The vaginal microbiota of pregnant women who subsequently have spontaneous preterm labor and delivery and those with a normal delivery at term

The cervicovaginal metabolome in women with favorable induction cervix and those unfavorable for induction when delivering at term

Background

Cervical ripening is crucial for induction. However, its influencing factors, mechanistic understanding, and effective risk stratification are still challenging. Recent research suggested that microorganisms and their metabolites in vaginal spaces correlate to preterm birth. However, it remains unclear whether the cervicovaginal metabolome is related to the natural physiological process of cervical maturation.

Objective

We aimed to analyze the cervicovaginal metabolome in women with favorable induction cervix and those unfavorable for induction when delivering at term.

Study design

Cervicovaginal swabs were collected between 40 and 41 weeks gestation from the following 2 different groups of patients: Ripe group (n = 25) which was favorable for the induction cervix and Unripe group which was unfavorable for the induction cervix (n = 25). Samples were tested using untargeted metabolomics analysis and analyzed by a bioinformatics platform. The correlation analysis between the metabolome and the previously acquired microbiome was also performed.

Results

A total of 629 metabolites were identified in cervicovaginal fluid. The cervicovaginal metabolome was significantly different between the women with the ripe cervix and those with the unripe cervix, especially within each stratum of the same CST. Metabolites within the amino acid, carbohydrate, and dipeptide pathways may play a role in this distinction. Thirty-four metabolites were significantly upregulated, and the remaining fourteen were significantly downregulated in the Unripe group with an unripe cervix unfavorable for induction. Statistical modeling identified Arachidonic Acid and Nicotinate associated with the risk of cervical maturation disorder (AUC 0.87) in negative ion mode. A combination of Choline and d-Mannose identified a risk of cervical maturation disorder (AUC 0.80) in positive ion mode, improved by Lactobacillus relative abundance (AUC 0.89).

Conclusion

These data suggested that the cervicovaginal space was metabolically active during pregnancy and significantly altered among the women with the mature and immature cervix. Combining the genera-level phylotypes and metabolites could build better cervix maturity prediction models. By using cervicovaginal fluid samples, we demonstrated the potential of multi-data type integration for developing composite models toward understanding the contribution of the vaginal environment to the remodeling of cervix during term pregnancy.

Biomarker Identification for Preterm Birth Susceptibility: Vaginal Microbiome Meta-Analysis Using Systems Biology and Machine Learning Approaches

PROBLEM

The vaginal microbiome has a substantial role in the occurrence of preterm birth (PTB), which contributes substantially to neonatal mortality worldwide. However, current bioinformatics approaches mostly concentrate on the taxonomic classification and functional profiling of the microbiome, limiting their abilities to elucidate the complex factors that contribute to PTB.

METHOD OF STUDY

A total of 3757 vaginal microbiome 16S rRNA samples were obtained from five publicly available datasets. The samples were divided into two categories based on pregnancy outcome: preterm birth (PTB) (N = 966) and term birth (N = 2791). Additionally, the samples were further categorized based on the participants' race and trimester. The 16S rRNA reads were subjected to taxonomic classification and functional profiling using the Parallel-META 3 software in Ubuntu environment. The obtained abundances were analyzed using an integrated systems biology and machine learning approach to determine the key microbes, pathways, and genes that contribute to PTB. The resulting features were further subjected to statistical analysis to identify the top nine features with the greatest effect sizes.

RESULTS

We identified nine significant features, namely Shuttleworthia, Megasphaera, Sneathia, proximal tubule bicarbonate reclamation pathway, systemic lupus erythematosus pathway, transcription machinery pathway, lepA gene, pepX gene, and rpoD gene. Their abundance variations were observed through the trimesters.

CONCLUSIONS

Vaginal infections caused by Shuttleworthia, Megasphaera, and Sneathia and altered small metabolite biosynthesis pathways such as lipopolysaccharide folate and retinal may increase the susceptibility to PTB. The identified organisms, genes, pathways, and their networks may be specifically targeted for the treatment of bacterial infections that increase PTB risk.

Vaginal microbiota and spontaneous preterm birth in pregnant women at high risk of recurrence

We describe vaginal microbiota, including Gardnerella species and sexually transmitted infections (STIs), during pregnancy and their associations with recurrent spontaneous preterm birth (sPTB). We performed a prospective cohort study in a tertiary referral centre in the Netherlands, among pregnant women with previous sPTB <34 weeks' gestation. Participants collected three vaginal swabs in the first and second trimester. Vaginal microbiota was profiled with 16S rDNA sequencing. Gardnerella species and STI's were tested with qPCR. Standard care was provided according to local protocol, including screening and treatment for bacterial vaginosis (BV), routine progesterone administration and screening for cervical length shortening. Of 154 participants, 26 (16.9 %) experienced recurrent sPTB <37 weeks' gestation. Microbiota composition was not associated with sPTB. During pregnancy, the share of Lactobacillus iners-dominated microbiota increased at the expense of diverse microbiota between the first and second trimester. This change coincided with treatment for BV, demonstrating a similar change in microbiota composition after treatment. In this cohort of high-risk women, we did not find an association between vaginal microbiota composition and recurrent sPTB. This should be interpreted with care, as these women were offered additional preventive therapies to reduce sPTB according to national guidelines including progesterone and BV treatment. The increase observed in L. iners dominated microbiota and the decrease in diverse microbiota mid-gestation was most likely mediated by BV treatment. Our findings suggest that in recurrent sPTB occurring despite several preventive therapies, the microbe-related etiologic contribution might be limited.

Spatiotemporal patterns of the pregnancy microbiome and links to reproductive disorders

The microbiome of females undergoes extensive remodeling during pregnancy, which is likely to have an impact on the health of both mothers and offspring. Nevertheless, large-scale integrated investigations characterizing microbiome dynamics across key body habitats are lacking. Here, we performed an extensive meta-analysis that compiles and analyzes microbiome profiles from  >10,000 samples across the gut, vagina, and oral cavity of pregnant women from diverse geographical regions. We have unveiled unexpected variations in the taxonomic, functional, and ecological characteristics of microbial communities throughout the course of pregnancy. The gut microbiota showed distinct trajectories between Western and non-Western populations. The vagina microbiota exhibited fluctuating transitions at the genus level across gestation, while the oral microbiota remained relatively stable. We also identified distinctive microbial signatures associated with prevalent pregnancy-related disorders, including opposite variations in the oral and gut microbiota of patients with gestational diabetes and disrupted microbial networks in preterm birth. This study establishes a comprehensive atlas of the pregnancy microbiome by integrating multidimensional datasets and offers foundational insights into the intricate interplay between microbes and host factors that underlie reproductive health.

Research Hotspots and Trends in the Diagnosis of Chorioamnionitis: Based on Bibliometric Analysis from 2010 to 2022

OBJECTIVE

This study aimed to conduct a bibliometric analysis of literature related to the diagnosis of chorioamnionitis (CAM) and to point out the current research progress, hotspots, and development trends of CAM research.

STUDY DESIGN

Literature on the diagnosis of CAM from the Web of Science Core Collection (WoSCC) between 2010 and 2022 was retrieved. CiteSpace, VOSviewer, and Online Analysis Platform (OALM) were used to draw maps of authors, articles, journals, institutions, countries/regions, and keywords.

RESULTS

A total of 312 articles were included, and the number of articles gradually increased over the study period. The author with the largest number of articles was Roberto Romero. The institution with the largest number of articles was Wayne State University School of Medicine, and the United States was the country that produced the largest number of articles. Analysis of keywords and outbreak words suggested that future research hotspots and trends may focus on early treatment of CAM and more precise, noninvasive, and more sensitive diagnoses.

CONCLUSION

In this study, visualization software and data information mining were innovatively used to conduct a bibliometric analysis of articles in the field of CAM diagnosis, and the current status, hotspots, and development of this field were obtained. Future research hotspots may be the precision diagnosis and treatment of CAM.

KEY POINTS

· There is no bibliometric study on CAM diagnosis in the existing literature.. · The prediction of CAM diagnosis is an important topic to improve maternal and infant prognosis.. · Bibliometrics can effectively guide the direction of future research..

Affective Symptoms in Pregnancy are Associated with the Vaginal Microbiome

Composition of the vaginal microbiome in pregnancy is associated with adverse maternal, obstetric, and child health outcomes. Identifying the sources of individual differences in the vaginal microbiome is therefore of considerable clinical and public health interest. The current study tested the hypothesis that vaginal microbiome composition during pregnancy is associated with an individual's experience of affective symptoms and stress exposure. Data were based on a prospective longitudinal study of a diverse and medically healthy community sample of 275 mother-infant pairs. Affective symptoms and stress exposure and select measures of associated biomarkers (diurnal salivary cortisol, serum measures of sex hormones) were collected at each trimester; self-report, clinical, and medical records were used to collect detailed data on socio-demographic factors and health behavior, including diet and sleep. Vaginal microbiome samples were collected in the third trimester (34-40 weeks) and characterized by 16S rRNA sequencing. Identified taxa were clustered into three community state types (CST1-3) based on dissimilarity of vaginal microbiota composition. Results indicate that depressive symptoms during pregnancy were reliably associated with individual taxa and CST3 in the third trimester. Prediction of functional potential from 16S taxonomy revealed a differential abundance of metabolic pathways in CST1-3 and individual taxa, including biosynthetic pathways for the neuroactive metabolites, serotonin and dopamine. With the exception of bioavailable testosterone, no significant associations were found between symptoms- and stress-related biomarkers and CSTs. Our results provide further evidence of how prenatal psychological distress during pregnancy alters the maternal-fetal microbiome ecosystem that may be important for understanding maternal and child health outcomes.

The effects of probiotics administration during pregnancy on preeclampsia and associated maternal, fetal, and newborn outcomes: a systematic review and meta-analysis

OBJECTIVE

This study aimed to synthesize the available evidence on probiotic administration during pregnancy for the prevention of preeclampsia and its effects on related maternal, fetal, and newborn outcomes.

DATA SOURCES

Six databases were systematically searched for eligible studies, namely Ovid MEDLINE, Embase, CINAHL, Cochrane, Global Index Medicus, and the Maternity and Infant Care Database, from inception to August 2, 2023.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials that evaluated the effects of probiotic administration on women during any stage of pregnancy were eligible for inclusion.

METHODS

The protocol was registered with the International Prospective Register of Systematic Reviews under identifier CRD42023421613. Evaluating study eligibility, extracting data, assessing risk of bias (ROB-2 tool), and rating certainty (Grading of Recommendations, Assessment, Development and Evaluations) were conducted independently by 2 authors. The primary outcomes were incidence of preeclampsia, eclampsia, and maternal mortality. A meta-analysis was performed, and the results were reported as risk ratios with 95% confidence intervals.

RESULTS

A total of 29 trials (7735 pregnant women) met the eligibility criteria. There was heterogeneity across the trials in the population of enrolled women and the type of probiotic tested (20 different strains), although most used oral administration. Probiotics may make no difference to the risk of preeclampsia (risk ratio, 1.14; 95% confidence interval, 0.84-1.53; 11 trials; 2401 women; low certainty evidence), preterm birth at <37 weeks' gestation (risk ratio, 0.93; 95% confidence interval, 0.66-1.30; 18 trials, 4016 women; low certainty evidence), or gestational age at delivery (mean difference, -0.03 weeks [≈0.2 days]; 95% confidence interval, -0.16 to 0.10 weeks [≈ -1.1 to 0.7 days]; 13 trials, 2194 women; low certainty evidence). It is difficult to assess the effects of probiotics on other secondary outcomes because the evidence was of very low certainty, however, no benefits or harms were observed.

CONCLUSION

Limited evidence suggests that probiotic supplementation does not affect the risk for preeclampsia. Further high-quality trials are needed to definitively assess the benefits and possible harms of probiotic supplementation during pregnancy. There is also a lack of data from trials that included women who were undernourished or who experienced microbial dysbiosis and for whom probiotic supplementation might be useful.

Garfield R, Yang J. Characteristics of cervicovaginal microflora at different cervical maturity during late pregnancy: A nested case-control study

OBJECTIVE

The mechanism of cervical ripening in late pregnancy is still unclear. The vaginal microbiome has been reported to correlate with the preterm birth and short cervix in pregnant women. However, the associations between the cervical maturity and the vaginal microbiome are still poorly understood. We aim to analyze the cervicovaginal microflora in women with ripe cervix and in those who are unripe when delivering at term.

METHODS

Cervicovaginal swabs were collected between 40 and 41 weeks of gestation from the following 2 different groups of patients: ripe group (n = 25) and unripe group (n = 25). Samples were tested using 16S ribosomal RNA gene high-throughput sequencing and analyzed by bioinformatics platform.

RESULTS

This study highlights the relationship between cervical maturity during late pregnancy and the composition of the cervicovaginal microflora. Both α- and β-diversity analyses demonstrated significant differences between women with a ripe cervix and those with an unripe cervix. Notably, the Lactobacillus profile was found to be closely linked to cervical maturity. There was a significant difference in the vaginal community state type, with CST IV being more prevalent in women with an unripe cervix. Furthermore, the association between CST IV and the unripe cervix group, as indicated by the odds ratio of 8.6, underscores its relevance in evaluating cervical maturity, when compared to other Lactobacillus-dominant community state types. Additionally, several bacterial taxa, particularly Lactobacillus, exhibited differential relative abundances between the two groups.

CONCLUSION

This study provided significant evidence regarding the relationship between the vaginal microbiome and cervical maturity, highlighting the differential diversity, community state types, and specific bacterial taxa, such as Lactobacillus, that are associated with cervical maturation status. These findings contributed to our understanding of the dynamics of the cervicovaginal microflora during late pregnancy and its implications for cervical health.

The role of neighborhood deprivation in the cervicovaginal microbiota

BACKGROUND

Lactobacillus-deficient cervicovaginal microbiota is associated with spontaneous preterm birth and is more common among Black individuals. Persistent racial segregation in the United States has led to differential neighborhood exposures by race that can affect pregnancy outcomes. The extent to which neighborhood exposures may explain racial differences in the cervicovaginal microbiota is unknown.

OBJECTIVE

This study aimed to determine whether neighborhood deprivation, defined as material community deprivation, is associated with a Lactobacillus-deficient cervicovaginal microbiota in a prospective cohort of pregnant individuals. Our hypothesis was that racial differences in neighborhood deprivation may explain the higher prevalence of Lactobacillus-deficient cervicovaginal microbiota in Black birthing people.

STUDY DESIGN

This study analyzed data from Motherhood and Microbiome, a prospective pregnancy cohort enrolled from prenatal clinics in a single hospital system 2013-2016 in which a Lactobacillus-deficient cervicovaginal microbiota was previously shown to be associated with spontaneous preterm birth. This study geocoded addresses to obtain census tract neighborhood deprivation data from the Brokamp Nationwide Community Deprivation Index that uses weighted proportions of poverty, income, public assistance, lack of health insurance, and vacant housing. Generalized linear mixed models quantified associations of deprivation with the cervicovaginal microbiota accounting for geographic clustering by census tract and potential confounders. Because of different distributions of neighborhood deprivation and the cervicovaginal microbiota, race-stratified models were used. Mediation analyses quantified the extent to which deprivation may contribute to racial differences in the cervicovaginal microbiota.

RESULTS

Higher neighborhood deprivation was associated with a Lactobacillus-deficient cervicovaginal microbiota. Per standard deviation increment of deprivation, participants had 28% higher adjusted odds (adjusted odds ratio, 1.28; 95% confidence interval, 1.04-1.58) of a Lactobacillus-deficient microbiota. Black participants had higher odds of a Lactobacillus-deficient microbiota than White participants (adjusted odds ratio, 4.00; 95% confidence interval, 2.05-8.26), and mediation analysis revealed that deprivation accounted for 22% (P=.046) of that disparity.

CONCLUSION

Neighborhood deprivation was associated with Lactobacillus-deficient cervicovaginal microbiota and may partially explain Black-White disparities in the cervicovaginal microbiota. Mechanistic studies to explore how environmental exposures modify the cervicovaginal microbiota are warranted to identify novel opportunities for future interventional strategies to prevent preterm birth. As the findings demonstrate a potential biological effect from neighborhood conditions, policies that drive urban planning should be explored to improve pregnancy outcomes.

Temporal dynamics of the fecal microbiome in female pigs from early life through estrus, parturition, and weaning of the first litter of piglets

BACKGROUND

Age-associated changes in the gastrointestinal microbiome of young pigs have been robustly described; however, the temporal dynamics of the fecal microbiome of the female pig from early life to first parity are not well understood. Our objective was to describe microbiome and antimicrobial resistance dynamics of the fecal microbiome of breeding sows from early life through estrus, parturition and weaning of the first litter of piglets (i.e., from 3 to 53 weeks of age).

RESULTS

Our analysis revealed that fecal bacterial populations in developing gilts undergo changes consistent with major maturation milestones. As the pigs progressed towards first estrus, the fecal bacteriome shifted from Rikenellaceae RC9 gut group- and UCG-002-dominated enterotypes to Treponema- and Clostridium sensu stricto 1-dominated enterotypes. After first estrus, the fecal bacteriome stabilized, with minimal changes in enterotype transition and associated microbial diversity from estrus to parturition and subsequent weaning of first litter piglets. Unlike bacterial communities, fecal fungal communities exhibited low diversity with high inter- and intra-pig variability and an increased relative abundance of certain taxa at parturition, including Candida spp. Counts of resistant fecal bacteria also fluctuated over time, and were highest in early life and subsequently abated as the pigs progressed to adulthood.

CONCLUSIONS

This study provides insights into how the fecal microbial community and antimicrobial resistance in female pigs change from three weeks of age throughout their first breeding lifetime. The fecal bacteriome enterotypes and diversity are found to be age-driven and established by the time of first estrus, with minimal changes observed during subsequent physiological stages, such as parturition and lactation, when compared to the earlier age-related shifts. The use of pigs as a model for humans is well-established, however, further studies are needed to understand how our results compare to the human microbiome dynamics. Our findings suggest that the fecal microbiome exhibited consistent changes across individual pigs and became more diverse with age, which is a beneficial characteristic for an animal model system.

Analysis of Vaginal Microbiota Variations in the Third Trimester of Pregnancy and Their Correlation with Preterm Birth: A Case-Control Study

This study conducted a detailed analysis of the vaginal microbiota in pregnant women to explore its correlation with preterm birth (PTB) outcomes. The primary objective was to identify microbial variations associated with increased PTB risk. Secondary objectives included investigating how changes in microbial composition relate to the local immune environment and PTB. Utilizing a retrospective case-control design, the study involved pregnant women with liveborn infants between 2019 and 2023. In total, 89 women who delivered preterm and 106 term deliveries were included. Data collection focused on third-trimester vaginal cultures. Statistically significant differences were observed between the preterm and full-term groups in several areas. The median white blood cell count (10.2 × 103/mm3 vs. 7.6 × 103/mm3, p = 0.009) and neutrophil count (7.2 × 103/mm3 vs. 5.1 × 103/mm3, p < 0.001) were higher in the preterm group. Vaginal pH was also elevated in preterm births (5.6 vs. 4.4, p < 0.001), with a higher prevalence of bacterial vaginosis (29.2% vs. 12.3%, p = 0.001) as indicated by the Nugent Score. The study noted a significant association of PTB with the presence of Candida spp. (OR = 1.84, p = 0.018), Gardnerella vaginalis (OR = 2.29, p = 0.003), Mycoplasma hominis (OR = 1.97, p = 0.007), and Ureaplasma urealyticum (OR = 2.43, p = 0.001). Conversely, a reduction in Lactobacillus spp. correlated with a decreased PTB risk (OR = 0.46, p = 0.001). The study provides compelling evidence that specific vaginal microbiota components, particularly certain pathogenic bacteria and an altered Lactobacillus profile, are significantly associated with PTB risk. These findings highlight the potential of targeting microbial factors in strategies aimed at reducing PTB rates. Further research is necessary to fully understand the complex interplay between microbial dynamics, host immunity, and PTB outcomes.

Relationship of Lactobacillus Vaginal Microbiota Changes and the Risk of Preterm Birth: A Systematic Review and Meta-Analysis

Objective: With a global incidence of more than 10%, preterm birth (PTB) remains a significant concern. The vaginal microbiome strongly influences the well-being of the female reproductive tract. This study examines the correlation between changes in Lactobacillus vaginal microbiota and the PTB risk. Materials and Methods: A thorough search of PubMed, Web of Science, Cochrane Library, and EMBASE was conducted to locate studies that examined the association between changes in Lactobacillus vaginal microbiota and the risk of PTB from January 1, 2010, to January 30, 2023. The risk of PTB was determined by calculating odds ratios (ORs) with 95% confidence intervals (CIs). Results: In our analysis, there were 11 studies with 1577 pregnant women. The findings revealed a significant negative correlation between higher Lactobacillus abundance and the PTB risk (OR = 0.49, 95% CI: 0.29-0.84, p = 0.009 < 0.05). Similarly, the four individual dominant species, Lactobacillus crispatus (OR = 0.3, 95% CI: 0.14-0.67, p = 0.003 < 0.05), Lactobacillus gasseri (OR = 0.34, 95% CI: 0.17-0.69, p = 0.003 < 0.05), Lactobacillus iners (OR = 0.68, 95% CI: 0.49-0.93, p = 0.016 < 0.05), and Lactobacillus jensenii (OR = 0.43, 95% CI: 0.21-0.89, p = 0.024 < 0.05), were also negatively associated with the PTB risk. The risk of Lactobacillus for PTB was significant in both America (OR = 0.67; 95% CI: 0.50-0.92) and Asia (OR = 0.20; 95% CI: 0.09-0.47), whereas no significant risk was found in Europe (OR = 0.49; 95% CI: 0.11-2.15). Conclusions: Our study demonstrated that the abundance of Lactobacillus and the four dominant individual species (L. crispatus, L. jensenii, L. iners, and L. gasseri) were significantly and negatively associated with the PTB risk.

Microbiome preterm birth DREAM challenge: Crowdsourcing machine learning approaches to advance preterm birth research

Every year, 11% of infants are born preterm with significant health consequences, with the vaginal microbiome a risk factor for preterm birth. We crowdsource models to predict (1) preterm birth (PTB; <37 weeks) or (2) early preterm birth (ePTB; <32 weeks) from 9 vaginal microbiome studies representing 3,578 samples from 1,268 pregnant individuals, aggregated from public raw data via phylogenetic harmonization. The predictive models are validated on two independent unpublished datasets representing 331 samples from 148 pregnant individuals. The top-performing models (among 148 and 121 submissions from 318 teams) achieve area under the receiver operator characteristic (AUROC) curve scores of 0.69 and 0.87 predicting PTB and ePTB, respectively. Alpha diversity, VALENCIA community state types, and composition are important features in the top-performing models, most of which are tree-based methods. This work is a model for translation of microbiome data into clinically relevant predictive models and to better understand preterm birth.

Relationship between Vaginal Bacterial Infections and Pregnancy Outcomes: A Systematic Review and Meta-Analysis

Background

Bacterial infections are among the most serious infections worldwide. They can cause miscarriage, premature birth, stillbirth, and ectopic pregnancy in pregnant women. The aim of this study was to investigate the relationship between bacterial infections and pregnancy outcomes through a systematic review and meta-analysis.

Materials and Methods

PubMed, Scopus, Web of Science, and Embase databases were searched from January 2000 to December 2018 using appropriate keywords to identify related articles. The final related studies were selected and evaluated using the Newcastle-Ottawa Scale (NOS).

Results

Results of this meta-analysis based on combining case-control studies showed that the presence of bacterial infections could lead increase in the odds of all pregnancy outcomes like premature infant birth (odd ratio [OR]: 1.50; 95% Confidence Interval [CI], 1.39-1.61), preterm delivery (OR: 1.54; 95% CI, 1.39-1.70), abortion (OR: 1.16; 95% CI, 1.04-1.29), stillbirth (OR, 1.29; 95% CI, 1.12-1.49), and ectopic pregnancy (OR: 1.12; 95% CI, 1.05--1.19). The results showed that the Risk Ratio (RR) of preterm delivery in pregnant women with vaginal infections was 1.57 (95% CI, 1.46-1.67), whereas the RR of abortion was 2.02 (95% CI, 1.72-2.38).

Conclusions

Based on the results of this meta-analysis, the presence of bacterial infections in pregnant women can lead increase in the risk of pregnancy outcomes especially, preterm delivery, abortion, stillbirth, and ectopic pregnancy. Therefore, it is necessary for obstetricians and gynecologists to pay attention to the diagnosis of these infections in women before pregnancy and during pregnancy in order to prevent the consequences of these infections.

From pandemic to syndemic: microbiota, pregnancy, and environment at a crossroad

Aim: SARS-CoV2 is the latest pandemic that have plagued the socio-health system as an epiphenomenon resulting from planetary resources abuse, crucial for biodiversity. The Anthropocene best defines the present epoch in which human activity irreversibly manipulates intricate and delicate geological and biological balances established over eons. The devastating ecological and socio-economic implications of COVID-19, underline the importance of updating the present pandemic framework to a syndemic. This paper stems from the need to suggest to scientists, doctors, and patients a mission that integrates responsibility from individual to collective health, from present to trans-generational, from human to the entire biotic network. Today's choices are crucial for the perspective on all levels: political, economic, and health as well as cultural.Methods: Research on PubMed and other specific web-sites journal was performed on the topic "Microbiota", "Covid-19", "Pandemic", "Zoonosis", "SARS-CoV-2", "Environmental Pollutants", "Epigenetics", "Fetal Programming", "Human Extinction". Data collected were analysed for an integrative model of interconnection between environment, pregnancy, SARS-CoV-2 infection, and microbiota. Moreover, systematic literature review allowed to summarise in a table information about the worst pandemics that afflicted the human species recently.Results: This paper offers a broad view of the current pandemic starting with pregnancy, the moment when a new life begins and the health trajectories of the unborn child are defined, which will inevitably have repercussions on his well-being. The fundamental role of the biodiversity-rich microbiota in avoiding the development of severe infectious diseases, is therefore highlighted. It is imperative to adjust the current reductionist paradigm based on mostly immediate symptom management towards a broader understanding of the spatial interconnection of ecological niches with human health and the impacts of today's choices on the future. Health and healthcare are elitist rather than egalitarian, therefore focusing on environmental health forces us to make a concerted and systemic effort that challenges political and economic barriers, which are biologically senseless. A healthy microbiota is essential to well-being, both by preventing chronic degenerative conditions, the infectiousness and pathogenicity of bacterial and viral diseases. SARS-CoV-2 should not be an exception. The human microbiota, forged by the first 1,000 days of life, is fundamental in shaping the health-disease trajectories, and by the everlasting exposome that is dramatically affected by the ecological disaster. Individual health is one world health whereas single and global well-being are interdependent in a space-time perspective.Conclusions: Is it not a convenient reductionism not to consider the COVID-19 emergency as a bio-social epiphenomenon of a far more devastating and multi-faceted crisis whose common denominator is the global biotic network loss of which humans are still part?

Histologic chorioamnionitis in extremely preterm births, microbiological findings and infant outcome

BACKGROUND

Histologic chorioamnionitis (HCA) is most often caused by ascending bacterial infection originating from the cervicovaginal tract.

OBJECTIVES

To investigate whether HCA with a fetal inflammatory response (FIR) has a worse clinical outcome than HCA alone. Further, if FIR or a positive maternal microbiologic culture obtained prior to birth were related to adverse neonatal outcomes in a cohort of extremely preterm (EP) neonates.

METHODS

Prospective observational cohort study recruiting EP singleton pregnancies (gestational age at birth ≤28 weeks) with confirmed HCA. FIR was defined by fetal neutrophils in the chorionic vessels and/or umbilical vessels. Positive culture was defined as growth of potentially pathogenic bacteria in a sample from the cervicovaginal tract prior to birth, or if a cervicovaginal culture was lacking, a culture result from the placenta was used. Logistic regression was used to estimate odds ratios and 95% confidence intervals for the associations between FIR, a positive culture result and adverse outcomes, defined as bronchopulmonary dysplasia (BPD), brain pathology assessed by magnetic resonance imaging, retinopathy of prematurity, necrotizing enterocolitis, early-onset neonatal sepsis, and perinatal death. A composite outcome variable included one or more adverse outcomes.

RESULTS

We included 71 cases with HCA, of which 51 (72%) had FIR. Maternal age, rate of clinical chorioamnionitis (CCA), preterm pre-labor rupture of membranes (PPROM), the number of women receiving antenatal steroids and antibiotics, and the rate of positive maternal cultures of potentially pathogenic bacteria were all significantly higher in the HCA with FIR. Neonates in the FIR group had significantly higher levels of blood leukocytes compared to those without. FIR was associated with a longer interval from PPROM to delivery (log-rank test: p = .022). Microbiological sampling had been performed in 63 (89%) cases, of which 60 (95%) were cervicovaginal samples. No associations were found between a positive culture and adverse neonatal outcomes, in contrast to FIR, that was significantly associated to BPD and brain pathology.

CONCLUSIONS

In a cohort of EP pregnancies with confirmed HCA, the presence of FIR was associated with advanced maternal age, CCA, PPROM, antenatal steroids and antibiotics, and a positive maternal culture of potentially pathogenic bacteria. However, the presence of FIR, and not a positive culture, was associated with adverse neonatal outcomes.

Profiling of vaginal Lactobacillus jensenii isolated from preterm and full-term pregnancies reveals strain-specific factors relating to host interaction

Each year, 15 million infants are born preterm (<37 weeks gestation), representing the leading cause of mortality for children under the age of five. Whilst there is no single cause, factors such as maternal genetics, environmental interactions, and the vaginal microbiome have been associated with an increased risk of preterm birth. Previous studies show that a vaginal microbiota dominated by Lactobacillus is, in contrast to communities containing a mixture of genera, associated with full-term birth. However, this binary principle does not fully consider more nuanced interactions between bacterial strains and the host. Here, through a combination of analyses involving genome-sequenced isolates and strain-resolved metagenomics, we identify that L. jensenii strains from preterm pregnancies are phylogenetically distinct from strains from full-term pregnancies. Detailed analysis reveals several genetic signatures that distinguish preterm birth strains, including genes predicted to be involved in cell wall synthesis, and lactate and acetate metabolism. Notably, we identify a distinct gene cluster involved in cell surface protein synthesis in our preterm strains, and profiling the prevalence of this gene cluster in publicly available genomes revealed it to be predominantly present in the preterm-associated clade. This study contributes to the ongoing search for molecular biomarkers linked to preterm birth and opens up new avenues for exploring strain-level variations and mechanisms that may contribute to preterm birth.

Meta-analysis reveals the vaginal microbiome is a better predictor of earlier than later preterm birth

BACKGROUND

High-throughput sequencing measurements of the vaginal microbiome have yielded intriguing potential relationships between the vaginal microbiome and preterm birth (PTB; live birth prior to 37 weeks of gestation). However, results across studies have been inconsistent.

RESULTS

Here, we perform an integrated analysis of previously published datasets from 12 cohorts of pregnant women whose vaginal microbiomes were measured by 16S rRNA gene sequencing. Of 2039 women included in our analysis, 586 went on to deliver prematurely. Substantial variation between these datasets existed in their definition of preterm birth, characteristics of the study populations, and sequencing methodology. Nevertheless, a small group of taxa comprised a vast majority of the measured microbiome in all cohorts. We trained machine learning (ML) models to predict PTB from the composition of the vaginal microbiome, finding low to modest predictive accuracy (0.28-0.79). Predictive accuracy was typically lower when ML models trained in one dataset predicted PTB in another dataset. Earlier preterm birth (< 32 weeks, < 34 weeks) was more predictable from the vaginal microbiome than late preterm birth (34-37 weeks), both within and across datasets. Integrated differential abundance analysis revealed a highly significant negative association between L. crispatus and PTB that was consistent across almost all studies. The presence of the majority (18 out of 25) of genera was associated with a higher risk of PTB, with L. iners, Prevotella, and Gardnerella showing particularly consistent and significant associations. Some example discrepancies between studies could be attributed to specific methodological differences but not most study-to-study variations in the relationship between the vaginal microbiome and preterm birth.

CONCLUSIONS

We believe future studies of the vaginal microbiome and PTB will benefit from a focus on earlier preterm births and improved reporting of specific patient metadata shown to influence the vaginal microbiome and/or birth outcomes.

The Vaginal Microbiota of Pregnant Women Varies with Gestational Age, Maternal Age, and Parity

The composition of the vaginal microbiota is heavily influenced by pregnancy and may factor into pregnancy complications, including spontaneous preterm birth. However, results among studies have been inconsistent due, in part, to variation in sample sizes and ethnicity. Thus, an association between the vaginal microbiota and preterm labor continues to be debated. Yet, before assessing associations between the composition of the vaginal microbiota and preterm labor, a robust and in-depth characterization of the vaginal microbiota throughout pregnancy in the specific study population under investigation is required. Here, we report a large longitudinal study (n = 474 women, 1,862 vaginal samples) of a predominantly African-American cohort-a population that experiences a relatively high rate of pregnancy complications-evaluating associations between individual identity, gestational age, and other maternal characteristics with the composition of the vaginal microbiota throughout gestation resulting in term delivery. The principal factors influencing the composition of the vaginal microbiota in pregnancy are individual identity and gestational age at sampling. Other factors are maternal age, parity, obesity, and self-reported Cannabis use. The general pattern across gestation is for the vaginal microbiota to remain or transition to a state of Lactobacillus dominance. This pattern can be modified by maternal parity and obesity. Regardless, network analyses reveal dynamic associations among specific bacterial taxa within the vaginal ecosystem, which shift throughout the course of pregnancy. This study provides a robust foundational understanding of the vaginal microbiota in pregnancy and sets the stage for further investigation of this microbiota in obstetrical disease. IMPORTANCE There is debate regarding links between the vaginal microbiota and pregnancy complications, especially spontaneous preterm birth. Inconsistencies in results among studies are likely due to differences in sample sizes and cohort ethnicity. Ethnicity is a complicating factor because, although all bacterial taxa commonly inhabiting the vagina are present among all ethnicities, the frequencies of these taxa vary among ethnicities. Therefore, an in-depth characterization of the vaginal microbiota throughout pregnancy in the specific study population under investigation is required prior to evaluating associations between the vaginal microbiota and obstetrical disease. This initial investigation is a large longitudinal study of the vaginal microbiota throughout gestation resulting in a term delivery in a predominantly African-American cohort, a population that experiences disproportionally negative maternal-fetal health outcomes. It establishes the magnitude of associations between maternal characteristics, such as age, parity, body mass index, and self-reported Cannabis use, on the vaginal microbiota in pregnancy.

A Narrative Review Discussing the Obstetric Repercussions Due to Alterations of Personalized Bacterial Sites Developed within the Vagina, Cervix, and Endometrium

BACKGROUND

The reproductive tract microbiota that evolved as an integrative component has been studied intensively in the last decade. As a result, novel research, clinical opportunities, and perspectives have been derived following the close investigation of this microecological environment. This has paved the way for an update to and improvement of the management strategies and therapeutic approaches. However, obscurities, contradictions, and controversies arise regarding the ascension route from the vagina to the endometrium via the cervix, with finality in adverse obstetric outcomes.

METHODS

Starting from these considerations, we aimed to gather all existing data and information from four major academic databases (PubMed, ISI Web of Knowledge, Scopus, and ScienceDirect) published in the last 13 years (2010-2023) using a controlled vocabulary and dedicated terminology to enhance the coverage, identification, and sorting of potentially eligible studies.

RESULTS

Despite the high number of returned entries (n = 804), only a slight percentage (2.73%) of all manuscripts were deemed eligible following two rounds of evaluation. Cumulatively, a low level of Lactobacillus spp. and of other core microbiota members is mandatory, with a possible eubiosis-to-dysbiosis transition leading to an impairment of metabolic and endocrine network homeostasis. This transposes into a change in the pro-inflammatory landscape and activation of signaling pathways due to activity exerted by the bacterial lipopolysaccharides (LPSs)/endotoxins that further reflect a high risk of miscarriage in various stages. While the presence of some pathogenic entities may be suggestive of an adverse obstetric predisposition, there are still pros and cons of the role of specific strains, as only the vagina and cervix have been targeted as opposed to the endometrium, which recently started to be viewed as the key player in the vagina-cervix-endometrium route. Consequently, based on an individual's profile, diet, and regime, antibiotics and probiotics might be practical or not.

CONCLUSIONS

Resident bacteria have a dual facet and are beneficial for women's health, but, at the same time, relaying on the abundance, richness, and evenness that are definitory indexes standing as intermediaries of a miscarriage.

Effect of vaginal microbiota on pregnancy outcomes of women from Northern China who conceived after IVF

Objective

This study aimed to investigate the correlation between vaginal microbiota and pregnancy outcomes of women who achieved pregnancy via in vitro fertilization (IVF) in Northern China, and to determine a biomarker for evaluation of the risk of preterm births in these women.

Methods

In total, 19 women from Northern China women who conceived after IVF and 6 women who conceived naturally were recruited in this study. The vaginal samples of the healthy participants were collected throughout pregnancy, that is, during the first, second, and third trimesters. The V3-V4 region of 16S rRNA was used to analyze the vaginal microbiome, and the bioinformatic analysis was performed using QIIME Alpha and Beta diversity analysis.

Results

Either IVF group or Natural conception group, bacterial community diversities and total species number of vagnal samples from who delivered at term were significantly higher than those who delivered before term. Low abundance of vaginal bacteria indicates an increased risk of preterm delivery. Further, more abundant vaginal bacteria was found in first trimesters instead of the next two trimesters. Vignal samples collected during first trimester showed richer differences and more predictive value for pregnancy outcoes. In addition, the diversity of the vaginal bacterial community decreased as the gestational age increased, in all samples. Alloscardovia was only found in participants who conceived after IVF, and the percentage of Alloscardovia in viginal samples of normal delivery group is much higher than the samples from preterm delivery group.Vobrio specifically colonized in vagina of pregnant woman in AFT group (those who conceived after IVF (A), first trimester (F), and delivered at term (T)) and Sporosarcina was detected only in women with AFT and AST (those who conceived after IVF (A), second trimester (S), and delivered at term (T)). These data indicates that Alloscardovia, Vobrio and Sporosarcina have great potential in predicting pregnancy outcomes who pregnanted by vitro fertilization.

Conclusions

Vaginal microbiota were more stable in women who conceived naturally and those who carried pregnancy to term. Oceanobacillus might act as a positive biomarker, whereas Sulfurospirillum and Propionispira may act as negative biomarkers for the risk of preterm birth.

Advances and challenges in studying the tissue-resident T cell compartment in the human female reproductive tract

Tissue-resident memory T cells (TRM ) are considered to be central to maintaining mucosal barrier immunity and tissue homeostasis. Most of this knowledge stems from murine studies, which provide access to all organs. These studies also allow for a thorough assessment of the TRM compartment for each tissue and across tissues with well-defined experimental and environmental variables. Assessing the functional characteristics of the human TRM compartment is substantially more difficult; thus, notably, there is a paucity of studies profiling the TRM compartment in the human female reproductive tract (FRT). The FRT is a mucosal barrier tissue that is naturally exposed to a wide range of commensal and pathogenic microbes, including several sexually transmitted infections of global health significance. We provide an overview of studies describing T cells within the lower FRT tissues and highlight the challenges of studying TRM cells in the FRT: different sampling methods of the FRT greatly affect immune cell recovery, especially of TRM cells. Furthermore, menstrual cycle, menopause, and pregnancy affect FRT immunity, but little is known about changes in the TRM compartment. Finally, we discuss the potential functional plasticity of the TRM compartment during inflammatory episodes in the human FRT to maintain protection and tissue homeostasis, which are required to ensure reproductive fitness.

Partial convergence of the human vaginal and rectal maternal microbiota in late gestation and early post-partum

The human vaginal and fecal microbiota change during pregnancy. Because of the proximity of these perineal sites and the evolutionarily conserved maternal-to-neonatal transmission of the microbiota, we hypothesized that the microbiota of these two sites (rectal and vaginal) converge during the last gestational trimester as part of the preparation for parturition. To test this hypothesis, we analyzed 16S rRNA sequences from vaginal introitus and rectal samples in 41 women at gestational ages 6 and 8 months, and at 2 months post-partum. The results show that the human vaginal and rectal bacterial microbiota converged during the last gestational trimester and into the 2nd month after birth, with a significant decrease in Lactobacillus species in both sites, as alpha diversity progressively increased in the vagina and decreased in the rectum. The microbiota convergence of the maternal vaginal-anal sites perinatally might hold significance for the inter-generational transmission of the maternal microbiota.

Maternal microbiota and gestational diabetes: impact on infant health

Gestational diabetes mellitus (GDM) is a common complication of pregnancy that has been associated with an increased risk of obesity and diabetes in the offspring. Pregnancy is accompanied by tightly regulated changes in the endocrine, metabolic, immune, and microbial systems, and deviations from these changes can alter the mother's metabolism resulting in adverse pregnancy outcomes and a negative impact on the health of her infant. Maternal microbiomes are significant drivers of mother and child health outcomes, and many microbial metabolites are likely to influence the host health. This review discusses the current understanding of how the microbiota and microbial metabolites may contribute to the development of GDM and how GDM-associated changes in the maternal microbiome can affect infant's health. We also describe microbiota-based interventions that aim to improve metabolic health and outline future directions for precision medicine research in this emerging field.

The Effect of Sexual Intercourse during Pregnancy on Preterm Birth: Prospective Single-Center Cohort Study in Japan

Several studies in Europe and the United States have shown that sexual intercourse (SI) during pregnancy is not associated with preterm birth. However, it is unclear whether these findings apply to pregnant Japanese women. The aim of this prospective cohort study was to elucidate the influence of SI during pregnancy on preterm birth in Japan. A total of 182 women who underwent antenatal care and delivery were included in this study. The frequency of SI was assessed using a questionnaire, and its association with preterm birth was analyzed. The results showed that SI during pregnancy was associated with a significantly higher cumulative preterm birth rate (p = 0.018), which was more pronounced for SI more than once a week (p < 0.0001). Multivariate analysis showed that SI, bacterial vaginosis in the second trimester, previous preterm birth, and smoking during pregnancy were independent risk factors for preterm birth. The combination of SI and second trimester bacterial vaginosis was associated with a 60% preterm birth rate, whereas either factor alone was associated with a lower rate, suggesting a synergistic effect (p < 0.0001). Future studies are needed to investigate the effect of prohibiting SI in pregnant women with bacterial vaginosis on preterm birth.

Impact of cervicovaginal microbiome on the risk of cervical abnormalities development

The vaginal microbiome has emerged as potentially influencing the natural history of Human Papillomavirus (HPV) infections and their clinical impact. We aimed to characterize the vaginal microbiome in samples from 807 high-risk HPVs (Hr-HPV) positive women with a mean age of 41.45 ± 10.79 years who participated in the Regional Cervical Cancer Screening Program from the Northern Region of Portugal. Microbiome analysis was performed with commercial kits for the detection of 21 microorganisms. The most frequent microorganisms were Ureaplasma parvum (52.5%), Gardnerella vaginalis (GV) (34.5%), Atopobium vaginae (AV) (32.6%), Lacto (30.7%), and Mycoplasma hominis (MH) (23.5%). The distribution according to age reveals that MH, Mega1, GV, BVab2, AV, and Mob were more prevalent in women older than 41 years of age (p < 0.050), while Lacto is significantly decreased in this group (23.5% vs. 39.4%, p < 0.001; RR = 0.47). The risk analysis showed that Hr-HPV-16/-18 and Hr-HPV-9val genotypes are associated with an increased risk of developing cervical abnormalities, while Lacto (p < 0.001; odd ratio [OR] = 0.33), GV (p = 0.0111; OR = 0.41), AV (p = 0.033; OR = 0.53) and Mob (p = 0.022; OR = 0.29) are associated with protection. Similar results were found for the risk of development atypical squamous cells cannot exclude HSIL/high-grade squamous intraepithelial lesion. Overall, the multivariate analysis confirmed that lactobacillus and bacteria associated with bacterial vaginosis (GV, AV, and Mob) are associated with protection against the development of cervical abnormalities. This study provides important data to be included in the future management of risk stratification for Hr-HPV-positive women.

Vaginal flora during pregnancy and subsequent risk of preterm birth or prelabor rupture of membranes: a nested case-control study from China

BACKGROUND

The findings of the association of vaginal flora with preterm birth (PTB) or prelabor rupture of membranes (PROM) were conflicts. Moreover, vaginal flora was different by ethnicity and the evidence from China was limited.

METHODS

This study was a nested case control study, based on Yiwu birth cohort. We assessed vaginal microbiota in the second or third trimester, using 16S rDNA Amplicon Sequencing and explored the association between the diversity and composition of vaginal flora and PTB or PROM.

RESULTS

We finally included 144 pregnant women. In present study, the alpha diversity of TPROM (Term prelabor rupture of membranes) samples was lower than that of full term samples (Chao1 index: P < 0.05). When we further categorized PTB (Preterm birth) into SPB (PTB without PROM) and PPROM (Preterm prelabor rupture of membranes), there was no difference between SPB and full term. In addition, we found that the proportion of PCoA2 in TPROM group was different from that in full term group and preterm group. The difference between groups was significant according to anosim analysis (R = 0.059, P < 0.001). With LEfSe (Linear discriminant analysis Effect Size) analysis, we found that the abundance of Lactobacillus in the vaginal flora of pregnant women with preterm birth was the highest (P = 0.003).

CONCLUSION

In Chinese pregnant women, the alpha diversity in TPROM group was significantly lower than that in both PTB and full term group. However, there was no difference between PTB and full term. Lactobacillus was the most abundant in preterm birth group. More studies should be conducted to confirm our findings.

Microbiome Preterm Birth DREAM Challenge: Crowdsourcing Machine Learning Approaches to Advance Preterm Birth Research

Globally, every year about 11% of infants are born preterm, defined as a birth prior to 37 weeks of gestation, with significant and lingering health consequences. Multiple studies have related the vaginal microbiome to preterm birth. We present a crowdsourcing approach to predict: (a) preterm or (b) early preterm birth from 9 publicly available vaginal microbiome studies representing 3,578 samples from 1,268 pregnant individuals, aggregated from raw sequences via an open-source tool, MaLiAmPi. We validated the crowdsourced models on novel datasets representing 331 samples from 148 pregnant individuals. From 318 DREAM challenge participants we received 148 and 121 submissions for our two separate prediction sub-challenges with top-ranking submissions achieving bootstrapped AUROC scores of 0.69 and 0.87, respectively. Alpha diversity, VALENCIA community state types, and composition (via phylotype relative abundance) were important features in the top performing models, most of which were tree based methods. This work serves as the foundation for subsequent efforts to translate predictive tests into clinical practice, and to better understand and prevent preterm birth.

Cervicovaginal mucus barrier properties during pregnancy are impacted by the vaginal microbiome

Introduction

Mucus in the female reproductive tract acts as a barrier that traps and eliminates pathogens and foreign particles via steric and adhesive interactions. During pregnancy, mucus protects the uterine environment from ascension of pathogens and bacteria from the vagina into the uterus, a potential contributor to intrauterine inflammation and preterm birth. As recent work has demonstrated the benefit of vaginal drug delivery in treating women's health indications, we sought to define the barrier properties of human cervicovaginal mucus (CVM) during pregnancy to inform the design of vaginally delivered therapeutics during pregnancy.

Methods

CVM samples were self-collected by pregnant participants over the course of pregnancy, and barrier properties were quantified using multiple particle tracking. 16S rRNA gene sequencing was performed to analyze the composition of the vaginal microbiome.

Results

Participant demographics differed between term delivery and preterm delivery cohorts, with Black or African American participants being significantly more likely to delivery prematurely. We observed that vaginal microbiota is most predictive of CVM barrier properties and of timing of parturition. Lactobacillus crispatus dominated CVM samples showed increased barrier properties compared to polymicrobial CVM samples.

Discussion

This work informs our understanding of how infections occur during pregnancy, and directs the engineering of targeted drug treatments for indications during pregnancy.

New challenges in cholangiocarcinoma candidates for elective surgery: harnessing the microbiome dysbiosis

BACKGROUND

The gut microbiota, composed by several species of microorganisms, works to preserve the liver-gut homeostasis and plays an important role during digestion and absorption of nutrients, and in the immune response of the host. In this review, we analyzed the influence of microbiota in patients with cholangiocarcinoma (CCA) who were candidates for elective surgery.

METHODS

A literature review was conducted to identify papers that provided empiric evidence to support that the altered microbiota composition (dysbiosis) is related also to CCA development.

RESULTS

Bacteria such as Helicobacter pylori, Helicobacter hepaticus, and Opisthorchis viverrini increase the risk of CCA. The most abundant genera were Enterococcus, Streptococcus, Bacteroides, Klebsiella, and Pyramidobacter in CCA's biliary microbiota. Additionally, levels of Bacteroides, Geobacillus, Meiothermus, and Anoxybacillus genera were significantly higher. An enrichment of Bifidobacteriaceae, Enterobacteriaceae, and Enterococcaceae families has also been observed in CCA tumor tissue. Microbiota is related to postoperative outcomes in abdominal surgery. The combination of caloric restriction diets in liver cancer or CCA increases the effect of the chemotherapy treatment.

CONCLUSION

The correct use of nutrition for microbiota modulation according to each patient's needs could be a therapeutic tool in combination with elective surgery and chemotherapy to diminish side effects and improve prognosis. Further investigations are needed to fully understand the mechanisms by which they are related.

Vaginal microbes confounders and implications on women's health

The vagina has diverse vaginal microbes (Vm). A disturbance in the delicate balance maintained in Vm is linked to women's obstetrical and reproductive tract problems. Vaginal microbes play an essential role in protecting the health of the female reproductive tract by alleviating gynecological infection. However, Vm profiling has many confounders that need to be addressed during sampling, including age, race, pregnancy, medical illness, and smoking. Vm profiling improves reproduction odds, may serve as a marker for genital malignancies and have a therapeutic application in menopausal women and women with cervical cancers.

Antibiotic treatment of bacterial vaginosis to prevent preterm delivery: Systematic review and individual participant data meta-analysis

BACKGROUND

Bacterial vaginosis (BV) increases preterm delivery (PTD) risk, but treatment trials showed mixed results in preventing PTD.

OBJECTIVES

Determine, using individual participant data (IPD), whether BV treatment during pregnancy reduced PTD or prolonged time-to-delivery.

DATA SOURCES

Cochrane Systematic Review (2013), MEDLINE, EMBASE, journal searches, and searches (January 2013-September 2022) ("bacterial vaginosis AND pregnancy") of (i) clinicaltrials.gov; (ii) Cochrane Central Register of Controlled Trials; (iii) World Health Organization International Clinical Trials Registry Platform Portal; and (iv) Web of Science ("bacterial vaginosis").

STUDY SELECTION AND DATA EXTRACTION

Studies randomising asymptomatic pregnant individuals with BV to antibiotics or control, measuring delivery gestation. Extraction was from original data files. Bias risk was assessed using the Cochrane tool. Analysis used "one-step" logistic and Cox random effect models, adjusting gestation at randomisation and PTD history; heterogeneity by I2 . Subgroup analysis tested interactions with treatment. In sensitivity analyses, studies not providing IPD were incorporated by "multiple random-donor hot-deck" imputation, using IPD studies as donors.

RESULTS

There were 121 references (96 studies) with 23 eligible trials (11,979 participants); 13 studies (6915 participants) provided IPD; 12 (6115) were incorporated. Results from 9 (4887 participants) not providing IPD were imputed. Odds ratios for PTD for metronidazole and clindamycin versus placebo were 1.00 (95% CI 0.84, 1.17), I2  = 62%, and 0.59 (95% CI 0.42, 0.82), I2  = 0 before; and 0.95 (95% CI 0.81, 1.11), I2  = 59%, and 0.90 (95% CI: 0.72, 1.12), I2  = 0, after imputation. Time-to-delivery did not differ from null with either treatment. Including imputed IPD, there was no evidence that either drug was more effective when administered earlier, or among those with a PTD history.

CONCLUSIONS

Clindamycin, but not metronidazole, was beneficial in studies providing IPD, but after imputing data from missing IPD studies, treatment of BV during pregnancy did not reduce PTD, nor prolong pregnancy, in any subgroup or when started earlier in gestation.

A Review Focusing on Microbial Vertical Transmission during Sow Pregnancy

Microorganisms are closely related to the body's physiological activities and growth and development of the body, and participate in many physiological metabolic activities. Analysis of the structure and source of early colonizing bacteria in the intestinal tract of humans and rodents shows that early colonizing bacteria in the intestinal tract of mammals have solid maternal characteristics, and maternal microbes play an essential role in the formation of progeny intestinal flora. The placental microbiome, maternal microbiome and breast milk microbiome are currently hot topics in the field of life science. This paper discusses the vertical transmission and endogenous sources of the mother-to-piglet microbiome through these three pathways, aiming to provide a new research idea for intervention in the intestinal microbiome in young piglets.

The Medium Is the Message: Defining a "Normal" Vaginal Microbiome in Healthy Reproductive-Age Women

The microbial composition of the human vagina differs from that of all other mammals, likely as a consequence of the unique composition of vaginal constituents that promote the selective maintenance and proliferation of distinct bacterial species. Similarly, variations between individual healthy women in genetic, environmental, and medical variables also modify the vaginal lumen composition. The direction and magnitude of immune reactions to microorganisms present in the vagina, responses to stress and non-infectious stimuli, coupled with medical and pregnancy history and environmental exposures, can greatly differ between women. Adaptations to both internal and external pressures will determine the ability of select resident vaginal bacteria to numerically dominate and, therefore, the definition of a "normal" vaginal microbiota will substantially differ between individual healthy women.

Preterm birth is associated with xenobiotics and predicted by the vaginal metabolome

Spontaneous preterm birth (sPTB) is a leading cause of maternal and neonatal morbidity and mortality, yet its prevention and early risk stratification are limited. Previous investigations have suggested that vaginal microbes and metabolites may be implicated in sPTB. Here we performed untargeted metabolomics on 232 second-trimester vaginal samples, 80 from pregnancies ending preterm. We find multiple associations between vaginal metabolites and subsequent preterm birth, and propose that several of these metabolites, including diethanolamine and ethyl glucoside, are exogenous. We observe associations between the metabolome and microbiome profiles previously obtained using 16S ribosomal RNA amplicon sequencing, including correlations between bacteria considered suboptimal, such as Gardnerella vaginalis, and metabolites enriched in term pregnancies, such as tyramine. We investigate these associations using metabolic models. We use machine learning models to predict sPTB risk from metabolite levels, weeks to months before birth, with good accuracy (area under receiver operating characteristic curve of 0.78). These models, which we validate using two external cohorts, are more accurate than microbiome-based and maternal covariates-based models (area under receiver operating characteristic curve of 0.55-0.59). Our results demonstrate the potential of vaginal metabolites as early biomarkers of sPTB and highlight exogenous exposures as potential risk factors for prematurity.

Adverse effect of lactobacilli-depauperate cervicovaginal microbiota on pregnancy outcomes in women undergoing frozen-thawed embryo transfer

Purpose

The cervicovaginal microbiota is essential for maintaining the health of the female reproductive tract. However, whether cervicovaginal microbiota status prior to frozen embryo transfer (FET) associates with pregnancy outcomes is largely unexplored.

Methods

Cervical mucus from 29 women who had undergone FET was collected. Microbial composition was analyzed using 16 S rRNA gene sequence to assess the correlation to the pregnancy outcomes.

Results

CST-categorized Lactobacillus was the most dominant (41.71%) in the pregnant group, while CST-IV-based and BV-related Gardnerella (34.96%) prevailed in the non-pregnant group. The average abundance of Gardnerella compared non-pregnant to pregnant women was the highest (34.96% vs. 4.22%, p = 0.0015) among other CST-IV indicator bacteria. Multivariate analysis revealed that CST-IV-related bacteria have a significantly adverse effect on ongoing pregnancy outcomes (odds ratio, 0.083; 95% confidence index, 0.012-0.589, p = 0.013*).

Conclusions

The study found that the CST-IV microbiota, with significantly increasing Gardnerella and the loss of Lactobacilli as the dominant bacteria, can potentially contribute to pregnancy failure. Therefore, dysbiotic microbiota may be a risk factor in women undergoing FET. Assessing the health of the cervicovaginal microbiota prior to FET would enable couples to make a more thoughtful decision on the timing and might improve pregnancy outcomes.

Compositional Changes in the Vaginal Bacterial Microbiome of Healthy Pregnant Women across the Three Gestational Trimesters in Ismailia, Egypt

The composition of the vaginal microbiome may lead to adverse pregnancy outcomes. Normal pregnancy is associated with changes in the vaginal bacterial community composition, which tend to be more enriched with one or two Lactobacillus species promoting a healthy vagina and favorable birth outcomes. The aim of the current study was to determine compositional changes in the healthy vaginal microbiome composition during the three trimesters of pregnancy in Ismailia, Egypt using Illumina MiSeq sequencing of the V3-V4 region of the 16S rRNA. The phylum Firmicutes and the genus Lactobacillus dominated across the three trimesters of pregnancy. L. iners was the most abundant species. However, L. coleohominis and L. reuteri represented the least dominant vaginal lactobacilli. Core microbiome analyses showed the Lactobacillus genus and L. iners species to have the highest prevalence in all the samples of our study groups. The phylum Firmicutes was found to be negatively correlated with almost all other vaginal phyla during pregnancy. Likewise, a negative correlation between Lactobacillus and almost all other genera was detected, including significant negative correlations with Dialister and Prevotella. Furthermore, negative correlations of L. iners were detected with almost all other species, including a significant negative correlation with L. helveticus, G. vaginalis, S. anginosus, and S. agalactiae.

Role of short interpregnancy interval, birth mode, birth practices, and the postpartum vaginal microbiome in preterm birth

There have been widely documented beneficial role of vaginal Lactobacillus species as an important biomarker for vaginal health and healthy pregnancy progression. When translating this to clinical settings, pregnant women with low proportions of Lactobacillus and commensurately high proportion of rich and highly diverse abnormal microbiota are most likely to encounter negative pregnancy outcome such as preterm birth and postpartum complications. However, multiple literatures have also addressed this notion that the absence of a Lactobacillus-dominated microbiota does not appear to directly imply to a diseased condition and may not be a major determinant of negative obstetric outcome. Caesarian delivery is notably a risk factor for preterm birth and postpartum endometritis, yet recent data shows a trend in the overuse of CS across several populations. Growing evidence suggest the potential role of vaginal/uterine cleaning practice during CS procedures in influencing postpartum infections, however there is a controversy that this practice is associated with increased rates of postpartum endometritis. The preponderance of bacterial vaginosis associated bacteria vagitype at postpartum which persist for a long period of time even after lochia regression in some women may suggest why short interpregnancy interval may pose a potential risk for preterm birth, especially multigravidas. While specifically linking a community of microbes in the female reproductive tract or an exact causative infectious agent to preterm birth and postpartum pathologies remains elusive, clinical attention should also be drawn to the potential contribution of other factors such as short interpregnancy interval, birth mode, birth practices and the postpartum vaginal microbiome in preterm birth which is explicitly described in this narrative review.

Association between the vaginal and uterine microbiota and the risk of early embryonic arrest

The aim of this study was to explore the microecological distribution and differences in the uterus and vaginal microbiome in women with early embryonic arrest and those with normal pregnancy by high-throughput sequencing. We systematically sampled the vaginal and uterine microbiomes of 56 pregnant women, namely, 38 patients with early embryonic arrest and 18 pregnant women with normal pregnancy-induced abortion. We obtained colonization data by 16S rRNA gene amplicon sequencing. In the vagina, Lactobacillus, Bacteroidetes and Helicobacter exhibited significant differences between the groups. We further found that Lactobacillus iners, Lactobacillus crispatus, Lactobacillus gasseri and Lactobacillus jensenii were the most dominant Lactobacillus species and that L. iners was significantly different between the groups. Receiver operating characteristic (ROC) curve analysis confirmed that Ensifer had the highest predictive value for early embryonic arrest. In the uterine cavity, we determined that Proteobacteria, Bacteroidetes, Firmicutes and Actinobacteria were the dominant bacteria at the phylum level and that Bacteroides, Pseudarthrobacter, Lactobacillus and Ralstonia were the dominant genera. Further classification of Lactobacillus revealed that L. iners, L. crispatus, L. gasseri, and L. jensenii were the main species. There was a significant difference in L. jensenii between the normal pregnancy group and early embryonic arrest group. Random forest analysis revealed 18 different genera in the uterus, and ROC curve analysis indicated that Candidatus Symbiobacter, Odoribacter, Blautia, Nocardioides and Ileibacterium had a certain predictive value.

Vaginal microbiota in women with spontaneous preterm labor versus those with term labor in Kenya: a case control study

Background

Preterm birth is a global problem with about 12% of births in sub-Saharan Africa occurring before 37 weeks of gestation. Several studies have explored a potential association between vaginal microbiota and preterm birth, and some have found an association while others have not. We performed a study designed to determine whether there is an association with vaginal microbiota and/or placental microbiota and preterm birth in an African setting.

Methods

Women presenting to the study hospital in labor with a gestational age of 26 to 36 weeks plus six days were prospectively enrolled in a study of the microbiota in preterm labor along with controls matched for age and parity. A vaginal sample was collected at the time of presentation to the hospital in active labor. In addition, a placental sample was collected when available. Libraries were constructed using PCR primers to amplify the V6/V7/V8 variable regions of the 16S rRNA gene, followed by sequencing with an Illumina MiSeq machine and analysis using QIIME2 2022.2.

Results

Forty-nine women presenting with preterm labor and their controls were enrolled in the study of which 23 matched case–control pairs had sufficient sequence data for comparison. Lactobacillus was identified in all subjects, ranging in abundance from < 1% to > 99%, with Lactobacillus iners and Lactobacillus crispatus the most common species. Over half of the vaginal samples contained Gardnerella and/or Prevotella; both species were associated with preterm birth in previous studies. However, we found no significant difference in composition between mothers with preterm and those with full-term deliveries, with both groups showing roughly equal representation of different Lactobacillus species and dysbiosis-associated genera. Placental samples generally had poor DNA recovery, with a mix of probable sequencing artifacts, contamination, and bacteria acquired during passage through the birth canal. However, several placental samples showed strong evidence for the presence of Streptococcus species, which are known to infect the placenta.

Conclusions

The current study showed no association of preterm birth with composition of the vaginal community. It does provide important information on the range of sequence types in African women and supports other data suggesting that women of African ancestry have an increased frequency of non-Lactobacillus types, but without evidence of associated adverse outcomes.

Amoxicillin modulates gut microbiota to improve short-term high-fat diet induced pathophysiology in mice

BACKGROUND

A high-fat diet (HFD) induced perturbation of gut microbiota is a major contributory factor to promote the pathophysiology of HFD-associated metabolic syndrome. The HFD could also increase the susceptibility to the microbial infections warranting the use of antibiotics which are independently capable of impacting both gut microbiota and metabolic syndrome. Further, the usage of antibiotics in individuals consuming HFD can impact mitochondrial function that can be associated with an elevated risk of chronic conditions like inflammatory bowel disease (IBD). Despite this high propensity  to infections in individuals on HFD, the link between duration of HFD and antibiotic treatment, and its impact on diversity of the gut microbiome and features of metabolic syndrome is not well established. In this study, we have addressed these knowledge gaps by examining how the gut microbiota profile changes in HFD-fed mice receiving antibiotic intervention in the form of amoxicillin. We also determine whether antibiotic treatment in HFD-fed mice may adversely impact the ability of immune cells to clear microbial infections.

METHODS AND RESULTS

We have subjected mice to HFD and chow diet (CD) for 3 weeks, and a subset of these mice on both diets received antibiotic intervention in the form of amoxicillin in the 3rd week. Body weight and food intake were recorded for 3 weeks. After 21 days, all animals were weighted and sacrificed. Subsequently, these animals were evaluated for basic haemato-biochemical and histopathological attributes. We used 16S rRNA sequencing followed by bioinformatics analysis to determine changes in gut microbiota in these mice. We observed that a HFD, even for a short-duration, could successfully induce the partial pathophysiology typical of a metabolic syndrome, and substantially modulated the gut microbiota in mice. The short course of amoxicillin treatment to HFD-fed mice resulted in beneficial effects by significantly reducing fasting blood glucose and skewing the number of thrombocytes towards a normal range. Remarkably, we observed a significant remodelling of gut microbiota in amoxicillin-treated HFD-fed mice. Importantly, some gut microbes associated with improved insulin sensitivity and recovery from metabolic syndrome only appeared in amoxicillin-treated HFD-fed mice reinforcing the beneficial effects of antibiotic treatment in the HFD-associated metabolic syndrome. Moreover, we also observed the presence of gut-microbiota unique to amoxicillin-treated HFD-fed mice that are also known to improve the pathophysiology associated with metabolic syndrome. However, both CD-fed as well as HFD-fed mice receiving antibiotics showed an increase in intestinal pathogens as is typically observed for antibiotic treatment. Importantly though, infection studies with S. aureus and A. baumannii, revealed that macrophages isolated from amoxicillin-treated HFD-fed mice are comparable to those isolated from mice receiving only HFD or CD in terms of susceptibility, and progression of microbial infection.  This finding  clearly indicated that amoxicillin treatment does not introduce any additional deficits in the ability of macrophages to combat microbial infections.

CONCLUSIONS

Our results showed that amoxicillin treatment in HFD-fed mice exert a beneficial influence on the pathophysiological attributes of metabolic syndrome which correlates with a significant remodelling of gut microbiota. A novel observation was the increase in microbes known to improve insulin sensitivity following amoxicillin treatment during short-term intake of HFD. Even though there is a minor increase in gut-resistant intestinal pathogens in amoxicillin-treated groups, there is no adverse impact on macrophages with respect to their susceptibility and ability to control infections. Taken together, this study provides a proof of principle for the exploration of amoxicillin treatment as a potential therapy in the people affected with metabolic syndrome.

Diversity of the gut, vaginal and oral microbiome among pregnant women in South Africa with and without pre-eclampsia

Background

Changes in microbial communities are a known characteristic of various inflammatory diseases and have been linked to adverse pregnancy outcomes, such as preterm birth. However, there is a paucity of information regarding the taxonomic composition and/or diversity of microbial communities in pre-eclampsia. The aim of this study was to determine the diversity of the gut, vaginal and oral microbiome in a cohort of South African pregnant women with and without pre-eclampsia. The diversity of the gut, vaginal and oral microbiome was determined by targeted next generation sequencing (NGS) of the V3 and V4 region of the 16S rRNA gene on the Illumina MiSeq platform.

Results

In this study population, pre-eclampsia was associated with a significantly higher alpha diversity (P = 0.0472; indicated by the Shannon index) in the vaginal microbiome accompanied with a significant reduction in Lactobacillus spp. (P = 0.0275), compared to normotensive pregnant women. Lactobacillus iners was identified as the predominant species of the vaginal microbiome in both cohorts. High inter-individual variation in alpha diversity was observed in the gut and oral microbiome in both cohorts. Although differences in the relative abundance of bacteria at all phylogenetic levels were observed, overall microbial composition of the gut, oral and vaginal microbiome was not significantly different in the pre-eclampsia cohort compared to the normotensive cohort.

Conclusion

Collectively, a reduction of Lactobacillus spp., and predominance of L. iners in pregnant women with pre-eclampsia could suggest an unstable vaginal microbiome that might predispose pregnant women to develop pre-eclampsia. The lack of significant structural changes in the gut, oral and vaginal microbiome does not suggest that the characterized communities play a role in pre-eclampsia, but could indicate a characteristic unique to the study population. The current study provided novel information on the diversity of the gut, oral and vaginal microbiome among pregnant women in South Africa with and without pre-eclampsia. The current study provides a baseline for further investigations on the potential role of microbial communities in pre-eclampsia.

Vaginales Mikrobiom und Frühgeburtlichkeit

Hintergrund

Die Rate an Frühgeburten steigt weltweit an, ein bekannter Risikofaktor sind vaginale Infektionen.

Fragestellung

Welche Rolle spielen Infektionen als Ursache für Frühgeburtsbestrebungen? Wie ist das vaginale Mikrobiom in der Schwangerschaft zusammengesetzt und welche Bedeutung hat es in der Erkennung und Behandlung von Frühgeburtsbestrebungen.

Material und Methoden

Literaturrecherche in PubMed zu Infektion und Frühgeburten, frühem vorzeitigem Blasensprung und vaginalem Mikrobiom.

Ergebnisse

Die bakterielle Vaginose, eine Verminderung von Lactobacillus spp. und eine hohe Diversität von Bakterienstämmen im vaginalen Mikrobiom sind mit einem erhöhten Frühgeburtsrisiko assoziiert. Die antibiotische Therapie der bakteriellen Vaginose bei symptomatischen Schwangeren senkt das Frühgeburtsrisiko. Ein Screening asymptomatischer Schwangerer mit dem Ziel der Prävention von Frühgeburten ist derzeit nicht empfohlen. Das kindliche Mikrobiom und Immunsystem beginnt sich bereits in utero zu entwickeln, wobei Ernährung und Antibiotikaeinnahme während der Schwangerschaft eine wichtige Rolle spielen.

Schlussfolgerungen

Das vaginale Mikrobiom beeinflusst den Schwangerschaftsverlauf. Zwischen gesundem Mikrobiom und vaginaler Dysbiose kann klinisch nicht immer unterschieden werden. Mikrobiomanalysen leisten einen Beitrag zum besseren Verständnis pathologischer Veränderungen, jedoch gibt es aufgrund individueller Unterschiede keine allgemeine Definition des „gesunden Mikrobioms“.

The effects of microbiota on reproductive health: A review

Reproductive issues are becoming an increasing global problem. There is increasing interest in the relationship between microbiota and reproductive health. Stable microbiota communities exist in the gut, reproductive tract, uterus, testes, and semen. Various effects (e.g., epigenetic modifications, nervous system, metabolism) of dysbiosis in the microbiota can impair gamete quality; interfere with zygote formation, embryo implantation, and embryo development; and increase disease susceptibility, thus adversely impacting reproductive capacity and pregnancy. The maintenance of a healthy microbiota can protect the host from pathogens, increase reproductive potential, and reduce the rates of adverse pregnancy outcomes. In conclusion, this review discusses microbiota in the male and female reproductive systems of multiple animal species. It explores the effects and mechanisms of microbiota on reproduction, factors that influence microbiota composition, and applications of microbiota in reproductive disorder treatment and detection. The findings support novel approaches for managing reproductive diseases through microbiota improvement and monitoring. In addition, it will stimulate further systematic explorations of microbiota-mediated effects on reproduction.

Microbial and human transcriptome in vaginal fluid at midgestation: Association with spontaneous preterm delivery

BACKGROUND

Intrauterine infection and inflammation caused by microbial transfer from the vagina are believed to be important factors causing spontaneous preterm delivery (PTD). Multiple studies have examined the relationship between the cervicovaginal microbiome and spontaneous PTD with divergent results. Most studies have applied a DNA-based assessment, providing information on the microbial composition but not transcriptional activity. A transcriptomic approach was applied to investigate differences in the active vaginal microbiome and human transcriptome at midgestation between women delivering spontaneously preterm versus those delivering at term.

METHODS

Vaginal swabs were collected in women with a singleton pregnancy at 18 + 0 to 20 + 6 gestational weeks. For each case of spontaneous PTD (delivery <37 + 0 weeks) two term controls were randomized (39 + 0 to 40 + 6 weeks). Vaginal specimens were subject to sequencing of both human and microbial RNA. Microbial reads were taxonomically classified using Kraken2 and RefSeq as a reference. Statistical analyses were performed using DESeq2. GSEA and HUMAnN3 were used for pathway analyses.

RESULTS

We found 17 human genes to be differentially expressed (false discovery rate, FDR < 0.05) in the preterm group (n = 48) compared to the term group (n = 96). Gene expression of kallikrein-2 (KLK2), KLK3 and four isoforms of metallothioneins 1 (MT1s) was higher in the preterm group (FDR < 0.05). We found 11 individual bacterial species to be differentially expressed (FDR < 0.05), most with a low occurrence. No statistically significant differences in bacterial load, diversity or microbial community state types were found between the groups.

CONCLUSIONS

In our mainly white population, primarily bacterial species of low occurrence were differentially expressed at midgestation in women who delivered preterm versus at term. However, the expression of specific human transcripts including KLK2, KLK3 and several isoforms of MT1s was higher in preterm cases. This is of interest, because these genes may be involved in critical inflammatory pathways associated with spontaneous PTD.

The Oncobiome in Gastroenteric and Genitourinary Cancers

Early evidence suggests a strong association of microorganisms with several human cancers, and great efforts have been made to understand the pathophysiology underlying microbial carcinogenesis. Bacterial dysbiosis causes epithelial barrier failure, immune dysregulation and/or genotoxicity and, consequently, creates a tumor-permissive microenvironment. The majority of the bacteria in our body reside in the gastrointestinal tract, known as gut microbiota, which represents a complex and delicate ecosystem. Gut microbes can reach the pancreas, stomach and colon via the bloodstream. Oral bacterial translocations can also occur. In the stomach, pancreas and colon, low microbial diversity is associated with cancer, in particular with a bad prognosis. The urogenital tract also harbors unique microbiota, distinct from the gut microbiota, which might have a role in the urinary and female/male reproductive cancers’ pathogenesis. In healthy women, the majority of bacteria reside in the vagina and cervix and unlike other mucosal sites, the vaginal microbiota exhibits low microbial diversity. Genital dysbiosis might have an active role in the development and/or progression of gynecological malignancies through mechanisms including modulation of oestrogen metabolism. Urinary dysbiosis may influence the pathogenesis of bladder cancer and prostate cancer in males. Modulation of the microbiome via pre, pro and postbiotics, fecal or vaginal microbiota transplantation and engineering bacteria might prove useful in improving cancer treatment response and quality of life. Elucidating the complex host-microbiome interactions will result in prevention and therapeutic efficacy interventions.

Meta-analysis of race and age influence on the vaginal microbiome in pregnant and nonpregnant healthy women

Aim: The presence of microbial species in reproductive tubes plays an essential protective role against the proliferation of harmful organisms and is an important factor in reproductive health. High-throughput culture-independent technologies allow the study of the vaginal microbiome on a large scale. This study aimed to compare the vaginal microbiota between pregnant and nonpregnant women of different ages and races using the meta-analysis method. Materials & methods: Seven articles with 16S rRNA gene sequences were studied and analyzed using CLC Genomics Workbench 20.1.1. Results & conclusion: This study revealed new insights into the effects of age and ethnicity on the pregnant and nonpregnant vaginal microbiome and found that the microbiome of Chinese women is more distinct than that of other ethnicities.

Gardnerella vaginalis alters cervicovaginal epithelial cell function through microbe-specific immune responses

BACKGROUND

The cervicovaginal (CV) microbiome is highly associated with vaginal health and disease in both pregnant and nonpregnant individuals. An overabundance of Gardnerella vaginalis (G. vaginalis) in the CV space is commonly associated with adverse reproductive outcomes including bacterial vaginosis (BV), sexually transmitted diseases, and preterm birth, while the presence of Lactobacillus spp. is often associated with reproductive health. While host-microbial interactions are hypothesized to contribute to CV health and disease, the mechanisms by which these interactions regulate CV epithelial function remain largely unknown.

RESULTS

Using an in vitro co-culture model, we assessed the effects of Lactobacillus crispatus (L. crispatus) and G. vaginalis on the CV epithelial barrier, the immune mediators that could be contributing to decreased barrier integrity and the immune signaling pathways regulating the immune response. G. vaginalis, but not L. crispatus, significantly increased epithelial cell death and decreased epithelial barrier integrity in an epithelial cell-specific manner. A G. vaginalis-mediated epithelial immune response including NF-κB activation and proinflammatory cytokine release was initiated partially through TLR2-dependent signaling pathways. Additionally, investigation of the cytokine immune profile in human CV fluid showed distinctive clustering of cytokines by Gardnerella spp. abundance and birth outcome.

CONCLUSIONS

The results of this study show microbe-specific effects on CV epithelial function. Altered epithelial barrier function through cell death and immune-mediated mechanisms by G. vaginalis, but not L. crispatus, indicates that host epithelial cells respond to bacteria-associated signals, resulting in altered epithelial function and ultimately CV disease. Additionally, distinct immune signatures associated with Gardnerella spp. or birth outcome provide further evidence that host-microbial interactions may contribute significantly to the biological mechanisms regulating reproductive outcomes. Video Abstract.