Mycoplasma bovis in Nordic European Countries: Emergence and Dominance of a New Clone

Abstract

<i>Mycoplasma</i> (<i>M</i>.) <i>bovis</i> is an important pathogen of cattle implicated in a broad range of clinical manifestations that adversely impacts livestock production worldwide. In the absence of a safe, effective commercial vaccine in Europe, the reported reduced susceptibility to antimicrobials for this organism has contributed to difficulties in controlling infection. Despite global presence, some countries have only recently experienced outbreaks of this pathogen. In the present study, <i>M. bovis</i> isolates collected in Denmark between 1981 and 2016 were characterized to determine (i) genetic diversity and phylogenetic relationships using whole genome sequencing and various sequence-based typing methods and (ii) patterns of antimicrobial resistance compared to other European isolates. The <i>M. bovis</i> population in Denmark was found to be highly homogeneous genomically and with respect to the antimicrobial resistance profile. Previously dominated by an old genotype shared by many other countries (ST17 in the PubMLST legacy scheme), a new predominant type represented by ST94-<i>adh1</i> has emerged. The same clone is also found in Sweden and Finland, where <i>M. bovis</i> introduction is more recent. Although retrieved from the Netherlands, it appears absent from France, two countries with a long history of <i>M. bovis</i> infection where the <i>M. bovis</i> population is more diverse.