TABLE 3.
MICs of antibiotics with or without PlnA1 analogs against E. colia
| Antibiotics | MIC (μg/mL) | MIC (μg/mL) (in combination) of: |
FICIb | MIC (μg/mL) (in combination) of: |
FICIb | ||
|---|---|---|---|---|---|---|---|
| Antibiotic | OP4 | Antibiotic | PlnA1 | ||||
| Ampicillin | 4 | 4 | 3.13 | 2.0 | 4 | 25 | 2.0 |
| Amoxicillin | 2 | 2 | 3.13 | 2.0 | 2 | 25 | 2.0 |
| Erythromycin | 500 | 8 | 0.78 | 0.266 | 32 | 6.25 | 0.314 |
| Streptomycin | 8 | 8 | 1.56 | 1.5 | 8 | 25 | 2.0 |
| Gentamycin | 2 | 2 | 1.56 | 1.5 | 2 | 25 | 2.0 |
| Kanamycin | 4 | 4 | 1.56 | 1.5 | 4 | 12.5 | 1.5 |
| Tetracycline | 2 | 0.25 | 0.78 | 0.375 | 0.5 | 12.5 | 0.75 |
| Oxytetracycline | 2 | 0.25 | 0.78 | 0.375 | 0.5 | 6.25 | 0.5 |
| Lincomycin | 500 | 500 | 3.13 | 2.0 | 250 | 25 | 1.5 |
| Chloramphenicol | 4 | 4 | 1.56 | 1.5 | 4 | 25 | 2.0 |
| Polymyxin B | 8 | 4 | 1.56 | 1.0 | 4 | 12.5 | 1.5 |
| Vancomycin | 125 | 125 | 3.13 | 2.0 | 125 | 12.5 | 1.5 |
| Ciprofloxacin | 0.06 | 0.008 | 0.78 | 0.38 | 0.016 | 6.25 | 0.5 |
| Norfloxacin | 0.04 | 0.008 | 0.78 | 0.445 | 0.01 | 6.25 | 0.5 |
| Trimethoprim | 8 | 0.5 | 0.78 | 0.3125 | 1 | 6.25 | 0.375 |
| Triclosan | 2 | 1 | 0.78 | 0.75 | 1 | 12.5 | 1.0 |
| Novobiocin | 62.5 | 7.81 | 0.78 | 0.375 | 7.81 | 6.25 | 0.375 |
| Fusidic acid | 125 | 15.625 | 0.39 | 0.25 | 15.625 | 3.125 | 0.25 |
| Clindamycin | 250 | 1.95 | 0.78 | 0.2578 | 1.95 | 12.5 | 0.5078 |
| Rifampicin | 3.125 | 0.195 | 0.39 | 0.1874 | 0.195 | 6.25 | 0.3124 |
a
The indicator strain used was E. coli ATCC 35218. The MIC of PlnA1 was 25 μg/mL, and the MIC of OP4 was 3.125 μg/mL.
b
FICI values of <0.5, >0.5 to 1, >1 to <2, and ≥2 indicate synergism, additive effects, indifference, and antagonism, respectively.