Molecular Characterization of β-Lactamase-Producing Escherichia coli Collected from 2001 to 2011 from Pigs in Korea

To survey the diversity of plasmid-mediated -lactamases, and the replicon types of the plasmids in Escherichia coli in the community, 95 multidrug-resistant E. coli isolates from stool samples of pigs in Korea from 2001 to 2011 were analyzed, and all isolates were confirmed as -lactamase-producing bacteria, which mostly carried genes encoding TEM (100%), ACC (95%), SHV (62%), OXA (28%), CTX-M (26%), and NDM-1 (15%). Moreover, each isolate contained at least three -lactamases genes on its plasmid. The polymerase chain reaction-based replicon typing method revealed that among the 18 replicon types, 15 types were identified in this work, and IncF groups (FIB; 100%, Frep; 99%) and HI1 (98%) type were predominant. Other replicon types such as Y, B/O, A/C, P, FIA, N, HI2, I1, and W were also detected; moreover at least three types were identified in each organism. In conclusion, a high prevalence of various types of -lactamases genes were identified in E. coli from pigs in Korea, and these genes appeared to be mainly associated with IncF group, IncHI1, and IncY plasmids.