Roles of the Microbiota of the Female Reproductive Tract in Gynecological and Reproductive Health

Microbiome alterations in primary Sjögren's syndrome: Regional dysbiosis and microbiome-targeted therapeutic strategies

Primary Sjögren's syndrome (pSS) is a complex autoimmune disease characterized by diverse clinical manifestations. While xerophthalmia and xerostomia are hallmark symptoms, the disease often involves multiple organ systems, including the kidneys, lungs, nervous system, and gastrointestinal tract, leading to systemic morbidity in severe cases. Despite extensive research, the precise pathogenesis of pSS remains unclear, likely involving infectious, hormonal, and genetic factors. Emerging evidence highlights the microbiome as a key contributor to autoimmune diseases, including pSS. Dysbiosis in the oral, ocular, gut, and genital microbiomes plays a critical role in disease onset, progression, and variability. This review summarizes current findings on microbiome alterations in pSS, emphasizing their role in pathogenesis and clinical features, and explores microbiome-targeted therapies. Understanding the role of the microbiome in pSS pathophysiology could advance disease management and inspire targeted therapeutic strategies.

Brown-shell eggs shows high incidence of blood and meat spots accompanied by unique microbial distribution patterns

Introduction

The blood and meat spots in eggs are recognized as defects for egg quality. The frequency of blood and meat spots in brown-shell eggs is much higher than that in white-shell eggs in previous studies. However, the actual occurrence frequency and their effects on the microbial composition in eggs remain poorly understood.

Methods

In this study, we examined the frequency of blood and meat spots in brown-shell and white-shell eggs, respectively, from Rhode Island Red and White Leghorn chickens at seven ages.

Results

The results showed that blood and meat spots in brown-shell eggs exhibit much higher average frequency (63.99%) than that in white-shell eggs (1.37%). Furthermore, we analyzed the relationship between the presence of blood and meat spots and the microbial community distribution in the egg albumen and yolk. Briefly, we selected brown-shell eggs (n = 112) from Rhode Island Red, among which 51 eggs showing blood/meat spots were classified as RIR_CASE, and 61 normal eggs without blood/meat spot were classified as RIR_CON. Additional white-eggshell eggs (n = 124) without blood/meat spots from White Leghorn were selected as WL_CON. 16S rRNA sequencing was performed in both egg white and yolk. The results indicated that neither egg white nor yolk is sterile, with Proteobacteria identified as the dominant bacterial phyla. The microbial alpha diversity in both egg white and yolk of RIR_CASE was significantly lower compared to RIR_CON and WL_CON. Beta diversity analysis showed that the Weighted UniFrac Distance between RIR_CASE and RIR_CON in the egg yolk group was significantly larger than the distance between WL_CON and RIR_CON. It suggested that the difference of microbial diversity was mainly caused by blood and meat spots other than by chicken breeds. LEfSe analysis identified eight microbial taxa closely linked to the presence of blood and meat spots in egg white or yolk. Moreover, through the combination of random forest analysis, we identified the unique microbial biomarkers Comamonas_F and Chryseobacterium in the egg white of the RIR_CASE group.

Discussion

Our study indicates that eggs with blood and meat spots occur at a higher frequency in brown-shell chickens and are accompanied by a distinct microbial community distribution.

Improving Vaginal Health with a Zinc-Containing Vaginal Hydrogel

Vulvovaginal symptoms affect up to 39% of women. These symptoms have a significant impact on quality of life and are often linked to imbalances in the vaginal microbiota. This study evaluates the therapeutic efficacy of a zinc-containing hydroxyethyl cellulose-based hydrogel in 37 women with different vulvovaginal symptoms (itching, burning, irritation, pain, dryness, discharge, and odor). Over 12 weeks, participants applied the gel intravaginally with both assessments conducted at baseline and follow-ups. Results revealed substantial improvements in symptoms, including reductions in vaginal discharge, itching, and burning, as measured by the Vulvovaginal Symptom Questionnaire (VSQ-21), with scores decreasing from 10.78 ± 3.66 at baseline to 3.17 ± 4.16 at week 12 (p < 0.01). Vaginal Health Index (VHI) scores improved significantly, from 20.78 ± 1.74 at baseline to 23.64 ± 2.59 (p < 0.01). Cervicovaginal lavage (CVL) zinc levels decreased from 110 ± 102 µg/L at baseline to 62 ± 48 µg/L at week 4 (p < 0.01), increased to 80 ± 55 µg/L at week 8 (p = 0.04), and reached 99 ± 92 µg/L by week 12 (NS). A correlation analysis showed an inverse relationship between baseline CVL zinc levels and VSQ-21 scores (r = -0.3586, p = 0.034), while no significant correlation was observed with VHI scores (r = -0.0187, p = 0.9545). Vaginal pH levels decreased significantly, dropping from 4.03 ± 0.42 to 3.71 ± 0.48 (p < 0.01). These findings support the gel's role as an effective, nonhormonal, drug-free, and local adjunct treatment for a variety of vulvovaginal symptoms.

Vaginal microbiota transplantation alleviates vaginal atrophy in ovariectomized mice

Vaginal atrophy is a prevalent symptom in menopausal women, affecting over 50% of older women and patients with loss of ovarian function. The role of factors other than estrogen, such as the vaginal microbiota (VM), in the development of vaginal atrophy has not been fully explored. Therefore, we selected 8-week-old C57 mice with bilateral ovariectomy for experimentation. After four weeks of treatment, we observed that the vaginal epithelium of ovariectomized mice showed signs of atrophy. There were also significant differences in the structure and metabolites of VM. Vaginal transplantation of microbiota from ovary-intact mice significantly alleviated the vaginal atrophy of ovariectomized mice and altered the structure and metabolism of VM. These findings indicate that ovarian activity significantly affects the structure and metabolism of VM. VM of ovary-intact mice may promote vaginal health by upregulating the estrogen receptor alpha gene (ESR1, one-way ANOVA, F4, 25 = 17.76, P < 0.0001) in vaginal epithelial cells in ovariectomized mice, which in turn promotes cell proliferation (the number of vaginal epithelial cell layers, one-way ANOVA, F4, 25 = 28.04, P < 0.0001). Further studies are needed to investigate the interactions between VM and vaginal health. This finding can help develop new therapeutic strategies and interventions for patients suffering from vaginal atrophy.

All Properties of Infertility Microbiome in a Review Article

BACKGROUND

The microbiome is crucial for many physiological processes, including immunity, metabolism, and reproduction.

AIMS

This review aims to contribute to a detailed understanding of the microbiome of the genital tract, which can lead to better management of dysbiosis and reproductive disorders.

METHODS

Data from the four international information databases Medline, Scopus, Embase, and Google Scholar. The search strategy was based on the combination of the following terms: "microbiota," "microbiome," "microfilm," "microflora," "fertility," or "infertility."

RESULT

The advent of next-generation sequencing-based technologies during the last decade has revealed the presence of microbial communities in nearly every part of the human body, including the reproductive system. Several studies have shown significant differences between the microbiota of the vagina and endometrium, as well as other parts of the upper genital tract.

DISCUSSION

The human microbiome plays a critical role in determining a person's health state, and the microbiome of the genital tract may impact fertility potential before and after assisted reproductive treatments (ARTs).

CONCLUSION

To completely understand the role of the microbiome, future research should focus not only on the description of microbiota but also on the interaction between bacteria, the production of biofilms, and the interaction of microorganisms with human cells.

The role of reproductive tract microbiota in gynecological health and diseases

The reproductive tract, as a lumen connected to the outside world, its microbial community is influenced by various factors. The changes in its microbiome are closely related to women's health. The destruction of the micro ecological environment will lead to various infections, such as Bacterial vaginosis, sexually transmitted infections, adverse pregnancy outcomes, infertility and tumors. In recent years, with the continuous development and progress of molecular biology, research on reproductive tract microbiota has become a clinical hotspot. The reproductive tract microbiota is closely related to the occurrence and development of female reproductive tract diseases such as vaginitis, pelvic inflammation, PCOS, cervical lesions, and malignant tumors. This article reviews the research on the relationship between vaginal microbiota and female reproductive tract diseases, in order to provide theoretical basis for the prevention and treatment of female reproductive tract diseases.

Genetic association between human skin microbiota with vaginitis: a two-sample Mendelian randomization study

The human skin microbiome is closely associated with various diseases. We aimed to find the causal association of the human skin microbiome with vaginitis. A two-way two-sample Mendelian randomization study used summary statistics of the human skin microbiota from the largest genome-wide association study meta-analysis. Pooled statistics for vaginitis disease were obtained from the FinnGen consortium R10 release. Inverse variance weighted, MR-Egger, weighted median, weighted model, MR-PRESSO, and STEIGER methods were used to test for causal associations between different parts of the human skin microbiota and vaginitis disease in either dry or moist environments. IVW estimates suggest that phylococcus hominischaracterizes a protective effect against vaginitis lesions at the Antecubitalfossa wet site. Staphylococcus in the dry state at the Dorsalforearm site also demonstrated a protective effect against vaginitis lesions. Micrococcus showed a trend of up-regulation of vaginitis risk under IVW method estimation. In contrast, Anaerococcus and Veillonella were associated with a low risk of vaginitis as estimated by the IVW method: ASV061 and ASV065. In the Class, IVW estimation showed that Bacilli at Antecubitalfossa site had an increased risk effect on vaginitis in the moist skin condition. Similarly in Genus, Staphylococcus at Antecubitalfossa sites had an increased risk effect against vaginitis in the moist skin condition. Based on the results of the inverse MR analysis, no significant causal effect of vaginitis on the human skin microbiota was found. This two-sample bidirectional Mendelian randomization study found a causal relationship between seven human skin microbiota and vaginitis, further enriching our understanding of the value of skin flora in reproductive diseases such as vaginitis.

Microbiota analysis of perimenopausal women experiencing recurrent vaginitis in conjunction with urinary tract infection

BACKGROUND

Recurrent vaginitis in conjunction with urinary tract infection (RV/UTI) in perimenopausal women is a common clinical condition that impacts both doctors and patients. Its pathogenesis is not completely known, but the urogenital microbiota is thought to be involved. We compared the urogenital and gut microbiotas of perimenopausal women experiencing RV/UTI with those of age-matched controls to provide a new microbiological perspective and scheme for solving clinical problems.

RESULTS

Fifty women of perimenopausal age who were diagnosed with RV/UTI and 50 age-matched healthy controls were enrolled. The urogenital and intestinal microbiota were analyzed via 16S ribosomal RNA gene sequencing by collecting samples from the mouth, anus, urine, cervix, and upper and lower vaginal ends. Among the microbiota of healthy perimenopausal women, the mouth had the highest richness, whereas the anus and mouth had the highest levels of diversity. Compared with those in healthy controls, in the microbiota of patients with RV/UTI, the evenness of the upper vaginal end, anus and cervix significantly increased, whereas the richness and diversity of the cervix significantly decreased. Lactobacillus accounted for 40.65% of the bacteria in the upper vaginal end and 39.85% of the bacteria in the lower vaginal end of healthy women of perimenopausal age, and there were no significant differences in Lactobacillus abundance among the patients with RV/UTI. The relative abundances of 54 genera and 97 species were significantly different between patients and healthy individuals, particularly in the cervix and urine. A total of 147 predicted pathways were significantly different between patients and healthy controls, with the microbiota of the anus exhibiting the greatest number of functional changes, followed by the urine microbiota. A random forest model composed of 16 genera in the lower vaginal end had the highest discriminatory power (AUC 81.48%) to predict RV/UTI.

CONCLUSIONS

Our study provides insight into the nature of the urogenital and intestinal microbiota in perimenopausal women, and reveals significant changes in the microbiota in patients with RV/UTI. This information will help characterize the relationship between the urogenital microbiota and RV/UTI, potentially aiding in the development of diagnostic and therapeutic strategies.

Linking reproductive tract microbiota to premature ovarian insufficiency: Pathophysiological mechanisms and therapies

Over the past decade, research on the human microbiota has become a hot topic. Among them, the female reproductive tract (FRT) also has a specific microbiota that maintains the body's health and dynamic balance, especially in the reproductive aspect. When the FRT ecosystem is dysregulated, changes in immune and metabolic signals can lead to pathological and physiological changes such as chronic inflammation, epithelial barrier disruption, changes in cell proliferation and apoptosis, and dysregulation of angiogenesis and metabolism, thereby causing disruption of the female endocrine system. Premature ovarian insufficiency (POI), a clinical syndrome of ovarian dysfunction, is primarily influenced by immune, genetic, and environmental factors. New evidence suggests that dysbiosis of the FRT microbiota and/or the presence of specific bacteria may contribute to the occurrence and progression of POI. This influence occurs through both direct and indirect mechanisms, including the regulation of estrogen metabolism. The use of probiotics or microbiota transplantation to regulate the microbiome has also been proven to be beneficial in improving ovarian function and the quality of life in women with premature aging. This article provides an overview of the interrelationships and roles between the FRT microbiome and POI in recent years, to fully understand the risk factors affecting female reproductive health, and to offer insights for the future diagnosis, treatment, and application of the FRT microbiome in POI patients.

Highlight signatures of vaginal microbiota and metabolome contributed to the occurrence and recurrence of vulvovaginal candidiasis

Vulvovaginal candidiasis (VVC) is a common vaginal infectious disease caused by Candida. The high recurrence rate of VVC is a great clinical challenge, with recurrent VVC (RVVC) defined as four or more episodes within a year. In this study, we recruited 31 RVVC patients, 28 VVC patients, and 29 healthy women. Vaginal samples were collected for metagenomic and metabolic analysis. RVVC and VVC groups presented similar clinical symptoms, with only a significantly increased incidence of swelling in the VVC group. Vaginal microbiota in VVC/RVVC exhibited a decreased abundance of Lactobacillus and increased bacterial vaginosis-associated bacteria, such as Gardnerella, Prevotella, and Atopobium. Notably, Lactobacillus iners was higher in RVVC, suggesting not all Lactobacillus species are protective. Healthy women showed lower overall microbiota diversity, emphasizing single-species dominance for stability. Glycogen metabolism pathways were enriched in RVVC/VVC, and were correlated with Atopobium vaginae, Prevotella bivia, and Lactobacillus jensenii. Peptidoglycan synthesis pathways, associated with P. bivia, were enriched, with the substrate L-glutamate elevated in RVVC, possibly promoted by L. iners. These findings shed light on potential therapeutic targets for recurrent VVC, contributing to the understanding of the intricate interplay between the metabolism of vaginal microbiome and disease.

IMPORTANCE

This study enhances our knowledge of the vaginal microbiota dynamics and the role of associated metabolites in individuals with vulvovaginal candidiasis (VVC) and recurrent vulvovaginal candidiasis through shotgun sequencing and multi-omics analysis. The relationship between metabolites and vaginal microbiota and disease state was revealed. The accumulation of L-glutamate generated in glycogen metabolism, which is governed by Lactobacillus iners or bacterial vaginosis-associated bacteria, may contribute to the incidence and recurrence of VVC. Such insights have the potential to impact the treatment and prevention strategies for these common yet distressing conditions, potentially leading to targeted therapies and improved patient outcomes.

Urogenital colonization and pathogenicity of E. Coli in the vaginal microbiota during pregnancy

This study explores the role of the vaginal microbiota (VM) in the pathophysiology of asymptomatic bacteriuria (ASB) in a cohort of 1,553 pregnant women. Worldwide, E. coli remains the most common etiological agent of bacteriuria during pregnancy and also a major causative agent of newborn infections. A healthy VM is typically characterized by low diversity and is dominated by lactic acid-producing species, notably those from the Lactobacillus genus. Our results point to decreases in Lactobacillus spp associated with an increase of gut-microbiota-associated species from the Enterobacterales order. Escherichia coli exhibited the most pronounced increase in abundance within the VM during bacteriuria and was notably associated with ASB. Molecular typing and antimicrobial resistance characterization of 72 metagenome assembled E. coli genomes (MAGs) from these pregnant women revealed a genomic signature of extraintestinal pathogenic E. coli ("ExPEC") strains, which are involved in various extraintestinal infections such as urinary tract infections, newborn infections and bacteremia. Microbial diversity within the vaginal samples from which an E. coli MAG was obtained showed a substantial variation, primarily marked by a decrease in abundance of Lactobacillus species. Overall, our study shows how disruption in key bacterial group within the VM can disrupt its stability, potentially leading to the colonization by opportunistic pathogens.

The ovarian cancer-associated microbiome contributes to the tumor's inflammatory microenvironment

A growing body of research has established a correlation between tumors and persistent chronic inflammatory infiltration. As a primary instigator of inflammation, the majority of microbiomes naturally residing within our bodies engage in a mutually beneficial symbiotic relationship. Nevertheless, alterations in the microbiome's composition or breaches in the normal barrier function can disrupt the internal environment's homeostasis, potentially leading to the development and progression of various diseases, including tumors. The investigation of tumor-related microbiomes has contributed to a deeper understanding of their role in tumorigenesis. This review offers a comprehensive overview of the microbiome alterations and the associated inflammatory changes in ovarian cancer. It may aid in advancing research to elucidate the mechanisms underlying the ovarian cancer-associated microbiome, providing potential theoretical support for the future development of microbiome-targeted antitumor therapies and early screening through convenient methods.

The Vaginal Microbiome: Patient- versus Physician-Collected Microbial Swab: A Pilot Study

The composition of the vaginal microbiota prior to an IVF/IVF-ICSI treatment can predict the chance of achieving a pregnancy. To improve clinical applicability and be more patient-friendly, the self-collection of vaginal samples would be preferable. However, the reliability of patient-collected samples compared to physician-collected samples remains unclear. This study compares microbiome outcomes from patient-collected versus physician-collected vaginal samples. This is a prospective pilot study consisting of two cohorts: Cohort I involved patient self-sampling of the vagina, followed by a physician-collected vaginal swab, while Cohort II involved the reversed order of collection. The interspace profiling (IS-Pro) technique was used to analyze the microbiota composition in all samples. From May 2021 to March 2022, a total of 444 samples were collected from n = 222 patients (aged 21-44 years), with Cohort I (n = 109) and Cohort II (n = 113). The vaginal microbiome composition of both cohorts was highly similar, regardless of the sampling order, with a mean cosine similarity of 0.93 (95% CI 0.91, 0.95) in Cohort I and 0.94 (95% CI 0.92, 0.96) in Cohort II. Furthermore, ANOVA analysis revealed no significant differences in bacterial species abundance between physician- and patient-collected samples, nor between first and second sample collections. The self-collection of vaginal samples can be considered comparable to physician-collected samples and indicates a more patient-friendly and convenient collection of the vaginal microbiome in an outpatient clinical setting.

WHO global research priorities for sexually transmitted infections

Sexually transmitted infections (STIs) are widespread worldwide and negatively affect sexual and reproductive health. Gaps in evidence and in available tools have long hindered STI programmes and policies, particularly in resource-limited settings. In 2022, WHO initiated a research prioritisation process to identify the most important STI research areas to address the global public health need. Using an adapted Child Health and Nutrition Research Initiative methodology including two global stakeholder surveys, the process identified 40 priority STI research needs. The top priorities centred on developing and implementing affordable, feasible, rapid point-of-care STI diagnostic tests and new treatments, especially for gonorrhoea, chlamydia, and syphilis; designing new multipurpose prevention technologies and vaccines for STIs; and collecting improved STI epidemiologic data on both infection and disease outcomes. The priorities also included innovative programmatic approaches, such as new STI communication and partner management strategies. An additional six research areas related to mpox (formerly known as monkeypox) reflect the need for STI-related research during disease outbreaks where sexual transmission can have a key role. These STI research priorities provide a call to action for focus, investment, and innovation to address existing roadblocks in STI prevention, control, and management to advance sexual and reproductive health and wellbeing for all.

Reproductive Tract Microbial Transitions from Late Gestation to Early Postpartum Using 16S rRNA Metagenetic Profiling in First-Pregnancy Heifers

Studies in recent years indicate that reproductive tract microbial communities are crucial for shaping mammals' health and reproductive outcomes. Following parturition, uterine bacterial contamination often occurs due to the open cervix, which may lead to postpartum uterine inflammatory diseases, especially in primiparous individuals. However, investigations into spatio-temporal microbial transitions in the reproductive tract of primigravid females remain limited. Our objective was to describe and compare the microbial community compositions in the vagina at late gestation and in the vagina and uterus at early postpartum in first-pregnancy heifers. Three swab samples were collected from 33 first-pregnancy Holstein Friesian heifers: one vaginal sample at gestation day 258 ± 4, and vaginal and uterine samples at postpartum day 7 ± 2. Each sample underwent 16S rRNA V4 region metagenetic analysis via Illumina MiSeq, with bioinformatics following Mothur MiSeq SOP. The reproductive tract bacterial communities were assigned to 1255 genus-level OTUs across 30 phyla. Dominant phyla, accounting for approximately 90% of the communities, included Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Fusobacteria. However, the results revealed distinct shifts in microbial composition between the prepartum vagina (Vag-pre), postpartum vagina (Vag-post), and postpartum uterus (Utr-post). The Vag-pre and Utr-post microbial profiles were the most distinct. The Utr-post group had lower relative abundances of Proteobacteria but higher abundances of Bacteroidetes, Fusobacteria, and Tenericutes compared to Vag-pre, while Vag-post displayed intermediate values for these phyla, suggesting a transitional profile. Additionally, the Utr-post group exhibited lower bacterial richness and diversity compared to both Vag-pre and Vag-post. The unsupervised probabilistic Dirichlet Multinomial Mixtures model identified two distinct community types: most Vag-pre samples clustered into one type and Utr-post samples into another, while Vag-post samples were distributed evenly between the two. LEfSe analysis revealed distinct microbial profiles at the genus level. Overall, specific microbial markers were associated with anatomical and temporal transitions, revealing a dynamic microbial landscape during the first pregnancy and parturition. These differences highlight the complexity of these ecosystems and open new avenues for research in reproductive biology and microbial ecology.

A multi-kingdom collection of 33,804 reference genomes for the human vaginal microbiome

The human vagina harbours diverse microorganisms-bacteria, viruses and fungi-with profound implications for women's health. Genome-level analysis of the vaginal microbiome across multiple kingdoms remains limited. Here we utilize metagenomic sequencing data and fungal cultivation to establish the Vaginal Microbial Genome Collection (VMGC), comprising 33,804 microbial genomes spanning 786 prokaryotic species, 11 fungal species and 4,263 viral operational taxonomic units. Notably, over 25% of prokaryotic species and 85% of viral operational taxonomic units remain uncultured. This collection significantly enriches genomic diversity, especially for prevalent vaginal pathogens such as BVAB1 (an uncultured bacterial vaginosis-associated bacterium) and Amygdalobacter spp. (BVAB2 and related species). Leveraging VMGC, we characterize functional traits of prokaryotes, notably Saccharofermentanales (an underexplored yet prevalent order), along with prokaryotic and eukaryotic viruses, offering insights into their niche adaptation and potential roles in the vagina. VMGC serves as a valuable resource for studying vaginal microbiota and its impact on vaginal health.

Anti-inflammatory effects of extracellular vesicles and cell-free supernatant derived from Lactobacillus crispatus strain RIGLD-1 on Helicobacter pylori-induced inflammatory response in gastric epithelial cells in vitro

Helicobacter pylori infection is the major risk factor associated with the development of gastric cancer. Currently, administration of standard antibiotic therapy combined with probiotics and postbiotics has gained significant attention in the management of H. pylori infection. In this work, the immunomodulatory effects of Lactobacillus crispatus-derived extracellular vesicles (EVs) and cell-free supernatant (CFS) were investigated on H. pylori-induced inflammatory response in human gastric adenocarcinoma (AGS) cells. L. crispatus-derived EVs were isolated by ultracentrifugation and physically characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Furthermore, the protein content of L. crispatus-derived EVs was also evaluated by SDS-PAGE. Cell viability of AGS cells exposed to varying concentrations of EVs and CFS was assessed by MTT assay. The mRNA expression of IL-1β, IL-6, IL-8, TNF-α, IL-10, and TGF-ß genes was determined by RT-qPCR. ELISA was used for the measurement of IL-8 production in AGS cells. In addition, EVs (50 μg/mL) and CFS modulated the H. pylori-induced inflammation by downregulating the mRNA expression of IL-1β, IL-6, IL-8, and TNF-α, and upregulating the expression of IL-10, and TGF-ß genes in AGS cells. Furthermore, H. pylori-induced IL-8 production was dramatically decreased after treatment with L. crispatus-derived EVs and CFS. In conclusion, our observation suggests for the first time that EVs released by L. crispatus strain RIGLD-1 and its CFS could be recommended as potential therapeutic agents against H. pylori-triggered inflammation.

Vaginal Microbiome and Pregnancy Complications: A Review

Background/Objectives: There are indications that the microbial composition of the maternal mucosal surfaces is associated with adverse events during pregnancy. The aim of this review is to investigate the link between vaginal microbiome alterations and gestational complication risk. Methods: This comprehensive literature review was performed using Medline and Scopus databases. The following search algorithm was used, "Pregnancy Complications" [Mesh] AND (Vagin*), and after the literature screening, 44 studies were included in the final review. Results: The studies that were included investigated the association between vaginal microbial composition and preterm birth, miscarriage, preeclampsia, ectopic pregnancy, gestational diabetes mellitus, chorioamnionitis, and preterm premature rupture of membranes. In most of the studies, it was well established that increased microbial diversity is associated with these conditions. Also, the depletion of Lactobacillus species is linked to most of the gestational complications, while the increased relative abundance and especially Lactobacillus crispatus may exert a protective effect in favor of the pregnant woman. Several pathogenic taxa including Gardnerella, Prevotella, Sneathia, Bacterial Vaginosis-Associated Bacteria-2, Atopobium, and Megasphera seem to be correlated to higher maternal morbidity. Conclusions: Vaginal microbiome aberrations seem to have an association with pregnancy-related adverse events, but more high-quality homogenous studies are necessary to reliably verify this link.

The prevalence of vulvovaginal symptoms in Japanese women of reproductive and perimenopausal ages: A cross-sectional study across generations

AIM

This cross-sectional study evaluated vaginal health and hygiene practices among reproductive and perimenopausal women in Japan using an online-based questionnaire.

METHODS

The questionnaire included 11 well-structured questions concerning vulvovaginal symptoms and hygiene care practices. Participants' responses were anonymized and analyzed descriptively. The relationships of age, family income, occupation, and childbearing with women's concerns regarding vaginal or vulvar problems were analyzed by chi-square tests.

RESULTS

About 80% of women in their 20s to 50s in Japan reported experiencing vulvovaginal symptoms. Women in their 40s had significantly fewer symptoms than women in their 20s (p = 0.04), and women in their 50s had significantly fewer symptoms than all other age groups (20s, 30s, and 40s) (p < 0.001). Among symptomatic women, 77.5% did not discuss their symptoms with anyone else and only 10% visited doctors. About 12.5% of women reported taking special care of their vagina or vulva regularly, whereas 38.2% expressed a desire to try some form of care but had not yet done so. Of the women who did not take special care of their vagina or vulva, 46.2% lacked knowledge about proper care, 42.2% did not want to spend money on care, 30.5% did not want to discuss care with others, and 21.3% were psychologically reluctant.

CONCLUSION

Determination of the prevalence of vulvovaginal symptoms among Japanese women can enhance understanding of this prevalent condition and its impact on women's health. These findings may help formulate effective public health interventions and promote better hygienic practices, thus improving the well-being of women in Japan.

Vaginal microbiota molecular profiling and diagnostic performance of artificial intelligence-assisted multiplex PCR testing in women with bacterial vaginosis: a single-center experience

Background

Bacterial vaginosis (BV) is a most common microbiological syndrome. The use of molecular methods, such as multiplex real-time PCR (mPCR) and next-generation sequencing, has revolutionized our understanding of microbial communities. Here, we aimed to use a novel multiplex PCR test to evaluate the microbial composition and dominant lactobacilli in non-pregnant women with BV, and combined with machine learning algorithms to determine its diagnostic significance.

Methods

Residual material of 288 samples of vaginal secretions derived from the vagina from healthy women and BV patients that were sent for routine diagnostics was collected and subjected to the mPCR test. Subsequently, Decision tree (DT), random forest (RF), and support vector machine (SVM) hybrid diagnostic models were constructed and validated in a cohort of 99 women that included 74 BV patients and 25 healthy controls, and a separate cohort of 189 women comprising 75 BV patients, 30 intermediate vaginal microbiota subjects and 84 healthy controls, respectively.

Results

The rate or abundance of Lactobacillus crispatus and Lactobacillus jensenii were significantly reduced in BV-affected patients when compared with healthy women, while Lactobacillus iners, Gardnerella vaginalis, Atopobium vaginae, BVAB2, Megasphaera type 2, Prevotella bivia, and Mycoplasma hominis were significantly increased. Then the hybrid diagnostic models were constructed and validated by an independent cohort. The model constructed with support vector machine algorithm achieved excellent prediction performance (Area under curve: 0.969, sensitivity: 90.4%, specificity: 96.1%). Moreover, for subjects with a Nugent score of 4 to 6, the SVM-BV model might be more robust and sensitive than the Nugent scoring method.

Conclusion

The application of this mPCR test can be effectively used in key vaginal microbiota evaluation in women with BV, intermediate vaginal microbiota, and healthy women. In addition, this test may be used as an alternative to the clinical examination and Nugent scoring method in diagnosing BV.

Effect of stress urinary incontinence on vaginal microbial communities

BACKGROUND

Postpartum women often experience stress urinary incontinence (SUI) and vaginal microbial dysbiosis, which seriously affect women's physical and mental health. Understanding the relationship between SUI and vaginal microbiota composition may help to prevent vaginal diseases, but research on the potential association between these conditions is limited.

RESULTS

This study employed 16S rRNA gene sequencing to explore the association between SUI and vaginal dysbiosis. In terms of the vaginal microbiota, both species richness and evenness were significantly higher in the SUI group. Additionally, the results of NMDS and species composition indicated that there were differences in the composition of the vaginal microbiota between the two groups. Specifically, compared to postpartum women without SUI (Non-SUI), the relative abundance of bacteria associated with bacterial dysbiosis, such as Streptococcus, Prevotella, Dialister, and Veillonella, showed an increase, while the relative abundance of Lactobacillus decreased in SUI patients. Furthermore, the vaginal microbial co-occurrence network of SUI patients displayed higher connectivity, complexity, and clustering.

CONCLUSION

The study highlights the role of Lactobacillus in maintaining vaginal microbial homeostasis. It found a correlation between SUI and vaginal microbiota, indicating an increased risk of vaginal dysbiosis. The findings could enhance our understanding of the relationship between SUI and vaginal dysbiosis in postpartum women, providing valuable insights for preventing bacterial vaginal diseases and improving women's health.

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.

Correlation between microbial characteristics and reproductive status of the yak uterus based on macrogenomic analysis

INTRODUCTION

This study aimed to investigate the microbial characteristics of yak uteri collected using intrauterine cotton swabs (CS) during different reproductive stages and the correlation of these microbial characteristics with reproductive status.

METHODS

We used a macrogenomic approach to analyze the functional aspects of different microorganisms in samples collected during the pre-estrus, estrus, late estrus, and diestrus stages.

RESULTS

The results revealed the presence of 1293 microbial genera and 3401 microbial species in the uteri of yaks at different reproductive stages. The dominant bacterial species varied across the different periods, with Micrococcus and Proteus being dominant during pre-estrus; Pseudomonas, Clostridium, Flavobacterium, Bacillus, and Staphylococcus during estrus; Acinetobacter, Bacillus and Proteus during late estrus; and Pseudomonas, Escherichia coli, and Proteus during diestrus.

DISCUSSION

The primary functions of these bacteria are enriched in various metabolic pathways, including carbohydrate and amino acid metabolism, intracellular transport and secretion, post-translational protein modification, and drug resistance. These findings suggest that the microbial diversity in the uterus of yaks plays a crucial role in reproductive regulation and can help prevent reproductive tract-related diseases.

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

IMPORTANCE

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

Association between co-infection with Chlamydia trachomatis or Mycoplasma genitalium and cervical lesions in HPV-positive population in Hunan, China: a cross-sectional study

OBJECTIVES

The aim of this study was to determine the prevalence of Chlamydia trachomatis (CT) and Mycoplasma genitalium (MG) among HPV-positive women undergoing colposcopy at the Second Xiangya Hospital of Central South University, Hunan, China. Additionally, we aimed to assess the impact of C. trachomatis or M. genitalium co-infection with HPV on the severity of cervical lesions.

METHODS

We collected HPV data, cervical cytology results, and demographic information from 439 women attending colposcopy. Cervical swabs were obtained for simultaneous amplification testing (SAT) of C. trachomatis and M. genitalium. Multivariate logistic regression analyses were performed to examine the association between sexually transmitted pathogens and cervical lesions.

RESULTS

Among the participants, C. trachomatis was detected in 17 (3.87%) individuals, and M. genitalium in 16 (3.64%) individuals. There was no co-infection of C. trachomatis and M. genitalium. The highest prevalence of M. genitalium was observed in women aged 19-30 years (10.20%; 95% CI, 1.41-18.99%), with a subsequent decline in prevalence with increasing age (Ptrend = 0.014). The most common HPV subtype in our study was HPV52 (30.79%), followed by HPV16 (18.62%), HPV58 (16.95%), and HPV53 (10.02%). Infection with HPV16 (OR = 3.43, 95% CI, 2.13-5.53), HPV31 (OR = 3.70, 95% CI, 1.44-9.50), and HPV33 (OR = 3.71, 95% CI, 1.43-9.67) was associated with an increased severity of cervical lesions, while HPV53 infection was not likely to lead to advanced cervical lesions (OR = 0.45, 95% CI, 0.23-0.89). The leukocyte level in vaginal secretions (P = 0.042) and cervical cytology results (P < 0.001) showed associations with the degree of cervical lesions. However, there was no significant association between C. trachomatis or M. genitalium infection and the severity of cervical lesions, nor with their co-infection with HPV16.

CONCLUSIONS

There was no correlation between co-infection of Chlamydia trachomatis or Mycoplasma genitalium and the degree of cervical lesions in HPV-positive population in Hunan, China. Our findings emphasized the need to pay more attention to M. genitalium infection among young women. Increased levels of leukocytes in vaginal secretions may be linked to cervical lesions. HPV16, HPV31, and HPV33 in Hunan province, China, may exhibit higher cervical pathogenicity.

Uterine microbial communities and their potential role in the regulation of epithelium cell cycle and apoptosis in aged hens

BACKGROUND

Alterations of the uterine microbiome are closely associated with various intrauterine diseases and physiological conditions, which are well-established in mammals. However, as representative oviparous animals, the research on the uterine microbial ecosystem and its functions with physiological homeostasis is limited in chickens. Additionally, continuous egg-laying disrupts the oviducal immune defenses of aged hens, susceptible to pathogen invasion, causing poor egg quality and food-borne infections in humans. Here, we investigated aging-related changes in the oviduct microbial colonization and transmission from the gut to eggs and their roles in a hen model.

RESULTS

The results of 16S rDNA sequencing showed significant differences in the oviduct microbial composition between young (38 weeks) and aged (77 weeks) laying hens. SourceTracker analysis further revealed differences in the effects of microbial transmission on the oviducal microbiota between young and aged hens. Enhanced barrier defense with cell apoptosis suppression and cell cycle arrest of the uterus were observed in aged hens reducing microbial transmission from the lower to upper reproductive tract. In addition, a total of 361 significantly differential metabolites were identified using metabolomics in the aged uterine microbiota, especially in products of amino acid metabolism and biosynthesis of various secondary metabolites, which might have essential effects on cell apoptosis by regulating immune responses and cell cycle. Notably, antibiotics disrupted uterine microbiota by dietary intervention and direct perfusion did not retard aging-related physiological changes but further aggravated aging processes by disrupting the cell cycle and apoptosis.

CONCLUSIONS

The microbiota continuum along the reproductive tract in aged birds differs from that in young birds, especially with a significant shift in the uterus. The aged uterine microbiota probably contributes to the regulation of cell cycle and apoptosis by microbial metabolites primarily involved in amino acid metabolism and biosynthesis of various secondary metabolites. These findings provide new insights into the roles of the reproductive tract microbiota in regulating the cell programming of the aged host, contributing to the exploration of the microbiome as a target for diagnosing aging health status and therapy for gynecological diseases in women. Video Abstract.

Dysbiosis of vaginal and cervical microbiome is associated with uterine fibroids

Dysbiosis of the female reproductive tract is closely associated with gynecologic diseases. Here, we aim to explore the association between dysbiosis in the genital tract and uterine fibroids (UFs) to further provide new insights into UF etiology. We present an observational study to profile vaginal and cervical microbiome from 29 women with UFs and 38 healthy women, and 125 samples were obtained and sequenced. By comparing the microbial profiles between different parts of the reproductive tract, there is no significant difference in microbial diversity between healthy subjects and UF patients. However, alpha diversity of UF patients was negatively correlated with the number of fibroids. Increased Firmicutes were observed in both the cervical and vaginal microbiome of UF patients at the phylum level. In differential analysis of relative abundance, some genera were shown to be significantly enriched (e.g., Erysipelatoclostridium, Mucispirillum, and Finegoldia) and depleted (e.g., Erysipelotrichaceae UCG-003 and Sporolactobacillus) in UF patients. Furthermore, the microbial co-occurrence networks of UF patients showed lower connectivity and complexity, suggesting reduced interactions and stability of the cervical and vaginal microbiota in UF patients. In summary, our findings revealed the perturbation of microbiome in the presence of UFs and a distinct pattern of characteristic vaginal and cervical microbiome involved in UFs, offering new options to further improve prevention and management strategies.

Characteristics of vaginal microbes and classification of the vaginal microbiome

Background

The vaginal microbiome (VMB) has been classified into several discrete community state types, some of which have been associated with adverse human health conditions. However, the roles of the many vaginal bacteria in modulating the VMB and health remain unclear.

Methods

The associations among the vaginal taxa and other vaginal taxa, the vaginal pH, and the host gene expression responses were determined by calculating the correlation among the relative abundance of the vaginal taxa, the association between the vaginal pH and the predominant taxon in the VMB, and the correlation between the relative abundance of the vaginal taxa and human gene expression at the transcriptional level, respectively. Using these associations, an alternative more informative method, the biological vagitype (BVT), is proposed to classify community state types of the VMB.

Findings

Most Lactobacillus spp., with the exception of Lactobacillus iners , show significant correlations with host gene expression profiles and negative associations with dysbiosis-associated vaginal taxa. Many non- Lactobacillus spp. exhibit varied correlations with Lactobacillus spp., the vaginal pH, and host gene expression. Compared to other dysbiotic taxa, including Candidatus Lachnocurva vaginae, Gardnerella vaginalis has a stronger positive correlation with vaginal pH and a stronger negative correlation with Lactobacillus spp. Most dysbiosis-associated taxa are associated with stress responses of the host at the transcriptional level, but the genus Mycoplasma has a uniquely strong positive correlation with host immune responses. The association between BVTs of the VMBs and host characteristics, e.g., race/ethnicity, microbial infection, smoking, antibiotics, high blood pressure, economic state, diet, and others, was examined. The BVT classification method improved overall performance in associating specific vaginal microbial populations with host characteristics and phenotypes.

Interpretation

This study sheds light on the biological characteristics of the vaginal microbiota, including some less abundant or still unculturable taxa. Since the BVT method was established based on these biological characteristics, the classification outcome of the VMB may have more clinical relevance. Because the BVT method performs better in associating specific vaginal community types with diseases, e.g., bacterial vaginosis and gonorrhea, it could be beneficial for the predictive modeling of adverse health.

Funding

This work was supported by grants [UH3AI083263, U54HD080784, and R01HD092415] from the National Institutes of Health; and support from the [GAPPS BMGF PPB] grant from the Global Alliance to Prevent Prematurity and Stillbirth. We would also like to thank the Office of Research on Women's Health at NIH for their generous support.

Research in context

Evidence before this study: The vaginal microbiome (VMB) refers to the community of microorganisms in the female lower reproductive tract. The VMB is often a simple ecosystem dominated by a single species. The most predominant bacteria in the VMB include several Lactobacillus species and two non- Lactobacillus species, i.e., Candidatus Lachnocurva vaginae and Gardnerella vaginalis. Lactobacillus species produce lactic acid to lower the vaginal pH and inhibit the growth of disease-associated bacteria. Thus, the predominance of protective Lactobacilli, i.e., L. crispatus, L. jensenii , and L. gasseri , in the VMB is associated with overall vaginal health. However, the role of L. iners in promoting a healthy vaginal ecosystem is less clear. Actually, the biological and health relevance of many bacteria in the female lower reproductive tract is largely unknown. Some bacteria have low relative abundances, e.g., Peptostreptococcus and Coriobacteriaceae spp.; and others are not yet culturable, e.g., Candidatus Lachnocurva vaginae and BVAB TM7. When abundance of a taxon is low, its association with a host characteristic is a challenge. Previous methods to classify the VMB were based simply on their microbial compositions, and the biological characteristics of the vaginal bacteria were largely ignored. Thus, classification of these VMBs into biologically relevant community types, as described herein, should be helpful in determining their relevance to women's reproductive health. Added value of this study: This study examines three biological characteristics of bacteria in the VMB, i.e., the associations among different bacterial taxa, the vaginal pH, and the host response. Based on these three characteristics, the influence of these bacteria, particularly low abundant and unculturable bacteria, on vaginal health is evaluated. L. iners seems to be neutral in maintaining overall vaginal health. Gardnerella vaginalis is apparently more easily inhibited by Lactobacillus spp. than Candidatus Lachnocurva vaginae because of its stronger positive correlation with vaginal pH and negative correlation with Lactobacillus . The genus of Mycoplasma has a unique positive correlation with local immune responses, implying a role for Mycoplasma in promoting inflammation. Compared with previous methods to classify the VMB, a new method, considering the above three biological characteristics of bacteria in the VMB, has been established. The new method performs better in associating specific vaginal communities with host characteristics and phenotypes; e.g., bacterial vaginosis and gonorrhea. Implications of all the available evidence: Accurate biological classification of the VMB is fundamental for assessing its impact on women's health. Our classification scheme represents a step further toward that correct classification, eventually leading to new strategies for clinical assessment of the potential use of the VMB to diagnose or predict women's reproductive health.

Comparative Analysis of the Pre-Parturition and Post-Parturition Genital Tract Microbiota in Plateau Bangor Sewa Sheep

(1) Background: Bangor Sewa sheep are an economically significant livestock species on the plateau. The roles of microbiota in reproduction are complex and critical for animal health. But little is known currently about the microbiome of plateau Bangor Sewa sheep. The purpose of this study was to discover the changes in the genital tract microbiota of pre- and post-partum Bangor Sewa sheep. (2) Methods: Samples from the birth canal were obtained for 16S rRNA sequencing, three days before and after delivery, respectively. (3) Results: The results showed that there was a noticeable difference in three phyla and 74 genera between the pre- and post-parturition groups in the microbiota of Bangor Sewa sheep. The changes included a decrease in the abundance of genera related to health (unclassified_Cellulomonadaceae, Cellulomonas, Fibrobacti, Flavobacterium, Eubacterium_ventriosum_group, Acetitomaculum, Aeromicrobium, Dietzia, Romboutsia, Ruminococcus, etc.) and an increased abundance of negatively related genera (Nocardioides, unclassified_Clostridia, Sphingobacteriaceae, unclassified_Ruminococcaceae, Prevotellaceae_UCG_004, Micromonospora, Streptococcus, Facklamia, Bosea, etc.) spp. (4) Conclusions: Microbes can serve as indicators of the physical state of Bangor Sewa sheep. These findings laid the foundation for deciphering the effects of microbial changes during birth on the reproductive health of plateau Bangor Sewa sheep.

Vaginal microbiome in obesity and its impact on reproduction

A number of reproductive outcomes have been increasingly found to be affected by the vaginal microbiota. Obesity has become a global epidemic, affecting increasing numbers of reproductive-age women, and has been shown to be a risk factor for a number of adverse female health outcomes. A healthy vaginal microbiome is characterized by Lactobacillus-dominance, in particular Lactobacillus crispatus; obesity has been found to be associated with higher diversity and a lower likelihood of Lactobacillus-dominance. In this review, we summarize the evidence on the vaginal microbiome in obese women and the impact on reproductive outcomes such as conception rates, early pregnancy, and preterm birth. We further explore the mechanisms by which obesity may result in an altered microbial composition and highlight future avenues for therapeutic targeting of the vaginal microbiota.

Orally administrated Lactobacillus gasseri TM13 and Lactobacillus crispatus LG55 can restore the vaginal health of patients recovering from bacterial vaginosis

Bacterial vaginosis (BV) is a common infection of the lower genital tract with a vaginal microbiome dysbiosis caused by decreasing of lactobacilli. Previous studies suggested that supplementation with live Lactobacillus may benefit the recovery of BV, however, the outcomes vary in people from different regions. Herein, we aim to evaluate the effectiveness of oral Chinese-origin Lactobacillus with adjuvant metronidazole (MET) on treating Chinese BV patients. In total, 67 Chinese women with BV were enrolled in this parallel controlled trial and randomly assigned to two study groups: a control group treated with MET vaginal suppositories for 7 days and a probiotic group treated with oral Lactobacillus gasseri TM13 and Lactobacillus crispatus LG55 as an adjuvant to MET for 30 days. By comparing the participants with Nugent Scores ≥ 7 and < 7 on days 14, 30, and 90, we found that oral administration of probiotics did not improve BV cure rates (72.73% and 84.00% at day 14, 57.14% and 60.00% at day 30, 32.14% and 48.39% at day 90 for probiotic and control group respectively). However, the probiotics were effective in restoring vaginal health after cure by showing higher proportion of participants with Nugent Scores < 4 in the probiotic group compared to the control group (87.50% and 71.43% on day 14, 93.75% and 88.89% on day 30, and 77.78% and 66.67% on day 90). The relative abundance of the probiotic strains was significantly increased in the intestinal microbiome of the probiotic group compared to the control group at day 14, but no significance was detected after 30 and 90 days. Also, the probiotics were not detected in vaginal microbiome, suggesting that L. gasseri TM13 and L. crispatus LG55 mainly acted through the intestine. A higher abundance of Prevotella timonensis at baseline was significantly associated with long-term cure failure of BV and greatly contributed to the enrichment of the lipid IVA synthesis pathway, which could aggravate inflammation response. To sum up, L. gasseri TM13 and L. crispatus LG55 can restore the vaginal health of patients recovering from BV, and individualized intervention mode should be developed to restore the vaginal health of patients recovering from BV.

Clinical trial registration

https://classic.clinicaltrials.gov/ct2/show/, identifier NCT04771728.

Advances in Research on the Relationship between Vaginal Microbiota and Adverse Pregnancy Outcomes and Gynecological Diseases

The human microbiota inhabiting different parts of the body has been shown to have a significant impact on human health, with the gut microbiota being the most extensively studied in relation to disease. However, the vaginal microbiota is also an essential commensal microbiota in the female body that plays a crucial role in female health. Despite receiving less attention than gut microbiota, its importance in regulating reproductive immunity and its complex dynamic properties have been increasingly recognized in recent years. Advances in research on the relationship between vaginal microbiota and pregnancy outcomes & gynecological diseases in women have shed light on the importance of maintaining a healthy vaginal microbiota. In this review, we aim to compile recent developments in the study of the vaginal microbial ecosystem and its role in female health and reproductive outcomes. We provide a comprehensive account of the normal vaginal microbiota, the association between the vaginal microbiota and pregnancy outcomes, and the impact of the vaginal microbiota on gynecological diseases in women. By reviewing recent research, we hope to contribute to the advancement of academic medicine's understanding of the vaginal microbiota's importance in female health. We also aim to raise awareness among healthcare professionals and the general public of the significance of maintaining a healthy vaginal microbiota for better reproductive health and the prevention of gynecological diseases.

The influence of maternal factors on the neonatal microbiome and health

The human microbiome plays an essential role in human health. However, the influence of maternal factors on the neonatal microbiome remains obscure. Herein, our observations suggest that the neonatal buccal microbiome is similar to the maternal buccal microbiome, but the neonatal gastrointestinal microbiome develops a unique composition at an early stage. The low complexity of the neonatal buccal microbiome is a hallmark of maternal and neonatal health, but that of the neonatal gastrointestinal microbiome is associated with maternal inflammation-related metabolites. Microbial infections in the maternal reproductive tract universally impact the complexity of the neonatal microbiomes, and the body site is most important in modulating the composition of the neonatal microbiomes. Additionally, maternal lipids attenuated the adverse influence of several maternal factors on the neonatal microbiomes. Finally, admission of neonates to the newborn intensive care unit is associated with sub-optimal states of the maternal buccal and rectal microbiomes and maternal health.

Immunomodulation of the Vaginal Ecosystem by Ligilactobacillus salivarius CECT 30632 Improves Pregnancy Rates among Women with Infertility of Unknown Origin or Habitual Abortions

In this study, the probiotic potential of Ligilactobacillus salivarius CECT 30632 was assessed, including properties specifically related with gynecological targets. This strain displayed co-aggregative and antimicrobial activity against a wide spectrum of vaginal pathogens while being respectful with the growth of vaginal lactobacilli. The strain produced a high concentration of lactic acid and displayed α-amylase activity when assayed in vitro. It showed a noticeable survival rate after exposition to conditions similar to those present in the human digestive tract and was adhesive to both vaginal and intestinal cells. Subsequently, their capacity to increase pregnancy rates among women with habitual abortion or infertility of unknown origin was studied. Administration of L. salivarius CECT 30632 (~9 log₁₀ CFU) daily for a maximum of six months to these women was safe and led to a successful pregnancy rate of 67.5% (80% and 55% for women with repetitive abortion and infertile women, respectively). Significant differences in Nugent score, vaginal pH, and vaginal concentrations of lactobacilli, TGF-β, and VEFG were observed when the samples collected before the intervention were compared with those collected after the treatment among those women who got pregnant. Therefore, this strain can modulate the vaginal ecosystem and lead to better fertility outcomes.