First comprehensive study on molecular diversity of Austrian Mycobacterium avium subspecies paratuberculosis isolates from domestic and wild ruminants

The aim of this study was to gain knowledge of Mycobacterium avium subspecies paratuberculosis (MAP) diversity, distribution and possible transmission in Austria. 249 isolates derived from 221 cattle (107 herds), 19 goats (one herd), one sheep and seven wild ruminants (red deer, roe deer, moufflon) were investigated. The isolates were subjected to Insertion Sequence 900 (IS900) based Restriction Fragment Length Polymorphism analysis (IS900-RFLP) and Mycobacterial Interspersed Repetitive Unit-Variable-Number Tandem-Repeat typing (MIRU-VNTR). Isolates originated from samples tested within the framework of the Austrian paratuberculosis control program and clinical diagnostics. Using IS900-RFLP and restriction enzyme BstEll seven types were found: Cl, C14, C18, C28 and three new ones. All isolates belonged to the C-type. Using Pstl restriction six profiles were obtained, of which only P1 was already published before. Eight INRA Nouzilly MIRU-VNTR (INMV) profiles were detected by MIRU-VNTR (INMV 1, 2, 5, 6, 12,13, 17, 80). The combination of IS900-RFLP and MIRU-VNTR allowed the discrimination between 20 combined MAP genotypes named AT (Austria) 1-20. AT 2 (C1-P1/INMV 2) was the most frequently found one, namely in 39% of the isolates. In nine out of 35 cattle herds with two or more isolates more than one combined MAP genotype was found. Examination of the seven wild ruminant isolates exhibited four combined genotypes also detected in local cattle and sheep herds suggesting MAP transmission among these species. The characterization of MAP using 15900-RFLP and MIRU-VNTR gives valuable information about diversity and distribution of MAP in Austria and of possible transmission routes.