TABLE 3.
Activity of fidaxomicin and rifampin toward antibiotic-resistant strains
| Microorganism (resistance characteristic) | MIC (µg/ml) |
|
|---|---|---|
| Fidaxomicin | Rifamycina | |
| C. difficile ATCC 700057 (antibiotic sensitive) | 0.25 | 0.016 |
| C. difficile 700057-8A (ORG 1632) (rifaximin-elevated MIC) | 0.125 | 0.5 |
| C. difficile 700057-6 (ORG 1629) (fidaxomicin-elevated MIC) | 4 | 0.016 |
| C. difficile ATCC 9689 (antibiotic sensitive) | 0.125 | 0.016 |
| C. difficile 9689-4B (ORG1626) (rifaximin resistant) | 0.125 | >1 |
| C. difficile 9689-7A (ORG 1669) (fidaxomicin-elevated MIC) | 2 | 0.016 |
| C. difficile ATCC 43255 (antibiotic sensitive) | ≤0.125 | ≤0.125 |
| C. difficile 43255-29C (fidaxomicin-elevated MIC) | 8 | ≤0.125 |
| S. aureus ATCC 29213 (antibiotic sensitive) | 4 | ≤0.125 |
| S. aureus ATCC BAA-44 (rifampin resistant) | 4 | 1 |
a
All strains were tested versus rifaximin, with the exception of C. difficile ATCC 43255, its derivative (43255-29C), and S. aureus strains, which were tested versus rifampin.