Facultatively anaerobic, Gram positive cocci, approximately 1 um in diameter, that grow in short chains in broth cultures. Carbohydrates are femented primarily to lactic acid and no gas. Catalase negative. Cell wall contains glycerol teichoic acid and rhamnose. Peptidoglycan type is Lys-Ala1-3
S. gordonii is similar to S. sanguis (sanguinis) but can be differentiated based on the following; DNA homology, lower G+C content of the DNA (42 vs 46 mol%), ferments amygdalin, has alkaline phosphatase and B-glucosaminidase activities, lacks IgA1 protease activity, multilocus enzyme analysis .
3 biovars of S. gordonii differ biochemically and serologically, but all biovars possess the group H antigen