In vitro activity of several antimicrobial agents against genital mycoplasmas.

The increasing resistance of genital mycoplasmas to tetracyclines is a serious problem, since this group of antibiotics is one of the few that is effective against virtually all species of mycoplasmas. Tetracyclines are also used to treat many sexually transmitted diseases. In this study, we assessed the susceptibility of Mycoplasma hominis and Ureaplasma urealyticum to macrolides, tetracyclines, spectinomycin, and trospectomycin by the agar dilution method. For M hominis, trospectomycin was the most active agent. Spectinomycin, tetracycline, and doxycycline had comparable mycoplasmatic activity, and the macrolides were ineffective. Against U urealyticum, spectinomycin and trospectomycin were the most active drugs, and were at least twofold more active than the macrolides and tetracyclines.