TABLE 2.
In vitro activities of quinupristin-dalfopristin and seven other antibiotics against S. epidermidis strains (n = 456) isolated from patients with bloodstream infections in Germanya
| Antibiotic | No. of strains for which MIC (mg/liter) is:
|
MIC90 (mg/liter) | Susceptibilityb
|
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ≤0.06 | 0.125 | 0.25 | 0.5 | 1 | 2 | 4 | 8 | 16 | 32 | ≥64 | % S | % R | ||
| Penicillin G | 36 | 10 | 15 | 24 | 43 | 59 | 68 | 90 | 111 | — | — | 16 | 10.1 | 89.9 |
| Oxacillin | 69 | 27 | 20 | 5 | 19 | 20 | 37 | 41 | 218 | — | — | ≥16 | 30.7 | 69.3 |
| Erythromycin | — | — | 91 | 50 | 26 | 4 | 1 | 0 | 4 | 6 | 274 | ≥64 | 36.6 | 62.3 |
| Clindamycin | — | — | 265 | 6 | 3 | 1 | 0 | 1 | 0 | 5 | 175 | ≥64 | 59.9 | 39.7 |
| Ciprofloxacin | 3 | 26 | 68 | 72 | 17 | 9 | 24 | 52 | 185 | — | — | ≥16 | 40.8 | 57.2 |
| Gentamicin | — | — | 170 | 8 | 4 | 5 | 6 | 23 | 240 | — | — | ≥16 | 39.9 | 57.7 |
| Teicoplanin | — | — | 22 | 22 | 66 | 133 | 142 | 65 | 6 | 0 | 0 | 8 | 84.4 | 1.3 |
| Vancomycin | — | — | 1 | 37 | 224 | 187 | 7 | 0 | 0 | 0 | 0 | 2 | 100 | 0 |
| Q-D | — | — | 434 | 12 | 6 | 4 | 0 | 0 | 0 | 0 | 0 | 0.25 | 99.1 | 0 |
Q-D, quinupristin-dalfopristin; S, susceptible; R, resistant; —, concentration not tested.
The following breakpoints were used for definition of susceptibility (resistance): penicillin, ≤0.125 mg/liter (≥0.25 mg/liter) (DIN); oxacillin, ≤1 mg/liter (≥2 mg/liter) (DIN); erythromycin, ≤1 mg/liter (≥8 mg/liter) (DIN); clindamycin, ≤1 mg/liter (≥8 mg/liter) (DIN); ciprofloxacin, ≤1 mg/liter (≥4 mg/liter) (DIN); gentamicin, ≤1 mg/liter (≥8 mg/liter) (DIN); teicoplanin, ≤1 mg/liter (≥16 mg/liter) (tentative breakpoint); vancomycin, ≤4 mg/liter (≥16 mg/liter) (DIN); quinupristin-dalfopristin, ≤1 mg/liter (≥4 mg/liter) (tentative breakpoint).