Characterisation and comparison of Mycoplasma bovis strain types from Irish and Scottish bovine isolates in a global context

Infection with Mycoplasma bovis (M. bovis) can present as a range of clinical manifestations of varying severity in beef and dairy cattle worldwide and can seriously impact cattle health and welfare. The objectives of this study were to characterise the strains and genetic diversity within isolates of M. bovis collected from bovine clinical samples in Ireland and Scotland, and to provide place these isolates a global phylogenetic context. We performed Illumina whole genome sequencing 19 M. bovis strains from 19 unique Irish animals and 5 M. bovis strains from 4 unique Scottish animals. The strains were then analysed against 117 downloaded Genbank assemblies to create a phylogenetic tree. The Irish strains clustered into 2 main groups which were identifiable as sequence type 29 (Group 1) and sequence type 21 (Group 2) using the pubMLST system. The Scottish strains all fell within Group 1 of our analysis and were identifiable as sequence type 29 using the pubMLST system. No novel sequence types were found. The Irish and Scottish strains are similar to the genetic variation of M. bovis currently seen in Europe and may suggest separate introductions. The impact of disease associated with M. bovis in cattle emphasises the importance of within and between herd biosecurity as well as the global nature of infectious disease due to widespread international cattle movement.