Identification of genetic markers for Mycobacterium pinnipedii through genome analysis.

Tuberculosis in seals is caused by Mycobacterium pinnipedii, a member of the Mycobacterium tuberculosis complex. In this study, we evaluated the extent of genetic variability among Mycobacterium bovis and M. pinnipedii by microarray-based comparative genomics. We identified two deletions that are exclusive to M. pinnipedii: PiD1 that removes the orthologues of the M. tuberculosis genes Rv3530c and Rv3531c, and PiD2 that encompasses genes Rv1977 and Rv1978. Interestingly, a deletion overlapping the previously described RD2 region was identified in some isolates of Mycobacterium microti and further characterised.