Brucella infections are mainly caused by smooth strains however, Brucella canis with a rough morphology is able to infect humans. From domestic animals, the dog is the animal more closely related to its owner as a result the contact of the dog with the members of the family is higher, thus increasing the possibility of infection. There are differences between the virulence of smooth and rough brucella, which are not given by the LPS for instance, the secretion system type IV, which contributes to the virulence of the smooth species of Brucella. The survival of rough Brucella and their capability for causing disease is of interest, the activity study of the virB locus in these organisms is important, since it is one of the main elements of virulence identified and represents a potential target for immune and therapeutic response mechanisms. Mutant strains were generated in this operon, where the capacity of infection and replication in a cell model was analysed. The B canis VirB mut ants are non-virulent strains, which immunogenic characteristics were evaluated for finally estimating the capacity thereof for acting as a vaccine candidate in an animal model. The Brucella canis VirB10 and AvirB11:Gm mutant strains conferred in mice a solid humoral and cellular immune response, and had a short residual virulence. The VirB10 protected, before the experimental challenge, the 100% of mice and the AvirB11::Gm protected the 93.75% of the mice.La presente invención se refiere a una cepa mutante virB de Brucella canis caracterizada porque comprende la inserción del casete no polar de virB10 con el gen de Gentamicina virB10: Gmr, del sistema de secreción tipo IV en Brucella canis, codificado por la secuencia de nucleótidos reprsentada como SEQ ID NO: 6. Las infecciones de Brucella son causadas principalmente por cepas lisas, sin embargo Brucella canis, la cual muestra una morfología rugosa también es capaz de infectar al humano. De los animales domésticos, el perro es el más es
