TABLE 2.
Resistance of E. coli KAM3 (ΔacrAB) and ZK796 (ΔtolC) cells harboring a plasmid carrying both the macA and -B genes or one of these genes against macrolide derivatives
| Ring size and compound | MIC (μg/ml)a
|
|||||
|---|---|---|---|---|---|---|
| KAM3 (host) | KAM3 harboring multicopy plasmid:
|
ZK796 (host) | ZK796 (pUCmacAB) | |||
| pUCmacAB | pUCmacA | pUCmacB | ||||
| 14 members | ||||||
| Erythromycin | 3.13 | 25 | 3.13 | 3.13 | 3.13 | 3.13 |
| Clarithromycin | 1.56 | 12.5 | 1.56 | 1.56 | 1.56 | 1.56 |
| Oleandomycin | 50 | 400 | 50 | 50 | 25 | 25 |
| 15 members azithromycin | 1.56 | 12.5 | 1.56 | 1.56 | 1.56 | 1.56 |
| 16 members | ||||||
| Rokitamycin | 6.25 | 12.5 | 3.13 | 3.13 | 12.5 | 12.5 |
| Josamycin | 3.13 | 6.25 | 3.13 | 3.13 | 6.25 | 6.25 |
| Leucomycin | 6.25 | 6.25 | 3.13 | 3.13 | NDb | ND |
a
MICs were measured without induction. The mac genes were expressed from the natural promoters. Values in boldface are significantly different from the control values.
b
ND, not done.