Title: In vitro activities of azithromycin, clarithromycin, erythromycin, and tetracycline against 13 strains of Chlamydia pneumoniae
Abstract: Thirteen strains of Chlamydia pneumoniae were evaluated for their in vitro susceptibilities to azithromycin, clarithromycin, erythromycin, and tetracycline. The MIC ranges were 0.125 to 0.5 micrograms/ml for azithromycin, 0.031 to 1.0 micrograms/ml for clarithromycin, 0.125 to 1.0 micrograms/ml for erythromycin, and 0.25 to 1.0 micrograms/ml for tetracycline. The ranges for the minimal lethal concentrations were 0.125 to 0.5 micrograms/ml for azithromycin, 0.031 to 1.0 micrograms/ml for clarithromycin, 0.125 to 1.0 micrograms/ml for erythromycin, and 0.25 to 1.0 micrograms/ml for tetracycline. Clarithromycin and azithromycin were the most active antibiotics against C. pneumoniae in vitro.