Table 2.

MICs of cationic peptidesa

StrainaMIC (μg/ml)
C18GLL-37, N-minimalCRAMP, N-minimalNP-1, N-minimalPG-1, N-minimal
N-minimalTSB
CS015 (PhoP null)ND0.62NDNDNDND
CS022 (PhoPC)2.502.502.502.500.620.31
TG61 (PhoPC ompT)0.311.251.251.250.620.31
CS435 (PhoPC pagP)0.621.252.501.250.620.31
TG66 (PhoPC pagP ompT)0.150.621.250.620.620.31
  • 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.