Table 3.
Comparative effects of polymyxin B and colistin at various equimolar dose levels against two strains of K. pneumoniae. Data are presented as mean ± SD (n = 4)
| Log10 cfu/thigh at 24 ha |
||||
|---|---|---|---|---|
| FADDI-KP032b |
ATCC BAA-2146c |
|||
| Dose leveld | polymyxin B | colistin | polymyxin B | colistin |
| 1 | 5.30 ± 0.27 | 5.42 ± 0.22 | 7.62 ± 0.81 | 7.03 ± 1.34 |
| 2 | 5.41 ± 0.17 | 5.57 ± 0.07 | 5.29 ± 0.25e | 5.68 ± 0.14 |
| 3 | 5.31 ± 0.20 | 5.55 ± 0.07 | 5.67 ± 0.98 | 5.28 ± 0.16 |
| 4 | 5.52 ± 0.13 | 5.43 ± 0.11 | ND | ND |
ND, not determined.
24 h represents end time of treatment with polymyxin B or colistin.
bStasis value 6.80 ± 0.08 log10 cfu/thigh at 0 h. 0 h represents time of commencing treatment with polymyxin B or colistin; the value of log10 cfu/thigh at this time is the baseline (stasis) value.
Stasis value 6.78 ± 0.13 log10 cfu/thigh at 0 h. 0 h represents time of commencing treatment with polymyxin B or colistin; the value of log10 cfu/thigh at this time is the baseline (stasis) value.
Dose levels 1, 2, 3 and 4 for polymyxin B were 22.5, 45, 90 and 120 mg/kg/24 h, respectively; the corresponding dose levels for colistin were 21.9, 43.9, 87.7 and 117.1 mg/kg/24 h. The daily dose was administered in three equal doses at intervals of 8 h.
Different from the corresponding value for colistin for this strain (P = 0.044).