Molecular analysis and MIRU-VNTR typing of Mycobacterium avium subsp. paratuberculosis strains from various sources

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of Johne's disease. Genotypic discrimination of MAP isolates is pivotal to epidemiological studies requisite for revealing infection sources and disease transmission. This study was undertaken to determine the genetic diversity of MAP strains from diverse sources.

Five hundred and sixty-nine MAP isolates were collected during an 8-year period from nine animal species, originating from seven European countries, including the whole geographic region of Hungary. Isolates were classified into cattle type and sheep type, and 515 strains were included in mycobacterial interspersed repetitive units-variable-number tandem repeat analysis.

The same genotype was found in different host species cohabiting on the same property, demonstrating interspecies transmission. Detecting identical patterns in numerous related animals underlines the importance of vertical transmission. The revealed 15 genotypes expose relatively low strain diversity and indicate the need of an improved typing system that provides higher resolution in the case of this subspecies.

Our results demonstrate the circulation and transmission of different MAP strain types among individuals, herds and even wildlife reservoirs in Hungary and other European countries; correlation between production type or breed and MAP genotype is hypothesized.