ARS | Publication request: EVALUATION OF THE ACCURACY AND REPRODUCIBILITY OF A PRACTICAL PCR PANEL ASSAY FOR RAPID DETECTION AND DIFFERENTIATION OF MYCOBACTERIUM AVIUM SUBSPECIES

Submitted to: Molecular and Cellular Probes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 10, 1999
Publication Date: N/A

Interpretive Summary: Johne's disease is an economically important disease of cattle that causes chronic diarrhea, weight loss, decreased milk production, and death. The disease is caused by infection with Mycobacterium paratuberculosis, which is a member of a closely related group of mycobacterial organisms. Cattle become infected with this organism when they are young, but do not develop disease for 3 to 5 years after infection. Diagnosis of the disease prior to the onset of clinical signs is a major problem in control of this disease. Currently, culture of the organism from fecal or tissue specimens is the most definitive method for detecting animals with Johne's disease. This procedure requires 8 to 16 weeks and, because of this, we are working to develop faster, more efficient diagnostic tests. New diagnostic tests designed to detect the genetic material of the bacteria in cattle feces and tissues are being developed. In this study, the performance of a new test to detect M. paratuberculosis and to differentiate this organism from othe closely related bacteria is reported. Improved diagnostic tests will be used for accurate detection of infected animals by diagnostic laboratories and will lead to an overall reduction in disease incidence.

Technical Abstract: This study was conducted to evaluate the performance of a PCR panel assay to detect and differentiate Mycobacterium avium subspecies (MAs) paratuberculosis from MAs avium and other closely related mycobacteria. Lysates of mycobacterial DNA from one hundred and twenty (n = 120) strains were tested with the PCR panel assay. The PCR panel assay specifically detected and differentiated 91/91 (100%) of MAs paratuberculosis and MAs avium strains tested. The PCR panel assay also specifically differentiated all MAs strains from all but one of the other mycobacterial strains tested. The reproducibility of the PCR panel assay when comparing the data from two different laboratories in a blinded study was found to be 100% (120/120). These results indicate that this easy-to-use, rapid PCR method can accurately and reliably detect and differentiate closely related members of MAs paratuberculosis and MAs avium from each other and from other mycobacterial species. The simplicity of this PCR method could be beneficial to laboratories that test for members of MAs.