PORPHYROMONAS CANORIS SP-NOV, AN ASACCHAROLYTIC, BLACK-PIGMENTED SPECIES FROM THE GINGIVAL SULCUS OF DOGS

A new species, Porphyromonas canoris, is proposed for black-pigmented asaccharolytic strains isolated from subgingival plaque samples from d ogs with naturally occurring periodontal disease. This bacterium is an obligately anaerobic, nonmotile, non-spore-forming, gram-negative, ro d-shaped organism. On laked rabbit blood or sheep blood agar plates, c olonies are light brown to greenish brown after 2 to 4 days of incubat ion and dark brown after 14 days of incubation. Colonies on egg yolk a gar and op nonhemolyzed sheep blood agar are orange. The cells do not grow in the presence of 20% bile and have a guanine-plus-cytosine cont ent of 49 to 51 mol%. The type strain is VPB 4878 (= NCTC 12835). The average levels of DNA-DNA hybridization between P. canoris strains and other members of the genus Porphyromonas are as follows: Porphyromona s gingivalis ATCC 33277(T) (T type strain), 6.5%; Porphyromonas gingiv alis cat strain VPB 3492, 5%; Porphyromonas endodontalis ATCC 35406(T) , 1%; Porphyromonas salivosa NCTC 11362(T), 5%; and Porphyromonas circ umdentaria NCTC 12469(T), 6%. The level of hybridization between P. ca noris NCTC 12835(T) DNA and Porphyromonas asaccharolytica ATCC 25260(T ) DNA is 3%. P. canoris cells produce major amounts of acetic, propion ic, isovaleric, and succinic acids and minor amounts of isobutyric and butyric acids as end products of metabolism in cooked meat medium. Th e major cellular fatty acid is 13-methyltetradecanoic acid (iso C,,,,) . Glutamate and malate dehydrogenases are present, as are glucose-6-ph osphate dehydrogenase activity (65.7 nmol mg of protein-l min-l) and 6 -phosphogluconate dehydrogenase activity (63.0 nmol mg of protein(-1) min(-1)). P. canoris cells do not agglutinate sheep erythrocytes but e xhibit brick red fluorescence at 265 nm and produce catalase.