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United States Department of Agriculture

Agricultural Research Service

Title: Pcr Identification of M. Tuberculosis Complex Or M. Avium Organisms in Formalin-Fixed Tissues from Culture-Negative Animals

item Miller, Janice
item Payeur, J - USDA-APHIS-NVSL,AMES, IA.

Submitted to: International Workshop on Tuberculosis in Animals
Publication Type: Abstract Only
Publication Acceptance Date: September 15, 1999
Publication Date: N/A

Technical Abstract: Formalin-fixed tissues from 102 ruminants that had lesions of mycobacterial disease (with acid-fast organisms) were examined by PCR to determine if M. tuberculosis complex or M. avium organisms could be detected. Bacterial culture had been attempted in all of the cases, but no isolations were made. The PCR tests successfully identified mycobacteria in 64 tissues, including 44 that were M. tuberculosis complex and 20 that were M. avium (14 of which were determined to be subspecies paratuberculosis). These results show that PCR testing of formalin-fixed tissue can sometimes detect and identify mycobacteria in cases that have given negative results by bacterial culture. In previous studies, however, we have also shown that tissues from culture-positive cases can sometimes give false negative PCR results. Therefore, we conclude that a combination of PCR testing and bacterial culture would maximize a diagnostic laboratory's capability for detection of mycobacterial infections. In addition to enhancing overall test sensitivity, a positive PCR test also allows the laboratory to make a rapid differential diagnosis of the most commonly recognized mycobacterial diseases in animals.

Last Modified: 3/4/2015
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