TABLE 3.
Molecular sizes and lipophilicities of antimicrobial agents and their relation with the effect of acrAB deletion on MICs in E. coli K-12a
| Agent | Molecular weight | Lipophilicity (XlogP3)c | MIC (μg/ml) for strain |
|
|---|---|---|---|---|
| acrAB+ | ΔacrAB | |||
| Lipophilic and/or large agents | ||||
| Clotrimazole | 345 | 5.0 | >32 | 16 |
| Cloxacillinb | 436 | 2.4 | 256 | 2 |
| Erythromycin | 734 | 2.7 | 50 | 1.56 |
| Fusidic acid | 517 | 5.5 | 400 | 3.125 |
| Methotrexate | 454 | −1.8 | >640 | 80 |
| Novobiocin | 613 | 3.3 | 100 | 1.56 |
| Puromycin | 472 | 0.0 | 100 | 1.56 |
| Rifampin | 823 | 4.0 | 5 | 2.5 |
| SDS | 288 | 4.7 | >12,800 | 100 |
| Small and hydrophilic agents | ||||
| Ampicillin | 349 | −1.1 | 12.5 | 3.12 |
| Cephalothinb | 396 | −0.4 | 4 | 4 |
| Cefoxitinb | 427 | 0.0 | 4 | 1 |
| Ceftazidimeb | 547 | 0.4 | 0.12 | 0.12 |
| Imipenemb | 317 | −0.7 | 0.12 | 0.12 |
| Nalidixic acid | 232 | 1.4 | 3.13 | 1.56 |
| Norfloxacin | 319 | −1.0 | 0.004 | 0.004 |
| Ciprofloxacin | 331 | −1.1 | 0.01 | 0.0025 |
| Chloramphenicol | 323 | 1.1 | 6.25 | 0.78 |
| Tetracycline | 444 | −2.0 | 1.25 | 0.156 |
a
The MIC data are mostly from reference 27.
b
MIC data are from reference 188.
c
The values of logP (the logarithm of the partition coefficient between n-octanol and water) are from PubChem (http://pubchem.ncbi.nlm.nih.gov/) based on the calculation by the XlogP3 method.