TABLE 6.
Changes in MIC after sequential in vitro passages with a subinhibitory concentration
| Organism | No. of isolates | Mean MIC (μg/ml)a
|
||||
|---|---|---|---|---|---|---|
| Pexiganan, initial | After four passesb
|
After seven passesb
|
||||
| Pexiganan | Control | Pexiganan | Control | |||
| Staphylococcus aureus | 3 | 5.8 | 5.8 | 4.6 | 8.3 | 6.6 |
| Coagulase-negative staphylococci | 3 | 1.4 | 2.3 | 2 | 2 | 2 |
| Enterobacter cloacae | 4 | 6.8 | 8.3 | 9.6 | 10.2 | 8.1 |
| Klebsiella pneumoniae | 4 | 13.6 | 9.6 | 9.2 | 14.3 | 12.6 |
| Pseudomonas aeruginosa | 5 | 8.2 | 11.3 | 9.8 | 19.7 | 10.4 |
| Acinetobacter baumannii | 4 | 7.7 | 12.1 | 12.4 | 10.7 | 8.8 |
| Stenotrophomonas maltophilia | 4 | 5.3 | 9.1 | 9.6 | 15.5 | 13.6 |
a
The geometric mean of MICs for all isolates tested.
b
The pexiganan-treated groups were passed on plates containing pexiganan at 50% of its MIC, while the controls were passed under the same conditions on plates without pexiganan.