ABSTRACT
Serial revisions of the genus Streptococcus have been implemented since its genesis. The designation “lactic” streptococci, although somewhat misleading since all streptococci produce lactic acid, was adopted for the species Streptococcus lactis and Streptococcus cremoris, since these common milk-souring streptococci had long been referred to as the “lactic acid streptococci.” The phenotypically closely related, but genetically distinctive species S. uberis and Streptococcus parauberis are economically important causative agents of bovine mastitis and in contrast to most other pyogenic streptococci they are α-hemolytic or nonhemolytic. The species Streptococcus porcinus was proposed in 1984 to accommodate physiologically related ß-hemolytic streptococci principally belonging to Lancefield groups E, P, U, and V. Streptococcus canis are large-colony-forming group G streptococci isolated most commonly from dogs and mastitis-infected cows, but also sometimes causing infections in humans. In clinical practice the term “group A streptococcus” has been used almost synonymously for S. pyogenes.
