Bacteriological epidemiology and treatment of bacterial vaginosis

Cervicovaginal bacterial communities in reproductive-aged Tanzanian women with Schistosoma mansoni, Schistosoma haematobium, or without schistosome infection

Schistosome infection is recognized as a potentially modifiable risk factor for HIV in women by the World Health Organization. Alterations in cervicovaginal bacteria have been associated with HIV acquisition and have not been studied in schistosome infection. We collected cervical swabs from Tanzanian women with and without S. mansoni and S. haematobium to determine effects on cervicovaginal microbiota. Infected women were treated, and follow-up swabs were collected after 3 months. 16S rRNA sequencing was performed on DNA extracted from swabs. We compared 39 women with S. mansoni with 52 uninfected controls, and 16 with S. haematobium with 27 controls. S. mansoni-infected women had increased abundance of Peptostreptococcus (p = 0.026) and presence of Prevotella timonesis (p = 0.048) compared to controls. High-intensity S. haematobium infection was associated with more diverse cervicovaginal bacterial communities than uninfected controls (p = 0.0159). High-intensity S. mansoni infection showed a similar trend (p = 0.154). At follow-up, we observed increased alpha diversity in S. mansoni (2.53 vs. 1.72, p = 0.022) and S. haematobium (2.05 vs. 1.12, p = 0.066) infection groups compared to controls. Modifications in cervicovaginal microbiota, particularly increased diversity and abundance of taxa associated with bacterial vaginosis and HIV (Peptostreptococcus, Prevotella), were associated with schistosome infection.

Local treatment of bacterial vaginosis with a bioadhesive metronidazole tablet

OBJECTIVES

Oral metronidazole is still the drug of choice in the treatment of bacterial vaginosis. Yet, side effects have been reported, and dosage as well as duration of therapy are still controversial. This study presents a possible alternative treatment using a single dose of metronidazole administered in a vaginal bioadhesive tablet.

STUDY DESIGN

Double blind, randomised, placebo-controlled trial.

SUBJECTS

The 116 patients were allocated to placebo; metronidazole 100; 250; 500mg in a 1:1:1:1 ratio.

RESULTS

A cure rate of 64% was obtained with a single 100mg dose of metronidazole formulated in a bioadhesive vaginal tablet compared to a cure rate of 29% in the placebo group. The cure rates with the higher doses were similar 61.5% for 250mg dose and 68% for the 500mg dose. No side effects were reported.

CONCLUSIONS

Treatment of bacterial vaginosis with a single application of 100mg metronidazole in a bioadhesive vaginal tablet was found to be a valid alternative. Further research in relation to tablet shaping and optimal dose finding might increase the cure rate.

Vaginal microflora in healthy women with Gardnerella vaginalis

In order to find the vaginal prevalence of Gardnerella vaginalis in a normal female population, we determined the incidence of G. vaginalis in relation to that of other bacterial genera and species in the vagina. Two-hundred and thirty-nine healthy women were the subjects of this study. Vaginal discharge was collected and bacteriological studies were performed. The mean total aerobe count in the G. vaginalis-positive group was 9.02 log10 colony-forming units (CFU)/g, which was significantly higher (P < 0.0001) than that (6.80 log10 CFU/g) in the G. vaginalis-negative group. In contrast, there was no difference in the mean total anaerobe count between the two groups of subjects (8.82 and 8.24 log10 CFU/g, respectively in the case of including Lactobacillus species count). Also, the mean pH level of vaginal secretion in the G. vaginalis-positive group was 4.58, which was significantly higher (P < 0.005) than that (4.10) in the G. vaginalis-negative group. Aerobes were isolated at equal incidence in the two groups. Anaerobes were isolated at a significantly higher rate in the G. vaginalis-positive group (P < 0.005) than in the G. vaginalis-negative group. The mean count of Lactobacillus species was significantly higher (P < 0.0001) in the G. vaginalis-negative group than in the positive counterpart (7.02 vs 8.66). Elevation of vaginal pH, an increase in the anaerobe count, and decreases in the Lactobacillus species count could be good predictors of the prevalence of bacterial vaginosis in healthy women.

Intravaginal bacterial flora in patients with uterine cervical cancer. High incidence of detection of Gardnerella vaginalis

Gynecological diseases may affect the growth of vaginal bacterial flora. We investigated the relationship between uterine cervical cancer and the vaginal bacterial flora. In 20 patients with uterine cervical cancer, we investigated the intravaginal bacterial flora, including Gardnerella vaginalis and Mobiluncus spp. In the patients with uterine cervical cancer, there was a mixed flora of aerobes and anaerobes and, of special note, G. vaginalis was detected in 50% of the patients with uterine cervical cancer (10/20). Bacterial vaginosis was present in 8 of these 10 patients (80%). The count of G. vaginalis detected was higher than that of the other coexisting species and was higher in both pre- and postmenopausal patients with uterine cervical cancer than in a control group of pre- and postmenopausal women with benign gynecological diseases. In contrast, none of Mobiluncus spp. was detected. G. vaginalis was detected at a high incidence in patients with uterine cervical cancer, suggesting that the lesions of uterine cervical cancer provide favorable conditions for the growth of G. vaginalis and anaerobes, which leads to bacterial vaginosis.

Elastase activity of anaerobes isolated from amniotic fluid with preterm premature rupture of membranes

OBJECTIVE

A total of 131 anaerobes isolated from amniotic fluid with preterm premature rupture of membranes and stored were examined for elastolytic activity by the method described by Williams et al (Lett Appl Microbiol 1988;7:173-6).

STUDY DESIGN

Each strain was spot inoculated on a Columbia blood agar plate containing 1% solubilized elastin and incubated for 5 days under anaerobic conditions. Undigested elastin was precipitated by flooding trichloroacetic acid solution onto the plate, and a clear zone was visible as the elastolytic reaction around the spot of bacterial growth.

RESULTS

Ninety-three (71.0%) of 131 organisms showed a positive elastolytic reaction. Eleven of 20 strains (55.0%) of Peptostreptococcus magnus, 9 of 18 strains (50.0%) of Peptostreptococcus micros, 12 of 12 strains (100.0%) of Fusobacterium nucleatum, 15 of 28 strains (53.6%) of Bacteroides fragilis, 8 of 15 strains (53.3%) of Bacteroides thetaiotaomicron, and 38 of 38 strains (100.0%) of Prevotella bivia were elastolytic.

CONCLUSION

Anaerobic bacterial species prevalent in the normal vaginal flora that were isolated from amniotic fluid of women with preterm rupture of membranes produced elastolytic activity, plausibly inducing the destruction of host constitutive components.

Bacterial isolates from patients with preterm labor with and without preterm rupture of the fetal membranes

OBJECTIVE

The aim of this study is to describe the bacterial flora of women in preterm labor with or without premature rupture of membranes.

METHODS

Retrospective studies of 239 patients with preterm labor were performed.

RESULTS

One hundred and twenty-three of 239 patients with preterm labor (51.5%) had bacterial vaginosis. Seventy of the 239 patients with preterm labor (29.3%) developed premature rupture of the membranes (preterm PROM). Of the 70 patients with preterm PROM, 51 (72.9%) had bacterial vaginosis. Therefore, 51 of the 123 patients with bacterial vaginosis (41.5%) developed preterm PROM. An increased number of organisms detected from the vaginal discharge in patients with preterm labor was associated with preterm PROM by Cochran-Armitage test. An increased number of organisms detected from the vaginal discharge in patients with preterm labor complicated with bacterial vaginosis was significantly associated with preterm PROM by Cochran-Armitage test.

CONCLUSIONS

In preterm labor, the number of different species detected in the vagina provide sensitive and specific prediction of preterm PROM in patients with preterm labor.