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 ba cteria were isolated from clinical specimens. Of the 15 strains isolat ed, 11 were derived from abscesses and purulent lesions, mostly from t he upper part of the body, and 3 were grown from blood cultures. Nine strains were associated with mixed anaerobic but no other aerobic flor a. Seven strains exhibited the classical biochemical profile of CDC co ryneform group 1; however, eight strains were unable to reduce nitrate and were called ''group 1-like.'' Other reactions to differentiate CD C group 1 and group 1-like coryneform rods include alpha-hemolysis on human blood agar, fermentation of adonitol, and the presence of alkali ne phosphatase. Fifteen strains showed marked CAMP reactions on differ ent erythrocyte agars. Gas-liquid chromatography of volatile and nonvo latile fatty acids as well as cellular fatty acid patterns and the com position of cell wall components suggest that CDC group 1 and group 1- like coryneform bacteria do not belong to the genus Corynebacterium bu t possibly to the genus Actinomyces or Arcanobacterium. DNA-DNA hybrid ization studies revealed that group 1 and group 1-like strains represe nt different species.