TABLE 1.
MICs of cethromycin, telithromycin, and comparative agents against a collection of 312 North American S. pneumoniae invasive clinical isolates
| Antimicrobial agent | MIC (μg/ml)
|
% Resistanta | ||
|---|---|---|---|---|
| 50% | 90% | Range | ||
| Cethromycin | 0.008 | 0.06 | ≤0.004-16 | NAb |
| Telithromycin | ≤0.015 | 0.25 | ≤0.015-4 | 0.3 |
| Erythromycin | 0.06 | 32 | ≤0.015->64 | 29.8 |
| Clindamycin | 0.06 | 32 | ≤0.015->64 | 15.1 |
| Penicillin | 0.03 | 4 | ≤0.015-8 | 22.4 |
| Cefotaximec | 0.03 | 4 | ≤0.015-16 | 10.3 |
a
Resistance defined by approved NCCLS breakpoints (17), including recently decided telithromycin breakpoints (susceptible, <1 μg/ml; intermediate, 2 μg/ml; and resistant, >4 μg/ml; T. Dooley, personal communication).
b
NA, not applicable; approved breakpoints do not yet exist for cethromycin.
c
Cefotaxime resistance defined in terms of NCCLS nonmeningitis breakpoints (17).