TABLE 3.
Susceptibility to MLS antibiotics of 65 clinical isolates of erythromycin-resistant S. pneumoniae, all identified as cMLS phenotype by the ECDD test and differentiated into cMLS and iMcLS types on the basis of macrolide MICs and MIC-induction tests
| Phenotype in MIC-induction tests (no. of strains) | Antibiotica | MIC (μg/ml)b
|
||
|---|---|---|---|---|
| Range | 50% | 90% | ||
| cMLS (10) | Erythromycin | 128–>128 | >128 | >128 |
| Clarithromycin | 128–>128 | >128 | >128 | |
| Azithromycin | 128–>128 | >128 | >128 | |
| Josamycin | 32–>128 | 128 | >128 | |
| Rokitamycin | 4–>128 | 64 | >128 | |
| Clindamycin | 16–>128 | 128 | >128 | |
| Josamycin (ind.) | 128–>128 | >128 | >128 | |
| Rokitamycin (ind.) | 128–>128 | >128 | >128 | |
| Clindamycin (ind.) | 32–>128 | >128 | >128 | |
| iMcLS (55) | Erythromycin | 2–>128 | 64 | >128 |
| Clarithromycin | 4–>128 | 64 | >128 | |
| Azithromycin | 8–>128 | 128 | >128 | |
| Josamycin | 0.5–32 | 8 | 32 | |
| Rokitamycin | 0.06–2 | 0.25 | 1 | |
| Clindamycin | 8–>128 | 32 | >128 | |
| Josamycin (ind.) | 16–>128 | >128 | >128 | |
| Rokitamycin (ind.) | 4–>128 | 64 | >128 | |
| Clindamycin (ind.) | 16–>128 | 128 | >128 | |
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.