Abstract
The activity of minocycline, doxycycline, tetracycline, erythromycin, mepartricin and lincomycin against 35 freshly isolatedUreaplasma urealyticum strains was tested. Doxycycline was the most active. Twelve strains were resistant to minocycline and four of these were sensitive to erythromycin. Mepartricin showed no activity against the organisms at a concentration of 10 µg/ml. The susceptibility of 30 low-laboratory-passageChlamydia trachomatis strains against tetracycline and erythromycin was tested. A variable degree of sensitivity to tetracycline and erythromycin was found, the median MIC values being 0.13 µg/ml and 0.025 µg/ml respectively. No resistantChlamydia trachomatis strain was found.