Biochemical differences among human and animal streptococci of Lancefield group C or group G

1 Division of Hospital and Respiratory Infection, Central Public Health Laboratory, London NW9 5HT * Institut für Hygiene der Bundesanstalt für Milchforschung, Postfach 60 69, D-24121 Kiel, Germany Department of Veterinary Science, 108 Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky 40546-0099, USA bioMérieux, 38390, La Balme les Grottes, Vercieu, France Received February 8, 1994 Accepted February 19, 1994 Pyogenic streptococci of Lancefield group C or group G from human or animal sources were examined with a view to increasing the number of diagnostic tests useful for their differentiation. Human strains of group G produced L-prolyl-L-arginine aminopeptidase but isolates of Streptococcus equisimilis (group C) did not. Tests for -L-glutamate aminopeptidase together with fermentation of glycogen or sorbitol distinguished S. dysgalactiae from strains of S. equisimilis isolated from animals. It was confirmed that fermentation tests were helpful in the study of S. equi and S. zooepidemicus and that enzyme reactions helped distinguish between S. canis and the human strains of group G.