TABLE 9.
In vitro activity of meropenem or cefepime combined with xeruborbactam or taniborbactam against isogenic efflux and porin mutants of K. pneumoniae and their NDM-1-producing derivatives
| Strain | Genotype a | Β-lactamΒ-lactamase | BLI | Meropenem MIC (µg/mL) with BLIs (µg/mL) | Cefepime MIC (µg/mL) with BLIs (µg/mL) | BLI MIC (µg/mL) | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| 0 | 4 | 8 | 0 | 4 | 8 | |||||
| KPM1026a | Wild type, ATCC 43816 | None | XER | 0.03 | 0.015 | 0.008 | 0.03 | 0.015 | 0.002 | 16 |
| TAN | 0.03 | 0.03 | 0.03 | 0.03 | 0.03 | 0.03 | >64 | |||
| KPM1281 | NDM-1 | XER | 32 | 0.06 | 0.004 | 16 | 0.03 | 0.008 | 16 | |
| TAN | 32 | 0.125 | 0.06 | 16 | 0.25 | 0.125 | >64 | |||
| KPM1027 | ramR* | None | XER | 0.06 | 0.015 | 0.004 | 0.25 | 0.125 | 0.015 | 16 |
| TAN | 0.06 | 0.06 | 0.06 | 0.25 | 0.25 | 0.25 | >64 | |||
| KPM1282 | NDM-1 | XER | 64 | 0.125 | 0.03 | 32 | 0.25 | 0.06 | 16 | |
| TAN | 64 | 0.25 | 0.125 | 32 | 0.5 | 0.5 | >64 | |||
| KPM2040 | mpK36_2040* | None | XER | 0.125 | 0.06 | 0.03 | 0.125 | 0.06 | 0.015 | 32 |
| TAN | 0.125 | 0.125 | 0.125 | 0.125 | 0.125 | 0.125 | >64 | |||
| KPM3820 | NDM-1 | XER | 128 | 4 | 1 | 128 | 1 | 0.5 | 32 | |
| TAN | 128 | 8 | 4 | 128 | 4 | 2 | >64 | |||
| KPM2013 | mpK36_2040 ΔompK35 | None | XER | 0.25 | 0.125 | 0.06 | 0.5 | 0.25 | 0.06 | 32 |
| TAN | 0.25 | 0.25 | 0.25 | 0.5 | 0.5 | 0.5 | >64 | |||
| KPM3825 | NDM-1 | XER | 256 | 8 | 2 | 256 | 2 | 1 | 32 | |
| TAN | 256 | 32 | 16 | 256 | 8 | 4 | >64 | |||
a
ramR, 18-bp insertion causing frameframeshift from aa#46 (results in overexpression of the acrAB efflux operon and downregulation of the ompK35 gene); ompK36_2040, the frameshift from aa#54.