Antimicrobial Susceptibilities of Ureaplasma urealyticum and Mycoplasma hominis in Pregnant Women

Background: Ureaplasma urealyticum and Mycoplasma hominis are associated with an increased risk of pregnancy complications, such as preterm birth and premature membrane rupture. The purpose of this study was to determine the isolation rates and antimicrobial susceptibilities of genital mycoplasma in a sample of pregnant women from Jinju, Korea. Methods: Vaginal swabs were obtained from 258 pregnant women between 2004 and 2008 and tested for the presence of U. urealyticum and M. hominis at Gyeongsang National University Hospital. The identification and antimicrobial susceptibilities of U. urealyticum and M. hominis were determined with a commercially available kit, the Mycoplasma IST2 Kit (bioMe rieux, Marcy-l’Etoile, France), and evaluated according to standards set by the Clinical and Laboratory Standards Institute (CLSI). Results: U. urealyticum only was detected in 105 specimens (38.6%), while M. hominis only was detected only in 2 specimens (1.8%). Seven specimens (6.7%) were positive both for U. urealyticum and M. hominis. Susceptibilities of U. urealyticum to azithromycin, erythromycin, clarithromycin, and doxycycline were 75.2%, 82.9%, 88.6%, and 88.6%, respectively, while almost all of the isolates were susceptible to josamycin (99.0%) and pristinamycin (100%). The susceptibility of U. urealyticum to ofloxacin and ciprofloxacin was 56.2% and 15.2%, respectively. Conclusion: The rate of isolation of genital mycoplasma in pregnant women was 44.2% in Jinju; most of the mycoplasma were U. urealyticum. U. urealyticum and M. hominis were highly resistant to quinolones, but susceptible to josamycin. Therefore, empirical treatment without prior identification and determination of the antimicrobial susceptibility of genital mycoplasma will fail in many cases. (Korean J Clin Microbiol 2009;12:159-162)