TABLE 2.
Comparison of some characteristics of the erythromycin-resistant S. pyogenes strains used as the donor and recipient in transfer experiments with those of the transconjugants obtained
| Characteristica | Donor (strain iB1) | Recipient (strain iC4fr) | Transconjugants (iB1 × iC4fr) |
|---|---|---|---|
| Erythromycin resistance | |||
| Genotype | erm(A) | erm (A) | erm(A) |
| Phenotype | iMLS-B | iMLS-C | iMLS-B |
| Active efflux present | Yes | No | Yes |
| MIC (μg/ml) | |||
| Erythromycin | >128 | 1 | >128 |
| Clarithromycin | >128 | 0.5 | >128 |
| Azithromycin | >128 | 4 | >128 |
| Josamycin | 0.06 | 0.06 | 0.06 |
| Josamycin (ind.) | >128 | 8 | >128 |
| Telithromycin | ≤0.015 | ≤0.015 | ≤0.015 |
| Telithromycin (ind.) | 8 | 0.03 | 8 |
| Clindamycin | 0.06 | ≤0.015 | 0.06 |
| Clindamycin (ind.) | >128 | >128 | >128 |
a
ind., induced by growth in erythromycin (0.05 μg/ml).