The susceptibility analysis of ureaplasma urealyticum to macrolides agents

Objective: To determine the susceptibility of ureaplasma urealyticum (Uu) to 14-membered(erythromycin and rox-ithromycin) ,15-membered(azithromycin) and 16-membered(josamycin and kitsamycin) macrolides for the rational use of antibiotics. Methods: The MIC of five macrolides against 203 strains of Uu were determined using broth microdilution method. Results: The resistant rates of 203 Uu strains were as follows: erythromycin 11.8%, roxithromycin 7.4%, azithromycin 6.9%, josamycin 3.9%, kitasamycin 3.5%. Among the five macrolides, josamycin and kitasamycin were the most active agents against Uu.the MIC50 being 0.125 mg/L and 0.5 mg/L,respectively;MIC90 being 0.5 mg/L and 1 mg/L, respectively;erythromycin and roxithromycin were less active against Uu, the MIC50 being 4 mg/L and 4 mg/L, and MIC90 being 8 mg/L and 8 mg/L. Conclusions: The degree of resistance of Uu to different macrolides varied 16-membered macrolides such as josamycin and kitasamycin are more active against Uu than 14-membered and 15-membered macrolides.