A study on the characterization of Corynebacterium acnes.

Abstract

Forty-nine strains of anaerobic gram-positive rods were used in a systematic study of their biochemical and physiological reactions and morphological characteristics and were also subjected to gas chromatographic analyses in an effort to classify them as strains of Corynebacterium acnes (C. acnes). The strains were isolated both from lesions in acne vulgaris and from normal skin. According to their biochemical and physiological characters, these 49 strains were divided into six subgroups (Subgroup A-F). They were also separated into two morphological types. The larger of these two types included gram-positive, unevently staining pleomorphic rods (35 strains); the smaller type contained shorter coccal rods similar to Peptostreptococci (14 strains). The macroscopic appearance of the colonies of both types was the same. All strains of the smaller type showed the same biochemical and physiological characteristics which were of the saccharolytic type (Subgroup B) suggesting a close relationship between the microscopic appearance of the strains and their biochemical and physiological characteristics. Upon microscopical observation, the changing the pH of the media did not cause any transformation of the organism from one type to another. Between pH 6.0 and 6.5 all strains grew well but above pH 8.0 growth was poor. The gas chromatographic analyses demonstrated that selected sample strains from each of the six subgroups showed the same characteristic chromatograph, suggesting that they could be of the same species, i.e., C. acnes.