Characterization of Brucella abortus strain 19 isolated from human and bovine tissues and fluids.

One hundred isolates of Brucella abortus, which were recovered from bovine and human tissues or fluids, were identified as strain 19 by conventional bacteriologic methods. Each isolate was examined using a Warburg respirometer to determine oxidative rates on substrates of D- and L-alanine, L-glutamic acid, d(+)-galactose, D-ribose, and i-erythritol. These results were compared with those of repository (seed) cultures of strain 19 used for making antigens and vaccines. Except on the substrate of i-erythritol, each of the 100 isolates oxidized these substrates with rates different from the repository cultures and indistinguishable from those of field strains of B abortus. Thus, oxidatively, i-erythritol was the only substrate useful to help distinguish between strain 19 and virulent strains of B abortus biotype 1.