Growth Requirements of Dysgonic and Eugonic Strains of Mycobacterium Tuberculosis

On pr imary isolation from natural sources, bovine tubercle bacilli grow more poorly on ordinary culture media than do human tubercle bacilli. After prolonged incubation or numerous transfers, however, they often give rise to variants which grow more rapidly (1-4). The primary, slow growing cultures have been called "dysgonic" and the var iant rapidly growing strains "eugonic" (S). The experiments to be presented here were planned to define the nutritional differences between dysgonic and eugonic strains.