Table 1.
MICs of colistin and PAP analysis for each E. cloacae mutant
| Frequency of appearance of subpopulations (PAPsa) | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Concentration of colistin | |||||||||
| Isolate | MIC of colistin (µg/ml) by BMDb | MIC of colistin (µg/ml) by Etest | 1 µg/ml | 2 µg/ml | 4 µg/ml | 8 µg/ml | 16 µg/ml | 32 µg/ml | 64 µg/ml |
| Wild type | ≥256* | 0.125** | 9.5 X 10−3 | 6.3 X 10−2 | 5.2 X 10−3 | 7.5 X 10−3 | 7.6 X 10−2 | 6.3 X 10−3 | 9.3 10−3 |
| ∆phoPQEcl | 0.5 | 0.125 | 2.6 X 10−3 | 0 | 0 | 0 | 0 | 0 | 0 |
| ∆phoPQEcl +pPhoPQEcl | ≥256* | 0.125** | 3.6 X 10−2 | 1.3 X 10−2 | 4.3 X 10−3 | 1.6 X 10−2 | 4.1 X 10−3 | 1.7 X 10−3 | 4.5 10−4 |
| ∆phoPQEcl +pPhoPQH277AEcl | 0.5 | 0.125 | 3.1 X 10−2 | 0 | 0 | 0 | 0 | 0 | 0 |
| ∆phoPQ +pPhoPD56AQEcl | 0.5 | 0.125 | 7.4 X 10−2 | 0 | 0 | 0 | 0 | 0 | 0 |
| ∆pmrABEcl | ≥256* | 0.125** | 2.9 X 10−2 | 1.8 X 10−3 | 7.7 X 10−2 | 9.2 X 10−3 | 5.5 X 10−2 | 1.3 X 10−3 | 2.3 X 10−4 |
| ∆arnTEcl | 0.5 | 0.125 | 4.0 X 10−2 | 0 | 0 | 0 | 0 | 0 | 0 |
a
PAP : Population Analysis Profile using an initial culture of 1010 CFU/mL
b
BMD : Broth microdilution method
*
Presence of skip wells
**
Presence of squatter colonies inside the zone of inhibition