Biochemical and structural characterization of an unusual group of gram-negative, anaerobic rods from human...

The biochemical and chemotaxonomic properties of three previously undescribed strains from human dental root canal infections are presented. The strains were obligately anaerobic Gram-negative rods with fimbriae and a thick capsule-like structure. Carbohydrates were not fermented and agglutination tests were negative. The presence of alpha-galactosidase, alpha- and beta-glucosidase, beta-N-acetylglucosaminidase and beta-galactosidase was confirmed. The strains produced acetic and succinic acids as metabolic end products. They contained a peptidoglycan structure based upon meso-diaminopimelic acid (Al gamma) and lacked respiratory quinones. The cellular fatty acids were mainly straight-chain saturated and methyl-branched molecules. High interstrain DNA homology was observed and the DNA base compositions were between 56 and 59 mol % G + C. These three strains appear to comprise the nucleus of a new genus of anaerobic, Gram-negative rods from odontogenic infections.