Streptococcosis became an increasingly significant health problem in intensive aquaculture in China. Fifteen
strains of Gram-positive, chain-forming coccus were isolated from moribund Amur sturgeon, Acipenser
schrenckii, farmed with high density in central China. The coccoid microorganism was identified as Streptococcus
dysgalactiae by means of physiological, biochemical properties and molecular analysis; furthermore,
this coccus was confirmed as pathogen of sturgeon by challenge experiments and its infection potential on
the cyprinid was also evaluated. To our knowledge, this was the first report of S. dysgalactiae linked to
diseased A. schrenckii