Table 1.
Synergistic effects of the violacein in combination with azole drugs against T. rubrum.
| Test organism | Agent | MIC/MFC (μg/ml) | FIC/FFC | FICIb/FFCIc | Outcome | |
|---|---|---|---|---|---|---|
| Alone | Combinationa | |||||
| T. rubrum | Violacein Ketaconazole |
32/64 1/2 |
2/4 0.25/0.25 |
0.06/0.06 0.13/0.13 |
0.19/0.19 | Synergistic/synergistic |
| Violacein Fluconazole |
32/64 2/4 |
4/4 0.5/0.5 |
0.13/0.06 0.25/0.13 |
0.38/0.19 | Synergistic/synergistic | |
|
Violacein Clotrimazole |
32/64 4/8 |
1/2 0.25/0.25 |
0.03/0.03 0.06/0.03 |
0.09/0.09 | Synergistic/synergistic | |
| Violacein Itraconazole |
32/64 2/2 |
8/8 0.25/0.5 |
0.25/0.13 0.13/0.25 |
0.38/0.38 | Synergistic/synergistic | |
MIC/MFC value of violacein and azoles alone was conducted by micro broth dilution method and MIC/MFC value of the combination was conducted by checkerboard assay. FICI index were obtained from the checkerboard assay: To evaluate the interaction of violacein with azoles against T. rubrum, checkerboard experiments were performed. FIC/FFC index = (MIC/MFC of azoles in combination with violacein/MIC/MFC of azoles alone) + (MIC/MFC of violacein in combination with azoles/MIC/MFC of violacein alone). A FICI/FFCI ≤ 0.5 is indicative of synergism.
The MIC and MFC of violacein in combination with azole.
The fractional inhibitory concentration index (FIC index).
The fractional fungicidal concentration index (FBC index).
Values in bold indicated best synergistic combination.