CONCENTRATION OF BRUCELLA SUISFROM BROTH CULTURE'

The manipulation in the laboratory of comparatively large amounts of patho-genic microorganisms is often complicated by the hazard of infection to which personnel are exposed. This is especially true in such operations as centrifuga-tion, a process which often results in the production of aerosols of the material being spun down. The use of such procedures with highly infective bacteria, e.g., Brtwefla and Pasteurella, is, therefore, not encouraged, and the available cell concentrates are limited to those which can be produced and harvested on agar media. The wartime shortage of agar and acceptable substitutes required that liquid cultures be made as adaptable and productive as possible. In the case of Brucella suis this was accomplished by means of aeration in deep liquid cultures. This method has been described in another report (Glassman and Elberg, 1946). The need for highly concentrated pastes of Brucella sui8 for investigations on airborne infection and for fractionation of antigenic components of the cell was satisfied by a filtration process utilizing ordinary equipment and readily available materials. The method of producing these concentrates also proved useful for other pathogenic organisms and reduced considerably the amount of glassware, labor, and time involved in obtaining bacterial pastes. The hazards of manipu-lating such materials were almost completely removed, since the separation sys-tem was closed except for an efficient air filter