TABLE 2.
Log burden of H. influenzae in rat lung at day 3 of therapy with clarithromycin or azithromycin
| Drug/dosagea | H. influenzae 43095b (% respondersc) | H. influenzae 1435b (% respondersc) | H. influenzae 3556b (% respondersc) | H. influenzae 3598b (% respondersc) | H. influenzae 3558b (% respondersc) |
|---|---|---|---|---|---|
| Clarithromycin | MIC = 4 | MIC = 8 | MIC = 16 | MIC = 16 | MIC = 16 |
| 150 mg/kg | 0.55 ± 1.10d (100%) | 0.91 ± 1.43d (100%) | 1.26 ± 1.88d (90%) | 0.90 ± 1.56d (100%) | NDe (100%) |
| 100 mg/kg | 1.99 ± 1.75d (90%) | 2.58 ± 1.64d (90%) | 3.44 ± 2.20d (78%) | 0.58 ± 1.15d (100%) | 1.03 ± 2.17 (80%) |
| Azithromycin | MIC = 2 | MIC = 2 | MIC = 4 | MIC = 4 | MIC = 4 |
| 50/25 mg/kg | 4.29 ± 1.88d (56%) | 2.10 ± 1.99d (90%) | 5.89 ± 1.01 (11%) | 4.72 ± 0.63 (33%) | 3.82 ± 1.70 (60%) |
| 25/12.5 mg/kg | 5.70 ± 1.42 (13%) | 3.89 ± 1.73d (60%) | 6.36 ± 1.03 (11%) | 5.59 ± 0.79 (17%) | 5.10 ± 0.49 (0%) |
| Untreated | 6.10 ± 0.79 | 6.22 ± 0.68 | 6.95 ± 0.63 | 6.66 ± 0.86 | 6.33 ± 0.73 |
a
Clarithromycin dosage, b.i.d. on days 0 to 2; azithromycin dosage, QD on days 1 to 2; 2× strength dosage on day 0.
b
Mean log count ± standard deviation.
c
Percent responders, percentage of rats with >2-log reduction in H. influenzae burden.
d
Significantly lower than untreated controls (P <0.01).
e
ND, none detected.