Drug-resistant Profiles of Clinical Isolates of Gardnerella vaginalis on Columbia Agar Base Supplemented with Human Erythrocyte Lysate and Horse Serum

ABSTRACT

BACKGROUND: To the best of our knowledge, there has been no any report on the antibiotic susceptibility profile of Gardnerella vaginalis, determined in domestic area by the agar dilution method. Therefore, we studied on 49 strains of G. vaginalis by the agar dilution method. METHODS: One standard strain (ATCC 14018) and Forty-eight strains isolated from patients with increased vaginal discharge were included in this study. Columbia agar base containing 1% proteose peptone No. 3 was supplemented with horse serum (5%) and human erythrocyte lysate (5%) which was prepared by a new method, and this medium was used for the antibiotic susceptibility test. RESULTS: The MICs90 of clindamycin and ciprofloxacin were 0.3 g/mL and 0.6 g/mL, respectively. Amoxicillin, cefazolin, doxycycline, and erythromycin were hardly effective against most strains of G. vaginalis (NCCLS, U.S.A., 2001). Especially, MICs90 of both metronidazole and tinidazole were 80 g/ mL under micro-aerobic condition of 5% O2. CONCLUSION: For the treatment of Bacterial vaginosis, it is suggested that clindamycin or ciprofloxacin should be combined with vaginal tablet or gel of metronidazole rather than single administration of metrondazole or tinidazole.