TABLE 7.
In vitro activity of new antibiotics against S. pneumoniae
| Antibiotic (no. of strains tested) | MIC50 (μg/ml) | MIC90 (μg/ml) | MIC range (μg/ml) | Reference |
|---|---|---|---|---|
| Streptogramins | ||||
| RP59500 (Quinupristin/Dalfopristin) (Synercid) | 110 | |||
| Penicillin susceptible (4) | 0.5 | 0.5 | 0.5 | |
| Penicillin intermediate (2) | 0.25 | 0.5 | 0.25–0.5 | |
| Penicillin resistant (4) | 0.5 | 1.0 | 0.5–1.0 | |
| RPR 106972 | 135 | |||
| Penicillin susceptible (75) | 0.03 | 0.125 | 0.016–0.5 | |
| Penicillin intermediate (55) | 0.125 | 0.5 | 0.016–0.5 | |
| Penicillin resistant (73) | 0.25 | 0.5 | 0.016–0.5 | |
| RPR 106972 | 135 | |||
| Erythromycin resistant, clindamycin susceptible (143) | 0.125 | 0.5 | 0.016–0.5 | |
| Erythromycin resistant, clindamycin resistant (60) | 0.125 | 0.25 | 0.016–0.5 | |
| RP 7293 | 110 | |||
| Penicillin susceptible (4) | 0.125 | 0.25 | 0.125–0.25 | |
| Penicillin intermediate (2) | 0.125 | 0.125 | 0.125 | |
| Penicillin resistant (4) | 0.25 | 0.25 | 0.125–0.25 | |
| Cephalosporin | ||||
| Cefditoren | 135 | |||
| Penicillin susceptible (75) | ≤0.06 | ≤0.06 | <0.06 | |
| Trimen | ||||
| GV104325 (Sanfetrinem) | 41 | |||
| Penicillin susceptible (1167) | 0.015 | 0.015 | 0.004–0.25 | |
| Penicillin intermediate (216) | ≤0.06 | 0.5 | 0.008–1.0 | |
| Penicillin resistant (145) | 0.5 | 1.0 | 0.12–2.0 | |
| Glycopeptide | ||||
| LY333328 | 45 | |||
| Penicillin susceptible (51) | 0.002 | 0.008 | 0.002–0.06 | |
| Penicillin intermediate (75) | 0.002 | 0.008 | 0.002–0.06 | |
| Penicillin resistant (76) | 0.005 | 0.03 | 0.002–0.125 | |
| Fluoroquinolone | ||||
| Levofloxacin | 119 | |||
| Penicillin susceptible (460) | 1.0 | 2.0 | 0.05–4.0 | |
| Penicillin intermediate (34) | 1.0 | 2.0 | 0.05–4.0 | |
| Penicillin resistant (5) | 1.0 | 2.0 | 0.05–4.0 | |
| Levofloxacin | 145 | |||
| Penicillin susceptible (3) | 1.0 | 2.0 | 1.0–2.0 | |
| Penicillin intermediate (3) | 1.0 | 2.0 | 1.0–2.0 | |
| Penicillin resistant (3) | 1.0 | 4.0 | 1.0–4.0 | |
| Sparfloxacin | 16 | |||
| Erythromycin, >256 μg/ml (21) | 0.5 | 1.0 | 0.25–1.0 | |
| Erythromycin, 4–64 μg/ml (29) | 0.5 | 1.0 | 0.25–1.0 | |
| Sparfloxacin | 145 | |||
| Penicillin susceptible (3) | 0.25 | 0.25 | 0.25 | |
| Penicillin intermediate (3) | 0.25 | 0.25 | 0.25 | |
| Penicillin resistant (3) | 0.5 | 0.5 | 0.25–0.5 | |
| Grepafloxacin | 111 | |||
| Penicillin intermediate (71) | 0.25 | 0.5 | 0.125–1.0 | |
| Penicillin resistant (58) | 0.25 | 0.5 | 0.125–1.0 | |
| DU-6859a | 145 | |||
| Penicillin susceptible (3) | 0.064 | 0.064 | 0.064 | |
| Penicillin intermediate (3) | 0.064 | 0.064 | 0.064 | |
| Penicillin resistant (3) | 0.064 | 0.064 | 0.064 | |
| Bay 12-8039 | 146 | |||
| Penicillin susceptible (53) | 0.125 | 0.25 | ||
| Penicillin intermediate (45) | 0.125 | 0.25 | ||
| Penicillin resistant (45) | 0.125 | 0.25 | ||
| Sparfloxacin | 105 | |||
| Penicillin nonsusceptible (28) | 0.06 | 0.12 | 0.03–0.25 | |
| Oxazolidinones | ||||
| Linezolid | 92 | |||
| Penicillin intermediate (162) | 0.5 | 1.0 | 0.06–2.0 | |
| Penicillin resistant (68) | 1.0 | 1.0 | 0.25–4.0 | |
| Eperezolid | 92 | |||
| Penicillin intermediate (162) | 0.25 | 0.25 | 0.06–1.0 | |
| Penicillin resistant (68) | 0.25 | 0.5 | 0.125–1.0 | |
| Rifamycins | 56 | |||
| Penicillin susceptibility unknown (20) | 0.0039 | 0.0313 | 0.0005–0.25 |