Table 2. Minimum inhibitory concentrations (MICs) of aminoglycoside antibiotics for strains with wild-type or mutant AadA.
nd, not determined.
| MIC† (gml1) | |||||||
|---|---|---|---|---|---|---|---|
| Strain | aadA genotype/amino-acid substitution | Streptomycin | Spectinomycin | Kanamycin | Tobramycin | Amikacin | Gentamicin |
| DA6192 | Wild type | 128 | 192 | 6 | 3 | 4 | 0.75 |
| DA18900 | aadA::cat ‡ | 4 | 24 | 6 | 3 | 4 | 0.75 |
| DA29580 | E87A | 4 | 24 | 6 | nd | nd | nd |
| DA29582 | E87Q | 4 | 24 | 6 | nd | nd | nd |
| DA29584 | W112A | 16 | 24 | 6 | nd | nd | nd |
| DA29586 | W112F | 48 | 24 | 6 | nd | nd | nd |
| DA29588 | D182A | 32 | 48 | 6 | nd | nd | nd |
| DA29590 | D182N | 24 | 48 | 6 | nd | nd | nd |
| DA29592 | R192A | 6 | 24 | 6 | nd | nd | nd |
| DA29594 | K205A | 4 | 24 | 6 | nd | nd | nd |
†
MICs were determined with E-tests (bioMrieux). All culture media were M9 plus 0.2% glycerol.
‡
The cat cassette replaced the entire aadA gene.