Table 2.
Antimicrobial susceptibility of 32 P. aeruginosa isolates from 28 patients with cystic fibrosis
| Antimicrobial agent | MIC50 (μg/mL) |
MIC90 (μg/mL) |
MIC range (μg/mL) |
%Sa (CLSI/US-FDA) |
%I or Ra (CLSI/US-FDA) |
|---|---|---|---|---|---|
| Ceftazidime–avibactam | 4 | 64 | 0.5–>128 | 71.9 | 28.1 |
| Ceftazidime | 64 | >128 | 16–>128 | 0 | 100 |
| Aztreonam | 64 | >128 | ≤1–>128 | 3.1 | 96.9 |
| Cefepime | >16 | >16 | 8–>16 | 0 | 100 |
| Meropenem | 8 | >16 | ≤0.12–>16 | 34.3 | 65.7 |
| Piperacillin/tazobactam | >128 | >128 | 16–>128 | 3.1 | 96.9 |
| Amikacin | 32 | >32 | 4–>32 | 25.0 | 75.0 |
| Gentamicin | >8 | >8 | 2–>8 | 12.5 | 87.5 |
| Colistin | 1 | 2 | 0.25–8 | 93.7 | 6.3 |
| Levofloxacin | >4 | >4 | 0.12–>4 | 21.9 | 78.1 |
| Ciprofloxacin | >4 | >4 | 0.06–>4 | 25.0 | 75.0 |
Note:
a
US-FDA breakpoints were applied for ceftazidime–avibactam, ceftazidime, and cefepime (≥8/≤16 µg/mL for S/R for all three drugs), and CLSI breakpoints were applied for the remaining drugs.
Abbreviations: FDA, Food and Drug Administration; CLSI, Clinical and Laboratory Standards Institute; R, resistant; I, intermediate; S, sensitive.