Associations between dietary micronutrient intake and molecular-Bacterial Vaginosis

OBJECTIVES

Bacterial vaginosis (BV), a clinical condition characterized by decreased vaginal Lactobacillus spp., is difficult to treat. We examined associations between micronutrient intake and a low-Lactobacillus vaginal microbiota as assessed by molecular methods (termed "molecular-BV").

METHODS

This cross-sectional analysis utilized data collected at the baseline visit of the Hormonal Contraception Longitudinal Study, a cohort of reproductive-aged women followed over 2 years while initiating or ceasing hormonal contraception (HC). The Block Brief 2000 Food Frequency Questionnaire was administered and micronutrient intakes were ranked. Vaginal microbiota composition was assessed using 16S rRNA gene amplicon sequencing and clustered into community state types (CSTs) based on the types and relative abundance of bacteria detected. Associations between the lowest estimated quartile intake of nutrients and having a low-Lactobacillus CST (molecular-BV) were evaluated by logistic regression. Separate models were built for each nutrient controlling for age, body mass index, behavioral factors, HC use and total energy intake. We also conducted a literature review of existing data on associations between micronutrient intakes and BV.

RESULTS

Samples from 104 women were included in this analysis. Their mean age was 25.8 years (SD 4.3), 29.8% were African American, 48.1% were using HC, and 25% had molecular-BV. In adjusted multivariable analyses, the lowest quartile of betaine intake was associated with an increased odds of molecular-BV (aOR 9.2, p value < 0.01, [CI 2.4-35.0]).

CONCLUSIONS

This is the first study to assess the association between estimated micronutrient intake and molecular-BV. Lower energy-adjusted intake of betaine was associated with an increased risk of molecular-BV. Betaine might have direct effects on the vaginal microenvironment or may be mediated through the gut microbiota. Additional research is needed to determine reproducibility of this finding and whether improved intake of select micronutrients such as betaine decreases the risk of BV and its sequelae.

The vaginal microbial communities of healthy expectant Brazilian mothers and its correlation with the newborn's gut colonization

The female lower genital tract harbors a complex microbial community essential for homeostasis and health. During pregnancy, the female body undergoes unique hormonal changes that contribute to weight gain as well as modulations in immune function that can affect microbiota composition. Several studies have described the vaginal microbiota of pregnant women from the USA, Europe and Mexico. Here we expand our knowledge about the vaginal microbial communities during the third trimester to healthy expectant Brazilian mothers. Vaginal samples were collected from patients delivering at the Hospital de Clínicas de Porto Alegre, Brazil. Microbial DNA was isolated from samples and the V4 region of the 16S rRNA gene was amplified and sequenced using the PGM Ion Torrent. Brazilian pregnant women presented three distinct types of microbial community at the time of labor. Two microbial communities, Cluster 1 and Cluster 3, presented an overall dominance of Lactobacillus while Cluster 2 tended to present higher diversity and richness, with the presence of Pseudomonas, Prevotella and other vaginosis related bacteria. About half of the Brazilian mothers sampled here had dominance of L. iners. The proportion of mothers without dominance of any Lactobacillus was higher in Brazil (22%) compared to UK (2.4%) and USA, where this community type was not detected. The vaginal microbiota showed significant correlation with the composition of the babies' gut microbiota (p-value = 0.002 with a R² of 15.8%). Mothers presenting different vaginal microbiota shared different microorganisms with their newborns, which would reflect on initial colonizers of the developing newborns' gut.

Group B Streptococcus colonization induces Prevotella and Megasphaera abundance-featured vaginal microbiome compositional change in non-pregnant women

Background

Previous studies have indicated that variations in the vaginal microbiome result in symptomatic conditions. Group B Streptococcus (GBS) is a significant neonatal pathogen and maternal vaginal colonization has been recognized as an important risk factor for neonatal disease. Therefore, it is important to discover the relationship between the composition of the vaginal microbiome and GBS colonization. This study explores the potential relationship between the composition of the vaginal microbiome and GBS colonization in non-pregnant Chinese women.

Methods

A total of 22 GBS-positive, non-pregnant women and 44 matched GBS-negative women were recruited for the current study. The composition of the vaginal microbiome was profiled by sequencing the 16S rRNA genes. The microbiome diversity and variation were then evaluated.

Results

The vaginal microbiome of the 66 subjects enrolled in the current study were compared and the results showed that GBS-positive women exhibited significant vaginal microbial differences compared with the GBS-negative women based on the analysis of similarities (r = 0.306, p < 0.01). The relative abundance of the bacterial genus Lactobacillus (p < 0.01) was significantly lower in the GBS-positive group, while the abundances of the bacterial genera Prevotella (p < 0.01), Megasphaera (p < 0.01), and Streptococcus (p < 0.01) were significantly higher in the GBS-positive group.

Discussion

The current study addressed significant variations across the communities of the vaginal microbiome in GBS-positive and GBS-negative women in a Chinese cohort, which paves the way for a larger cohort-based clinical validation study and the development of therapeutic probiotics in the future.

Association between the vaginal microbiome and high-risk human papillomavirus infection in pregnant Chinese women

BACKGROUND

In this study, the association between high-risk human papillomavirus (hrHPV) infection and the vaginal microbiome in pregnant women was evaluated in Chinese cohorts.

METHODS

The vaginal bacterial composition of four groups, 38 hrHPV-infected pregnant women (PHR, n = 38), pregnant women without HPV infection (PN, n = 48), nonpregnant women with hrHPV infection (NPHR, n = 19) and nonpregnant women without HPV infection (NPN, n = 30), was characterized by deep sequencing of barcoded 16S rRNA gene fragments (V3-4) using Illumina MiSeq.

RESULTS

The results revealed that both pregnancy and HPV infection can increase vaginal bacterial microbial richness and diversity, with the bacterial composition being most influenced by pregnancy. Lactobacillus was the most dominant genus among all samples. NPN samples were dominated by CST (community state type) III, mainly composed of Lactobacillus iners. Both pregnancy and hrHPV infection were accompanied by an increased proportion of CST I (dominated by Lactobacillus crispatus), as opposed to CST III. Bifidobacterium, Bacillus, Megasphaera, Sneathia, Prevotella, Gardnerella, Fastidiosipila and Dialister were found to be biomarkers for hrHPV-infected women, though different genera (Bifidobacterium, Megasphaera, Bacillus, Acidovorax, Oceanobacillus and Lactococcus) were associated with hrHPV-infected pregnant women.

CONCLUSIONS

This work uncovered a probable synergistic effect of hrHPV infection and pregnancy on the vaginal microbial composition. HPV infection in pregnant women was associated with a more complex and diverse microbial environment.

Contribution of Epithelial Cells to Defense Mechanisms in the Human Vagina

PURPOSE OF REVIEW

The vaginal milieu in women differs from that of other mammals, including non-human primates, in composition of secretions, the endogenous microbiota, and level of acidity. These changes apparently reflect evolutionary variations that maximized productive responses to a uniquely human vaginal environment. This review will highlight recent findings on properties of human vaginal epithelial cells that contribute to maintenance of a healthy vaginal environment.

RECENT FINDINGS

Vaginal epithelial cells are responsive to the composition of the vaginal microbiome even in women who are in apparently good health and do not exhibit any adverse physical symptoms. This is especially important during pregnancy when immune defenses are modified and an effective epithelial cell-derived anti-microbial activity is essential to prevent the migration to the uterus of bacteria potentially harmful to pregnancy progression. When Lactobacillus crispatus numerically predominates in the vagina, epithelial cell activity is low. Conversely, predominance of Lactobacillus iners, Gardnerella vaginalis, or other non-Lactobacilli evokes production and release of a large variety of compounds to minimize the potentially negative consequences of an altered microbiome. The extent of autophagy in vaginal epithelial cells, a basic process that functions to maintain intracellular homeostasis and engulf microbial invaders, is also sensitive to the external microbial environment Vaginal epithelial cells bind and release norepinephrine and upregulate their anti-microbial activity in response to external stress. Vaginal epithelial cells in women are responsive to local conditions that are unique to humans and, thereby, contribute to maintenance of a healthy milieu.

Vaginal Glycogen, Not Estradiol, Is Associated With Vaginal Bacterial Community Composition in Black Adolescent Women

PURPOSE

The purpose of this study was to characterize the composition of vaginal bacterial communities in a cohort of black adolescent women and to determine how the species composition of these communities correlates with levels of estradiol, glycogen, and stress.

METHODS

Twenty-one black adolescent women were sampled longitudinally. The composition of their vaginal communities was determined by analyzing the sequences of the V1-V3 regions of 16S rRNA genes, and they were grouped based on patterns in species abundances. The relationships between estradiol, glycogen, psychosocial stress, and the composition of these communities were assessed.

RESULTS

Vaginal communities could be distinguished and classified into three groups that differed in the abundances of Lactobacillus. Eighty-one percent of study participants had communities dominated by species of Lactobacillus. Glycogen levels were higher in communities dominated by one or multiple species of Lactobacillus compared with those having low proportions of Lactobacillus. Estradiol and psychosocial stress measurements did not differ among the three groups, whereas estradiol and glycogen exhibited a weak positive relationship that was not statistically significant.

CONCLUSIONS

The findings of this pilot study suggest that glycogen levels are associated with vaginal community composition in young black women; however, estradiol and psychosocial stress are not. In addition, the results suggest there is no simple relationship between levels of estradiol and the production of vaginal glycogen.

Interplay Between the Host, the Human Microbiome, and Drug Metabolism

The human microbiome is composed of four major areas including intestinal, skin, vaginal, and oral microbiomes, with each area containing unique species and unique functionalities. The human microbiome may be modulated with prebiotics, probiotics, and postbiotics to potentially aid in the treatment of diseases like irritable bowel syndrome, bacterial vaginosis, atopic dermatitis, gingivitis, obesity, or cancer. There is also potential for many of the inhabitants of the human microbiome to directly modulate host gene expression and modulate host detoxifying enzyme activity like cytochrome P450s (CYPs), dehydrogenases, and carboxylesterases. Therefore, the microbiome may be important to consider during drug discovery, risk assessment, and dosing regimens for various diseases given that the human microbiome has been shown to impact host detoxification processes.

Microbiome and its relation to gestational diabetes

PURPOSE

Gestational diabetes mellitus (GDM), the major endocrine pathology in pregnancy, has been associated with the development of an intense inflammatory process and increased insulin resistance. The maternal microbiota is involved in several metabolic functions; however, its role in GDM physiopathology remains unclear. The aim of this study was to assess the composition of the microbiota at different sites and evaluate its relationship with the occurrence of GDM.

METHODS

This cross-sectional study recruited women in the third trimester of gestation with and without GDM. Oral, vaginal, and stool samples were evaluated using next-generation sequencing. We included 68 participants: 26 with and 42 without GDM.

RESULTS

The analysis of the oral microbiome did not show significant differences in phyla and genus among the studied groups. In contrast, GDM patients presented a specific vaginal and intestinal microbiome composition, which was less diverse than those found in the control group, showing genera related to dysbiosis.

CONCLUSIONS

Our findings suggest that changes in the composition of the vaginal and intestinal microbiome might be involved in the development of GDM. The follow-up of these patients in order to evaluate vaginal and intestinal samples after delivery may contribute to understanding the development of metabolic disease in women with previous GDM.

The influence of the vaginal microbiota on preterm birth: A systematic review and recommendations for a minimum dataset for future research

OBJECTIVE

This systematic review aims to identify, critically appraise and summarize the results of studies examining the relationship between the vaginal microbiota and preterm birth (PTB).

METHODS

We searched the electronic databases Medline, EMBASE and the Cochrane Controlled Register of Trials for studies in any language reporting on vaginal microbiota and PTB published from 1990 to November 29th, 2017. We included any study that performed lower genital tract microbiota assessment in asymptomatic pregnant women and reported on spontaneous preterm birth, with either intact or ruptured membranes.

RESULTS

The search strategy yielded 2171 unique citations, of which nine studies were eligible for inclusion in this review. In six studies an association was found between the composition of the vaginal microbiota and PTB, but findings differed between subgroups, ethnicities and degree of risk of PTB. In three studies no association was found. Two of these studies found a significant difference in richness and Shannon diversity between term and PTB.

CONCLUSIONS

We have demonstrated that there is a paucity of molecular based, culture-independent studies that analyse the relationship between the vaginal microbiota and PTB as an outcome. The heterogeneity precluded a meta-analysis. Studies provide contradictory evidence and the quality of the clinical information in the studies is poor. To improve quality of future studies we have provided a database of essential and desirable items of quality that are method and topic specific.

Regulation of Vaginal Microbiome by Nitric Oxide

In this review, the composition and regulation of vaginal microbiome that displays an apparent microbial diversity and interacts with other microbiota in the body are presented. The role of nitric oxide (NO) in the regulation of vaginal microflora in which lactobacillus species typically dominate has been delineated from the perspective of maintaining gynecologic ecosystem and prevention of onset of bacteriostatic vaginosis (BV) and/or sexually transmitted diseases (STD) including HIV-1 transmission. The interactions between NO and vaginal microbiome and its influence on the levels of Lactobacillus, hormones and other components are described. The recent progress, such as NO drugs, probiotic Lactobacilli and Lactobacillus microbots, that can be explored to alleviate abnormality of vagina microbiome, is also discussed. An identification of Oral-GI-Vagina axis, as well as the relationship between NO and Lactobacillus regulation in the healthy or pathological status of vagina microbiome, surely offers the advanced drug delivery option against BV or STD including AIDS.

Differential effects of depot medroxyprogesterone acetate administration on vaginal microbiome in Hispanic White and Black women

The use of depot medroxyprogesterone acetate (DMPA), a 3-monthly injectable hormonal contraceptive, is associated with an increased risk of HIV acquisition possibly through alteration of the vaginal microbiome. In this longitudinal interventional study, we investigated the impact of DMPA administration on the vaginal microbiome in Hispanic White and Black women at the baseline (visit 1), 1 month (visit 2), and 3 months (visit 3) following DMPA treatment by using 16S rRNA gene sequencing. No significant changes in the vaginal microbiome were observed after DMPA treatment when Hispanic White and Black women were analysed as a combined group. However, DMPA treatment enriched total vaginosis-associated bacteria (VNAB) and Prevotella at visit 2, and simplified the correlational network in the vaginal microbiome in Black women, while increasing the network size in Hispanic White women. The microbiome in Black women became more diversified and contained more VNAB than Hispanic White women after DMPA treatment. While the Firmicutes to Bacteroidetes (F/B) ratio and Lactobacillus to Prevotella (L/P) ratio were comparable between Black and Hispanic White women at visit 1, both ratios were lower in Black women than in Hispanic White women at visit 2. In conclusion, DMPA treatment altered the community network and enriched VNAB in Black women but not in Hispanic White women. The Lactobacillus deficiency and enrichment of VNAB may contribute to the increased risk of HIV acquisition in Black women. Future studies on the impact of racial differences on the risk of HIV acquisition will offer insights into developing effective strategies for HIV prevention. Abbreviations: DMPA: depot medroxyprogesterone acetate; PCR: polymerase chain reaction; OTU: operational taxonomic unit; STI: sexually transmitted infections; VNAB: vaginosis-associated bacteria.

The murine vaginal microbiota and its perturbation by the human pathogen group B Streptococcus

BACKGROUND

Composition of the vaginal microbiota has significant influence on female urogenital health and control of infectious disease. Murine models are widely utilized to characterize host-pathogen interactions within the vaginal tract, however, the composition of endogenous vaginal flora remains largely undefined with modern microbiome analyses. Here, we employ 16S rRNA amplicon sequencing to establish the native microbial composition of the vaginal tract in adult C57Bl/6 J mice. We further interrogate the impact of estrous cycle and introduction of the human vaginal pathobiont, group B Streptococcus (GBS) on community state type and stability, and conversely, the impact of the vaginal microbiota on GBS persistence.

RESULTS

Sequencing analysis revealed five distinctive community states of the vaginal microbiota dominated largely by Staphylococcus and/or Enterococcus, Lactobacillus, or a mixed population. Stage of estrus did not impact microbial composition. Introduction of GBS decreased community stability at early timepoints; and in some mice, GBS became the dominant bacterium by day 21. Endogenous Staphylococcus abundance correlated with GBS ascension into the uterus, and increased community stability in GBS-challenged mice.

CONCLUSIONS

The murine vaginal flora is diverse and fluctuates independently of the estrous cycle. Endogenous flora may impact pathogen colonization and dissemination and should be considered in urogenital infection models.

Evaluation of patient- versus provider-collected vaginal swabs for microbiome analysis during pregnancy

Objective

We aimed to evaluate if patient- and provider-collected vaginal swabs in pregnant women reflect similar bacterial community characteristics. Pregnant patients performed a self-collected vaginal swab, then underwent a provider-collected swab via speculum exam. DNA pyrosequencing of the 16S rRNA gene V1V3 and V3V5 variable regions was performed. Relative abundance of taxa, alpha diversity, and beta diversity of patient- and provider-collected swabs were compared.

Results

Ninety-four vaginal swabs from 47 women were analyzed. On non-metric multi-dimensional scaling plots, paired patient- and provider-collected swabs clustered closely. The median Pearson correlation coefficient was 0.993 (interquartile range 0.951–0.999) for V1V3 and 0.987 (interquartile range 0.902–0.999) for V3V5. Among paired V1V3 and V3V5 sequences, 83.0% and 73.9% showed strong Pearson correlation (> 0.9), respectively, between patient- and provider-collected swabs; V1V3 and V3V5 sequences with weaker Pearson correlation (< 0.9) had correlation coefficients 0.57–0.89 and 0.49–0.89, respectively. No taxa were preferentially detected by sampling method, with relative abundance of taxa highly conserved. No significant difference in Shannon diversity for V1V3 (p = 0.22) and V3V5 (p = 0.11) sequences among paired samples was seen. We demonstrate that bacterial communities defined from patient- and provider-collected vaginal swabs in pregnant women are similar, validating utilization of patient-collected swabs for vaginal bacterial microbiome sampling during pregnancy.

The microbiome in preterm birth

The microbiome is thought to play a role in the maintenance of a healthy pregnancy and thus may either contribute to or protect from preterm birth. Study of the human microbiome has been aided by metagenomic sequencing approaches, providing greater insight into the commensal bacteria that coexist in and on our bodies. The vaginal microbiome has been the most widely studied, though there have been recent efforts to explore the gut, cervical-vaginal, placental and oral microbiomes in the further search of etiologies of preterm birth. To date, a specific microbiome community or microorganism has yet to be reliably associated with preterm birth. This is partly due to the fact that the 'normal' constituents' microbiome can vary widely between healthy individuals. Before our knowledge of the microbiome can be utilized and applied in clinical practice, a greater understanding of the 'healthy' microbiome must be achieved. In particular, we must first appreciate how our microbes influence our biology to promote a healthy pregnancy or alternately render preterm birth.

Treatment of biofilms in bacterial vaginosis by an amphoteric tenside pessary-clinical study and microbiota analysis

BACKGROUND

Bacterial vaginosis (BV) is the most common vaginal syndrome among women in their reproductive years. It is associated with an increased risk of acquiring sexually transmitted infections and complications like preterm labor. BV is characterized by a high recurrence rate for which biofilms frequently found on vaginal epithelial cells may be a reason.

RESULTS

Here, we report a controlled randomized clinical trial that tested the safety and effectiveness of a newly developed pessary containing an amphoteric tenside (WO3191) to disrupt biofilms after metronidazole treatment of BV. Pessaries containing lactic acid were provided to the control group, and microbial community composition was determined via Illumina sequencing of the V1-V2 region of the 16S rRNA gene. The most common community state type (CST) in healthy women was characterized by Lactobacillus crispatus. In BV, diversity was high with communities dominated by either Lactobacillus iners, Prevotella bivia, Sneathia amnii, or Prevotella amnii. Women with BV and proven biofilms had an increased abundance of Sneathia sanguinegens and a decreased abundance of Gardnerella vaginalis. Following metronidazole treatment, clinical symptoms cleared, Nugent score shifted to Lactobacillus dominance, biofilms disappeared, and diversity (Shannon index) was reduced in most women. Most of the patients responding to therapy exhibited a L. iners CST. Treatment with WO 3191 reduced biofilms but did not prevent recurrence. Women with high diversity after antibiotic treatment were more likely to develop recurrence.

CONCLUSIONS

Stabilizing the low diversity healthy flora by promoting growth of health-associated Lactobacillus sp. such as L. crispatus may be beneficial for long-term female health.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02687789.

The composition of the vaginal microbiome in first trimester pregnant women influences the level of autophagy and stress in vaginal epithelial cells

Epithelial cells lining the vagina are major components of genital tract immunity. The influence of the vaginal microbiome on properties of host epithelial cells is largely unexplored. We evaluated whether differences in the most abundant lactobacilli species or bacterial genera in the vagina of first trimester pregnant women were associated with variations in the extent of stress and autophagy in vaginal epithelial cells. Vaginal swabs from 154 first trimester pregnant women were analyzed for bacterial composition by amplification and sequencing of the V1-V3 region of bacterial 16S rRNA genes. Vaginal epithelial cells were lysed and autophagy quantitated by measurement of p62. Intracellular levels of the inducible 70kDa heat shock protein (hsp70), an indicator of cell stress and an autophagy inhibitor, were determined. When Lactobacillus crispatus was the most abundant member of the vaginal microbiota, epithelial p62 and hsp70 levels were lowest as compared to when other bacterial taxa were most abundant. The highest concentrations of p62 and hsp70 were associated with Streptococcus and Bifidobacterium abundance. The p62 level associated with Gardnerella abundance was lower than that observed when lactobacilli other than L. crispatus were most abundant. In conclusion, in the first trimester of pregnancy the abundance of different bacterial taxa is associated with variations in autophagy and magnitude of the stress response in vaginal epithelial cells.

Eve's garden: myths, legends and secrets unmasked

This special issue of Research in Microbiology aims to provide some insights in one of women's most fascinating interacting microbial communities: the vaginal microbiome. Even in the 21st century, with many advanced methods at hand, the definition of the healthy vaginal microbiome remains under debate. The interest in studying the dysbiosis of the vaginal microbiome is increasing and goes well beyond the study of bacterial vaginosis. The selection of contributions in this issue summarizes what is currently known in terms of inter- and intra-microorganisms interaction as well as the virulence factors that some of them may deploy.

Quantification, isolation and characterization of Bifidobacterium from the vaginal microbiomes of reproductive aged women

The vaginal microbiome plays an important role in women's reproductive health. Imbalances in this microbiota, such as the poorly defined condition of bacterial vaginosis, are associated with increased susceptibility to sexually transmitted infections and negative reproductive outcomes. Currently, a "healthy" vaginal microbiota in reproductive aged women is understood to be dominated by Lactobacillus, although "atypical" microbiomes, such as Bifidobacterium-dominated profiles, have been described. Despite these observations, vaginal bifidobacteria remain relatively poorly characterized, and questions remain regarding their actual abundance in the microbiome. In this study, we used quantitative PCR to confirm the relative abundance of Bifidobacterium in the vaginal microbiomes of healthy reproductive aged women (n = 42), previously determined by deep sequencing. We also isolated and phenotypically characterized vaginal bifidobacteria (n = 40) in the context of features thought to promote reproductive health. Most isolates were identified as B. breve or B. longum based on cpn60 barcode sequencing. Fermentation patterns of vaginal bifidobacteria did not differ substantially from corresponding type strains of gut or oral origin. Lactic acid was produced by all vaginal isolates, with B. longum strains producing the highest levels, but only 32% of isolates produced hydrogen peroxide. Most vaginal bifidobacteria were also able to tolerate high levels of lactic acid (100 mM) and low pH (4.5 or 3.9), conditions typical of vaginal fluid of healthy women. Most isolates were resistant to metronidazole but susceptible to clindamycin, the two most common antibiotics used to treat vaginal dysbiosis. These findings demonstrate that Bifidobacterium is the dominant member of some vaginal microbiomes and suggest that bifidobacteria have the potential to be as protective as lactobacilli according to the current understanding of a healthy vaginal microbiome.

Aerobic vaginitis: no longer a stranger

Aerobic vaginitis (AV) is the name given in 2002 to a vaginal infectious entity which was not recognized as such before. It is characterized by abnormal (dysbiotic) vaginal microflora containing aerobic, enteric bacteria, variable levels of vaginal inflammation and deficient epithelial maturation. Although AV and bacterial vaginosis (BV) share some characteristics, such as a diminished number or absence of lactobacilli, increased discharge (fishy smelling in BV, while in severe forms of AV, a foul, rather rotten smell may be present) and increased pH (often more pronounced in AV), there are also striking differences between the two. There is no inflammation in women with BV, whereas the vagina of women with AV often appears red and edematous, and may even display small erosions or ulcerations. The color of the discharge in BV is usually whitish or gray and of a watery consistency, whereas in AV it is yellow to green and rather thick and mucoid. Women with BV do not have dyspareunia, while some women with severe AV do. Finally, the microscopic appearance differs in various aspects, such as the presence of leucocytes and parabasal or immature epithelial cells in AV and the absence of the granular aspect of the microflora, typical of BV. Despite all these differences, the distinction between AV and BV was not recognized in many former studies, leading to incomplete and imprecise diagnostic workouts and erroneous management of patients in both clinical and research settings. The prevalence of AV ranges between 7 and 12%, and is therefore less prevalent than BV. Although still largely undiagnosed, many researchers and clinicians increasingly take it into account as a cause of symptomatic vaginitis. AV can co-occur with other entities, such as BV and candidiasis. It can be associated with dyspareunia, sexually transmitted infections (such as human papilloma virus, human immunodeficiency virus, Trichomonas vaginalis and Chlamydia trachomatis), chorioamnionitis, fetal infection, preterm birth and cervical dysplasia. Many other possible pathological associations are currently under investigation. The diagnosis of AV is made using wet mount microscopy, ideally using phase contrast. An AV score is calculated, according to: lactobacillary grade, presence of inflammation, proportion of toxic leucocytes, characteristics of the microflora and presence of immature epithelial cells. To circumvent the hurdle of microscopic investigation, some groups have begun to develop nucleic-acid-based and enzymatic diagnostic tests, but the detailed information obtained with phase contrast microscopy is irreplaceable. The best treatment is not yet fully determined, but it must be tailored according to the microscopic findings and the patient's needs. There is a role for local estrogen therapy, corticosteroids, antimicrobials and probiotics. Further research will reveal more precise data on diagnosis, pathogenesis, management and prevention.

Methodology for a vaginal and urinary microbiome study in women with mixed urinary incontinence

INTRODUCTION AND HYPOTHESIS

We describe the rationale and methods of a study designed to compare vaginal and urinary microbiomes in women with mixed urinary incontinence (MUI) and similarly aged, asymptomatic controls.

METHODS

This paper delineates the methodology of a supplementary microbiome study nested in an ongoing randomized controlled trial comparing a standardized perioperative behavioral/pelvic floor exercise intervention plus midurethral sling versus midurethral sling alone for MUI. Women in the parent study had at least "moderate bother" from urgency and stress urinary incontinence symptoms (SUI) on validated questionnaire and confirmed MUI on bladder diary. Controls had no incontinence symptoms. All participants underwent vaginal and urine collection for DNA analysis and conventional urine culture. Standardized protocols were designed, and a central lab received samples for subsequent polymerase chain reaction (PCR) amplification and sequencing of the bacterial16S ribosomal RNA (rRNA) gene. The composition of bacterial communities will be determined by dual amplicon sequencing of variable regions 1-3 and 4-6 from vaginal and urine specimens to compare the microbiome of patients with controls. Sample-size estimates determined that 126 MUI and 84 control participants were sufficient to detect a 20 % difference in predominant urinary genera, with 80 % power and 0.05 significance level.

RESULTS

Specimen collection commenced January 2015 and finished April 2016. DNA was extracted and stored for subsequent evaluation.

CONCLUSIONS

Methods papers sharing information regarding development of genitourinary microbiome studies, particularly with control populations, are few. We describe the rigorous methodology developed for a novel urogenital microbiome study in women with MUI.

Vaginal ecosystem modeling of growth patterns of anaerobic bacteria in microaerophilic conditions

The human vagina constitutes a complex ecosystem created through relationships established between host mucosa and bacterial communities. In this ecosystem, classically defined bacterial aerobes and anaerobes thrive as communities in the microaerophilic environment. Levels of CO₂ and O₂ present in the vaginal lumen are impacted by both the ecosystem's physiology and the behavior and health of the human host. Study of such complex relationships requires controlled and reproducible causational approaches that are not possible in the human host that, until recently, was the only place these bacterial communities thrived. To address this need we have utilized our ex vivo human vaginal mucosa culture system to support controlled, reproducible colonization by vaginal bacterial communities (VBC) collected from healthy, asymptomatic donors. Parallel vaginal epithelial cells (VEC)-VBC co-cultures were exposed to two different atmospheric conditions to study the impact of CO₂ concentrations upon the anaerobic bacteria associated with dysbiosis and inflammation. Our data suggest that in the context of transplanted VBC, increased CO₂ favored specific lactobacilli species defined as microaerophiles when grown as monocultures. In preliminary studies, the observed community changes also led to shifts in host VEC phenotypes with significant changes in the host transcriptome, including altered expression of select molecular transporter genes. These findings support the need for additional study of the environmental changes associated with behavior and health upon the symbiotic and adversarial relationships that are formed in microbial communities present in the human vaginal ecosystem.

Mollicutes in vaginal microbiology: Mycoplasma hominis, Ureaplasma urealyticum, Ureaplasma parvum and Mycoplasma genitalium

Mycoplasma hominis was isolated in 1937 from the human genital tract, followed 17 years later by Ureaplasma urealyticum and 27 years after that by Mycoplasma genitalium. The first two proved relatively easy to culture but the latter required a polymerase chain reaction assay for further studies. In sexually mature women, M. hominis may be found in the vagina/cervix of about 20-50%, ureaplasmas in 40-80% and M. genitalium in 0-5%. Some heterogeneity has been found among strains of all these species, sufficient to divide ureaplasmas into two species, namely U. urealyticum and Ureaplasma parvum. Studies in female mice show that sex hormones have a profound influence on colonization, multiplication and persistence of mycoplasmas/ureaplasmas in the genital tract and provoke the question, unanswered, of whether there is such an effect in the human tract. In women, there is no evidence that any of the mycoplasmal species stimulate an inflammatory vaginitis. M. hominis organisms increase hugely in number in the case of bacterial vaginosis (BV), and to a lesser extent so do ureaplasmas. Despite this, they have not been incriminated as a sole cause of BV. Evidence for the involvement of M. genitalium remains controversial. The strong association of BV with preterm birth raises the possibility that the genital mycoplasmas might play a part, but assurance that any do will be difficult to obtain. Detailed examination of the vaginal microbiome has not yet provided an answer.

Analysis of the Vaginal Microbiome by Next-Generation Sequencing and Evaluation of its Performance as a Clinical Diagnostic Tool in Vaginitis

Background

Next-generation sequencing (NGS) can detect many more microorganisms of a microbiome than traditional methods. This study aimed to analyze the vaginal microbiomes of Korean women by using NGS that included bacteria and other microorganisms. The NGS results were compared with the results of other assays, and NGS was evaluated for its feasibility for predicting vaginitis.

Methods

In total, 89 vaginal swab specimens were collected. Microscopic examinations of Gram staining and microbiological cultures were conducted on 67 specimens. NGS was performed with GS junior system on all of the vaginal specimens for the 16S rRNA, internal transcribed spacer (ITS), and Tvk genes to detect bacteria, fungi, and Trichomonas vaginalis. In addition, DNA probe assays of the Candida spp., Gardnerella vaginalis, and Trichomonas vaginalis were performed. Various predictors of diversity that were obtained from the NGS data were analyzed to predict vaginitis.

Results

ITS sequences were obtained in most of the specimens (56.2%). The compositions of the intermediate and vaginitis Nugent score groups were similar to each other but differed from the composition of the normal score group. The fraction of the Lactobacillus spp. showed the highest area under the curve value (0.8559) in ROC curve analysis. The NGS and DNA probe assay results showed good agreement (range, 86.2-89.7%).

Conclusions

Fungi as well as bacteria should be considered for the investigation of vaginal microbiome. The intermediate and vaginitis Nugent score groups were indistinguishable in NGS. NGS is a promising diagnostic tool of the vaginal microbiome and vaginitis, although some problems need to be resolved.

Ovarian cycling and reproductive state shape the vaginal microbiota in wild baboons

BACKGROUND

The vaginal microbiome is an important site of bacterial-mammalian symbiosis. This symbiosis is currently best characterized for humans, where lactobacilli dominate the microbial community and may help defend women against infectious disease. However, lactobacilli do not dominate the vaginal microbiota of any other mammal studied to date, raising key questions about the forces that shape the vaginal microbiome in non-human mammals.

RESULTS

We used Illumina sequencing of the bacterial 16S rRNA gene to investigate variation in the taxonomic composition of the vaginal microbiota in 48 baboons (Papio cynocephalus), members of a well-studied wild population in Kenya. Similar to prior studies, we found that the baboon vaginal microbiota was not dominated by lactobacilli. Despite this difference, and similar to humans, reproductive state was the dominant predictor of baboon vaginal microbiota, with pregnancy, postpartum amenorrhea, and ovarian cycling explaining 18% of the variance in community composition. Furthermore, among cycling females, a striking 39% of variance in community composition was explained by ovarian cycle phase, with an especially distinctive microbial community around ovulation. Periovulatory females exhibited the highest relative abundance of lactic acid-producing bacteria compared to any other phase, with a mean relative abundance of 44%. To a lesser extent, sexual behavior, especially a history of shared sexual partners, also predicted vaginal microbial similarity between baboons.

CONCLUSIONS

Despite striking differences in their dominant microbes, both human and baboon vaginal microbiota exhibit profound changes in composition in response to reproductive state, ovarian cycle phase, and sexual behavior. We found major shifts in composition during ovulation, which may have implications for disease risk and conception success. These findings highlight the need for future studies to account for fine-scale differences in reproductive state, particularly differences between the various phases of the ovarian cycle. Overall, our work contributes to an emerging understanding of the forces that explain intra- and inter-individual variation in the mammalian vaginal microbiome, with particular emphasis on its role in host health and disease risk.

The interaction between vaginal microbiota, cervical length, and vaginal progesterone treatment for preterm birth risk

BACKGROUND

Preterm birth is the primary cause of infant death worldwide. A short cervix in the second trimester of pregnancy is a risk factor for preterm birth. In specific patient cohorts, vaginal progesterone reduces this risk. Using 16S rRNA gene sequencing, we undertook a prospective study in women at risk of preterm birth (n = 161) to assess (1) the relationship between vaginal microbiota and cervical length in the second trimester and preterm birth risk and (2) the impact of vaginal progesterone on vaginal bacterial communities in women with a short cervix.

RESULTS

Lactobacillus iners dominance at 16 weeks of gestation was significantly associated with both a short cervix <25 mm (n = 15, P < 0.05) and preterm birth <34⁺⁰ weeks (n = 18; P < 0.01; 69% PPV). In contrast, Lactobacillus crispatus dominance was highly predictive of term birth (n = 127, 98% PPV). Cervical shortening and preterm birth were not associated with vaginal dysbiosis. A longitudinal characterization of vaginal microbiota (<18, 22, 28, and 34 weeks) was then undertaken in women receiving vaginal progesterone (400 mg/OD, n = 25) versus controls (n = 42). Progesterone did not alter vaginal bacterial community structure nor reduce L. iners-associated preterm birth (<34 weeks).

CONCLUSIONS

L. iners dominance of the vaginal microbiota at 16 weeks of gestation is a risk factor for preterm birth, whereas L. crispatus dominance is protective against preterm birth. Vaginal progesterone does not appear to impact the pregnancy vaginal microbiota. Patients and clinicians who may be concerned about "infection risk" associated with the use of a vaginal pessary during high-risk pregnancy can be reassured.