TABLE 2.
MICs of cationic peptidesa
| Straina | MIC (μg/ml)
|
|||||
|---|---|---|---|---|---|---|
| C18G
|
LL-37, N-minimal | CRAMP, N-minimal | NP-1, N-minimal | PG-1, N-minimal | ||
| N-minimal | TSB | |||||
| CS015 (PhoP null) | ND | 0.62 | ND | ND | ND | ND |
| CS022 (PhoPC) | 2.50 | 2.50 | 2.50 | 2.50 | 0.62 | 0.31 |
| TG61 (PhoPCompT) | 0.31 | 1.25 | 1.25 | 1.25 | 0.62 | 0.31 |
| CS435 (PhoPCpagP) | 0.62 | 1.25 | 2.50 | 1.25 | 0.62 | 0.31 |
| TG66 (PhoPCpagP ompT) | 0.15 | 0.62 | 1.25 | 0.62 | 0.62 | 0.31 |
a
PhoPC, PhoP constitutive. Bacterial strains were grown either in N minimal medium containing 8 μM Mg2+ or in tryptic soy broth (TSB) prior to incubation with the peptides. Bacterial cells were diluted in N minimal medium when incubated with alpha-helical peptides C18G, LL-37, and CRAMP and in 1% TSB in 10 mM sodium phosphate buffer (pH 7.4) when incubated with defensin NP-1 and protegrin PG-1. ND, not determined. N minimal medium (13) does not support growth of CS015.