Location: Infectious Bacterial Diseases Research
2023 Annual Report
Accomplishments
1. New, improved primers for detection of Johne’s disease in nucleic acid-based diagnostic tests. Mycobacterium avium subspecies avium (MAP) is a chronic debilitating disease that causes high economic costs for the dairy industry. ARS scientists at Ames, Iowa, used applied genomic data studies to improve performance of DNA-based PCR diagnostic tests. A IS900 insertion repetitive sequence, termed IS900, is present in the MAP genome at least 16 times and has been previously used as a target for polymerase chain reaction (PCR) assays. However, current PCR primers were designed using sequence data from a single copy of IS900 instead of considering all 16 copies collectively. The current project designed new primers based on all copies of IS900 collectively. Legacy and newly designed primers were compared in real time PCR assays. The new primers demonstrated improved sensitivity for detecting MAP in purified DNA and field samples. This research improved the sensitivity of PCR tests for detecting MAP infection in cattle. These findings will be of interest to animal producers, veterinarians, researchers, and diagnostic laboratories.
