Fig 4. Resistance against tetracycline and macrolides is encoded by genes carried by integrative and conjugative elements (ICEs) in most ST25 S. suis strains.

Genomic comparison identified at least five ICEs carrying genes encoding resistance among the 51 ST25 strains under investigation. The majority of strains, including the reference strain NSUI060 possessed two ICEs, one (ICENsui60t) carrying gene tetO-1 (top, left), and a second (ICENsui60e) carrying gene ermB-20 (top, right). In most other strains a single ICE carried genetic determinants for both resistances, encoded by different tetO and ermB alleles. Homology between ICE genes is depicted by the different shades of grey.