In vitro activities of peptide deformylase inhibitors against gram-positive pathogens

The activities of six peptide deformylase (PDF) inhibitors against 107 respiratory tract pathogens were studied and compared to those of ciprofloxacin and amoxicillin-clavulanate. Against Streptococcus pneumoniae, BB-83698 and BB-83815 were the most active PDF inhibitors (MIC at which 90% of the organisms tested were inhibited [MIC90], 0.25 mug/ml). Five of the agents showed similar activity against Moraxella catarrhatis (MIC90, 0.12 mug/ml). All PDF inhibitors were less active against Haemophilus influenzae; BB-3497 was the most active agent (MIC90, 2 mug/ml). Five agents were studied against Chlamydia spp. and showed activity similar to that of ciprofloxacin (MIC, 0.5 to 4 mug/ml). This study demonstrates that PDF inhibitors have the potential to be developed for the treatment of respiratory tract infections.