Table 7. Chequerboard results of colistin in combination with fluoroquinolones (ciprofloxacin, levofloxacin and moxifloxacin) against colistin resistant K. pneumoniae isolates.
| Isolates | Antibiotics | Combined MIC (μg/mL) | FICI | Fold reduction | Outcome |
|---|---|---|---|---|---|
| 1NT4Ng/1 | COL | 64 | 0.257 | 4 | Synergy |
| 128 | |||||
| CIP | 2 | ||||
| COL | 16 | 0.125 | 16 | Synergy | |
| LEV | 32 | 16 | |||
| COL | 8 | 0.093 | 32 | Synergy | |
| MOX | 32 | 16 | |||
| 1NT6Ng/1 | COL | 64 | 0.257 | 4 | Synergy |
| CIP | 2 | 128 | |||
| COL | 16 | 0.187 | 16 | Synergy | |
| LEV | 64 | 8 | |||
| COL | 8 | 0.093 | 32 | Synergy | |
| MOX | 32 | 16 | |||
| 1NT6Tu/1 | COL | ND | ND | ND | ND |
| CIP | ND | ||||
| COL | 16 | 0.093 | 16 | Synergy | |
| LEV | 16 | 32 | |||
| COL | 8 | 0.093 | 32 | Synergy | |
| 16 | |||||
| MOX | 32 | ||||
| 1NT6R | COL | 32 | 0.375 | 8 | Synergy |
| CIP | 64 | 4 | |||
| COL | 16 | 0.125 | 16 | Synergy | |
| LEV | 32 | 16 | |||
| COL | 8 | 0.093 | 32 | Synergy | |
| MOX | 32 | 16 | |||
| 1NT7R | COL | 64 | 0.500 | 4 | Synergy |
| CIP | 64 | 4 | |||
| COL | 16 | 0.125 | 16 | Synergy | |
| LEV | 32 | 16 | |||
| COL | 16 | 0.125 | 16 | Synergy | |
| MOX | 32 | 16 | |||
| 1NT8Th | COL | 64 | 0.500 | 4 | Synergy |
| CIP | 64 | 4 | |||
| COL | 16 | 0.125 | 16 | Synergy | |
| 16 | |||||
| LEV | 32 | ||||
| COL | 16 | 0.093 | 16 | Synergy | |
| MOX | 16 | 32 | |||
| 1NT6Ng(CCU)/1 | COL | ND | ND | ND | ND |
| CIP | ND | ||||
| COL | 64 | 0.250 | 8 | Synergy | |
| 8 | |||||
| LEV | 8 | ||||
| COL | 128 | 0.312 | 4 | Synergy | |
| MOX | 2 | 16 | |||
| 1NT6Th(CCU)/1 | COL | ND | ND | ND | ND |
| CIP | ND | ||||
| COL | 32 | 0.250 | 8 | Synergy | |
| LEV | 8 | 8 | |||
| COL | 32 | 0.156 | 8 | Synergy | |
| MOX | 1 | 32 | |||
| 1NT6R(CCU) | COL | ND | ND | ND | ND |
| CIP | ND | ||||
| COL | 16 | 0.187 | 16 | Synergy | |
| LEV | 64 | 8 | |||
| COL | 8 | 0.093 | 32 | Synergy | |
| MOX | 32 | 16 | |||
| 1SK5R | COL | ND | ND | ND | ND |
| CIP | ND | ||||
| COL | 16 | 0.255 | 64 | Synergy | |
| LEV | 0.12 | 4 | |||
| COL | ND | ND | ND | ND | |
| MOX | ND |
CCU, Cardiac Care Unit; MIC, Minimum inhibitory concentrations; CIP, Ciprofloxacin; COL, Colistin; FICI, Fractional inhibitory concentration index; LEV, Levofloxacin; MOX, Moxifloxacin; ND, not determined.