Vaginal Microbiota Composition Correlates Between Pap Smear Microscopy and Next Generation Sequencing and Associates to Socioeconomic Status

Untangling Associations of Microbiomes of Pregnancy and Preterm Birth

This review illuminates the complex interplay between various maternal microbiomes and their influence on preterm birth (PTB), a driving and persistent contributor to neonatal morbidity and mortality. Here, we examine the dynamics of oral, gastrointestinal (gut), placental, and vaginal microbiomes, dissecting their roles in the pathogenesis of PTB. Importantly, focusing on the vaginal microbiome and PTB, the review highlights (1) a protective role of Lactobacillus species; (2) an increased risk with select anaerobes; and (3) the influence of social health determinants on the composition of vaginal microbial communities.

Host factors are associated with vaginal microbiome structure in pregnancy in the ECHO Cohort Consortium

Using pooled vaginal microbiota data from pregnancy cohorts (N = 683 participants) in the Environmental influences on Child Health Outcomes (ECHO) Program, we analyzed 16S rRNA gene amplicon sequences to identify clinical and demographic host factors that associate with vaginal microbiota structure in pregnancy both within and across diverse cohorts. Using PERMANOVA models, we assessed factors associated with vaginal community structure in pregnancy, examined whether host factors were conserved across populations, and tested the independent and combined effects of host factors on vaginal community state types (CSTs) using multinomial logistic regression models. Demographic and social factors explained a larger amount of variation in the vaginal microbiome in pregnancy than clinical factors. After adjustment, lower education, rather than self-identified race, remained a robust predictor of L. iners dominant (CST III) and diverse (CST IV) (OR = 8.44, 95% CI = 4.06-17.6 and OR = 4.18, 95% CI = 1.88-9.26, respectively). In random forest models, we identified specific taxonomic features of host factors, particularly urogenital pathogens associated with pregnancy complications (Aerococcus christensenii and Gardnerella spp.) among other facultative anaerobes and key markers of community instability (L. iners). Sociodemographic factors were robustly associated with vaginal microbiota structure in pregnancy and should be considered as sources of variation in human microbiome studies.

Economic microbiology: exploring microbes as agents in economic systems

Microbial communities exhibit striking parallels with economic markets, resembling intricate ecosystems where microorganisms engage in resource exchange akin to human market transactions. This dynamic network of resource swapping mirrors economic trade in human markets, with microbes specializing in metabolic functions much like businesses specializing in goods and services. Cooperation and competition are central dynamics in microbial communities, with alliances forming for mutual benefit and species vying for dominance, similar to businesses seeking market share. The human microbiome, comprising trillions of microorganisms within and on our bodies, is not only a marker of socioeconomic status but also a critical factor contributing to persistent health inequalities. Social and economic factors shape the composition of the gut microbiota, impacting healthcare access and quality of life. Moreover, these microbes exert indirect influence over human decisions by affecting neurotransmitter production, influencing mood, behavior, and choices related to diet and emotions. Human activities significantly impact microbial communities, from dietary choices and antibiotic use to environmental changes, disrupting these ecosystems. Beyond their natural roles, humans harness microbial communities for various applications, manipulating their interactions and resource exchanges to achieve specific goals in fields like medicine, agriculture, and environmental science. In conclusion, the concept of microbial communities as biological markets offers valuable insights into their intricate functioning and adaptability. It underscores the profound interplay between microbial ecosystems and human health and behavior, with far-reaching implications for multiple disciplines. To paraphrase Alfred Marshall, "the Mecca of the economist lies in economic microbiology."

Changes in the Vaginal Microbiome During Pregnancy and the Postpartum Period in South African Women: a Longitudinal Study

Pregnant women in sub-Saharan Africa have high rates of maternal morbidity. There is interest in the impact of the vaginal microbiome on maternal health, including HIV and sexually transmitted infection (STI) acquisition. We characterized the vaginal microbiota of South African women ≥ 18 years with and without HIV in a longitudinal cohort over two visits during pregnancy and one visit postpartum. At each visit, we obtained HIV testing and self-collected vaginal swabs for point-of-care testing for STIs and microbiota sequencing. We categorized microbial communities and evaluated changes over pregnancy and associations with HIV status and STI diagnosis. Across 242 women (mean age 29, 44% living with HIV, 33% diagnosed with STIs), we identified four main community state types (CSTs): two lactobacillus-dominant CSTs (dominated by Lactobacillus crispatus and Lactobacillus iners respectively) and two diverse, non-lactobacillus-dominant CSTs (one dominated by Gardnerella vaginalis and one by diverse facultative anaerobes). From the first antenatal visit to the third trimester (24-36 weeks gestation), 60% of women in the Gardnerella-dominant CST shifted to lactobacillus-dominant CSTs. From the third trimester to postpartum (mean 17 days post-delivery), 80% of women in lactobacillus-dominant CSTs shifted to non-lactobacillus-dominant CSTs with a large proportion in the facultative anaerobe-dominant CST. Microbial composition differed by STI diagnosis (PERMANOVA R2 = 0.002, p = 0.004), and women diagnosed with an STI were more likely to be categorized as L. iners-dominant or Gardnerella-dominant CSTs. Overall, we found a shift toward lactobacillus dominance during pregnancy and the emergence of a distinct, highly diverse anaerobe-dominant microbiota profile in the postpartum period.

Longitudinal analysis of vaginal microbiota during IVF fresh embryo transfer and in early pregnancy

IMPORTANCE

Infertility is a global public health issue which leads many couples to seek fertility treatments, of which in vitro fertilization (IVF) is considered to be the most effective. Still, only about one-third of the women achieve live birth after the first IVF embryo transfer (IVF-ET). Factors affecting embryo implantation are poorly known, but the female reproductive tract microbiota may play a key role. Our study confirms the beneficial role of vaginal lactobacilli, especially Lactobacillus crispatus, in the probability of achieving clinical pregnancy and live birth following IVF-ET. Our findings regarding the intra-individual shift of vaginal microbiota between non-pregnancy and pregnancy states are novel and provide new information about the dynamics of microbiota in the early steps of human reproduction. These findings may help clinicians in their attempts to optimize the conditions for ET by microbiota screening or modulation and timing the ET when the microbiota is the most favorable.

Structural Racism and Adverse Pregnancy Outcomes Through the Lens of the Maternal Microbiome

Microbiome science offers a glimpse into personalized medicine by characterizing health and disease states according to an individual's microbial signatures. Without a critical examination of the use of race as a variable, microbiome studies may be susceptible to the same pitfalls as other areas of science grounded in racist biology. We will examine the use of race as a biological variable in pregnancy-related microbiome research. Emerging data from studies that investigate the intestinal microbiome in pregnancy suggest strong influence of a poor diet on adverse pregnancy outcomes. Differences in the vaginal microbiome implicated in adverse pregnancy outcomes are frequently attributed to race. We review evidence that links systemic racism to pregnancy health outcome differences with a focus on the vaginal and intestinal microbiomes as well as diet. We also review how structural racism ultimately contributes to inequitable access to healthy food and higher risk environmental exposures among pregnant people of lower socioeconomic status and exacerbates common pregnancy comorbidities.

Joint effects of individual socioeconomic status and residential neighborhood context on vaginal microbiome composition

Introduction

The vaginal microbiome is a dynamic ecosystem that is important for women's health. Its composition has been associated with risk for menopausal symptoms, sexually transmitted infections, gynecologic cancer, and preterm birth. Conventional risk factors for a vaginal microbiome linked with these adverse health outcomes include sexual behaviors, hygiene practices, individual social factors, and stress levels. However, there has been limited research on socio-contextual determinants, and whether neighborhood context modifies the association with individual socioeconomic factors.

Methods

Socioeconomically diverse pregnant African American women in Atlanta, Georgia (n = 439) provided residential addresses and first trimester vaginal swab samples, which underwent sequencing, taxonomic classification, and assignment into mutually exclusive CST (community state types) via hierarchical clustering. Linear probability models were used to estimate prevalence differences (PD) for the associations of neighborhood factors with vaginal microbiome CST and to evaluate for additive interaction with maternal level of education, health insurance type, and recruitment hospital.

Results

Factors such as higher (vs. lower) maternal education, private (vs. public) insurance, and private (vs. public) hospital were associated with higher prevalence of Lactobacillus-dominant vaginal microbiome CSTs typically associated with better health outcomes. When considering the joint effects of these individual socioeconomic status and residential neighborhood factors on vaginal microbiome CST, most combinations showed a greater than additive effect among the doubly exposed; however, in the case of local income homogeneity and local racial homogeneity, there was evidence of a crossover effect between those with less-advantaged individual socioeconomic status and those with more-advantaged individual socioeconomic status. Compared to women at the public hospital who lived in economically diverse neighborhoods, women at the private hospital who lived in economically diverse neighborhoods had a 21.9% higher prevalence of Lactobacillus-dominant CSTs, while women at the private hospital who lived in less economically diverse neighborhoods (the doubly exposed) had only an 11.7% higher prevalence of Lactobacillus-dominant CSTs, showing a crossover effect (interaction term p-value = 0.004).

Discussion

In this study, aspects of residential neighborhood context were experienced differently by women on the basis of their individual resources, and the joint effects of these exposures on vaginal microbiome CST showed a departure from simple additivity for some factors.

Transplantation of maternal intestinal flora to the newborn after elective cesarean section (SECFLOR): study protocol for a double blinded randomized controlled trial

Background

A complication of elective cesarean section (CS) delivery is its interference with the normal intestinal colonization of the infant, affecting the immune and metabolic signaling in early life— a process that has been associated with long-term morbidity, such as allergy and diabetes. We evaluate, in CS-delivered infants, whether the normal intestinal microbiome and its early life development can be restored by immediate postnatal transfer of maternal fecal microbiota (FMT) to the newborn, and how this procedure influences the maturation of the immune system.

Methods

Sixty healthy mothers with planned elective CS are recruited and screened thoroughly for infections. A maternal fecal sample is taken prior to delivery and processed according to a transplantation protocol. After double blinded randomization, half of the newborns will receive a diluted aliquot of their own mother’s stool orally administered in breast milk during the first feeding while the other half will be similarly treated with a placebo. The infants are clinically followed, and fecal samples are gathered weekly until the age of 4 weeks, then at the ages of 8 weeks, 3, 6, 12 and 24 months. The parents fill in questionnaires until the age of 24 months. Blood samples are taken at the age of 2–3 days and 3, 6, 12 and 24 months to assess development of major immune cell populations and plasma proteins throughout the first years of life.

Discussion

This is the first study to assess long-time effects on the intestinal microbiome and the development of immune system of a maternal fecal transplant given to term infants born by CS.

Trial registration

ClinicalTrials.gov NCT04173208, registration date 21.11.2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03609-3.

Cervicovaginal Complement Activation and Microbiota During Pregnancy and in Parturition

Background

Vaginal microbiome and the local innate immune defense, including the complement system, contribute to anti- and proinflammatory homeostasis during pregnancy and parturition. The relationship between commensal vaginal bacteria and complement activation during pregnancy and delivery is not known.

Objective

To study the association of the cervicovaginal microbiota composition to activation and regulation of the complement system during pregnancy and labor.

Study design

We recruited women during late pregnancy (weeks 41 + 5 to 42 + 0, n=48) and women in active labor (weeks 38 + 4 to 42 + 2, n=25). Mucosal swabs were taken from the external cervix and lateral fornix of the vagina. From the same sampling site, microbiota was analyzed with 16S RNA gene amplicon sequencing. A Western blot technique was used to detect complement C3, C4 and factor B activation and presence of complement inhibitors. For semiquantitative analysis, the bands of the electrophoresed proteins in gels were digitized on a flatbed photo scanner and staining intensities were analyzed using ImageJ/Fiji win-64 software. Patient data was collected from medical records and questionnaires.

Results

The vaginal microbiota was Lactobacillus-dominant in most of the samples (n=60), L. iners and L. crispatus being the dominant species. L. gasseri and L. jensenii were found to be more abundant during pregnancy than active labor. L. jensenii abundance correlated with C4 activation during pregnancy but not in labor. Gardnerella vaginalis was associated with C4 activation both during pregnancy and labor. The amount of L. gasseri correlated with factor B activation during pregnancy but not during labor. Atopobium vaginae was more abundant during pregnancy than labor and correlated with C4 activation during labor and with factor B activation during pregnancy. Activation of the alternative pathway factor B was significantly stronger during pregnancy compared to labor. During labor complement activation may be inhibited by the abundant presence of factor H and FHL1.

Conclusions

These results indicate that bacterial composition of the vaginal microbiota could have a role in the local activation and regulation of complement-mediated inflammation during pregnancy. At the time of parturition complement activation appears to be more strictly regulated than during pregnancy.

Parity and gestational age are associated with vaginal microbiota composition in term and late term pregnancies

Background

Vaginal microbiota and its potential contribution to preterm birth is under intense research. However, only few studies have investigated the vaginal microbiota in later stages of pregnancy or at the onset of labour.

Methods

We used 16S rRNA gene amplicon sequencing to analyse cross-sectional vaginal swab samples from 324 Finnish women between 37–42 weeks of gestation, sampled before elective caesarean section, at the onset of spontaneous labour, and in pregnancies lasting ≥41 weeks of gestation. Microbiota data were combined with comprehensive clinical data to identify factors associated with microbiota variation.

Findings

Vaginal microbiota composition associated strongly with advancing gestational age and parity, i.e. presence of previous deliveries. Absence of previous deliveries was a strong predictor of Lactobacillus crispatus dominated vaginal microbiota, and the relative abundance of L. crispatus was higher in late term pregnancies, especially among nulliparous women.

Interpretation

This study identified late term pregnancy and reproductive history as factors underlying high abundance of gynaecological health-associated L. crispatus in pregnant women. Our results suggest that the vaginal microbiota affects or reflects the regulation of the duration of gestation and labour onset, with potentially vast clinical utilities. Further studies are needed to address the causality and the mechanisms on how previous labour, but not pregnancy, affects the vaginal microbiota. Parity and gestational age should be accounted for in future studies on vaginal microbiota and reproductive outcomes.

Funding

This research was supported by EU H2020 programme Sweet Crosstalk ITN (814102), Academy of Finland, State Research Funding, and University of Helsinki.

The vaginal microbiome: A complex milieu affecting risk of human papillomavirus persistence and cervical cancer

The purpose of this review is to describe the existing literature regarding the relationship between the vaginal microbiome, human papillomavirus persistence, and cervical cancer risk, as well as to discuss factors that mediate these relationships. Data suggest that alterations in the vaginal microbiome affect the risk of human papillomavirus infection and persistence, which has downstream effects on cervical dysplasia and cancer risk. The homeostatic Lactobillus species L. crispatus, L. gasseri, L. jensenii act to promote a healthy vaginal environment, while L. iners and pathogens causing bacterial vaginosis are associated with increased inflammation, human papillomavirus infection, cervical dysplasia, and potentially cancer. There are, however, still several large gaps in the literature, particularly related to the modifiable and non-modifiable factors that affect the vaginal microbiome and ensuing risk of pre-cancerous and cancerous lesions. Evidence currently suggests that endogenous and exogenous hormones, tobacco products, and sexual practices influence vaginal microbiome composition, but the nuances of these relationships and how changes in these factors affect dysplasia risk are yet to be delineated. Other studies examining how diet, exercise, race, socioeconomic status, and genetic factors influence the vaginal microbiome are difficult to interpret in the setting of multiple confounders. Future studies should focus on how changes in these modulatory factors might promote a healthy vaginal microbiome to prevent or treat dysplasia in the lower female genital tract.

Potential pathobionts in vaginal microbiota are affected by fish oil and/or probiotics intervention in overweight and obese pregnant women

New means to stabilize the microbial balance during pregnancy could benefit maternal health. Our objectives were to investigate in overweight/obese pregnant women 1) the impact of long-chain polyunsaturated fatty acids (fish oil) and/or probiotics on the vaginal microbiota, 2) its relation to gestational diabetes mellitus (GDM) and 3) its interaction with vaginal active matrix metalloproteinase-8 (aMMP-8) and serum high sensitivity C-reactive protein (hsCRP) and phosphorylated insulin-like growth factor-binding protein-1 (phIGFBP-1), IGFBP-1 and aMMP-8. The women were allocated to fish oil + placebo, probiotics + placebo, fish oil + probiotics and placebo + placebo-groups, from early pregnancy onwards (fish oil: 1.9 g docosahexaenoic acid and 0.22 g eicosapentaenoic acid; probiotics: Lacticaseibacillus rhamnosus HN001 (formerly Lactobacillus rhamnosus HN001) and Bifidobacterium animalis ssp. lactis 420, 10¹⁰ colony-forming units each). Vaginal and serum samples (early pregnancy, n = 112; late pregnancy, n = 116), were analyzed for vaginal microbiota using 16S rRNA gene amplicon sequencing and vaginal aMMP-8 and serum hsCRP, aMMP-8, phIGFBP-1 and IGFBP-1 by immunoassays. GDM was diagnosed from a 2-h 75 g OGTT. ClinicalTrials.gov, NCT01922791. The intervention exerted effects on many low-abundant bacteria. Compared to the placebo-group, there was a lower abundance of potential pathobionts, namely Ureaplasma urealyticum in the fish oil-group, Ureaplasma, U. urealyticum and Prevotella disiens in the probiotics-group, Dialister invisus and Prevotella timonensis in the fish oil + probiotics-group. Moreover, probiotics decreased the abundance of a few potential pathobionts during pregnancy. Many bacteria were related to GDM. The vaginal aMMP-8 level correlated significantly with α-diversity and inversely with two Lactobacillus species. Dietary interventions, especially probiotics, may have beneficial effects on the vaginal microbiota during pregnancy.

Healthy Vaginal Microbiota and Influence of Probiotics Across the Female Life Span

Vaginal microbiota plays a central role in women’s health and reproduction. Vaginal microbiota is dynamic and shaped by hormonal shifts in each stage of a woman’s life from pre-puberty to postmenopause. Current research has mainly focused on vaginal bacterial and fungal members of the community and emphasized their role in disease. However, the impact of balanced vaginal microbiota on health and its interaction with the host is yet poorly understood. High abundance of vaginal lactobacilli is most strongly associated with health, but the concept of health may vary as vaginal dysbiosis may be asymptomatic. Furthermore, there is a lot of variation between ethnic groups in terms of dominating vaginal bacteria. Probiotic lactobacilli could be a safe and natural means to balance and maintain healthy vaginal microbiota. Research evidence is accumulating on their role in supporting women’s health throughout life. This review describes the current literature on vaginal microbiota, the major factors affecting its composition, and how the communities change in different life stages. Furthermore, we focused on reviewing available literature on probiotics and their impact on vaginal microbiota and health.

Vaginal Secretion Epithelium Count as a Prognostic Indicator of High Abundance of Ureaplasmas in Women with a Normal Nugent Score

Genital tract ureaplasma infections are associated with numerous complications, ranging from inflammation, through infertility, to problematic pregnancy. In the course of ureaplasma infection, the risk of human papillomavirus infection increases. Diagnostic tests for urea-plasma infections are not always carried out, especially in women with the normal Nugent test results. The study attempts to check whether it is possible to find a prognostic indicator that could suggest a high abundance of ureaplasmas (≥ 10⁴ CFU/ml) at the stage of the initial examination of vaginal discharge. Such a prognostic factor could qualify women for further tests to detect infections with these atypical bacteria. Six hundred twenty-seven white women with a score of 0–3 on the Nugent scale were tested, including 322 patients with a high abundance of ureaplasmas (≥ 10⁴ CFU/ml) and 305 who tested negative for these bacteria. Ureaplasma infections were detected statistically significant in women who had few or no epithelial cells in the genital swab specimens compared to the results obtained for women with numerous or very numerous epithelial cells (p < 0.001). The risk of the high density of ureaplasmas was 38.7% higher with fewer or no epithelial cells than with high numbers. In patients aged 18–40 years with few or no epithelial cells, a high density of ureaplasmas (≥ 10⁴ CFU/ml) was observed significantly more frequently (p = 0.003). Determining the number of epithelial cells in Gram-stained slides may be the prognostic indicator of ureaplasma infection. Testing for genital ureaplasma infection should be considered, especially in women of childbearing age (18–40 years), even if the Nugent test value is normal and pH ≤ 4.6.

Fecal Bacteria Implicated in Biofilm Production Are Enriched and Associate to Gastrointestinal Symptoms in Patients With APECED - A Pilot Study

Backgrounds and Aims

APECED is a rare autoimmune disease caused by mutations in the Autoimmune Regulator gene. A significant proportion of patients also have gastrointestinal symptoms, including malabsorption, chronic diarrhea, and obstipation. The pathological background of the gastrointestinal symptoms remains incompletely understood and involves multiple factors, with autoimmunity being the most common underlying cause. Patients with APECED have increased immune responses against gut commensals. Our objective was to evaluate whether the intestinal microbiota composition, predicted functions or fungal abundance differ between Finnish patients with APECED and healthy controls, and whether these associate to the patients' clinical phenotype and gastrointestinal symptoms.

Methods

DNA was isolated from fecal samples from 15 patients with APECED (median age 46.4 years) together with 15 samples from body mass index matched healthy controls. DNA samples were subjected to analysis of the gut microbiota using 16S rRNA gene amplicon sequencing, imputed metagenomics using the PICRUSt2 algorithm, and quantitative PCR for fungi. Extensive correlations of the microbiota with patient characteristics were determined.

Results

Analysis of gut microbiota indicated that both alpha- and beta-diversity were altered in patients with APECED compared to healthy controls. The fraction of Faecalibacterium was reduced in patients with APECED while that of Atopobium spp. and several gram-negative genera previously implicated in biofilm formation, e.g. Veillonella, Prevotella, Megasphaera and Heamophilus, were increased in parallel to lipopolysaccharide (LPS) synthesis in imputed metagenomics. The differences in gut microbiota were linked to patient characteristics, especially the presence of anti-Saccharomyces cerevisiae antibodies (ASCA) and severity of gastrointestinal symptoms.

Conclusions

Gut microbiota of patients with APECED is altered and enriched with predominantly gram-negative bacterial taxa that may promote biofilm formation and lead to increased exposure to LPS in the patients. The most pronounced alterations in the microbiota were associated with more severe gastrointestinal symptoms.

Correlations between microbiota and metabolites after faecal microbiota transfer in irritable bowel syndrome

Faecal microbiota transfer (FMT) consists of the infusion of donor faecal material into the intestine of a patient with the aim to restore a disturbed gut microbiota. In this study, it was investigated whether FMT has an effect on faecal microbial composition, its functional capacity, faecal metabolite profiles and their interactions in 16 irritable bowel syndrome (IBS) patients. Faecal samples from eight different time points before and until six months after allogenic FMT (faecal material from a healthy donor) as well as autologous FMT (own faecal material) were analysed by 16S RNA gene amplicon sequencing and gas chromatography coupled to mass spectrometry (GS-MS). The results showed that the allogenic FMT resulted in alterations in the microbial composition that were detectable up to six months, whereas after autologous FMT this was not the case. Similar results were found for the functional profiles, which were predicted from the phylogenetic sequencing data. While both allogenic FMT as well as autologous FMT did not have an effect on the faecal metabolites measured in this study, correlations between the microbial composition and the metabolites showed that the microbe-metabolite interactions seemed to be disrupted after allogenic FMT compared to autologous FMT. This shows that FMT can lead to altered interactions between the gut microbiota and its metabolites in IBS patients. Further research should investigate if and how this affects efficacy of FMT treatments.

The Association Between Vaginal Microbiota Dysbiosis, Bacterial Vaginosis, and Aerobic Vaginitis, and Adverse Pregnancy Outcomes of Women Living in Sub-Saharan Africa: A Systematic Review

Background: Previous studies have described the association between dysbiosis of the vaginal microbiota (VMB) and related dysbiotic conditions, such as bacterial vaginosis (BV) and aerobic vaginitis (AV), and various adverse pregnancy outcomes. There is limited overview of this association from countries in sub-Saharan Africa (SSA), which bear a disproportionally high burden of both vaginal dysbiotic conditions and adverse pregnancy outcomes. This systematic review assesses the evidence on the association between VMB dysbiosis, BV, and AV, and late adverse pregnancy outcomes in women living in SSA.

Methods: The Preferred Reporting Items for Systematic Review and Meta-Analysis Statement (PRISMA) guidelines were followed. Three databases [PubMed, Embase (Ovid), and Cochrane] were used to retrieve observational and intervention studies conducted in SSA that associated VMB dysbiosis, BV, or AV and preterm birth/labor/delivery, preterm rupture of membranes (PROM), low birthweight, small for gestational age, intrauterine growth restriction, intrauterine infection, intrauterine (fetal) death, stillbirth, perinatal death, or perinatal mortality.

Results: Twelve studies out of 693 search records from five SSA countries were included. One study identified a positive association between VMB dysbiosis and low birthweight. Despite considerable differences in study design and outcome reporting, studies reported an association between BV and preterm birth (7/9), low birthweight (2/6), PROM (2/4), intrauterine infections (1/1), and small for gestational age (1/1). None of the retrieved studies found an association between BV and pregnancy loss (5/5) or intrauterine growth retardation (1/1). At least two studies support the association between BV and PROM, low birthweight, and preterm birth in Nigerian pregnant women. No reports were identified investigating the association between AV and late adverse pregnancy outcomes in SSA.

Conclusion: Two of the included studies from SSA support the association between BV and PROM. The remaining studies show discrepancies in supporting an association between BV and preterm birth or low birthweight. None of the studies found an association between BV and pregnancy loss. As for the role of VMB dysbiosis, BV, and AV during pregnancy among SSA women, additional research is needed. These results provide useful evidence for prevention efforts to decrease vaginal dysbiosis and its contribution to adverse pregnancy outcomes in SSA.

Revealing the Disturbed Vaginal Micobiota Caused by Cervical Cancer Using High-Throughput Sequencing Technology

Cervical cancer is the fourth most prevalent cancer type among all malignancies, so it is of great significance to find its actual pathogenesis mechanisms. In the present study, 90 women were enrolled, and high-throughput sequencing technology was firstly used to analyze the vaginal microbiota of healthy women (C group), cervical intraepithelial neoplasia patients (CIN group) and cervical cancer patients (CER group). Our results indicates that compared with C group, a higher HPV infection rate as well as increased Neutrophil ratio and tumor marker squamous cell carcinoma antigen (SCCA) were obtained, and a decrease in Lymphocyte ratio and Hemoglobin were also present. In addition, the cervical cancer showed a strong association with reduced probiotics Lactobacillus, increased pathogens Prevotella spp., Sneathia spp. and Pseudomonas spp. These results prove that the immunological changes generated by the cervical cancer and the vaginal microbiota can interact with each other. However, further study investigating the key bacteria for cervical cancer is still needed, which can be a clue for the diagnosis or treatment of cervical cancer.

Shotgun sequencing of the vaginal microbiome reveals both a species and functional potential signature of preterm birth

An association between the vaginal microbiota and preterm birth (PTB) has been reported in several research studies. Population shifts from high proportions of lactobacilli to mixed species communities, as seen with bacterial vaginosis, have been linked to a twofold increased risk of PTB. Despite the increasing number of studies using next-generation sequencing technologies, primarily involving 16S rRNA-based approaches, to investigate the vaginal microbiota during pregnancy, no distinct microbial signature has been associated with PTB. Shotgun metagenomic sequencing offers a powerful tool to reveal community structures and their gene functions at a far greater resolution than amplicon sequencing. In this study, we employ shotgun metagenomic sequencing to compare the vaginal microbiota of women at high risk of preterm birth (n = 35) vs. a low-risk control group (n = 14). Although microbial diversity and richness did not differ between groups, there were significant differences in terms of individual species. In particular, Lactobacillus crispatus was associated with samples from a full-term pregnancy, whereas one community state-type was associated with samples from preterm pregnancies. Furthermore, by predicting gene functions, the functional potential of the preterm microbiota was different from that of full-term equivalent. Taken together, we observed a discrete structural and functional difference in the microbial composition of the vagina in women who deliver preterm. Importance: with an estimated 15 million cases annually, spontaneous preterm birth (PTB) is the leading cause of death in infants under the age of five years. The ability to accurately identify pregnancies at risk of spontaneous PTB is therefore of utmost importance. However, no single cause is attributable. Microbial infection is a known risk factor, yet the role of vaginal microbes is poorly understood. Using high-resolution DNA-sequencing techniques, we investigate the microbial communities present in the vaginal tracts of women deemed high risk for PTB. We confirm that Lactobacillus crispatus is strongly linked to full-term pregnancies, whereas other microbial communities associate with PTB. Importantly, we show that the specific functions of the microbes present in PTB samples differs from FTB samples, highlighting the power of our sequencing approach. This information enables us to begin understanding the specific microbial traits that may be influencing PTB, beyond the presence or absence of microbial taxa.

Vaginal microbiota evaluation and prevalence of key pathogens in ecuadorian women: an epidemiologic analysis

Vaginal infection is a gynecological problem in women of reproductive age with multiple health outcomes. The most common forms of infection include bacterial vaginosis (BV), vulvovaginal candidiasis (VC), and aerobic vaginitis (AV). Our main goals were to evaluate different types of vaginal infections in Ecuadorian women in a large urban area (Quito) and to characterize the vaginal microbiota colonization by opportunistic species. We collected vaginal swabs and epidemiological surveys from 414 women from June 2016 to July of 2017. We analyzed vaginal samples for the presence of any vaginal infection. The microbiological examination was done through Gram-stain, wet mount smears, and polymerase chain reaction (PCR) assays using primers for target genes, such as 16S rRNA (Atopobium vaginae, Mobiluncus mulieris, and Gardnerella species), ddl (Enterococcus faecalis), adk (Escherichia coli) and KER1 (Candida albicans) genes. Most women showed a healthy vaginal microbiota (66.7%). Nearly one-tenth (10.4%) of the participants had intermediate microbiota, and the remaining women (22.9%) had a single vaginal infection (BV, AV, or VC) or coinfections. From the 95 participants that had an infection, AV was the main diagnosed vaginal infection (51.6%), followed by BV (24.2%) and finally VC (7.4%). The remaining women (16.8%) showed coinfections, being BV and AV the most common coinfection. Using univariable logistic regression analyses we found an increased odds of healthy microbiota in women with a sexual partner (P = 0.02, OR = 1.64). Also, women in a free union relationship (P = 0.000, OR = 16.65) had an increased odds of having coinfections. On the other hand, the use of birth control (condom OR = 0.388 or other contraceptive method OR = 0.363) was associated with significantly lower odds of intermediate microbiota (P ≤ 0.05). We found no statistically significant differences between women with infection and a particular group age. Using multivariate logistic regression analyses we initially found an increased odds of having BV in women with M. mulieris (P = 0.020, OR = 4.98) and Gardnerella species (P = 0.010, OR = 4.16). Women with E. coli showed an increased odds of having AV (P = 0.009, OR = 2.81). The presence of C. albicans in women showed an increased odds of having VC (P = 0.007, OR = 17.94). Finally, women with M. mulieris showed a reverse odds of having healthy microbiota (P = 0.008, OR = 0.06). We found no statistically significant differences between women with symptomatic and asymptomatic infections or the presence of Enterococcus faecalis. We found using logistic regression analyses that M. mulieris was the most prevalent opportunistic pathogen among women with vaginal infection. Further studies should evaluate the possibility to use M. mulieris as a potential key predictor for vaginal infections.

Changes in the vaginal microbiota following antibiotic treatment for Mycoplasma genitalium, Chlamydia trachomatis and bacterial vaginosis

The human vagina harbor a rich microbiota. The optimal state is dominated by lactobacilli that help to maintain health and prevent various diseases. However, the microbiota may rapidly change to a polymicrobial state that has been linked to a number of diseases. In the present study, the temporal changes of the vaginal microbiota in patients treated for sexually transmitted diseases or bacterial vaginosis (BV) and in untreated controls were studied for 26 days. The patients included 52 women treated with azithromycin, tetracyclines or moxifloxacin for present or suspected infection with Chlamydia trachomatis or Mycoplasma genitalium. Women with concurrent BV were also treated with metronidazole. The controls were 10 healthy women of matching age. The microbiota was analyzed by 16S rRNA gene deep sequencing, specific qPCRs and microscopy. There was generally good correlation between Nugent score and community state type (CST) and qPCR confirmed the sequencing results. By sequencing, more than 600 different taxa were found, but only 33 constituted more than 1 ‰ of the sequences. In both patients and controls the microbiota could be divided into three different community state types, CST-I, CST-III and CST-IV. Without metronidazole, the microbiota remained relatively stable regarding CST although changes were seen during menstrual periods. Administration of metronidazole changed the microbiota from CST-IV to CST-III in approximately 50% of the treated patients. In contrast, the CST was generally unaffected by azithromycin or tetracyclines. In 30% of the BV patients, Gardnerella vaginalis was not eradicated by metronidazole. The majority of women colonized with Ureaplasma parvum remained positive after azithromycin while U. urealyticum was eradicated.

Recovery of Vaginal Microbiota After Standard Treatment for Bacterial Vaginosis Infection: An Observational Study

Vaginal microbiota dysbiosis and bacterial vaginosis (BV) affect negatively women’s health. Understanding vaginal microbiota fluctuations in BV during and after antibiotic treatment would facilitate accurate decision-making on the treatment regimen, avoid unnecessary antibiotic use, and potentially mitigate recurrence. We investigated vaginal microbiota composition of 30 women with BV before and after 5-day metronidazole treatment and compared the results with 30 healthy women. Vaginal microbiota was assessed by Nugent score and analyzed by 16S rRNA gene sequencing in swabs on baseline Day 1, and on Day 8 and 15, after completion of antibiotic treatment by women with BV. Prior to antibiotic treatment (Day 1), BV-positive women were dominated by Lactobacillus iners (25.8%), Prevotella timonensis/bivia (18.0%), and Gardnerella vaginalis (14.6%), whereas healthy women were dominated by L. iners (37.5%) and Lactobacillus crispatus/acidophilus (19.2%). On Day 8, L. iners abundance increased in BV-treated women being significantly higher compared with healthy women (67.8% vs. 37.5%, p = 0.049). On Day 15, the relative abundance of all microbial taxa was similar between the groups. Vaginal microbiota of women with BV shifted to resemble that of healthy controls after metronidazole. Sequencing analysis provides more in-depth understanding of changes in vaginal microbiota. The role of L. iners in vaginal health and dysbiosis requires further investigations.

Diversity of vaginal microbiome and metabolome during genital infections

We characterized the vaginal ecosystem during common infections of the female genital tract, as vulvovaginal candidiasis (VVC, n = 18) and Chlamydia trachomatis infection (CT, n = 20), recruiting healthy (HC, n = 21) and bacterial vaginosis-affected (BV, n = 20) women as references of eubiosis and dysbiosis. The profiles of the vaginal microbiome and metabolome were studied in 79 reproductive-aged women, by means of next generation sequencing and proton based-nuclear magnetic resonance spectroscopy. Lactobacillus genus was profoundly depleted in all the genital infections herein considered, and species-level analysis revealed that healthy vaginal microbiome was dominated by L. crispatus. In the shift from HC to CT, VVC, and BV, L. crispatus was progressively replaced by L. iners. CT infection and VVC, as well as BV condition, were mainly characterised by anaerobe genera, e.g. Gardnerella, Prevotella, Megasphaera, Roseburia and Atopobium. The changes in the bacterial communities occurring during the genital infections resulted in significant alterations in the vaginal metabolites composition, being the decrease of lactate a common marker of all the pathological conditions. In conclusion, according to the taxonomic and metabolomics analysis, we found that each of the four conditions is characterized by a peculiar vaginal microbiome/metabolome fingerprint.