TABLE 1.
FQ resistance mutations in E. coli AG100 and its Mar mutant AG112a
| Strain or mutant | OFL MIC (μg/ml) | Fold increase in OFL MICb | Substitution in gyrA | Mutation in marOR | marA expression | CIP uptake (% of deenergized accumulation) |
|---|---|---|---|---|---|---|
| AG100 | 0.03 | None | None | Wild type | 51 | |
| 1-AG100 | 0.25 | 8 | D87G | None | Wild type | 43 |
| 2-AG100 | 1 | 32 | D87G | Frameshift at aa 14 (position 1485 + 1 bp) | Overexpression | 30 |
| 3*-AG100 | 2 | 64 | D87G | Asp67Tyr (1643G→T) | Overexpression | 9 |
| 4*-AG100 | 4 | 128 | S83L, D87G | Asp67Tyr (1643G→T) | Overexpression | 9 |
| AG112 | 0.125 | 4 | None | 5-bp deletion (Δ1481–1485) | Overexpression | 25 |
| 1-AG112 | 1 | 32 | D87G | 5-bp deletion (Δ1481–1485) | Overexpression | 24 |
| 2-AG112c | 4 | 128 | D87G | 5-bp deletion (Δ1481–1485) | Overexpression | 12 |
| 3-AG112c | 8 | 256 | D87G | 5-bp deletion (Δ1481–1485) | Overexpression | 9 |
a
Abbreviations and symbols: aa, amino acid; Δ, deletion of the bases at the indicated positions; *, mutants were not derived from 2-AG100.
b
Fold change in MIC compared to the MIC for AG100 (wild type).
c
Strains have putative mutations at additional unknown loci that affect acrAB.