Ciprofloxacin was found to be the most active of a group of 4-quinolone antibiotics tested against the SA
2 f strain of
Chlamydia trachomatis (MBC and MIC 1.0 mg/l). Against genital isolates of
Chlamydia trachomatis, Ciprofloxacin was twice as active as rosoxacin. Ciprofloxacin showed similar activity to that of oxytetracycline against clinical isolates of
Mycoplasma hominis and
Ureaplasma urealyticum, and was 8-fold more active than rosoxacin against the latter.