Characteristics of CDC group 1 and group 1-like coryneform bacteria isolated from clinical specimens.

Fifteen strains of CDC group 1 coryneform and biochemically similar bacteria were isolated from clinical specimens. Of the 15 strains isolated, 11 were derived from abscesses and purulent lesions, mostly from the upper part of the body, and 3 were grown from blood cultures. Nine strains were associated with mixed anaerobic but no other aerobic flora. Seven strains exhibited the classical biochemical profile of CDC coryneform group 1; however, eight strains were unable to reduce nitrate and were called "group 1-like." Other reactions to differentiate CDC group 1 and group 1-like coryneform rods include alpha-hemolysis on human blood agar, fermentation of adonitol, and the presence of alkaline phosphatase. Fifteen strains showed marked CAMP reactions on different erythrocyte agars. Gas-liquid chromatography of volatile and nonvolatile fatty acids as well as cellular fatty acid patterns and the composition of cell wall components suggest that CDC group 1 and group 1-like coryneform bacteria do not belong to the genus Corynebacterium but possibly to the genus Actinomyces or Arcanobacterium. DNA-DNA hybridization studies revealed that group 1 and group 1-like strains represent different species.