Geographic spread, host switching and adaptive genomic signatures in GBS clonal groups 103 and 314

Group B Streptococcus (GBS) is a pathogen of global relevance in neonatal and maternal disease as well as bovine mastitis. The two closely related clonal groups, denoted 103 and 314 (CG103/314) have been detected in humans and cattle on multiple continents in recent decades but are poorly characterised compared to other host-generalist clades. In the context of an in depth-analysis of their evolutionary history and host association patterns, we sequenced isolates sampled from animals in Italy.