TABLE 2.
Antimicrobial activities of tigecycline and comparators against carbapenemase-producing Enterobacteriaceae
| Organism (no. tested) and agent | MIC50 | MIC90 | % Susceptiblea | % Resistanta |
|---|---|---|---|---|
| All Enterobacteriaceae (104) | ||||
| Tigecycline | 0.5 | 1 | 100.0 | 0.0 |
| Tetracycline | 4 | >8 | 35.6 | 19.2 |
| Imipenem | 8 | >8 | 37.5 | 37.5 |
| Meropenem | 8 | >8 | 32.7 | 50.0 |
| Ertapenem | 8 | 32 | 7.7 | 73.1 |
| Piperacillin-tazobactam | >64 | >64 | 10.7 | 76.2 |
| Cefepime | >16 | >16 | 26.2 | 59.5 |
| Aztreonam | >16 | >16 | 15.5 | 78.6 |
| Ciprofloxacin | 4 | >4 | 32.1 | 60.7 |
| Gentamicin | 4 | >8 | 50.0 | 33.3 |
| Amikacin | 8 | 32 | 73.3 | 8.3 |
| Polymyxin B | ≤1 | >4 | 88.1b | 11.9b |
| Klebsiella spp. (60) | ||||
| Tigecycline | 1 | 2 | 100.0 | 0.0 |
| Tetracycline | 4 | >8 | 66.7 | 13.3 |
| Imipenem | 8 | 16 | 21.7 | 46.7 |
| Meropenem | >8 | >8 | 20.0 | 61.7 |
| Ertapenem | >8 | >32 | 5.0 | 83.3 |
| Piperacillin-tazobactam | >64 | >64 | 0.0 | 95.8 |
| Cefepime | >16 | >16 | 18.8 | 64.6 |
| Aztreonam | >16 | >16 | 10.4 | 87.5 |
| Ciprofloxacin | >4 | >4 | 14.6 | 79.2 |
| Gentamicin | ≤2 | >8 | 58.3 | 31.2 |
| Amikacin | 16 | >32 | 53.3 | 13.3 |
| Polymyxin B | ≤1 | ≤1 | 93.3b | 6.7b |
| Enterobacter spp. (24) | ||||
| Tigecycline | 0.25 | 0.5 | 100.0 | 0.0 |
| Tetracycline | 4 | >8 | 70.8 | 20.8 |
| Imipenem | 4 | >8 | 54.2 | 17.7 |
| Meropenem | 8 | >8 | 33.3 | 41.7 |
| Ertapenem | >8 | >16 | 8.3 | 12.5 |
| Piperacillin-tazobactam | 32 | >64 | 19.0 | 42.9 |
| Cefepime | >16 | >16 | 9.5 | 85.7 |
| Aztreonam | >16 | >16 | 28.6 | 57.1 |
| Ciprofloxacin | 0.5 | >4 | 61.9 | 33.3 |
| Gentamicin | 8 | >8 | 42.9 | 38.1 |
| Amikacin | 2 | 16 | 95.2 | 4.8 |
| Polymyxin B | ≤1 | ≤1 | 95.2b | 4.8b |
a
According to breakpoints established by the CLSI (4).
b
CLSI breakpoints for P. aeruginosa were applied for comparison purposes only.