ARS | Publication request: USE OF THE POLYMERASE CHAIN REACTION (PCR) FOR DETECTION OF MYCOBACTERIUM TUBERCULOSIS COMPLEX ORGANISMS IN FORMALIN-FIXED, PARAFFIN-EMBEDDED TISSUE SAMPLES

Submitted to: Bovine Tuberculosis in Michigan Meeting Abstracts
Publication Type: Proceedings
Publication Acceptance Date: January 6, 1999
Publication Date: N/A

Technical Abstract: Mycobacterium bovis, which is a member of the M. tuberculosis complex, can cause tuberculosis in animals and human beings and is the organism that has been isolated from the deer, coyotes, raccoons, bear and cattle from northeast Michigan. A polymerase chain reaction (PCR) assay has been developed for detection of M. tuberculosis complex organisms in formalin-fixed, paraffin-embedded tissue samples. The primers used for th PCR assay are specific for IS6110, which is an insertion sequence present in the DNA of M. tuberculosis complex organisms. The PCR assay was designed to be used as a tool in conjunction with other tests and epidemiological information for diagnosis of tuberculosis. An advantage of using the PCR test is that it is rapid. Results usually are available within one week of sample collection compared to up to eight weeks required for culture. In addition, the PCR test is safer than culture because it does not involve handling of live M. bovis, which can infect human beings. However, because it is not possible to determine the DNA fingerprint of organisms in formalin-fixed tissue samples, cultivation of the organisms still is needed. There also are cases where tuberculosis is diagnosed by isolation of the organism from animals that do not have characteristic lesions. Conversely, it is also possible for results of the PCR test to be positive for tissues with lesions and acid-fast organisms and for culture results to be negative. This can occur if the sample tested by culture does not contain organisms or if the organisms are present but not viable. Therefore, it is important to use all of the available tools for diagnosis of tuberculosis in animals.