Table 3.
In vitro activity of besifloxacin and comparator fluoroquinolones against ciprofloxacin resistant Staphylococcus aureus and Staphylococcus epidermidis: Results of the expanded range retest
| Organism | Fluoroquinolone | MIC (μg/mL) | MIC90 versus besifloxacin | ||
|---|---|---|---|---|---|
| Range | MIC50 | MIC90 | |||
| MSSA–CR (n = 14) | Besifloxacin | 0.5–2 | 0.5 | 1 | – |
| Moxifloxacin | 2–16 | 2 | 4 | 4× | |
| Gatifloxacin | 2–16 | 4 | 8 | 8× | |
| Levofloxacin | 4–128 | 8 | 16 | 16× | |
| Ciprofloxacin | 16–256 | 32 | 128 | 128× | |
| MRSA–CR (n = 15) | Besifloxacin | 0.5–16 | 1 | 4 | – |
| Moxifloxacin | 2–128 | 4 | 64 | 16× | |
| Gatifloxacin | 2–256 | 8 | 64 | 16× | |
| Levofloxacin | 4–512 | 16 | 512 | 128× | |
| Ciprofloxacin | 16–256 | 128 | 256 | 64× | |
| MSSE–CR (n = 9)a | Besifloxacin | 0.5 | 0.5 | ||
| Moxifloxacin | 2–4 | 4 | |||
| Gatifloxacin | 2–4 | 4 | |||
| Levofloxacin | 8–16 | 16 | |||
| Ciprofloxacin | 8–128 | 64 | |||
| MRSE–CR (n = 13) | Besifloxacin | 0.5–8 | 0.5 | 4 | – |
| Moxifloxacin | 2–32 | 4 | 32 | 8× | |
| Gatifloxacin | 2–64 | 4 | 64 | 16× | |
| Levofloxacin | 4–256 | 16 | 256 | 64× | |
| Ciprofloxacin | 8–64 | 64 | 64 | 16× | |
a
Note: Due to the limited isolates, only the MIC50 value is given.
Abbreviations: MSSA-CR, methicillin-susceptible ciprofloxacin-resistant Staphylococcus aureus; MRSA-CR, methicillin-resistant ciprofloxacin-resistant S. aureus; MSSECR, methicillin-susceptible ciprofloxacin-resistant Staphylococcus epidermidis; MRSE-CR, methicillin-resistant ciprofloxacin-resistant S. epidermidis; MIC, minimum inhibitory concentration.