Table 1.

Polymyxin B-resistant isolate of Acinetobacter baumannii is sensitive to rBPI21 and to cecropin P1a

Antibacterial agentMIC and MBC (μM)LD90 (μM)
L1D41L1D41A1
Polymyxin B>100.5>100.10.1
rBPI21 3.01.00.30.30.2
Cecropin P12.01.00.50.3NTb
  • a The MIC and MBC of polymyxin B, rBPI21, and cecropin P1 for Acinetobacter baumannii were determined by incubation of bacteria (5 × 105 bacteria/ml) overnight at 37°C in Mueller-Hinton broth containing increasing concentrations of the antibacterial (poly)peptides. Under all conditions, the MIC and MBC were the same. The bactericidal activities of these agents for Acinetobacter baumannii were also measured by incubation with bacteria (106 bacteria/ml) in phosphate-buffered (pH 7.4) nutrient broth–0.9% sodium chloride for 2 h at 37°C. All results shown are the means of at least three independent determinations. LD90, 90% lethal dose.

  • b NT, not tested.