An antibiotic and LpxC inhibitor (Kis = 1-1.7 nM in A. aeolicus); active against Gram-negative bacteria (MICs = 0.05, 0.78, and 0.10-6.25 mg/ml for E. coli, P. aeruginosa, and various B. multivorans (II) strains, respectively); comparable in strength to ciprofloxacin in disc assays,