Table 1 In vitro activities of colistin, imipenem, and ceftazidime against drug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii isolates
Organism and antimicrobial agents | CLSI Breakpoint (μg/mL) | MIC (μg/mL) | Susceptibility (%) | ||||||
|---|---|---|---|---|---|---|---|---|---|
S | I | R | Range | 50% | 90% | S | I | R | |
A. baumannii | |||||||||
Imipenem | ≤ 2 | 4 | ≥ 8 | 8–> 32 | > 32 | > 32 | 0 | 0 | 100 |
Ceftazidime | ≤ 8 | 16 | ≥ 32 | 16–> 256 | 32 | > 256 | 0 | 16.7 | 83.3 |
Colistin | ≤ 2 | – | ≥ 4 | 0.19–1.5 | 0.75 | 1.5 | 100 | – | 0 |
P. aeruginosa | |||||||||
Imipenem | ≤ 2 | 4 | ≥ 8 | 1.5–> 32 | 6 | > 32 | 23.8 | 33.3 | 42.9 |
Ceftazidime | ≤ 8 | 16 | ≥ 32 | 0.75–> 256 | 2 | > 256 | 81 | 0 | 19 |
Colistin | ≤ 2 | – | ≥ 4 | 0.094–1.5 | 0.5 | 1 | 100 | - | 0 |