Distribution of in spp. and Strains from Pig Farms in China and Characterization of a Novel -Carrying F43:A-:B- Plasmid.

The multi-resistance gene is widely distributed among various gram-positive and gram-negative species in livestock in China. To better understand the epidemiology of among spp. and isolates, 254 spp. and 398 strains collected from six swine farms in China were subjected to prevalence and genetic analysis. Forty (15.7%) spp. isolates, including 38 strains, one strain, and one strain, and two (0.5%) isolates were found to contain the gene. Most of the 38 strains were clonally unrelated; however, clonal dissemination of -positive was detected at the same farm. In eight randomly selected -positive staphylococci, a -harboring module (ISΔ) was detected in six isolates; was bracketed by two copies of IS or IS in the remaining two isolates. In the two isolates, EP25 and EP28, was flanked by two IS elements in the same or opposite orientation, respectively. Complete sequence analysis of the novel F43:A-:B- plasmid pHNEP28 revealed that it contains two multi-resistance regions: together with , interspersed with IS, ΔIS and IS, and together with (M) interspersed with IS, IS, ΔTn, and ΔIS. The coexistence of with other resistance genes on a conjugative plasmid may contribute to the dissemination of these genes by co-selection. Thus, rational drug use and continued surveillance of in swine farms are warranted.