In Vitro Activity of ABT 773, a New Ketolide Antibiotic, against Chlamydia pneumoniae

The in vitro activities of ABT 773, telithromycin (HMR 3647), azithromycin, clarithromycin, erythromycin, and levofloxacin were tested against 20 strains of Chlamydia pneumoniae. The MIC at which 90% of the isolates were inhibited and the minimal bactericidal concentration at which 90% of the isolates were killed by ABT 773 were 0.015 μg/ml (range, 0.008 to 0.015 μg/ml). ABT 773 was the most active antibiotic tested in this study.