TABLE 2.
Susceptibility to macrolides of 85 clinical isolates of erythromycin-resistant S. pneumoniae, subdivided into macrolide resistance phenotypes by the ECDD test
| Phenotype (no. of strains) | Antibiotica | MIC (μg/ml)b
|
||
|---|---|---|---|---|
| Range | 50% | 90% | ||
| cMLS (65) | Erythromycin | 4–>128 | 64 | >128 |
| Clarithromycin | 2–>128 | 128 | >128 | |
| Azithromycin | 8–>128 | >128 | >128 | |
| Josamycin | 0.5–>128 | 16 | 128 | |
| Rokitamycin | 0.06–>128 | 0.25 | 16 | |
| Josamycin (ind.) | 16–>128 | >128 | >128 | |
| Rokitamycin (ind.) | 4–>128 | 128 | >128 | |
| M (20) | Erythromycin | 2–16 | 4 | 16 |
| Clarithromycin | 1–16 | 4 | 8 | |
| Azithromycin | 2–32 | 16 | 16 | |
| Josamycin | 0.03–0.25 | 0.06 | 0.12 | |
| Rokitamycin | 0.03–0.06 | 0.06 | 0.06 | |
| Josamycin (ind.) | 0.06–0.25 | 0.06 | 0.25 | |
| Rokitamycin (ind.) | 0.03–0.12 | 0.06 | 0.06 | |
a
ind., after induction by pregrowth in 0.05 μg of erythromycin per ml.
b
50% and 90%, MICs at which 50 and 90% of isolates were inhibited, respectively.