Table 2.
Checkerboard synergy testing results for the combinations of linezolid with several antibiotics against staphylococcal isolates: 5 S. aureus (Sa) and 5 S. epidermidis (Se).
| Isolate Number | FICImin (Interpretation) Minimum MICs (mg/L) at Synergistic Point |
||||||
|---|---|---|---|---|---|---|---|
| LNZ-AMK | LNZ-GM | LNZ-PLZ | LNZ-FOSF | LNZ-IMP | LNZ-MER | LNZ-DOR | |
| HCSC-Sa3 | 1 (I) | 0.53 (PS) | 1 (I) |
0.257 (S)
L(0.25)/F(64) * |
0.625 (PS) | 0.56 (PS) | 0.625 (PS) |
| HCSC-Sa8 | 1 (I) | 0.75 (PS) | 0.75 (PS) | 0.75 (PS) |
0.375 (S)
L(4)/I(32) |
0.75 (PS) | 1 (I) |
| HCSC-Sa11 | 1 (I) | 0.625 (PS) |
0.25 (S)
L(4)/P(0.25) * |
0.75 (PS) |
0.5 (S)
L(8)/I(32) |
0.75 (PS) | 0.625 (PS) |
| HCSC-Sa13 | 1 (I) | 0.75 (PS) |
0.14 (S)
L(0.5)/P(0.25) * |
1 (I) |
0.375 (S)
L(8)/I(32) |
0.75 (PS) | 0.75 (PS) |
| HCSC-Sa14 | 1 (I) | 0.625 (PS) |
0.26 (S)
L(0.5)/P(0.125) * |
0.28 (S)
L(1)/F(128) |
0.5 (S)
L(8)/I(32) |
0.75 (PS) |
0.375 (S)
L(4)/D(32) |
| HCSC-Se12 | 0.5 (S) | 0.625 (PS) | 0.75 (PS) | 0.625 (PS) |
0.5 (S)
L(0.25)/I(2) * |
0.75 (PS) |
0.5 (S)
L(128)/D(1) |
| HCSC-Se31 | 0.75 (PS) | 0.625 (PS) | 0.53 (PS) | 1 (I) |
0.375 (S)
L(4)/I(2) * |
0.375 (S)
L(8)/M(4) * |
0.25 (S)
L(4)/D(2)* |
| HCSC-Se39 |
0.5 (S)
L(0.125)/A(128) |
1 (I) | 0.625 (PS) |
0.5 (S)
L(0.125)/F(2) * |
0.5 (S)
L(2)/I(0.25) * |
0.625(PS) |
0.375 (S)
L(8)/D(1) * |
| HCSC-Se45 |
0.09 (S)
L(32)/A(8) |
0.09 (S)
L(32)/G(16) |
0.078 (S)
L(32)/P(0.0156) |
0.187 (S)
L(32)/F(0.5) |
0,187 (S)
L(4)/I(2) * |
0.078 (S)
L(32)/M(0.25) |
0.0625 (S)
L(16)/D(0.25) |
| HCSC-Se47 | 0.75 (PS) |
0.375 (S)
L(8)/G(64) |
0.75 (PS) |
0.5 (S)
L(8)/F(2) * |
0.315 (S)
L(4)/I(2) * |
0.375 (S)
L(8)/M(4) * |
0.3125 (S)
L(8)/D(0.5) * |
LNZ, L: linezolid; AMK, A: amikacin; GM, G: gentamicin; PLZ, P: plazomicin; FOSF, F: fosfomycin; IMP, I: imipenem; MER, M: meropenem; DOR, D: doripenem. FICmin: minimum fractional inhibitory concentration index; S: synergy; PS: partial synergy; I: indifferent. Value interpretation: ≤0.5, synergy; >0.5–1.0, partial synergy; >1–<4, indifferent; >4.0, antagonism. Synergistics results are marked with bold characters. * Clinical usefulness, as the concentrations are <SSC values in plasma (SSC, steady state soncentration).