THE GROWTH OF BRUCELLA IN AERATED LIQUID CULTURES'

Studies conducted on the immunochemistry of members of the genus Brucella required the growing of comparatively large amounts of these organisms in liquid culture medium. The production of a culture which would retain its full virulence over a period of six months was one of the major requirements of our work. Very little information on the growth requirements of Brucella was available in the literature from which to draw any conclusions on the practica-bility of culturing this group of microorganisms in deep columns of liquid media. Although the genus Brucella is known to exhibit pseudoanaerobic growth, a property which is put to diagnostic use in the nitrate to nitrite reduction test, the yield of Brucella cells in statically grown flasks of tryptose broth is, in 48 to 72 hours at 37 C, very small except when very shallow layers of media are used. An apparatus has been designed for producing, in routine fashion, 15-liter amounts of Brucella suis that are characterized by uniformity of yield, a virulence as high as that of the parent culture, and prolonged viability in the presence of protective substances such as dextrin