Emergence of CTX-M-2-producing Escherichia coli in diseased horses: evidence of genetic exchanges of bla(CTX-M-2) linked to ISCR1.

from plasmid pSCFS1, was found downstream of the cfr gene in pMSA16. The 2848 bp fragment containing the cfr gene and its downstream pre/mob gene showed 100% nucleotide sequence identity to the corresponding parts in plasmids pBS-01 and pBS-02. In conclusion, this is the first report describing the presence of the cfr gene in a bovine MRSA ST9 strain. Moreover, this is also the first report of an erm(A) gene on a small plasmid. The findings of this study suggested that plasmid pMSA16 consists of a pSES22 backbone from which the erm(C) gene was exchanged for an erm(A) gene and into which a pBS-01/pBS-02-related cfr-carrying segment was integrated. These observations underline that inter-plasmid recombination, but also recombination between a plasmid and a transposon, plays a role in the dissemination of cfr and erm(A).