The present genotyping system could, however, clearly separate R. salmoninarum strains M-Q (group 2), EPZ015666 indicating an origin not associated with ATCC33209T. The majority of these strains were of wild origin and have not been reported in wild or farmed fish since their original description in the 1930s. The locus BKD1935 was previously described by [22] referred to as the Exact Tandem Repeat A (ETR-A). It was demonstrated that the ETR-A can successfully separate the wild-fish isolates such as NCIMB1114 and NCIMB1116 (tandem repeat 1) from the farmed isolates such

as MT452 and MT1363 (tandem repeat 2). Further investigation on a larger data set, focusing on loci BKD396 and BKD1935, which are solely responsible for differentiation between groups 1 and 2, might bring more insight into a relationship between farmed and wild R. salmoninarum strains and confirm the origin of R. salmoninarum in Scottish aquaculture. Conclusions Cross-species infectivity of R. salmoninarum strains also has wider implications for marine ecosystems; including possible transfer of R. salmoninarum from farmed to wild fish or vice versa. In Scotland, recent studies provided evidence of a relatively low prevalence of R. salmoninarum in wild fish captured in close proximity to farms, suggesting that the transmission of this pathogen

between wild and farmed fish is limited [16, 31]. However, this scenario might not apply for other regions or countries such as England or Norway [32] and the described VNTR typing system learn more can be utilized to identify and understand farmed and wild fish interactions in terms of R. salmoninarum transmission if a larger Teicoplanin data set OICR-9429 molecular weight should become available. Methods Preparation of Renibacterium isolates and DNA extraction Twenty-five R. salmoninarum isolates from confirmed disease outbreaks on Scottish farms were selected for this study. Number and

selection of Scottish R. salmoninarum isolates represents the geographic range, habitat, frequency of disease outbreaks in the salmonid aquaculture sector, supply of fish stock and takes into account difficulties of bacteria culturing from asymptomatic fish and resuscitation of archived material. In addition, 14 Norwegian isolates and two isolates derived from the first successful cultivation of R. salmoninarum from the River Dee [7] were included. Isolate details including country of origin, date of isolation, host species and environment are summarized in Additional file 2: Table S2. For Scottish strains, lyophilised cultures were resuscitated onto Mueller-Hinton L-cysteine agar (MHCA) containing polymyxin-B-sulphate, D-cycloserine, oxolinic acid and cycloheximide and incubated at 15°C for several weeks to allow growth. Suspensions of culture in 0.