Nutritional requirements of Corynebacterium pyogenes

The nutritional requirements of Corynebacterium pyogenes (strains C100, 5, and 1909), a commonly encountered animal pathogen, were determined in this study. A semidefined medium (SDM) containing glucose, HCO3-, hemin, charcoal-treated Trypticase, and a defined mixture of purines and pyrimidines, amino acids, and minerals which supported optimal growth of C. pyogenes was employed in all nutritional studies. Adenine and uracil were required for optimal growth of strains 5 and C100 but were not required for strain 1909. Riboflavin and nicotinic acid were required for good growth of all three strains; biotin and thiamin were stimulatory but did not appear to be required for growth. Hemin and NaHCO3 were stimulatory for growth, whereas lipoic acid and Tween 80 were neither stimulatory nor required for growth. The replacement of Trypticase with a specific peptide fraction (obtained by fractionation of Trypticase on Sephadex G-25) rich in dipeptides gave growth comparable to that in SDM, indicating a peptide requirement for the growth of C. pyogenes. It was of considerable interest that growth comparable to that in SDM was obtained when Trypticase was replaced by inositol (1 microgram/ml of SDM).