The present invention relates to an isolated microorganism belonging to the Mycobacterium genus, characterised in that it comprises the inactivation of the Rv0757 gene that confers a PhoP- phenotype and the inactivation of a second gene that prevents DIM production (DIM- phenotype). Additionally, the present invention comprises the use of said microorganism for the preparation of a vaccine for the immunisation or prevention of tuberculosis.
