TABLE 1.
Results of synergy testing with gram-negative organisms
| Organism | MIC (μg/ml)
|
Result for drug combination at time (h)a
|
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clinafloxacin | Ceftazidime | Amikacin | Imipenem | Clinafloxacin + ceftazidime
|
Clinafloxacin + amikacin
|
Clinafloxacin + imipenem
|
|||||||
| 6 | 12 | 24 | 6 | 12 | 24 | 6 | 12 | 24 | |||||
| P. aeruginosa | 1 | >128 | >64 | 32 | Sy (0.25/32) | Ad | Ad | Sy (0.25/8) | Ad | Ad | Ad | Sy (0.25/2) | Ad |
| 2 | >128 | >64 | 128 | Ad | Sy (0.25/32) | Ad | Ad | Sy (0.25/32) | Ad | Ad | Sy (0.25/64) | Ad | |
| 2 | 64 | 8 | 4 | Ad | Ad | Ad | Ad | Ad | Ad | Sy (0.25/0.5) | Ad | Ad | |
| S. maltophilia | 2 | 128 | >64 | >128 | Ad | Sy (0.25/16) | Sy (0.25/16) | Ad | Ad | Ad | Ad | Sy (0.25/64) | Sy (0.25/64) |
| 1 | >128 | 32 | >128 | Ad | Sy (0.5/32) | Ad | Ad | Ad | Ad | Ad | Ad | Ad | |
| 1 | 128 | 32 | >128 | Ad | Sy (1/32) | Ad | Ad | Ad | Ad | Ad | Ad | Ad | |
| Acinetobacter spp. | 4 | 8 | 4 | 0.25 | Sy (0.5/2) | Ad | Ad | Sy (0.5/1) | Ad | Ad | Sy (0.5/0.06) | Ad | Ad |
| 4 | 32 | 2 | 0.5 | Ad | Ad | Ad | Ad | Sy (1/1) | Ad | Ad | Sy (1/0.12) | Sy (1/0.12) | |
| 0.25 | 8 | 4 | 0.25 | Ad | Ad | Sy (0.06/2) | Ad | Sy (0.06/1) | Sy (0.06/1) | Ad | Sy (0.06/0.06) | Ad | |
| B. cepacia | 2 | 4 | >64 | 16 | Ad | Sy (0.5/2) | Sy (0.5/2) | Ad | Sy (0.5/32) | Sy (0.5/32) | Ad | Ad | Sy (0.5/8) |
| 4 | 2 | 32 | 64 | Ad | Sy (2/1) | Ad | Ad | Ad | Ad | Sy (2/32) | Sy (2/32) | Sy (2/32) | |
| 2 | 8 | >64 | 128 | Ad | Ad | Sy (0.5/2) | Ad | Ad | Sy (0.5/16) | Sy (0.5/32) | Sy (0.5/32) | Sy (0.5/32) | |
| E. coli | 2 | 0.125 | 2 | 0.125 | Ad | Ad | Ad | Sy (0.5/1) | Ad | Ad | Ad | Ad | Ad |
| 1 | 0.25 | 4 | 0.06 | Ad | Ad | Ad | Ad | Ad | Ad | Ad | Ad | Ad | |
| 4 | 64 | 32 | 0.5 | Ad | Ad | Ad | Ad | Sy (2/16) | Ad | Sy (2/0.25) | Sy (2/0.25) | Ad | |
| K. pneumoniae | 1 | 0.5 | 1 | 0.06 | Ad | Ad | Ad | Ad | Ad | Ad | Ad | Ad | Sy (0.25/0.03) |
| 4 | >128 | 1 | 0.25 | Ad | Sy (1/32) | Sy (1/32) | Ad | Sy (1/0.5) | Ad | Ad | Ad | Ad | |
| 8 | 1 | 1 | 0.125 | Ad | Ad | Ad | Ad | Ad | Ad | Ad | Ad | Ad | |
| E. cloacae | 2 | 8 | 2 | 1 | Ad | Ad | Ad | Ad | Ad | Ad | Ad | Ad | Ad |
| 4 | 8 | 2 | 0.125 | Ad | Ad | Ad | Ad | Sy (2/1) | Ad | Ad | Ad | Ad | |
| 1 | 0.5 | 2 | 0.5 | Sy (0.12/0.12) | Ad | Sy (0.12/0.12) | Ad | Ad | Ad | Ad | Ad | Ad | |
| E. aerogenes | 2 | 1 | 2 | 4 | Ad | Ad | Ad | Ad | Ad | Ad | Ad | Ad | Ad |
| C. freundii | 2 | 1 | 2 | 0.125 | Ad | Sy (0.5/0.5) | Ad | Ad | Sy (0.5/1) | Sy (0.5/1) | Ad | Sy (0.5/0.06) | Ad |
| 1 | 64 | 2 | 0.25 | Sy (0.25/16) | Ad | Ad | Ad | Sy (0.25/0.5) | Ad | Sy (0.25/0.12) | Ad | Ad | |
| 1 | 64 | 2 | 0.25 | Ad | Sy (0.25/16) | Sy (0.25/16) | Ad | Sy (0.25/1) | Sy (0.25/1) | Ad | Sy (0.25/0.12) | Sy (0.25/0.12) | |
| S. marcescens | 4 | 1 | 4 | 2 | Ad | Sy (1/0.12) | Sy (1/0.12) | Ad | Sy (1/2) | Sy (1/2) | Ad | Ad | Ad |
| 0.5 | 1 | 2 | 2 | Ad | Sy (0.12/0.25) | Sy (0.12/0.25) | Ad | Sy (0.12/1) | Ad | Ad | Sy (0.12/0.5) | Sy (0.12/0.5) | |
| 1 | 0.5 | 2 | 1 | Sy (0.25/0.12) | Sy (0.25/0.12) | Ad | Sy (0.25/1) | Sy (0.25/1) | Ad | Ad | Sy (0.25/0.25) | Sy (0.25/0.25) | |
| P. mirabilis | 2 | ND | 16 | 8 | ND | ND | ND | Ad | Ad | Ad | Ad | Sy (0.5/1) | Sy (0.5/1) |
| 0.5 | ND | 16 | 8 | ND | ND | ND | Ad | Ad | Ad | Ad | Sy (0.12/0.5) | Sy (0.12/0.5) | |
| P. stuartii | 1 | 0.25 | 1 | 1 | Sy (0.25/0.06) | Ad | Sy (0.25/0.06) | Sy (0.25/0.25) | Ad | Sy (0.25/0.25) | Ad | Sy (0.25/0.5) | Sy (0.25/0.5) |
| 2 | 0.5 | 2 | 0.5 | Sy (0.5/0.06) | Sy (0.5/0.06) | Sy (0.5/0.06) | Ad | Sy (0.5/1) | Sy (0.5/1) | Ad | Ad | Sy (0.5/0.12) | |
| M. morganii | 8 | >128 | 8 | 2 | Sy (1/4) | Ad | Sy (1/4) | Ad | Ad | Ad | Ad | Ad | Ad |
a
Sy, synergistic; Ad, additive. Values in parentheses are MICs, i.e., the lowest concentrations (in micrograms per milliliter) of each compound that yielded a ≥2-log10 decrease in CFU per milliliter compared to the more active single compound. ND, not done because of trailing endpoints.