TABLE 3.
In vitro activity (MIC, µg/mL) of β-lactams alone, BLIs alone, and β-lactam/BLI combinations against reference β-lactamβ-lactamase-producing bacterial strains a
| Strains | Escherichia coli NCTC 13353 (ECM7514) | Klebsiella pneumoniae ATCC 700603 (KPM2881) | K. pneumoniae ATCC BAA-1705 (KPM1123) | K. pneumoniae ATCC BAA-2814 (KP1074) | P. aeruginosa BAA-3197 (PA5257) | E. coli CDC 0069 (EC1106) | K. pneumoniae CDC 0135 (KP1291) | |
|---|---|---|---|---|---|---|---|---|
| Β-lactamΒ-lactamases | CTX-M-15 | SHV-18 | KPC-2 | KPC-3 | KPC-2 | NDM-1 | VIM-1 | |
| MIC (µg/mL) | MEM | ≤0.03 | ≤0.03 | 32 | >64 | >64 | 32 | 8 |
| MEM + XER (at 4 µg/mL) | ≤0.03 | ≤0.03 | ≤0.03 | 0.06 | 2 | ≤0.06 | ≤0.06 | |
| MEM + XER (at 8 µg/mL) | ≤0.03 | ≤0.03 | ≤0.03 | ≤0.03 | 2 | ≤0.06 | ≤0.06 | |
| MEM + VAB (at 8 µg/mL) | ≤0.03 | ≤0.03 | ≤0.03 | 0.25 | 32 | 32 | 8 | |
| FEP | >64 | 1 | 32 | >64 | >64 | 64 | >64 | |
| FEP + TAN (at 4 µg/mL) | 0.125 | 0.25 | 0.125 | 0.5 | 8 | 0.5 | 1 | |
| CAZ | 64 | 16 | 64 | >64 | >64 | >64 | >64 | |
| CAZ + AVI (at 4 µg/mL) | 0.25 | 0.5 | 0.125 | 1 | 8 | >64 | >64 | |
| IMP | 0.125 | 0.06 | 8 | 64 | >64 | 16 | 8 | |
| IMP + REL (at 4 µg/mL) | 0.125 | 0.06 | 0.125 | 0.125 | 4 | 16 | 8 | |
| TOL | >64 | 8 | 64 | >64 | 32 | >64 | >64 | |
| TOL + TAZ (at 4 µg/mL) | 1 | 1 | 64 | >64 | 16 | >64 | >64 | |
| XER | 8 | 16 | 16 | 32 | >64 | 16 | 16 | |
| TAN | >64 | >64 | >64 | >64 | >64 | >64 | >64 | |
| AVI | 16 | 32 | 16 | 64 | >64 | 8 | >64 | |
| REL | >64 | >64 | >64 | >64 | >64 | >64 | >64 | |
| VAB | >64 | >64 | >64 | >64 | >64 | >64 | >64 | |
a
AVI, avibactam; CAZ, avibactam; FEP, cefepime; IMP, imipenem; MEM, meropenem; REL, relebactam; TAN, taniborbactam; TAZ, tazobactam; TOL, ceftolozane; XER, xeruborbactam. All inhibitors were tested in combination with antibiotics at specific fixed concentrations (shown in brackets). MIC values in bold are for the strains that are CLSI-approved quality control strains for specific combinations. All these values are within acceptable QC ranges (27).