<i>bla</i> _ROB-1 -Carrying Plasmids Among Macrolide-Resistant Bovine <i>Pasteurella multocida</i> from the National Resistance Monitoring Program GE <i>RM</i> -Vet 2008–2022

During whole-genome analysis of 179 Pasteurella multocida isolates from bovine respiratory tract infections collected in the German national resistance monitoring program GE RM -Vet, two isolates carried plasmid-borne bla ROB-1 genes for a small-spectrum β-lactamase. Both plasmids varied slightly in their sizes, 4,320 bp (pHKH171865) and 4,615 bp (pHKH211885), respectively, and carried besides the bla ROB-1 gene, closely related mobilization gene clusters comprising the genes mobA , mobB , and mobC . In vitro intergenus transfer into Escherichia coli confirmed that both plasmids mediated ampicillin resistance. Comparisons with sequences deposited in the National Center for Biotechnology Information (NCBI) database revealed that both plasmids were unique, although similar sized, and structurally closely related plasmids have been identified in a number of other members of the family Pasteurellaceae , including the genera Actinobacillus , Glaesserella , Haemophilus , Histophilus , and Mannheimia , from humans and different animals in North America, Europe, and Australia. These observations suggest in vivo intergenus transfer rather than independent generation of these plasmids in the respective bacterial hosts.