DETECTION OF MYCOBACTERIUM-PARATUBERCULOSIS IN FORMALIN-FIXED PARAFFIN-EMBEDDED TISSUES BY THE POLYMERASE CHAIN-REACTION

The polymerase chain reaction (PCR) utilizing primers specific for the IS900 sequence of Mycobacterium paratuberculosis was applied to tissu e sections of formalin-fixed, paraffin-embedded ileum from cattle with Johne's disease and the results compared to those obtained with acid- fast (Ziehl-Neelsen) and immunohistochemical staining, The PCR was pos itive in 19/21 tissues (90%) while Ziehl-Neelsen staining was positive in 18/21 (86%) and immunohistochemical staining in 21/21 (100%). The Ziehl-Neelsen and immunohistochemical stains are not, however, specifi c for M. paratuberculosis. The PCR for detection of M. paratuberculosi s using the IS900 sequence is a specific and relatively sensitive meth od for confirmation of Johne's disease and its application to formalin -fixed, paraffin-embedded tissues may be useful for confirmation of du bious cases, for retrospective studies and for epidemiological analyse s.