The mutation of Corynebacterium pyogenes to Corynebacterium haemolyticum.

Abstract

SUMMARY: Corynebacterium pyogenes has been observed to give rise to mutants which are indistinguishable from Corynebacterium haemolyticum. C. pyogenes ferments lactose and xylose (Xyl +), elaborates a soluble haemolysin and/or a proteolytic enzyme (H+), and its cell walls contain glucose units in addition to certain other components. On horse blood agar C. pyogenes forms small colonies (s) surrounded by large zones of haemolysis. C. haemolyticum and the mutant derived from C. pyogenes ferment lactose but not xylose, produce no soluble haemolysin, and glucose cannot be detected in hydrolysates of their cell walls. The change in the basal structure of the cell wall is accompanied by a lack of immunochemical cross-reaction between the wild type and the mutant or C. haemolyticum. On horse blood agar both C. haemolyticum and the mutant produce relatively large colonies (L) surrounded by narrow bands of haemolysis. The possibility that a single mutation involving cell- wall structure may account for the apparent change from Xyl+H+ to Xyl−H− is discussed. It is suggested that neither C. pyogenes nor C. haemolyticum is a corynebacterium, and that taxonomically both organisms belong to the genus Streptococcus.