BAY 12-8039, a novel fluoroquinolone. Activity against important respiratory tract pathogens.

BAY 12-8039 or moxifloxacin is a new 8-methoxyquinolone with documented, improved activity against Gram-positive cocci and anaerobic bacteria. This study tested 1250 commonly isolated respiratory tract pathogens (251 Moraxella catarrhalis, 499 Haemophilus influenzae, 500 Streptococcus pneumoniae) from 1996-1997 clinical infections at more than 30 medical centers. Among the M. catarrhalis strains (81% beta-lactamase-positive) the BAY 12-8039 MIC90 was 0.06 microgram/mL, a potency equal to ofloxacin but less than all other tested fluoroquinolones (ciprofloxacin, clinafloxacin, levofloxacin, sparfloxacin, trovafloxacin). The H. influenzae strains were generally less susceptible to BAY 12-8039 (MIC90, 0.03 microgram/mL) than the tested fluoroquinolones, and the other comparison compounds were less active overall. All S. pneumoniae strains were susceptible to BAY 12-8039 at < or = 0.25 microgram/mL (MIC90, 0.06-0.12 microgram/mL), a value equal-potent to trovafloxacin. This new fluoroquinolone, BAY 12-8039, appears promising for the treatment of community-acquired respiratory tract infections caused by common bacterial species.