Microbiological and Molecular Diagnosis of Mycobacterium tuberculosis Infection in Spotted Deer (Axis axis) of an Indian Zoo

A detailed laboratory investigation was undertaken to correlate the cause of death in two spotted deer (Axis axis) of Nandankanan Zoological Park, Odisha, India, suspected due to Tuberculosis based on necropsy findings. The pus samples collected from lungs nodules were inoculated to Lowenstein‒Jensen medium with glycerol which showed growth of buff colored smooth to bread-crump like colonies after 6‒10 weeks of incubation at 37°C. The culture positive samples were subjected to 16SrRNA PCR that amplified both the isolates producing an amplicon of 500bp size upon gel electrophoresis. Sequencing of this product yielded a gene sequence of 520 nucleotides which upon blast, showed 99% similarity with Mycobacterium tuberculosis (NCBI accession no. MH393632 and MH393637). A chip-based real-time PCR tests showing a peak Ct value of 19.5 confirmed this species. Identification of human type TB amongst spotted deer warranted implementation of effective managemental practices in the zoo.