Genotyping of Mycobacterium avium field isolates based on repetitive elements

The economic and zoonotic importance of infections caused by Mycobacterium avium complex (MAC) strains in human, animals and birds are increasing. At present, few data are available about the genetic diversity of field isolates of M. avium subsp. hominissuis (MAH) and subspecies avium (MAA). The close relationship between human and swine isolates indicates a possible zoonotic role for such strains. In the present work 73 M. avium field strains isolated from feces and lymph nodes of diseased/slaughtered animals in Hesse State, Germany were investigated. Forty eight primers were used for the confirmation, differentiation and finally the genotyping of the isolates based on the presence of polymorphism of different repetitive loci. These include the Large Sequence Polymorphism (LSP), the Mycobacterial Interspersed Repetitive Units (MIRU) and Variable Number Tandem Repeats (VNTR). The genotyping of MAA (n = 27) and MAH (n = 16) isolates revealed 33 different genotypes (18 MAA, 14 MAH and 1 shared profile). The described methods show great potential for epidemiological mapping of M. avium subspecies