In vitro activities of gemifloxacin (SB 265805, LB20304) against recent clinical isolates of Chlamydia pneumoniae.

We compared the in vitro activity of gemifloxacin, a new quinolone antibiotic, to the activities of levofloxacin, moxifloxacin, trovafloxacin, erythromycin, and doxycycline against 20 isolates of Chlamydia pneumoniae. Gemifloxacin was the most active quinolone tested, with a MIC at which 90% of the isolates are inhibited and a minimal bactericidal concentration at which 90% of strains tested are killed of 0.25 microg/ml, but this activity was less than those of doxycycline and erythromycin.