Determination of polymorphism of IS-1311 sequence in Mycobacterium avium subspecies paratuberculosis strains isolated from milk samples.

The study was aimed at the genetic typing of Mycobacterium avium subspecies paratuberculosis (MAP) with PCR-REA method based on the polymorphism of IS-1311 sequence. MAP strains were isolated from milk samples collected from cows free of disease symptoms and anti-MAP antibodies. Samples of udder milk were collected from 310 cows originating from the herd with a low seroprevalence of paratuberculosis; every 5 samples were pooled. The polymorphism typing of the IS-1311 sequence of the isolated strains demonstrated the presence of two types of the mycobacterium: sheep and cattle ones, of which the bovine type constituted 98.5%.