Population Dynamics of Brucella on Solid Media.

An examination is presented of the growth characteristics on solid media of one strain each of Brucella abortus and B. neotomae. It was observed that, during the exponential growth phase, generation times of approximately 100 min were measured for both organisms under a variety of conditions. The logarithmic growth phase did not extend beyond 18 hr in most instances. It was noted that erythritol added to Trypticase Soy Agar did not enhance the growth rate or the total viable yield of either organism. Phosphate buffer failed to exert a significant effect upon pH changes during culture. B. neotomae cultures on solid media produced markedly acidic reactions in 48 hr. If cells in an active growth phase are desired, it is suggested that solid media cultures of laboratory strains be harvested before 24 hr.