Table 2. Minimum inhibitory concentrations (MIC) of the studied strains.
| MICs (μg/mL)b | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Antimicrobialsa | Environmental strains | Recipient strain | Transconjugants/Transformant | |||||||||
| 1-CAR | 2-CAR | 3-CAR | 4-CAR | 5-CAR | 6-CAR | 7-CAR | 8-CAR | TC-1-CARe | TC-7-CARf | TF-4-CARg | ||
| E. coli | E. coli | E. cloacae | E. coli | R. ornithinolytica | K. pneumoniae | E. cloacae | K. oxytoca | E. coli-HB101d | E. coli-HB101 | E. coli-HB101 | E. coli-HB101 | |
| KPC-2 | KPC-2 | IMI-2 | KPC-2 | VIM-1 | KPC-2 | KPC-2 | KPC-2, VIM-1 | KPC-2 | KPC-2 | KPC-2 | ||
| AMP | >256 | >256 | >256 | >256 | >256 | >256 | >256 | >256 | 2 | >256 | >256 | >256 |
| AMC | 48 | 48 | 128 | >256 | 48 | 128 | 96 | 96 | 2 | 32 | 32 | 24 |
| TZP | >256 | 32 | 4 | >256 | >256 | 192 | >256 | >256 | 1.5 | >256 | >256 | >256 |
| FOXc | 64 | 192 | >256 | >256 | >256 | 24 | >256 | 48 | 3 | 24 | 24 | 32 |
| CAZ | 4 | 6 | 0.25 | 6 | >256 | 8 | 4 | >256 | 0.064 | 4 | 6 | 2 |
| CTX | 6 | 6 | 0.25 | 8 | 32 | 6 | 16 | 48 | 0.064 | 8 | 6 | 3 |
| FEP | 8 | 6 | 0.94 | 16 | 24 | 3 | 6 | 4 | 0.047 | 5 | 4 | 2 |
| ATM | 32 | 32 | >256 | >256 | 0.5 | 192 | 16 | 48 | 0.016 | 48 | 48 | 12 |
| IPM | 3 | 1.5 | ≥32 | 12 | 8 | 4 | 4 | 3 | 0.19 | 4 | 4 | 2 |
| MEM | 4 | 1.5 | ≥32 | ≥32 | 1.5 | 12 | 1.5 | 4 | 0.016 | 2 | 1.5 | 0.5 |
| ERT | ≥32 | 24 | ≥32 | ≥32 | 2 | ≥32 | 1.5 | 4 | 0.002 | 1.5 | 1.5 | 2 |
| GEN | 0.38 | 0.38 | 0.25 | 1.5 | 1.5 | 0.19 | 1.5 | 0.38 | 0.19 | 0.5 | 1 | 0.25 |
| AMK | 3 | 1.5 | 2 | 4 | 1.5 | 1 | 12 | 2 | 0.75 | 4 | 12 | 0.75 |
| NALc | 256 | >256 | 4 | 12 | 6 | 16 | >256 | >256 | 2 | 4 | 4 | 4 |
| CIP | 2 | 0.38 | 0.125 | 0.75 | 0.5 | 0.75 | 16 | 2 | 0.002 | 0.064 | 0.064 | 0.006 |
| SXT | 0.19 | 0.19 | 0.94 | 0.19 | 0.19 | 0.19 | 0.38 | >32 | 0.094 | 0.032 | 0.032 | 0.064 |
| FOF | 1 | 8 | >1024 | 384 | >1024 | 1024 | 16 | >1024 | 2 | 4 | 2 | 1.5 |
| CST | 0.047 | 0.032 | 0.047 | 0.094 | 0.094 | 0.064 | 0.032 | 0.064 | 0.094 | 0.094 | 0.094 | 0.125 |
a, AMP, ampicillin; AMC, amoxicillin/clavulanic acid; TZP, piperacillin/tazobactam; CAZ, ceftazidime; CTX, cefotaxime, FEP, cefepime; ATM, aztreonam; IPM, imipenem; MEM, meropenem; ERT, ertapenem; GEN, gentamicin; AMK, amikacin; CIP, ciprofloxacin; SXT, trimethoprim-sulfamethoxazole; FOF, fosfomycin; CST, colistin.
b, Numbers in bold-face indicate resistance values according to EUCAST.
c, Bold-face numbers for cefoxitin and nalidixic acid refer to resistance values according to CLSI breakpoints as no value is reported in EUCAST guidelines.
d, E. coli HB101 was the strain used as recipient in the conjugation and transformation experiments.
e, E. coli transconjugant obtained from strain 1-CAR and HB101 that received blaKPC-2-encoding plasmid.
f, E. coli transconjugant obtained from strain 7-CAR and HB101 that received blaKPC-2-encoding plasmid.
g, E. coli transformant obtained from strain 4-CAR and HB101 that received blaKPC-2-encoding plasmid.