TABLE 2.
Results of time-kill assays
| Drug and concn | No. of strains with the indicated decrease (log10 CFU/ml) in the colony counta at:
|
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 6 h
|
12 h
|
24 h
|
48 h
|
|||||||||
| −1 | −2 | −3 | −1 | −2 | −3 | −1 | −2 | −3 | −1 | −2 | −3 | |
| Telithromycin | ||||||||||||
| 8× MIC | 5 | 2 | 1 | 6 | 4 | 2 | 9 | 8 | 5 | 11 | 8 | 7 |
| 4× MIC | 4 | 2 | 1 | 6 | 4 | 2 | 9 | 8 | 4 | 11 | 9 | 6 |
| 2× MIC | 4 | 1 | 0 | 3 | 2 | 1 | 9 | 6 | 3 | 10 | 9 | 6 |
| MIC | 2 | 0 | 0 | 4 | 1 | 1 | 6 | 3 | 2 | 6 | 5 | 3 |
| 0.5× MIC | 0 | 0 | 0 | 2 | 1 | 0 | 4 | 2 | 1 | 2 | 2 | 0 |
| Erythromycin A | ||||||||||||
| 8× MIC | 6 | 2 | 1 | 8 | 3 | 1 | 10 | 9 | 5 | 10 | 10 | 9 |
| 4× MIC | 5 | 2 | 1 | 7 | 3 | 1 | 10 | 9 | 5 | 9 | 9 | 9 |
| 2× MIC | 5 | 1 | 1 | 7 | 3 | 1 | 10 | 6 | 5 | 9 | 8 | 6 |
| MIC | 5 | 1 | 1 | 6 | 2 | 1 | 7 | 6 | 4 | 6 | 6 | 5 |
| 0.5× MIC | 2 | 0 | 0 | 4 | 1 | 1 | 5 | 3 | 3 | 6 | 4 | 4 |
| Azithromycin | ||||||||||||
| 8× MIC | 5 | 2 | 1 | 7 | 4 | 3 | 9 | 7 | 4 | 11 | 9 | 7 |
| 4× MIC | 5 | 2 | 1 | 7 | 4 | 3 | 9 | 6 | 4 | 11 | 10 | 7 |
| 2× MIC | 4 | 1 | 1 | 5 | 3 | 3 | 9 | 6 | 3 | 9 | 9 | 7 |
| MIC | 3 | 1 | 1 | 3 | 2 | 1 | 6 | 4 | 2 | 6 | 6 | 2 |
| 0.5× MIC | 0 | 0 | 0 | 3 | 2 | 1 | 4 | 3 | 2 | 5 | 5 | 2 |
| Clarithromycin | ||||||||||||
| 8× MIC | 5 | 2 | 1 | 6 | 3 | 1 | 10 | 9 | 5 | 10 | 10 | 9 |
| 4× MIC | 5 | 2 | 1 | 6 | 3 | 1 | 10 | 8 | 4 | 10 | 10 | 9 |
| 2× MIC | 5 | 1 | 0 | 6 | 1 | 1 | 10 | 8 | 3 | 9 | 9 | 5 |
| MIC | 3 | 0 | 0 | 5 | 1 | 0 | 6 | 3 | 2 | 6 | 5 | 3 |
| 0.5× MIC | 0 | 0 | 0 | 2 | 1 | 0 | 4 | 3 | 2 | 5 | 4 | 2 |
| Roxithromycin | ||||||||||||
| 8× MIC | 3 | 1 | 0 | 7 | 3 | 2 | 10 | 8 | 4 | 10 | 10 | 9 |
| 4× MIC | 3 | 1 | 0 | 6 | 2 | 2 | 10 | 7 | 4 | 10 | 10 | 10 |
| 2× MIC | 2 | 1 | 0 | 6 | 2 | 1 | 9 | 6 | 4 | 9 | 8 | 8 |
| MIC | 1 | 0 | 0 | 6 | 0 | 0 | 8 | 5 | 3 | 7 | 6 | 5 |
| 0.5× MIC | 0 | 0 | 0 | 1 | 0 | 0 | 3 | 1 | 0 | 3 | 2 | 0 |
| Clindamycin | ||||||||||||
| 8× MIC | 4 | 2 | 0 | 8 | 3 | 1 | 10 | 7 | 4 | 10 | 10 | 9 |
| 4× MIC | 4 | 2 | 0 | 8 | 2 | 1 | 10 | 7 | 4 | 10 | 10 | 8 |
| 2× MIC | 3 | 1 | 0 | 8 | 2 | 1 | 10 | 7 | 3 | 10 | 10 | 8 |
| MIC | 2 | 0 | 0 | 7 | 2 | 1 | 10 | 6 | 3 | 10 | 9 | 8 |
| 0.5× MIC | 3 | 0 | 0 | 6 | 2 | 0 | 9 | 3 | 2 | 8 | 7 | 6 |
| Pristinamycin | ||||||||||||
| 8× MIC | 7 | 4 | 0 | 8 | 5 | 2 | 11 | 7 | 4 | 11 | 10 | 7 |
| 4× MIC | 6 | 3 | 0 | 7 | 5 | 1 | 11 | 7 | 4 | 11 | 10 | 8 |
| 2× MIC | 7 | 2 | 0 | 6 | 4 | 1 | 10 | 7 | 4 | 10 | 9 | 8 |
| MIC | 5 | 2 | 0 | 7 | 4 | 2 | 10 | 6 | 4 | 10 | 8 | 7 |
| 0.5× MIC | 4 | 0 | 0 | 4 | 3 | 0 | 8 | 4 | 3 | 5 | 3 | 3 |
| Amoxicillin-clavulanate | ||||||||||||
| 8× MIC | 7 | 6 | 3 | 8 | 8 | 6 | 11 | 8 | 7 | 11 | 11 | 9 |
| 4× MIC | 7 | 5 | 2 | 8 | 7 | 4 | 11 | 8 | 7 | 11 | 10 | 8 |
| 2× MIC | 7 | 5 | 2 | 8 | 7 | 4 | 10 | 7 | 6 | 10 | 9 | 6 |
| MIC | 7 | 4 | 2 | 7 | 7 | 3 | 9 | 7 | 5 | 9 | 8 | 7 |
| 0.5× MIC | 1 | 0 | 0 | 5 | 2 | 1 | 2 | 1 | 1 | 3 | 2 | 2 |
| Metronidazole | ||||||||||||
| 8× MIC | 10b | 8 | 3 | 10 | 10 | 9 | 10 | 10 | 10 | 10 | 10 | 10 |
| 4× MIC | 10 | 7 | 4 | 10 | 10 | 9 | 10 | 10 | 10 | 10 | 10 | 8 |
| 2× MIC | 9 | 6 | 2 | 10 | 10 | 5 | 10 | 9 | 7 | 7 | 6 | 6 |
| MIC | 6 | 4 | 1 | 5 | 3 | 3 | 5 | 3 | 2 | 4 | 2 | 2 |
| 0.5× MIC | 2 | 2 | 0 | 3 | 2 | 0 | 2 | 2 | 1 | 0 | 0 | 0 |
a
Compared to the colony count at 0 h.
b
Metronidazole was not tested against P. acnes.