|ROBBE-AUSTERMAN, SUELEE - Animal And Plant Health Inspection Service (APHIS)|
|STUBER, TOD - Animal And Plant Health Inspection Service (APHIS)|
Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/7/2015
Publication Date: 7/26/2015
Citation: Thacker, T.C., Palmer, M.V., Robbe-Austerman, S., Stuber, T.P., Waters, W.R. 2015. Anatomical distribution of Mycobacterium bovis genotypes in experimentally infected white-tailed deer. Veterinary Microbiology. 180(1-2):75-81.doi: 10.1016/j.vetmic.2015.07.006.
Interpretive Summary: Mycobacterium bovis (M. bovis) causes tuberculosis in white-tailed deer (WTD). Tuberculosis in free-ranging WTD seriously threatens ongoing efforts to eradicate tuberculosis in cattle. M. bovis was isolated from different tissues from infected deer. The genome of each isolate was sequenced and the genomes were compared to each other. The majority of the WTD tissues were colonized by a single bacterium. When deer are infected with a mix of different M. bovis genotypes, then each tissue may contain a different genotype. Recently, the USDA has started using whole-genome sequencing to aid in epidemiological investigations. These results suggest that multiple tissues should be sampled to accurately identify the M. bovis genotypes in an individual animal.
Technical Abstract: Mycobacterium bovis (M. bovis) causes tuberculosis in white-tailed deer (WTD). Natural infection of WTD with M. bovis is most closely mimicked by instilling inoculum into palatine tonsilar crypts. One hundred fifty days after intratonsilar inoculation, M. bovis was cultured from 30 tissues originating from 14 deer. Whole-genome sequencing (WGS) was performed on the original inoculum, single colonies subcultured from the original inoculum, and M. bovis isolated from each culture positive tissue. Single nucleotide polymorphisms (SNP) were identified by comparing the derived sequences to the reference strain AF2122/97. Results indicate that the majority of the SNPs that were identified were homogeneous between the inoculum and the isolates from the tissues. The majority of individual tissues had different WGS genotypes from each other. These data suggest that dissemination of M. bovis beyond the initial site of infection may require few mycobacteria and represent a bottleneck.