Table 2. Minimum inhibitory concentrations of different antibiotics for isogenic KP strains.
| Strain | MIC (mg/L) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| MER | MER/VAB | CAZ | CAZ/AVI | IMP | IMP/REL | AZT | AZT/AVI | FDC | |
| KPΔ36 | 512 | 1 | 64 | 1 | 512 | 4 | >1024 | 1 | 0.25 |
| KP36WT | 16 | 0.06 | 16 | 0.5 | 8 | 0.5 | >1024 | 0.25 | 0.06 |
| KP36WT+D | 64 | 0.5 | 32 | 0.5 | 32 | 0.5 | >1024 | 0.5 | ≤0.06 |
| KP36WT+GD | 64 | 0.25 | 64 | 1 | 32 | 0.5 | >1024 | 0.5 | ≤0.06 |
| KP36WT+TD | 64 | 1 | 128 | 4 | 64 | 0.25 | >1024 | 1 | ≤0.06 |
All strains express KPC-2 from a pKpQIL-like plasmid and contain a genomic ompK35 deletion.
MER = meropenem, MER/VAB = meropenem/vaborbactam, CAZ = ceftazidime, CAZ/AVI = ceftazidime/avibactam, IMP = imipenem, IMP/REL = imipenem/relebactam, AZT = aztreonam, AZT/AVI = aztreonam/avibactam, FDC = cefiderocol. Values in bold and underlined represent MICs in the resistant range.
EUCAST breakpoints used are as follows: MER: S = ≤2; R = >8, MER/VAB: S = ≤8; R = >8, CAZ: S = ≤1; R = >4, CAZ/AVI: S = ≤8; R = >8, AZT: S = < = 1; R = >4, AZT/AVI: S = ≤1; R = >4 (AZT breakpoints used in the absence of a consensus for the combination), IMP: S = ≤2; R = >4, IMP/REL: S = ≤2; R = >2, FDC: S≤2; R = >2.