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

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.

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

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.

Diagnosis of Bacterial Vaginosis with Relation to Isolation of Gardnerella vaginalis

Among 104 patients who visited a local clinic with increased, bad-smelling vaginal discharge, twenty-nine women (27.9%) were found to have bacterial vaginosis (BV) according to the Amsel's composite clinical criteria (homogeneous thin gray discharge, positive amine test, vaginal pH over 4.5, positivity of clue cell by Gram stain). The specificity, sensitivity and positive and negative predictive values of the Amsel's composite clinical criteria were estimated in relation to the G. vaginalis isolation rate. Fifty-two strains of G. vaginalis (50%) were isolated from vaginal swabs taken from 104 patients. The sensitivities of clue cells and G. vaginalis isolation were both 96.6% (28) in the 29 BV patients. The specificities of clue cells and the presence of G. vaginalis were 85.3% and 68.0%, respectively. But the sensitivity, specificity, and positive and negative predictive values of the combination of clue cells and morphotype of G. vaginalis were 93.1%, 92.0%, 81.8% and 97.2%, respectively. The sensitivity, specificity and positive and negative predictive values of amine test were 89.7%, 98.7%, 96.2% and 94.9% in the 29 BV patients. Among 52 strains of G. vaginalis, 34 strains (87.2%) were isolated from the 39 clue cell positive samples and the remaining 18 (27.7%) from the 65 clue cell negative cases. Twenty-four strains (92.3%) were isolated from 26 amine test positive samples and the remaining 28 (35.9%) from 78 amine test negative cases. According to these results, it seems that the amine test is a useful test for the diagnosis of BV. However, we propose the combination criteria of clue cells and G. vaginalis morphotype in vaginal discharge should give more objective results than the amine test for the diagnosis of BV. The sensitivity and specificity of vaginal pH over 4.5 were 86.2% and 57.3%, and those of homogeneous discharge 93.1% and 65.3%, respectively. These two criteria were not as specific as clue cells and amine test for the diagnosis of BV. These results suggest that BV could be diagnosed more simply and precisely with the finding of clue cells spotted with Gram variable polymorphic bacteria by means of Gram stain of vaginal wall swabs.

Patterns of Iron Utilization According to the Growth of Staphylococcus aureus

To elucidate iron utilization patterns of Staphylococcus aureus according to the growth, we checked the residual iron concentration and the production of siderophores at the indicated times while culturing S. aureus ATCC 6538 and 25923 strains in brain heart infusion broth. By using streptonigrin susceptibility test and investigating growth curves in three culture media of which iron concentration is 0.2, 20, 45 uM, respectively, we found out that iron metabolism of 6538 strain was more active than that of 25923 strain. In point of tendency of iron consumption, 6538 strain steeply consumed iron just before the onset of stationary phase, but 25923 strain did gradually iron throughout the growth phase. Nevertheless, total amount of iron consumed by each strain during the growth was almost no difference between the strains. CAS diffusion assay in detecting siderophores showed that siderophore production followed iron consumption. These results suggest that the siderophores play significant role in iron utilization in vitro.