BB-83857

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 Streptococcuspneumoniae , BB-83698 and BB-83815 were the most active PDF inhibitors (MIC at which 90% of the organisms tested were inhibited [MIC 90 ], 0.25 μg/ml). Five of the agents showed similar activity against Moraxellacatarrhalis (MIC 90 , 0.12 μg/ml). All PDF inhibitors were less active against Haemophilusinfluenzae ; BB-3497 was the most active agent (MIC 90 , 2 μg/ml). Five agents were studied against Chlamydia spp. and showed activity similar to that of ciprofloxacin (MIC, 0.5 to 4 μg/ml). This study demonstrates that PDF inhibitors have the potential to be developed for the treatment of respiratory tract infections.