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Tests useful for the identification of Enterococcus strains were applied to a collection of isolates from animal intestines and to reference strains, all of which were capable of growth on 40% bile and in 6.5% NaCl. Most strains could be identified as known species, and their characteristics corresponded, with a few exceptions of minor importance, with those described for Enterococcus hirae, Enterococcus durans, Enterococcus mundtii, Enterococcus gallinarum, Enterococcus avium, and Enterococcus casseliflavus. However, some diagnostically important carbohydrate reactions of Enterococcus faecalis and Enterococcus faecium strains differed from those given in the species descriptions and in recent reports. Production of acid from D-raffinose and D-xylose by E . faecium varied with the host species from which the strains were isolated. E . durans and E. gallinarum were isolated only from poultry, whereas E. avium was found only in mammals.Enterococci are an important group of intestinal bacteria whose taxonomy has undergone important changes in the last few years. The enterococci (sensu Sherman [9]), Streptococcus bovis, and Streptococcus equinus have been classified traditionally as serological group D streptococci. However, nucleic acid studies have shown that Streptococcus faecalis and Streptococcus faecium are only distantly related to S. bovis and S. equinus (5,7). These studies resulted in the proposal to transfer S. faecalis and S. faecium to a new genus, Enterococcus, as E. faecalis and E. faecium (8).Other group D streptococci which belong to the enterococcal MATERIALS AND METHODS Strains.A total of 264 strains (Table 1) were selected solely on the basis of their ability to grow in the presence of 40% bile (bile-esculin agar, Difco Laboratories, Detroit, Mich.) and in 6.5% NaCl in brain heart infusion agar (Oxoid Ltd., London, England). The selection was made from a larger collection of catalase-negative, gram-positive cocci and short rods isolated from the intestines of farm animals on mitis salivarius agar (GIBCO, Paisley, Scotland) or brain heart infusion agar (Oxoid) with 10 pg of oxolinic acid

f3-Hemolytic group G streptococci from cows with mastitis and from dogs with different pathological conditions were characterized and named Streptococcus canis sp. nov. These animal group G strains were differentiated from Streptococcus dysgalactiae (group G strains of human origin, as well as group L strains and certain animal and human group C strains) by simple physiological and biochemical tests. Deoxyribonucleic acid-deoxyribonucleic acid hybridization showed that the S . canis strains differed from S . dysgalactiae, Streptococcus pyogenes, Streptococcus equi, and Streptococcus salivarius. These organisms contain a rare cell wall peptidoglycan type, namely, Lys-Thr-Gly. The specific epithet of S . canis, which has been in use for many years in veterinary textbooks to designate group G strains isolated from dogs, was chosen for this proposed new species because it comprises animal but not human group G streptococci. The type strain is strain STR-T1 (= DSM 20715).Streptococci belonging to Lancefield group G (15) form a heterogeneous collection of organisms. At least the following three distinct groups can be found: (i) the large-colony form of P-hemolytic group G streptococci isolated from humans; (ii) large-colony P-hemolytic strains from animals which were first shown to differ from human group G strains in their fibrinolytic activity (3) and later also in several other characteristics (6); and (iii) the "minute P-hemolytic colony" group G strains from humans.Animal group G strains have been associated mainly with genital, skin, and wound infections (2, 10) in dogs and with bovine mastitis (6, 16). The naming of these strains has always been confusing and contradictory. Stafseth et al. (20) first used the name "Streptococcus canis" to designate dog strains belonging to group C. However, these strains had a characteristic carbohydrate fermentation pattern which was found later only in animal group G strains (2). Widely used veterinary textbooks (4,5) refer to group G strains from dogs as "Streptococcus canis," but this name has never been accepted officially.Recent nucleic acid hybridization and cell wall composition studies (13) have shown that human large-colony group G strains are closely related to group L strains, the Phemolytic group C organism "Streptococcus equisimilis," and a-hemolytic group C strains isolated from cases of bovine mastitis and polyarthritis in lambs. Similar observations led to an emended description of Streptococcus dysgalactiae (9) which fits these animal group C P-hemolytic " S . equisimilis," group C a-hemolytic S . dysgalactiae, and group L strains, as well as human group C "S. equisimilis," group L, and group G strains. The older description of S . dysgalactiae given in Bergey 's Manual of Determinative Bacteriology, 8th ed. (7), applied only to the animal ahemolytic group C strains.However, it has been found that several characteristics of animal group G strains in our collection did not correspond to the characteristics given in the new description of S . dysgalactiae. The...