EPT

2 DC-159a is a new 8-methoxy fluoroquinolone that possesses broad spectrum of antibacterial activity with extended activity against Gram-positive pathogens, especially streptococci and staphylococci from community-acquired infections. Against Streptococcus spp., DC-159a showed antibacterial activity with its MIC90 of 0.12 µg/mL and inhibited the growth of 90 % of levofloxacin-intermediate and-resistant strains at 1 µg/mL. The MIC90s of DC-159a against Staphylococcus spp. were 0.5 µg/mL or less except for quinolone and methicillin-resistant Staphylococcus aureus, for which MIC90 of DC-159a was 8 µg/mL. DC-159a was the most active against Enterococcus spp. (MIC90, 4 to 8 µg/mL) than the marketed fluoroquinolones, such as levofloxacin, ciprofloxacin, and moxifloxacin. The MIC90s of DC-159a against Haemophilus influenzae, Moraxella catarrhalis and Klebsiella pneumoniae were 0.015, 0.06 and 0.25 µg/mL, respectively. The antibacterial activity of DC-159a against Mycoplasma pneumoniae was 8-fold more potent than that of levofloxacin. The MICs of DC-159a against Chlamydophila pneumoniae were comparable to those of moxifloxacin, more potent than those o