TABLE 1

Sources and MICs for the two mcr-1-positive E. coli isolates, their transformants, and the recipient strain

IsolateCountryTime of isolationSourceSTMIC (mg/liter)a
AMPGENCIPNALTMPMEMTETCTXCHLTGCCAZCST
BB1290VenezuelaAugust 2015Human feces19>64>32>8>128>328>64>4>1281>84
BB1290TbLaboratory4<0.50.0664<0.25<0.03<2<0.25<8<0.25<0.54
BB1291VenezuelaAugust 2015Swine feces452>64>32>8>128>32<0.03>64>4>128<0.2544
BB1291TbLaboratory4<0.50.0664<0.25<0.03<2≤0.25≤8<0.25<0.54
E. coli HST08Laboratory4<0.50.0364<0.25<0.03<2<0.25<8<0.25<0.5<1
  • a AMP, ampicillin; GEN, gentamicin; CIP, ciprofloxacin; NAL, nalidixic acid; TMP, trimethoprim; MEM, meropenem; TET, tetracycline; CTX, cefotaxime; CHL, chloramphenicol; TGC, tigecycline; CAZ, ceftazidime; CST, colistin. Resistance is highlighted in bold.

  • b E. coli HST08 transformed with a mcr-1-bearing plasmid.