An Enterococcus faecium Isolated from Bovine Feces in Italy Shares optrA - and poxtA -Carrying Plasmids with Enterococci from Switzerland.

To investigate the occurrence of oxazolidinone resistance genes, 18 florfenicol-resistant enterococci were isolated from 66 fecal samples collected from several cattle farms in central Italy. The PCR screening indicated that only a bovine florfenicol-resistant isolate, 249031-C, was positive for the presence of and genes. The strain was tested for its susceptibility to florfenicol, chloramphenicol, linezolid, tedizolid, tetracycline, erythromycin, and vancomycin. Whole Genome Sequencing analysis showed that 249031-C, belonging to the ST22 lineage, harbored two plasmids: the -carrying p249031-S (179 kb) and the -carrying p1818-c (23 kb). p249031-S, containing a new -carrying Tn transposon, was closely related to the plasmid pF88_1 of F88, whereas p1818-c had already been detected in a human , both enterococci were from Switzerland. The linezolid resistance genes were cotransferred to the 64/3 recipient. Circular forms from both - and -carrying genetic contexts were obtained. The occurrence of oxazolidinone resistance genes in a bovine isolate and their localization on conjugative and mobilizable plasmids pose a risk for public health.