Production of phenylacetic acid by strains of Bacteroides asaccharolyticus and Bacteroides gingivalis (sp. nov.).

Strains of Bacteroides asaccharolyticus and Bacteroides melaninogenicus subspecies isolated from human and animal sources were examined for the production of phenylacetic acid. B. asaccharolyticus strains isolated from sites in humans and monkeys always produced phenylacetic acid. B. asaccharolyticus strains isolated from human nonoral sites consistently failed to produce this product. This metabolic difference correlates with the genetic dichotomy recently found to exist between oral and nonoral B. asaccharolyticus strains.