Activity of ciprofloxacin against genital tract pathogens.

The in vitro activity of the quinolone carboxylic acid, ciprofloxacin, against a variety of genital tract pathogens was examined. Each of 35 isolates of Neisseria gonorrhoeae, including some beta-lactamase producing strains and strains resistant to tetracycline, was inhibited at a concentration of 0.01 mg/l. Most (13 of 20) strains of Gardnerella vaginalis were inhibited at 1 mg/l but three isolates had minimum inhibitory concentrations (MICs) of 8 mg/l or more. Each of seven strains of Chlamydia trachomatis was completely inhibited at a concentration of 2 mg/l. Prolonged (72 hours) exposure of the chlamydiae to ciprofloxacin was required for inhibition at this concentration.