TABLE 2.
Median MIC values [mg/L] of colistin in artificial urine and human serum.
| Artificial urine | Native serum | Heat inactivated serum | ||||
| 105CFU/mL | 106CFU/mL | 105CFU/mL | 106CFU/mL | 105CFU/mL | 106CFU/mL | |
| Colistin-susceptible E. coli | ||||||
| ATCC 25922 | 2 | 4 | 0.25 | 0.25 | 2 | 2 |
| UTI89 | 0.5 | 2 | nd | 0.25 | 1 | 1 |
| CHD3 | 0.5 | 2 | nd | nd | 1 | 1 |
| CHD4 | 0.5 | 2 | nd | nd | 0.5 | 1 |
| CHD5 | 0.25 | 2 | 0.125 | 1 | 1 | 1 |
| CHD6 | 0.5 | 2 | 0.0625 | 0.5 | 0.5 | 2 |
| CHD7 | 0.5 | 1 | nd | nd | 0.25 | 1 |
| CHD8 | 0.5 | 2 | 0.0625 | 1 | 0.25 | 2 |
| CHD10 | 1 | 4 | 0.5 | 2 | 2 | 4 |
| CHD11 | 0.5 | 1 | nd | nd | 1 | 1 |
| CHD12 | 0.5 | 4 | 0.125 | 2 | 1 | 4 |
| CHD16 | 0.25 | 1 | 0.5 | 2 | 1 | 1 |
| Median (range) | 0.5 (0.25–2) | 2 (1–4)b | 0.13 (0.063–0.5) | 1 (0.25–2) | 1 (0.25–2) | 1 (1–4) |
| mcr-1-positive E. coli | ||||||
| Af23 | 64 | 64 | 0.0625 | 0.5 | 8 | 16 |
| Af24 | >64 | 64 | nd | nd | 16 | 16 |
| Af31 | 64 | 64 | nd | nd | 8 | 8 |
| Af40 | >64 | >64 | 0.125 | nd | 8 | 8 |
| Af45 | >64 | 64 | nd | 0.25 | 16 | 8 |
| Af48 | 64 | 64 | nd | nd | 8 | 8 |
| Af49 | 64 | 64 | 4 | 4 | 8 | 16 |
| CDF1 | 64 | 64 | 0.5 | 1 | 8 | 8 |
| CDF2 | >64 | >64 | nd | nd | 32 | 32 |
| CDF6 | >64 | 64 | nd | 0.5 | 16 | 16 |
| CDF8 | 64 | >64 | 0.5 | 0.25 | 8 | 8 |
| S115 | >64 | >64 | nd | 0.5 | 16 | 16 |
| PS1 | >64 | 64 | nd | 0.5 | 8 | 8 |
| Median (range) | >64 (64−>64)a | 64 (64−>64)a | 0.5 (0.063–4) | 0.5 (0.25–4) | 8 (8–32) | 8 (8–32) |
≥4 fold (± 2 log2) difference with p < 0.0001: acompared to corresponding inoculum in CAMHB; bcompared to 105 CFU/ml in same media; nd – not definable.