Bacterial Vaginosis-associated Bacteria Research Articles

Relationship of Specific Vaginal Bacteria and Bacterial Vaginosis Treatment Failure in Women Who Have Sex with Women

Bacterial vaginosis frequently persists after treatment. The role of newly defined bacterial vaginosis-associated bacteria (BVAB), which have a specificity for this condition of 97% or greater, has not been assessed. To define risks for bacterial vaginosis persistence, including pretreatment detection of specific vaginal bacteria, among women reporting sex with women. Observational cohort study. University-based research clinic. 335 women age 16 to 29 years reporting sex with at least 1 woman in the past year. Participants were recruited through advertisements and provider referral. Bacterial vaginosis was treated with intravaginal metronidazole gel (0.75%), 37.5 mg nightly for 5 nights. Species-specific 16S recombinant DNA polymerase chain reaction assays targeting 17 bacterial species were applied to vaginal fluid obtained at baseline. Test of cure by clinical criteria and Gram stain analysis and repeated polymerase chain reaction assays of vaginal fluid were performed 1 month after treatment, and interim behaviors were assessed by using computer-assisted self-interview. Of 335 women, 24% of whom also reported sex with men within 3 months before enrollment, 131 (39%) had bacterial vaginosis. In the 120 (92%) women who returned for follow-up, the incidence of persistent bacterial vaginosis was 26% and was statistically significantly higher in women with baseline detection of 3 Clostridiales bacteria, designated as BVAB1 (risk ratio, 2.0 [95% CI, 1.1 to 4.0]), BVAB2 (risk ratio, 8.7 [CI, 2.5 to infinity]), or BVAB3 (risk ratio, 3.1 [CI, 1.7 to 5.8]); Peptoniphilus lacrimalis (risk ratio, 3.5 [CI, 1.6 to 15.5]); and Megasphaera phylotype 2 (risk ratio, 3.4 [CI, 1.4 to 5.5]). Persistence was lower with treatment adherence (risk ratio, 0.4 [0.2 to 0.9]). Detection of these bacteria at the test-of-cure visit was associated with persistence, whereas posttreatment sexual activity was not. Findings may not be generalizable to women who have sex only with men, or to women whose bacterial vaginosis is treated with oral antibiotics. The study may be too small and may involve a population that is too highly selected to draw definitive conclusions about associations of persistent infection with posttreatment sexual behaviors. Persistent bacterial vaginosis is associated with several bacteria in the Clostridiales order, Megasphaera phylotype 2, and P. lacrimalis, suggesting that vaginal microbiology at diagnosis may determine risk for antibiotic failure.

Atopobium vaginae triggers an innate immune response in an in vitro model of bacterial vaginosis

Bacterial vaginosis is the most common vaginal disorder among women of reproductive age. The pathogenesis of bacterial vaginosis is poorly understood, but is defined by a transition in the vaginal flora from the predominant Lactobacillus species to other bacterial species such as Atopobium vaginae and Gardnerella vaginalis. This change is associated with an increase in vaginal cytokine secretion. We hypothesize that vaginal epithelial cells respond to bacterial vaginosis-associated bacteria by triggering an innate immune response. We observed that vaginal epithelial cells secreted interleukin-6 and interleukin-8 in response to Atopobium vaginae and Gardnerella vaginalis, but not to Lactobacillus crispatus. Atopobium vaginae induced increased levels of interleukin-6 and interleukin-8 transcripts, as well as increased transcripts for the antimicrobial peptide β-defensin 4. This innate immune response required live bacteria capable of protein synthesis in direct contact with vaginal epithelial cells. The response of vaginal epithelial cells was mediated by Toll-like receptor 2, required the adaptor protein MyD88, and involved activation of the NFκB signaling pathway. These results suggest that Atopobium vaginae stimulates an innate immune response from vaginal epithelial cells, leading to localized cytokine and defensin production, and possibly contributes to the pathogenesis of bacterial vaginosis.

いわゆる嫌気性菌が関与する感染症に関する最近の話題

Considerable information has been accumulated in the field of anaerobic bacteria and anaerobic infections in the last ten years. Here we tried to briefly introduce several selected topics of clinical importance in this field: Proposal of the term "Nanaerobe", Changes of classification and nomenclature of anaerobes, Anaerobic bacteremia, Lemierre's syndrome as a revival anaerobic infection, Atopobium vaginae as Bacterial Vaginosis-associated bacteria, and new actions of the Clostridium perfringens toxins.

Relationship between maternal group B streptococcal colonization and pregnancy outcome

Objective: To examine the association of maternal colonization with group B streptococcus (GBS) with preterm labor and premature rupture of the membranes (PROM). Methods: Vaginal cultures were conducted in 615 women at 22–26 weeks’ gestation and again on admission for term delivery, preterm labor, or PROM. Antibiotics were not given antenatally based on a GBS-positive culture result. Fisher exact test and maximum likelihood analysis were used for statistical analysis. Results: The rates of preterm labor and PROM were not significantly different between GBS-positive and GBS-negative women in both the antenatal screening and the screening on admission. According to maximum-likelihood analyses, the known risk factors for preterm labor and PROM collectively were important risk factors for preterm labor (odds ratio: 6.48), but GBS colonization during pregnancy was not a risk factor for preterm labor or PROM. In the antenatal screening, the proportion of subjects with lactobacilli-reduced vaginal flora was significantly higher in GBS-positive women (14.3%; ten of 70) than in GBS-negative women (6.4%; 35 of 545) ( P = 0.26). Bacteria associated with bacterial vaginosis (Gardnerella vaginalis and anaerobes) were isolated in only 3.7% (23 of 615) of all subjects. Conclusion: Vaginal colonization with GBS was not associated with preterm labor and PROM in an obstetric population with a low incidence of bacterial vaginosis-associated bacteria, despite the presence of lactobacilli-reduced flora in GBS-positive women.

Vaginal microflora in postmenopausal women who have not received estrogen replacement therapy.

We studied the vaginal microflora of 73 postmenopausal women who had never received estrogen replacement therapy. The median age of these women was 67 years, and none of them had bacterial vaginosis. Lactobacilli were detected in 36 (49%) of these women at a mean concentration of 10(5.7) cfu/g of vaginal fluid. H2O2-producing lactobacilli were recovered from 38% of the women. Some of the other organisms that were recovered, including Gardnerella vaginalis (27% of the women), Ureaplasma urealyticum (13%), Candida albicans (1%), and Prevotella bivia (33%), were less frequently isolated from postmenopausal women than from women of reproductive age, while coliforms (41%) were recovered at higher frequencies. Lactobacilli, yeasts, and bacterial vaginosis-associated bacteria are less commonly part of the vaginal microflora in postmenopausal women than in women of reproductive age, which may explain the decrease in the incidence of bacterial vaginosis and yeast vaginitis among these women.

Role of Bacterial Vaginosis in Pelvic Inflammatory Disease

Pelvic inflammatory disease (PID) is a frequent infection in sexually active young women and results in adverse sequelae, including tubal-factor infertility and ectopic pregnancy. In the 1970s investigations using culdocentesis demonstrated that anaerobic bacteria played an important role in the etiology of PID. This finding has subsequently been confirmed by studies utilizing laparoscopy and/or endometrial biopsy to obtain specimens directly from the upper genital tract (uterine cavity and fallopian tube) of patients with acute PID. Recently, several investigations have shown an association between bacterial vaginosis and the development of acute PID. The microorganisms associated with bacterial vaginosis include anaerobes such as Prevotella bivia, other Prevotella species, and Peptostreptococcus species. These studies that have demonstrated the presence of bacterial vaginosis-associated bacteria in addition to the sexually transmitted organisms Neisseria gonorrhoeae and Chlamydia trachomatis suggest that treatment of acute PID must be broad spectrum in nature and effective against anaerobic bacteria as well as N. gonorrhoeae and C. trachomatis.