Table 6.
Comparative table of the three methods used.
| Isolates | Comb. | Check. | Etest | Time kill (MICxMIC) | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Drug A+B | FICI | FICI | 16 × 16 | 8 × 8 | 4 × 4 | 2 × 2 | 1 × 1 | 0.5 × 0.5 | 0.25 × 0.25 | 0.125 × 0.125 | |
| (Δ Log 10) | |||||||||||
| 3 | C+I | 1.20 | 1.16 | 0.60 | −0.34 | −0.84 | −0.60 | −3.61 | −0.68 | 0.00 | |
| C+M | 1.05 | 1.60 | 0.74 | −0.74 | 0.08 | −0.60 | −1.38 | −0.06 | 0.00 | ||
| 4 | C+I | 1.04 | 2.00 | 0.01 | 0.05 | 0.02 | −0.10 | −0.01 | −0.08 | −1.37 | |
| C+M | 1.04 | 2.00 | −0.09 | −0.23 | −0.26 | −0.33 | −0.24 | −0.26 | −1.51 | ||
| 8 | C+I | 1.41 | 2.00 | −0.01 | −0.01 | −0.05 | 0.00 | 0.01 | −0.02 | −1.50 | |
| C+M | 1.49 | 2.00 | −0.01 | −0.02 | −0.03 | −0.04 | 0.02 | −0.02 | −1.58 | ||
| 13 | C+I | 1.41 | 1.60 | 0.14 | 0.05 | −0.12 | −0.42 | −2.65 | −2.72 | −2.71 | |
| C+M | 1.09 | 1.60 | 0.00 | 0.11 | −0.11 | −0.13 | −0.37 | −2.08 | −2.16 | ||
| 21 | C+I | 1.23 | 1.50 | −0.01 | 0.00 | −0.04 | −0.03 | −0.03 | −0.02 | −0.04 | |
| C+M | 1.23 | 2.00 | 0.02 | −0.01 | 0.00 | −0.03 | −0.03 | −0.02 | −0.02 | ||
| 24 | C+I | 1.05 | 1.25 | 0.00 | −0.34 | −0.20 | −2.86 | −0.22 | −0.05 | −0.01 | |
| C+M | 0.98 | 1.75 | 0.40 | −0.34 | 0.00 | −3.20 | −0.14 | 0.00 | 0.00 | ||
| 30 | C+I | 1.83 | 1.00 | 0.03 | −0.02 | −0.04 | −0.02 | −0.03 | 0.01 | −0.34 | |
| C+M | 1.72 | 1.75 | 0.00 | −0.03 | −0.01 | −0.02 | −0.08 | −0.14 | 0.02 | ||
| 32 | C+I | 1.05 | 2.00 | 0.14 | −1.00 | −3.67 | −3.68 | −3.06 | −0.24 | 0.00 | |
| C+M | 0.94 | 1.75 | 0.00 | −1.00 | −3.27 | −3.68 | −0.13 | 0.03 | 0.01 | ||
| 34 | C+I | 0.99 | 1.25 | −0.01 | 0.00 | 0.00 | −1.25 | −1.49 | −1.54 | −0.05 | |
| C+M | 0.78 | 2.00 | 0.02 | 0.02 | 0.04 | −1.21 | −1.43 | −0.16 | 0.04 | ||
| 44 | C+I | 1.05 | 1.75 | 0.05 | −0.05 | −0.03 | 0.09 | −1.33 | −1.54 | −0.30 | |
| C+M | 0.61 | 1.16 | −0.01 | −0.10 | −0.03 | 0.05 | −1.33 | −0.21 | 0.07 | ||
| 48 | C+I | 1.42 | 1.40 | 0.03 | 0.05 | 0.02 | 0.06 | 0.44 | 0.00 | −1.38 | |
| C+M | 1.13 | 0.88 | 0.08 | 0.07 | 0.07 | 0.05 | 0.53 | 0.11 | −1.43 | ||
| 51 | C+I | 1.09 | 1.50 | −0.01 | −0.02 | 0.00 | −1.07 | −1.45 | −1.59 | −0.03 | |
| C+M | 0.81 | 2.00 | 0.01 | 0.03 | 0.03 | −1.06 | −1.42 | −0.18 | −0.02 | ||
| 63 | C+I | 1.33 | 1.40 | −0.03 | −0.03 | −0.04 | −0.03 | −1.91 | −1.46 | −0.31 | |
| C+M | 1.53 | 0.75 | 0.00 | −0.01 | 0.03 | −0.02 | −1.33 | −0.42 | −0.14 | ||
| 65 | C+I | 1.46 | 1.25 | −0.04 | −0.07 | −0.07 | −1.67 | −1.74 | −0.15 | 0.00 | |
| C+M | 1.05 | 1.25 | −0.08 | −0.12 | −0.11 | −1.71 | −0.98 | 0.00 | 0.02 | ||
| 69 | C+I | 0.81 | 1.25 | 0.07 | 0.03 | 0.01 | −0.09 | −1.51 | −1.63 | −1.72 | |
| C+M | 0.92 | 2.00 | 0.05 | 0.04 | 0.00 | 0.04 | −1.38 | −1.48 | −1.38 | ||
| 70 | C+I | 0.68 | 2.00 | −0.05 | −0.05 | −0.06 | −1.37 | −1.30 | −1.51 | −0.03 | |
| C+M | 0.72 | 2.00 | 0.05 | 0.02 | −0.04 | −1.41 | −1.48 | −1.55 | −0.06 | ||
| 71 | C+I | 2.54 | 2.00 | −0.07 | 0.08 | −0.05 | 0.09 | −0.06 | 0.05 | −0.04 | |
| C+M | 2.09 | 2.00 | 0.00 | −0.14 | −0.11 | 0.00 | −0.05 | −0.03 | −0.10 | ||
| 73 | C+I | 0.67 | 1.25 | −0.14 | −0.07 | −0.01 | −0.66 | −1.39 | −1.50 | −1.58 | |
| C+M | 0.66 | 1.08 | −0.12 | −0.11 | 0.05 | −0.64 | −1.35 | −1.51 | −1.57 | ||
| 75 | C+I | 0.92 | 1.00 | −0.10 | −0.11 | −0.12 | −0.29 | −0.94 | −0.02 | 0.00 | |
| C+M | 0.68 | 0.85 | −0.09 | −0.09 | −0.11 | −0.29 | −0.91 | 0.01 | 0.05 | ||
| 78 | C+I | 0.83 | 1.60 | 0.09 | 0.02 | 0.00 | −0.07 | −0.08 | −0.04 | −0.10 | 0.00 |
| C+M | 0.93 | 1.00 | 0.05 | 0.06 | −0.02 | −0.07 | −0.07 | −0.04 | −0.10 | ||
| 93 | C+I | 0.70 | 1.25 | 0.00 | −0.07 | −0.93 | −0.40 | −0.32 | −0.07 | 0.21 | |
| 0.76 | 1.50 | 0.33 | 0.16 | 0.18 | −0.07 | 0.10 | 0.11 | −0.09 | |||
C+I, Col-Imipenem; C+M, Col-meropenem. Comb, Combination; Check, Checkerboard. Synergistic effect is determined by ETEST and checkerboard whenever ∑FICI ≤ 0.5 was detected, and additivity was determined for the range 0.5< ∑FICI< 2. All the tested isolates showed additivity in both techniques. The values in bold represent a synergistic effect by time kill curve (< −2). At 2 × 2MIC: Synergistic rate: 4.7% for C+I and C+M respectively, at 1 × 1MIC: synergistic rate: 14.3% for C+I, and 9.5% for C+M, at 0.5 × 0.5MIC synergistic rate 14.3% for C+l, and 4.7% for C+M, at 0.25 × 0.25MIC synergistic rate of 4.7% for C+I and C+M, respectively.