Serogroups and biotypes among beta-hemolytic streptococci of canine origin

Abstract

A study of hemolytic streptococci from clinical infections in dogs revealed the presence of 4 serogroups, with 1-4 biotypes in each, based on carbohydrate fermentation patterns. Of 254 isolates tested, 206 belonged to Lancefield group G, 30 to group C, 7 to group E and 1 to group A. Ten isolates could not be grouped. Reactions on the 3 key carbohydrates, lactose, trehalose and sorbitol, revealed 4 biotypes each in groups G and C and 2 in group E and among the ungroupable cultures. The most common pattern, seen in 154 cultures, was lactose fermentation with no action on trehalose and sorbitol and corresponded to that described for Streptococcus canis. Most of the strains originated from skin, subcutaneous and wound infections, genitourinary lesions, otitis externa and respiratory disease. Data suggest that group G streptococci may be preferentially parasites of the urogenital tract.