General Information: Streptococcus equi subsp. zooepidemicus str. MGCS10565 was responsible for a large and severe epidemic outbreak of poststreptococcal glomerulonephritis. Streptococci are Gram-positive, nonmotile, nonsporeforming, catalase-negative cocci that occur in pairs or chains. Members of this genus vary widely in pathogenic potential. Most streptococci are facultative anaerobes, and some are obligate anaerobes. Serologic grouping is based on antigenic differences in cell wall carbohydrates, in cell wall pili-associated protein, and in the polysaccharide capsule in group B streptococci. Streptococcus equi is comprised of three subspecies equi, zooepidemicus and ruminatorum all of which cause disease in horses, sheep or goats. Streptococcus equi subsp. zooepidemicus has also been isolated from clinical cases in humans and other animals. This species is a Lancefield C group bacterium.