TABLE 1.
Antimicrobial activity of VXc-486 against M. tuberculosis laboratory strains and clinical isolatesa
| Strain | Phenotype | MIC or MIC range (μg/ml) of: |
|
|---|---|---|---|
| VXc-486 | Moxifloxacin | ||
| Erdman | DS | 0.06–0.125 | 0.015–0.03 |
| H37Rv | DS | 0.12–0.25 | 0.06 |
| CDC1551 | DS | 0.015 | 0.03 |
| HN878 (Beijing type) | DS | 0.015 | 0.015–0.03 |
| GN9 | DS | 0.03 | 0.015–0.03 |
| hh9 | DS | 0.008–0.015 | 0.015 |
| H13571 | DS | 0.03–0.06 | 0.03 |
| MC19062 | DS | 0.06–0.125 | 0.015–0.03 |
| H10460 | MDR | 0.25 | 0.5 |
| Wg565 | MDR | 0.008–0.015 | 1.00 |
| LL | MDR | 0.015 | 0.008–0.15 |
| W10 | MDR | 0.125 | 0.03 |
| 210 | MDR | 0.03–0.06 | 0.015 |
| W33 | MDR | 0.015–0.06 | 0.5 |
| C913 | MDR | 0.06 | 0.03 |
| AH517 | MDR | 0.06 | 0.03 |
| BW9 | MDR | 0.06–0.125 | 0.008 |
| AH13 | MDR | 0.06 | 0.125–0.25 |
| Lvxr variants | |||
| 2J | FQ resistant | 0.03 | 1.0 |
| 2D | FQ resistant | 0.015 | 2.0 |
| 8D | FQ resistant | 0.125 | 4–8 |
| Lvxr Gatr variants | |||
| 2I1 | FQ resistant | 0.125–0.25 | 16 |
| 8D2 | FQ resistant | 0.03 | 8–16 |
| 2C | FQ resistant | 0.06 | 8.0 |
| 2H2 | FQ resistant | 0.125 | 1.0 |
| BK35 | FQ resistant | 0.03 | 0.25–0.5 |
| BK49 | FQ resistant | 0.03 | 2.0 |
| XDR 5 | XDR | 0.125 | 4–8 |
Drug-sensitive (DS), multidrug-resistant (MDR; resistant to INH and RIF), and extensively drug-resistant (XDR) isolates were evaluated. M. tuberculosis Lvxr 2D, 2J, and 8D isolates were selected by plating M. tuberculosis Erdman on 7H10 agar containing levofloxacin (LVX). LVX and gatifloxacin (GAT) originally had MICs of 0.06 μg/ml. After selection, the MIC for LVX was 4 μg/ml and that of GAT was 1 μg/ml for the Lvxr 2D isolate. M. tuberculosis Lvxr 2D was subsequently cultured on 7H10 agar containing GAT to further enhance its quinolone resistance, and the following fluoroquinolone (FQ)-resistant isolates were recovered: 2I1, 2C, 8D2, and 2H2. The M. tuberculosis 2C isolate's MIC for LVX was 2 μg/ml, and its MIC for GAT was 8 μg/ml.