Intact Purine Biosynthesis Pathways Are Required for Wild-Type Virulence of Brucella abortus 2308 in the BALB/c Mouse Model

Brucella abortus 2308 derivatives with mini-Tn 5 insertions in purE , purL , and purD display significant attenuation in the BALB/c mouse model, while isogenic mutants with mini-Tn 5 insertions in pheA , trpB , and dagA display little or no attenuation in cultured murine macrophages or mice. These experimental findings confirm the importance of the purine biosynthesis pathways for the survival and replication of the brucellae in host macrophages. In contrast to previous reports, however, these results indicate that exogenous tryptophan and phenylalanine are available for use by the brucellae in the phagosomal compartment.