Volume 11, Number 6—June 2005
Dispatch
Macrolide- and Telithromycin-resistant Streptococcus pyogenes, Belgium, 1999–20031
Table A1
In vitro activity of 6 antimicrobial agents against macrolide-resistant Streptococcus pyogenes phenotypes during 1999–2003
Antimicrobial* | Constitutive (n = 209) |
M (n = 279) |
Inducible (n = 18) |
||||||
---|---|---|---|---|---|---|---|---|---|
Range | MIC50 | MIC90 | Range | MIC50 | MIC90 | Range | MIC50 | MIC90 | |
Erythromycin | 4–>512 | >512 | >512 | 1–128 | 8 | 16 | 1–>512 | 4 | >512 |
Clindamycin | 2–>512 | >512 | >512 | ≤0.03–4 | 0.06 | 1 | 0.125–256 | 0.75 | 128 |
Clarithromycin | 1–>512 | >512 | >512 | 1–256 | 8 | 16 | 0.5–>512 | 2 | >512 |
Azithromycin | 4–>512 | >512 | >512 | 1–128 | 8 | 16 | 0.5–>512 | 4 | >512 |
Tetracycline | 0.06–128 | 32 | 64 | ≤0.03–64 | 0.25 | 0.5 | 0.06–64 | 0.5 | 64 |
Telithromycin† | 0.0075–32 | 1 | 8 | 0.0075–2 | 0.5 | 0.5 | 0.003–4 | 0.06 | 0.5 |
*Dilution range of 0.03 to 512 μg/mL for all antimicrobial agents except telithromycin, which is 0.00375 to 64 μg/mL.
†Breakpoints for telithromycin, susceptible ≤1μg/mL, resistant ≥4 μg/mL.
1A preliminary account of this work was presented at the 44th Interscience Conference on Antimicrobial Agents and Chemotherapy, October 30–November 2, 2004, Washington DC, USA.