Differentiation of Mycobacterium paratuberculosis isolates by rDNA-spacer analysis and random amplified polymorphic DNA patterns.

The ability to distinguish between isolates of Mycobacterium paratuberculosis isolates was studied using two molecular techniques. Nucleotide sequence analysis of the rDNA-spacer and random amplified polymorphic DNA (RAPD) analysis using decamer primers with GC contents of 60 to 70% were evaluated on 16 isolates of M. paratuberculosis from cattle. The rDNA spacer analysis did not discriminate between isolates as it revealed an identical sequence for all 16 strains tested but it showed one common difference to the sequence previously described for M. paratuberculosis J2A. In the RAPD analysis, 14 of the 60 decamer primers used resulted in distinct amplification products for most of the isolates. For seven of the primers the size of the amplification products varied among strains thus allowing the specific identification of eight of the 16 isolates; of the remaining eight isolates five could each be differentiated from 14 other isolates, two from 13, and one from 12 isolates. Therefore, these data illustrate the possibility of using RAPD-analysis with certain primers for the differentiation of individual M. paratuberculosis isolates.