Abstract: Disclosed is a recombinant slow-growing mycobacterium comprising at least one mycobacterial gene containing an unmarked mutation, where an “unmarked mutation” is a mutated nucleotide sequence introduced into a mycobacterium where the introduced mutated nucleotide sequence does not contain a selectable marker, such as a gene conferring antibiotic resistance to the recombinant mycobacterium incorporating the mutated nucleotide sequence. Also disclosed is a method for preparing a recombinant slow-growing mycobacterium comprising at least one mycobacterial gene containing an unmarked mutation, as well as a vaccine comprising a recombinant slow-growing mycobacterium having at least one mycobacterial gene containing an unmarked mutation dispersed in a physiologically acceptable carrier. Further disclosed is a method of treating or preventing tuberculosis in a subject comprising administering the vaccine of the present invention in an amount effective to treat or prevent tuberculosis in the subject.

Abstract: The present invention refers in general to novel recombinant mycobacteria that are auxotrophic for diaminopimelate. In particular, this invention relates to novel auxotrophic recombinant mycobacteria, to methods of making the mycobacteria, and to uses of the mycobacteria to deliver vaccines. This invention also provides for uses of the mycobacteria in drug screening processes.