TABLE 4.
Interaction of sitafloxacin with antibiotics frequently used to treat clinical M. abscessus infections.
| Isolate | Subspecies | FICIa |
|||||||||
| STFX + CLAb |
STFX + AZM |
STFX + AMK |
STFX + LZD |
STFX + CFZ |
STFX + IPM |
STFX + TGC |
STFX + BDQ |
STFX + FOX |
STFX + RFB |
||
| 156 | abscessus | 1 | 0.75 | 1 | 1 | 1.5 | 2 | 2 | 2 | 1.5 | 2 |
| 204 | abscessus | 0.75 | 1 | 1.5 | 1 | 2 | 1.5 | 2 | 2 | 2 | 1.5 |
| 206 | abscessus | 1 | 1 | 1.5 | 1.5 | 2 | 1.5 | 1.5 | 1 | 1.5 | 1.25 |
| 98 | massiliense | 0.75 | 1 | 1 | 1.5 | 1.5 | 1 | 1.5 | 2 | 2 | 1.5 |
| 163 | massiliense | 1 | 0.75 | 2 | 1.5 | 2 | 2 | 1.5 | 2 | 2 | 1 |
| 220 | massiliense | 1 | 1 | 1 | 1.5 | 2 | 1.5 | 1.5 | 1.5 | 2 | 1.5 |
| ATCC 19977 | abscessus | 0.75 | 1 | 1 | 1 | 1.5 | 1 | 1.5 | 2 | 1.25 | 1 |
| CIP 108297 | massiliense | 0.75 | 0.75 | 1.25 | 1.5 | 1 | 1 | 1.5 | 2 | 1.5 | 1 |
aFICI (fractional inhibitory concentration index), [(MIC of STFX in combination/MIC of STFX alone) + (MIC of second antibiotic in combination/MIC of second antibiotic alone)]. Synergy, FICI ≤ 0.5; indifference, FICI between 0.5 and ≤ 4; antagonism, FICI > 4. bSTFX, sitafloxacin; CLA, clarithromycin; AZM, azithromycin; AMK, amikacin; LZD, linezolid; CFZ, clofazimine; IPM, imipenem; TGC, tigecycline; BDQ, bedaquiline; FOX, cefoxitin; RFB, rifabutin.