TABLE 3.
Comparison of the in vitro activities of ABT-773 and the macrolides against 1,529 isolates of H. influenzae and 726 isolates of M. catarrhalisa
| Organism | Antimicrobial agent | Value for strain type:
|
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Beta-lactamase positive
|
Beta-lactamase negative
|
||||||||||
| MIC50 | MIC90 | MIC range | % I | % R | MIC50 | MIC90 | MIC range | % I | % R | ||
| H. influenzae | ABT-773 | 2 | 4 | 0.12–>8 | 2 | 4 | 0.06–>8 | ||||
| Azithromycin | 2 | 4 | 0.25–64 | 2 | 4 | ≤0.12–>256 | |||||
| Clarithromycin | 8 | 16 | 0.5–128 | 26.9 | 6.5 | 8 | 16 | ≤0.12–>256 | 29.1 | 3.1 | |
| Erythromycin | 8 | 16 | 0.25–64 | 8 | 16 | ≤0.12–>256 | |||||
| M. catarrhalis | ABT-773 | 0.06 | 0.06 | ≤0.004–0.12 | 0.12 | 0.12 | 0.008–0.12 | ||||
| Azithromycin | 0.06 | 0.12 | 0.03–0.25 | 0.0 | 0.0 | 0.06 | 0.12 | 0.06–0.25 | 0.0 | 0.0 | |
| Clarithromycin | 0.12 | 0.12 | ≤0.015–0.5 | 0.0 | 0.0 | 0.12 | 0.12 | 0.03–0.12 | 0.0 | 0.0 | |
| Erythromycin | 0.25 | 0.25 | 0.06–1 | 0.0 | 0.0 | 0.25 | 0.25 | 0.06–0.25 | 0.0 | 0.0 | |
a
For beta-lactamase-positive strains, n = 476 for H. influenzae and 687 for M. catarrhalis; for beta-lactamase-negative strains, n = 1,053 for H. influenzae and 39 for M. catarrhalis. MICs are expressed as micrograms per milliliter. % I, percent intermediate; % R, percent resistant.