In vitro activity of moxifloxacin against recent community-acquired respiratory tract pathogens isolated in France: a national survey.

Between February and June 2000, 2345 consecutive strains of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus and Klebsiella pneumoniae were isolated from 2088 adult patients suffering from community-acquired respiratory tract infections, in 97 hospital laboratories. Of the 1037 S. pneumoniae isolates, 48.3% were intermediately or highly penicillin resistant. For invasive isolates, the MIC90s of penicillin G, amoxycillin, cefuroxime, ceftriaxone, erythromycin, ofloxacin, ciprofloxacin and moxifloxacin were 2, 2, 4, 0.5, 1024, 2, 2 and 0.25 mg/l, respectively. All but one invasive strain were susceptible to moxifloxacin whereas 97.5% were susceptible to levofloxacin. The MIC90s of clinical isolates with intermediate susceptibility or high resistance to penicillin G, were 2, 2, 4, 1, 1024, 2, 2 and 0.25 mg/l. About 98.1, 97.0, and 83.1% of strains were inhibited by concentrations < or = 1 mg/l of moxifloxacin, levofloxacin and ciprofloxacin, respectively (E-test). Eight of the 1037 S. pneumoniae strains were not susceptible to moxifloxacin and had mutations in gyrA (eight strains), parC (four strains) or parE (three strains). Against H. influenzae (32.7% were beta-lactamase producers) and M. catarrhalis (96.3% were beta-lactamase producers), the MIC90s of moxifloxacin, amoxycillin and co-amoxiclav were 0.094 and 0.125 mg/l, 64 and 8 mg/l, and 1.5 and 0.25 mg/l, respectively. Against oxacillin-susceptible S. aureus and K. pneumoniae, the MIC90s of moxifloxacin were 0.125 and 0.84 mg/l respectively. Moxifloxacin had the highest in vitro activity of all antibiotics tested.