TABLE 3.
Susceptibility and growth rates of endpoint clones from evolved lineagesa
| Strain | Combination used for selection | Evolution endpoint concn (β-lactam/inhibitor) (mg/L) | Mean growth rate ± SD | MIC (mg/L) |
||
|---|---|---|---|---|---|---|
| SAM | TZP | CZA | ||||
| DA65027 | SAM | 256/128 | 0.46 ± 0.03 | >256 | >256 | 1 |
| DA65028 | 256/128 | 0.52 ± 0.01 | >256 | >256 | 1 | |
| DA65029 | 256/128 | 0.50 ± 0.01 | >256 | >256 | 2 | |
| DA65030 | 256/128 | 0.52 ± 0.04 | >256 | >256 | 2 | |
| DA65031 | 256/128 | 0.62 ± 0.02 | >256 | >256 | 1 | |
| DA65032 | 256/128 | 0.55 ± 0.01 | >256 | >256 | 2 | |
| DA65043 | TZP | 256/32 | 0.59 ± 0.02 | >256 | >256 | 0.25 |
| DA65044 | 256/32 | 0.40 ± 0.01 | >256 | >256 | 0.5 | |
| DA65045 | 256/32 | 0.40 ± 0.01 | >256 | >256 | 0.25 | |
| DA65046 | 256/32 | 0.60 ± 0.04 | >256 | >256 | 0.5 | |
| DA65047 | 256/32 | 0.47 ± 0.05 | >256 | >256 | 0.25 | |
| DA65048 | 256/32 | 0.44 ± 0.01 | >256 | >256 | 4 | |
| DA65159 | CZA | 64/16 | 0.32 ± 0.01 | >256 | 256 | 256 |
| DA65160 | 32/8 | 0.36 ± 0.01 | >256 | >256 | 256 | |
| DA65161 | 32/8 | 0.40 ± 0.02 | >256 | 256 | >256 | |
| DA65162 | 16/4 | 0.41 ± 0.01 | >256 | >256 | 32 | |
| DA65163 | 32/8 | 0.26 ± 0.03 | >256 | >256 | >256 | |
| DA65164 | 8/2 | 0.66 ± 0.01 | >256 | 64 | 16 | |
| DA65165 | 32/8 | 0.41 ± 0.01 | >256 | >256 | >256 | |
| DA65166 | 64/16 | 0.31 ± 0.01 | >256 | 256 | >256 | |
a
SAM, ampicillin-sulbactam; TZP, piperacillin-tazobactam; CZA, ceftazidime-avibactam. Values in boldface type exceed the clinical breakpoints set by EUCAST. For all combinations, resistance (R) breakpoints were >8 mg/L of the antibiotic with 4 mg/L of the inhibitor.