TABLE 2.
MIC ranges of macrolides for resistant S. pyogenes strainsa
| Antibiotic | MIC (μg/ml) or MIC range for group:
|
|||||
|---|---|---|---|---|---|---|
| A (2 strains) | B (1 strain) | C (7 strains) | D (5 strains) | Eb (5 strains) | Fb (7 strains) | |
| Erythromycin A | 1–2 | 2 | 4–8 | >32 | >32 | >32 |
| Azithromycin | 4 | 8 | 4–16 | >32 | >32 | >32 |
| Clarithromycin | 0.25–0.5 | 0.5 | 4–8 | >32 | >32 | >32 |
| Roxithromycin | 2–4 | 4 | 8–32 | >32 | >32 | >32 |
| Clindamycin | 0.03–0.06 | >32 | 0.0–0.12 | 0.12–0.25 | >32 | >32 |
a
Resistance phenotypes for strains in groups A to F were iMLSB, iMLSB, M, cMLSB, cMLSB, and cMLSB, respectively; resistance genes for strains in these groups were ermTR, ermTR, mefA, ermB, ermB, and ermB, respectively.
b
E and F groups were separated on the basis of susceptibility to telithromycin.