IMPROVEMENT OF THE BRUCELLA-ABORTUS B19 VACCINE BY ITS PREPARATION INA GLYCEROL BASED MEDIUM

The Brucella abortus B19 vaccine strain differs from other Brucella st rains in its sensitivity to erythritol. However, erythritol tolerant ( Eri(t)) mutants arise from sensitive cultures of B19 at high rate, and may cause persistence and/or abortion when the vaccine is inoculated on adult cattle. Twelve different batches of B19 have been examined fo r the presence of Eri(t) mutants. All contained Eri(t) variants at a p roportion ranging from 10(-4) to 10(-6). In order to eliminate these m utants from the vaccine cultures, we have developed a minimal medium w ith glycerol as the sole carbon source, named MMG30. Growth of the par ental strain B19 (erythritol sensitive) in this medium was fairly good compared with the growth of its Eri(t) derivatives. Culture of the 12 different batches of B19 in liquid MMG30 produced up to a thousandfol d decrease in the proportion of Eri(t) mutants present in the vaccine cultures. Use of this medium to grow B19 could represent an easy and c onsiderable improvement of the vaccine, by the reduction of the presen ce of potentially dangerous Eri(t) mutants. Copyright (C) 1996 Publish ed by Elsevier Science Ltd.