Table 9.
The combined effect of clinically used antibiotics with 1a–e, 2a, 3a, 4, 7–9 against multidrug-resistant strains. MICs are expressed in mg/mL.
| Compound | E. coli SA/2 | E. faecalis B3/101 | E. faecium 1/6/63 | S. aureus 66/1 | ||||
|---|---|---|---|---|---|---|---|---|
| CTX | VAN | VAN | OXA | |||||
| Disc Diffusion | MIC | Disc Diffusion | MIC | Disc Diffusion | MIC | Disc Diffusion | MIC | |
| Antibiotic | + | 512 | - | 1024 | - | 1024 | - | 64 |
| Antibiotic + 1a | - | 512 | - | 1024 | - | 1024 | - | 64 |
| Antibiotic + 1b | + | 512 | - | 1024 | - | 1024 | - | 64 |
| Antibiotic + 1c | - | >512 | - | 1024 | - | 1024 | - | 64 |
| Antibiotic + 1d | - | 512 | - | 512 | - | 1024 | - | 64 |
| Antibiotic + 1e | - | 512 | - | 1024 | - | >1024 | - | 64 |
| Antibiotic + 2a | - | 512 | - | 1024 | - | 1024 | - | 64 |
| Antibiotic + 3a | - | 512 | - | 512 | - | 1024 | - | 64 |
| Antibiotic + 4 | - | 512 | - | 1024 | - | 1024 | - | 64 |
| Antibiotic + 7 | - | >512 | - | 1024 | - | 1024 | - | 64 |
| Antibiotic + 8 | - | 512 | + | * | - | * | - | 64 |
| Antibiotic + 9 | - | 512 | - | 512 | - | 512 | - | 64 |
MIC = minimal inhibitory concentration; (-) = no inhibition halo or no increase in the inhibition halo; (+) = halo of inhibition or increase of the inhibition halo by 2 mm; CTX = cefotaxime; VAN = vancomycin; OXA = oxacillin. * For this compound, the checkerboard assay was performed and, with FICI = 0.7 for E. faecalis B3/101 and FICI = 2 for E. faecium 1/6/63, no interaction between 8 and VAN was found (0.5 < FICI ≤ 4, ‘no interaction’).