THE DEFECT IN THE METABOLISM OF ERYTHRITOL OF THE BRUCELLA-ABORTUS B19 VACCINE STRAIN IS UNRELATED WITH ITS ATTENUATED VIRULENCE IN MICE

The role of the defect in erythritol catabolism in the attenuated viru lence of Brucella abortus B19 vaccine strain in mice was investigated by means of five different strains: (i) the erythritol sensitive B19 v accine strain; (ii) a natural erythritol tolerant (NET) mutant obtaine d spontaneously from B19; (iii) an erythritol resistant derivative fro m B19 (FJS19) obtained by gene replacement of the deleted ery region; (iv) the erythritol resistant B, abortus 2308 reference virulent strai n; and (v) an erythritol sensitive mutant (227 strain) obtained from s train 2308 by a transposon insertion in the chromosomal ery region. Be sides virulence for mice, erythritol oxidation as well as other phenot ypic markers were tested in all the strains. The 2308 and FJS19 strain s grew in the presence of erythritol and oxidized the sugar whereas th e B19 and 277 strains did not. The NET strain grew in presence of eryt hritol but was unable to oxidize it. The B19 vaccine strain and its tw o erythritol resistant derivatives, NET and FJS19, showed similar resi dual virulence and splenic time courses in mice. Moreover the virulent strain 2308 and its erythritol sensitive derivative (227 strain) exhi bited similar levels of splenic infection. Altogether; these results d emonstrate that the genetic region implicated in erythritol catabolism is not related to the low virulence exhibited by B19 in mice. (C) 199 8 Elsevier Science Ltd, All rights reserved.