The in vitro susceptibilities of 12 strains of Chlamydia pneumoniae to
a new quinolone, trovafloxacin, and ofloxacin, doxycycline, erythromy
cin, and azithromycin were determined. The activity of trovafloxacin w
as similar to that of ofloxacin, with a MIC at which 90% of the isolat
es are inhibited and a minimal concentration at which 90% of the isola
tes are killed of 1.0 mu g/ml, but trovafloxacin was less active than
doxycycline, erythromycin, and azithromycin.