TABLE 1.
Drug susceptibility of 14-day-old starved versus exponentially growing M. smegmatis cultures
| Drug | Fold kill ina: |
|
|---|---|---|
| Growing culture | Nongrowing culture | |
| Isoniazid | 60 | 1 |
| Rifampin | 40 | 1 |
| Ethambutol | 20 | 1 |
| Linezolid | 30 | 1 |
| Tetracycline | 22 | 1 |
| Clarithromycin | 14 | 1 |
| Chloramphenicol | 8 | 1 |
| Erythromycin | 6 | 1 |
| Ciprofloxacinb | >10,000 | 100 |
| Ofloxacin | >10,000 | 30 |
| Moxifloxacinb | >10,000 | 16 |
| Streptomycin | >10,000 | >10,000 |
| Kanamycin | >10,000 | >10,000 |
| Amikacin | >10,000 | >10,000 |
a
Cultures were exposed to the drugs at 100 μM for 1 day, and survival was determined via CFU enumeration. Fold kill was calculated as the ratio of initial CFU/ml (106)/surviving CFU/ml after 1 day of drug treatment. 1, no kill; >10,000, surviving CFU/ml for the particular drug was below the limit of detection (102 CFU/ml).
b
See Fig. 1 for a higher resolution of lethal activities of ciprofloxacin and moxifloxacin.