Table 1. Minimum inhibitory concentrations of ST147 NDM-producing Klebsiella pneumoniae strains described in this study, Pisa, Italy (n = 8 strains).
| Antibiotic |
Klebsiella pneumoniae strains/isolates Minimum inhibitory concentrations in mg/L |
|||||||
|---|---|---|---|---|---|---|---|---|
| Kp-P1 Kp-P2 |
Kp-8Pi | Kp-9Pi | Kp-11Pi | Kp-12Pi | Kp-14Pi | Kp-16Pi | Kp-17Pi | |
| Ceftazidime | > 128 | > 128 | > 128 | > 128 | > 128 | > 128 | > 128 | > 128 |
| Cefepime | > 32 | 32 | > 32 | > 32 | > 32 | > 32 | > 32 | > 32 |
| Ceftriaxone | > 4 | > 4 | > 4 | > 4 | > 4 | > 4 | > 4 | > 4 |
| Cefiderocol | 2 | NT | NT | NT | NT | NT | NT | NT |
| Meropenem | > 8 | 8 | 8 | 8 | 8 | 4 | 8 | 64 |
| Imipenem | > 8 | 4 | 8 | 8 | 8 | 4 | 16 | > 16 |
| Ciprofloxacin | > 2 | > 2 | > 2 | > 2 | > 2 | > 2 | > 2 | > 2 |
| Levofloxacin | > 4 | > 4 | > 4 | > 4 | > 4 | > 4 | > 4 | > 4 |
| Amikacin | > 16 | > 16 | > 16 | > 16 | > 16 | > 16 | > 16 | > 16 |
| Gentamycin | > 4 | > 4 | > 4 | > 4 | > 4 | > 4 | > 4 | > 4 |
| SXT | > 4 | > 4 | > 4 | > 4 | > 4 | > 4 | > 4 | > 4 |
| Tigecycline | 2 | 0.25 | 0.25 | 0.5 | 0.5 | 0.25 | 1 | 0.25 |
| Fosfomycin | > 128 | ≤ 16 | ≤ 16 | ≤ 16 | ≤ 16 | ≤ 16 | 32 | 16 |
| Colistin | 16 | < 0.5 | < 0.5 | < 0.5 | 16 | <0.5 | 16 | < 0.5 |
| Aztreonam | > 32 | > 32 | > 32 | > 32 | > 32 | > 32 | > 32 | > 32 |
| Ceftazidime/avibactam | > 8/4 | > 8/4 | > 8/4 | > 8/4 | > 8/4 | > 8/4 | > 8/4 | > 8/4 |
| Ceftazidime/avibactam plus aztreonama | FICI 0.03 | Synergistic | NT | NT | NT | NT | NT | NT |
ATM: aztreonam; AVI: avibactam; FICI: fractional inhibitory concentration index; MIC: minimum inhibitory concentration; NDM: New Delhi metallo-beta-lactamase; NT: not tested; SXT: sulfamethoxazole-trimethoprim.
MICs were obtained using the Merlin ITGN Panel, Tecan automated system, Tecan Trading AG, Switzerland.
a FICI ATM MIC = 0.25 mg/L with AVI at concentration of 4 mg/L.