TABLE 3.
Effect of PBP4 overproduction on vancomycin susceptibility
| Strain or isolate | Vancomycin MIC (μg/ml)a
|
|||||
|---|---|---|---|---|---|---|
| Broth
microdilutionb
|
E-test
|
|||||
| Parent | Parent + pJF3(pbp4) | Parent + pRN5543 | Parent | Parent + pJF3(pbp4) | Parent + pRN5543 | |
| RN450M | 2 | 2 | 2 | 2 | 2 | 2 |
| Mu3 | 2 | 2 | 2 | 3 | 2 | 3 |
| Mu50 | 6 | 3 | 6 | 8 | 3 | 8 |
| HIP5827 | 12 | 3 | 12 | 12 | 4 | 12 |
| HIP5836 | 8 | 2 | 8 | 8 | 6 | 8 |
| HIP6297 | 6 | 3 | 6 | 6 | 3 | 6 |
a
Microdilution MICs were determined at 1-μg/ml increments of vancomycin.
b
In order to keep pressure on plasmid pJF3, 5 μg of chloramphenicol per ml was also added. Failure to do so resulted in loss of the plasmid.