Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2001
Publication Date: N/A
Interpretive Summary: In previous work, polymerase chain reaction (PCR) tests were developed to allow rapid identification of certain mycobacteria in tissues. A rapid test was needed for use in the U.S. bovine tuberculosis surveillance program because it takes 6 weeks or more to culture pathogenic mycobacteria. Such a delay in diagnosis can seriously hamper the efforts of state and federal regulatory agencies as they attempt to locate and eliminate other potentially exposed animals. The PCR tests were validated by testing tissues from which mycobacteria had been cultured. The current study was done to determine if PCR tests could also be used to identify mycobacteria in culture-negative tissues. The PCR tests were able to identify a specific mycobacterial agent in 61 of 102 specimens examined. Of these 61 identifications, 41 were Mycobacterium bovis, the cause of bovine tuberculosis, and the remaining 20 were shown to be infections caused by other mycobacteria. These results show that PCR testing, in combination with bacterial culture, can increase the effectiveness of laboratory efforts to diagnose mycobacterial disease in animals.
Technical Abstract: Formalin-fixed tissues from 102 ruminants that had lesions of mycobacterial disease with acid-fast organisms were examined by polymerase chain reaction (PCR) to determine if Mycobacterium tuberculosis complex or Mycobacterium avium organisms could be detected. Bacterial culture had been attempted in all of the cases, but mycobacteria were not isolated. The PCR tests successfully identified mycobacteria in 61 tissues, including 41 that were M. tuberculosis complex and 20 that were M. avium (14 of which were subspecies paratuberculosis). These results show that PCR testing of formalin-fixed tissues, in combination with bacterial culture, may increase the effectiveness of laboratory efforts to diagnose mycobacterial disease in animals.