TABLE 3.
Parameter estimates for the in vitro PK/PD model
| Parameter | Explanation | Value for strain: |
||
|---|---|---|---|---|
| ATCC 19606 | A. baumannii 1845 | A. baumannii 2092 | ||
| kgrowth (h−1) | Rate constant of bacterial net growth | 0.250 | 1.01 | 0.640 |
| Bmax (log10CFU/ml) | Bacterial count in the stationary phase | 8.56 | 8.02 | 8.03 |
| Emax_CST (h−1) | Maximum achievable kill rate constant by colistin | 7.21 | 0.998 | 4.66 |
| EC50_CST (mg/liter) | Colistin concentration that results in 50% of Emax | 0.0715 | 0.374 | 0.730 |
| Emax_MEM (h−1) | Maximum achievable kill rate constant by meropenem | 1.11 | 0.947 | 0.095 |
| EC50_MEM (mg/liter) | Meropenem concentration that results in 50% of Emax | 15.5 | 14.8 | 13.5 |
| γCST | Hill factor for colistin | 1.27 | 1.05 | 1.55 |
| γMEM | Hill factor for meropenem | 0.306 | 0.773 | 7.30 |
| f | Maximal adaptation factor | 290 | 3.60 | 9.54 |
| k | Rate of adaptation | 1.06 | 0.156 | 0.444 |
| Int | Parameter describing drug interaction | 0.190 | 0.0118 | 0.0117 |
| fval (%) | Residual error fraction | 5.99 | 3.77 | 2.23 |