Potency and spectrum of activity of AN3365, a novel boron-containing protein synthesis inhibitor, tested against clinical isolates of Enterobacteriaceae and nonfermentative Gram-negative bacilli.

AN3365 (MIC(50/90), 0.5/1 μg/ml) was active against Enterobacteriaceae, including a subset of Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae strains (MIC(50/90), 1/2 μg/ml). AN3365 inhibited 98.0 and 92.2% of wild-type (MIC(50/90), 2/8 μg/ml) and carbapenem-resistant (MIC(50/90), 4/8 μg/ml) Pseudomonas aeruginosa strains, respectively, at ≤ 8 μg/ml. AN3365 also demonstrated activity against wild-type Acinetobacter baumannii (MIC(50/90), 2/8 μg/ml) and Stenotrophomonas maltophilia (MIC(50/90), 2/4 μg/ml), while it was less active against multidrug-resistant A. baumannii (MIC50/90, 8/16 μg/ml) and Burkholderia cepacia (MIC(50/90), 8/32 μg/ml).