-ketogluconate, inositol, inulin, lyxose, lactose, melibiose, D-raffinose, rhamnose, sorbitol, L-sorbose, turanose,
tagatose D- or L-xylose, methylxyloside & xylitol.

Variable galactose fermentation results.
(c) Costin Stoica
Culture media
Biochemical tests
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