High Rate of MCR-1–Producing Escherichia coli and Klebsiella pneumoniae among Pigs, Portugal

摘要: The mcr-1 (mobile colistin resistance 1) gene, which encodes phosphoethanolamine transferase, has been recently identified as a source of acquired to polymyxins in Escherichia coli. Using the SuperPolymyxin selective medium, we prospectively screened 100 pigs at 2 farms Portugal for polymyxin-resistant Enterobacteriaceae and recovered 98 plasmid-mediated MCR-1-producing isolates. Most isolates corresponded nonclonally related E. coli belonging many sequence types; also found Klebsiella pneumoniae types. gene was carried on IncHI2 or IncP plasmid backbones. Our finding high rate MCR-1 producers pig highlights diffusion that colistin-resistance determinant farm level. fact received metaphylaxis their feed during 6 weeks before sampling suggests pressure.