TABLE 2.
Estimated PD parameters from the 2-subpopulation model based on in vivo time-kill data
| Parameter | Abbreviation | ATCC 27853 |
PAO1 |
FADDI-PA022 |
|||
|---|---|---|---|---|---|---|---|
| Estimated value | SE (%) | Estimated value | SE (%) | Estimated value | SE (%) | ||
| Colistin concn causing 50% Emax for susceptible subpopulation (mg/liter) | EC50S | 1 | Fixed | 1 | Fixed | 1 | Fixed |
| Colistin concn causing 50% Emax for resistant-subpopulation (mg/liter) | EC50R | 51.6 | 8.99 | 187 | 4.57 | 229 | 11.2 |
| Maximum colistin-induced killing rate constant (1/h) | Emax,colistin | 5.56 | 43.2 | 23.2 | 3.72 | 38.9 | 18.5 |
| Natural bacterial death rate (1/h) | Kd | 0.3 | Fixed | 0.3 | Fixed | 0.3 | Fixed |
| Bacterial density at which growth rate is half maximal (CFU/lung) | Log10 CFUm | 8.98 | 0.386 | 9.38 | 0.278 | 9.30 | 0.539 |
| Maximum bacterial population (CFU/lung) | Log10 CFUmax | 9.33 | Fixed | 9.65 | Fixed | 9.56 | Fixed |
| Hill coefficient for bacterial killing | Log10 Hill | 1.3 | Fixed | 1.3 | Fixed | 1.3 | Fixed |
| Log10 initial inoculum for total bacterial population (CFU/lung) | Log10 CFU0 | 4.18 | Fixed | 6.29 | Fixed | 7.09 | Fixed |
| Log10 initial inoculum for CFURa | Log10 (initial inoculum for CFUR) | −1.16 | 45.1 | −1.75 | 16.9 | −1.07 | 28.3 |
a
CFUR, bacterial density for resistant subpopulation.