Table 1.
Characteristics of the two E. coli strains 690 and 701 from fresh vegetables and their transconjugants with plasmids either harboring mcr-1 or blaNDM-5/-9
| Strain | Resistance genes | MICs (μg/mL) | Resistance profiles | Plasmids carrying mcr-1 or blaNDM in transconjugants | ||||
|---|---|---|---|---|---|---|---|---|
| COL | MEM | CTX | FOS | Replicon type | Size (kb) | |||
| 690 | mcr-1, blaNDM-5, fosA3 | 16 | >16 | >64 | >256 | MEM, CTF, CTX, AMP, COL, DOX, TET, GEN, KAN, NAL, ENR, LEV, CIP, FOS, FFL | ||
| COL690 | mcr-1 | 16 | 0.125 | 0.031 | 4 | COL, STR | X4 | ~33 |
| MER690 | blaNDM-5 | 0.25 | >16 | >64 | 8 | MEM, CTF, CTX, AMP, STR | X3 | ~46 |
| 701 | mcr-1, blaNDM-9, fosA3 | 16 | >16 | >64 | >256 | MEM, CTF, CTX, AMP, COL, DOX, TET, GEN, STR, NAL, ENR, LEV, CIP, FOS, FFL | ||
| COL701 | mcr-1 | 16 | 0.125 | 0.031 | 4 | COL, STR | I2 | ~60 |
| MER701 | blaNDM-9, fosA3 | 0.25 | >16 | >64 | >256 | MEM, CTF, CTX, AMP, FOS, STR, | UT | ~110 |
| C600 | 0.25 | 0.125 | 0.031 | 4 | STR | |||
Abbreviations: AMP, ampicillin; CTX, cefotaxime; CTF, ceftiofur; MEM, meropenem; COL, colistin; GEN, gentamicin; KAN, kanamycin; STR, streptomycin; CIP, ciprofloxacin; LEV, levofloxacin; ENR, enrofloxacin; NAL, nalidixic acid; DOX, doxycycline; TET, tetracycline; FFL, florfenicol; FOS, fosfomycin; UT, untypable; C600, recipient strain in the conjugation experiment.