[In vitro activity of sparfloxacin against mycoplasmas]

The in vitro activity of the new difluorinated quinolone sparfloxacin against mycoplasmas was studied comparatively with ofloxacin, doxycycline, and erythromycin. Minimal inhibitory concentrations (MICs) were determined by agar dilution for 21 strains of Mycoplasma pneumoniae (Mp), 20 strains of M. hominis (Mh), 7 strains of M. genitalium (Mg), and 3 strains of M. fermentans (Mf), and by broth dilution for 49 strains of Ureaplasma urealyticum (Uu). Sparfloxacin was very active against all tested mycoplasmas, with the following MICs (microgram/ml): 0.1 for Mp, 0.05-0.1 for Mg, less than or equal to 0.01 for Mh, less than or equal to 0.01-0.05 for Mf, and 0.1-0.5 for Uu. Minimal bactericidal concentration was 1 microgram/ml for Uu. Sparfloxacin was more active than ofloxacin against all the mycoplasmas tested and was the most active compound against Mh and Mf. Erythromycin had the lowest MICs against Mp and Mg. Sparfloxacin exhibited comparable effectiveness against doxycycline-susceptible and doxycycline-resistant strains. Sparfloxacin appears to be one of the most active agents in vitro against mycoplasmas.