Women and Their Microbes: The Unexpected Friendship

Vaginal flora in HPV infection: a cross‑sectional analysis

OBJECTIVE

The vaginal flora has been reported to be associated with human papillomavirus (HPV) infection. The purpose of this study was to investigate the characteristics of the cervical microbiota in patients with HPV infection and to analyse the changes in the vaginal flora and enzyme profiles in females with HPV infection.

METHODS

We conducted a cross-sectional study involving 206 participants who underwent HPV genotyping, sexually transmitted diseases pathogen testing, cytology examination, and microbiome analysis. Additionally, we collected 115 HPV-negative samples and 48 HPV-positive samples for 16S rRNA amplicon sequencing. The vaginal microbial communities of both groups were analysed for diversity and differences to explore their association with HPV infection.

RESULTS

The abundance of Lactobacillus was found to be reduced, while Gardnerella vaginalis was significantly more prevalent in the HPV + group. In terms of alpha diversity indices, the Shannon index (P = .0036) and Simpson index (P = .02) were higher in the HPV + group compared to the HPV - group, indicating greater community diversity in the HPV + group. Among the 10 sexually transmitted diseases pathogens analysed, Uup3 and Uup6 were significantly associated with HPV infection. Statistically significant differences were observed in Nugent scores and bacterial vaginosis between the two groups (P < .05). In functional analysis, 11 proteins and 13 enzymes were found to be significantly altered in the HPV + group.

CONCLUSION

Our study demonstrates that disruptions in the vaginal flora are associated with HPV infection. Reduced levels of Lactobacillus, increased prevalence of Gardnerella, and abnormal enzyme profiles are closely linked to HPV infection.

Comparison of Vaginal microbiota in HPV-negative and HPV-positive pregnant women using a culture-based approach

The purpose of this study was to conduct a comparative analysis of the composition of the dominant groups of vaginal microorganisms in healthy pregnant women and pregnant women infected with HPV using a microbiological culture-based method. The MALDI TOF MS method and 16S rRNA gene fragment sequencing were used to identify microorganisms isolated from healthy pregnant women (n=32) and pregnant women infected with HPV (n=24). It was found that vaginal secretion samples from both groups contained bacteria of 4 phyla: Bacillota, Actinomycetota, Pseudomonadota, Bacteroidota, and Ascomycota fungi. The most common microbial community in healthy pregnant women being CST I (p=0.0007), and CST V in pregnant women infected with HPV (p=0.0001). At the genus level, a total of 25 taxa were found in all samples, with Lactobacillus being the dominant genus overall. Escherichia (p<0.0001) and Prevotella (p=0.0001) concentrations were higher in HPV infected patients. When calculating the Pearson correlation coefficient for the phyla, it was found that Bacillota correlated negatively with HPV genotypes 16 and 51 (p≤0.05), but positively with HPV genotype 59 (p≤0.05), just like Actinomycetota (p≤0.05). Bacteroidota correlated positively with HPV genotype 56 (0.001 Collapse

Key Words

• 16s rRNA sequencing
• Community state types
• Human papillomavirus
• Lactobacillus crispatus
• Lactobacillus gasseri
• Lactobacillus iners
• Lactobacillus jensenii
• MALDI TOF MS
• Papillomavirus infection
• a Culture-Based Approach

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MESH Headings

• Humans
• Female
• Vagina/microbiology
• Vagina/virology
• Pregnancy
• Papillomavirus Infections/virology
• Papillomavirus Infections/microbiology
• Microbiota/genetics
• Adult
• RNA, Ribosomal, 16S/genetics
• Bacteria/classification
• Bacteria/isolation & purification
• Bacteria/genetics
• Papillomaviridae/genetics
• Papillomaviridae/isolation & purification
• Papillomaviridae/classification
• Young Adult
• Pregnancy Complications, Infectious/microbiology
• Pregnancy Complications, Infectious/virology
• Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
• Sequence Analysis, DNA

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Affiliation(s)

Podoprigora Irina Department of Microbiology named after V.S. Kiktenko, Medical Institute, RUDN University named after Patrice Lumumba, Moscow, Russia; Research Institute of Molecular and Cellular Medicine, Medical Institute, RUDN University named after Patrice Lumumba, Moscow, Russia.
Vasina Alena Mytishchi Regional Clinical Hospital, Mytishchi, Russia
Mbarga Manga Joseph Arsene Department of Microbiology named after V.S. Kiktenko, Medical Institute, RUDN University named after Patrice Lumumba, Moscow, Russia; Research Institute of Molecular and Cellular Medicine, Medical Institute, RUDN University named after Patrice Lumumba, Moscow, Russia.
Das Milana Department of Microbiology named after V.S. Kiktenko, Medical Institute, RUDN University named after Patrice Lumumba, Moscow, Russia; Research Institute of Molecular and Cellular Medicine, Medical Institute, RUDN University named after Patrice Lumumba, Moscow, Russia
Pikina Alla Department of Microbiology and Virology, Pirogov Russian National Research Medical University, Russia
Kafarskaya Lyudmila Department of Microbiology and Virology, Pirogov Russian National Research Medical University, Russia
Efimov Boris Department of Microbiology and Virology, Pirogov Russian National Research Medical University, Russia

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Insights into the assembly of the neovaginal microbiota in Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome patients

Neovaginas are surgically constructed to correct uterovaginal agenesis in women with Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome or as part of gender-affirming surgery for transfeminine individuals. Understanding the assembly of the neovaginal microbiota is crucial for guiding its management. To address this, we conducted a longitudinal study on MRKH patients following laparoscopic peritoneal vaginoplasty. Our findings reveal that the early microbial assemblage exhibited stochastic characteristics, accompanied with a notable bloom of Enterococcus faecalis and genital Mycoplasmas. While both the pre-surgery dimple microbiota and the fecal microbiota constituted the primary species pool, the neovaginal microbiota developed into a microbiota that resembled that of a normal vagina at 6-12 months post-surgery, albeit with a bacterial vaginosis (BV)-like structure. By 2-4 years post-surgery, the neovaginal microbiota had further evolved into a structure closely resembling with the homeostatic pre-surgery dimple microbiota. This concords with the development of the squamous epithelium in the neovagina and highlights the pivotal roles of progressive selective forces imposed by the evolving neovaginal environment and the colonization tropism of vaginal species. Notably, we observed that strains of Lactobacillus crispatus colonizing the neovagina primarily originated from the dimple. Since L. crispatus is generally associated with vaginal health, this finding suggests potential avenues for future research to promote its colonization.

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.

Lactobacillus gasseri and Gardnerella vaginalis produce extracellular vesicles that contribute to the function of the vaginal microbiome and modulate host-Trichomonas vaginalis interactions

Trichomonas vaginalis is an extracellular protozoan parasite of the human urogenital tract, responsible for a prevalent sexually transmitted infection. Trichomoniasis is accompanied by a dysbiotic microbiome that is characterised by the depletion of host-protective commensals such as Lactobacillus gasseri, and the flourishing of a bacterial consortium that is comparable to the one seen for bacterial vaginosis, including the founder species Gardnerella vaginalis. These two vaginal bacteria are known to have opposite effects on T. vaginalis pathogenicity. Studies on extracellular vesicles (EVs) have been focused on the direction of a microbial producer (commensal or pathogen) to a host recipient, and largely in the context of the gut microbiome. Here, taking advantage of the simplicity of the human cervicovaginal microbiome, we determined the molecular cargo of EVs produced by L. gasseri and G. vaginalis and examined how these vesicles modulate the interaction of T. vaginalis and host cells. We show that these EVs carry a specific cargo of proteins, which functions can be attributed to the opposite roles that these bacteria play in the vaginal biome. Furthermore, these bacterial EVs are delivered to host and protozoan cells, modulating host-pathogen interactions in a way that mimics the opposite effects that these bacteria have on T. vaginalis pathogenicity. This is the first study to describe side-by-side the protein composition of EVs produced by two bacteria belonging to the opposite spectrum of a microbiome and to demonstrate that these vesicles modulate the pathogenicity of a protozoan parasite. Such as in trichomoniasis, infections and dysbiosis co-occur frequently resulting in significant co-morbidities. Therefore, studies like this provide the knowledge for the development of antimicrobial therapies that aim to clear the infection while restoring a healthy microbiome.

Microbiome-Stealth Regulator of Breast Homeostasis and Cancer Metastasis

Cumulative evidence attests to the essential roles of commensal microbes in the physiology of hosts. Although the microbiome has been a major research subject since the time of Luis Pasteur and William Russell over 140 years ago, recent findings that certain intracellular bacteria contribute to the pathophysiology of healthy vs. diseased tissues have brought the field of the microbiome to a new era of investigation. Particularly, in the field of breast cancer research, breast-tumor-resident bacteria are now deemed to be essential players in tumor initiation and progression. This is a resurrection of Russel's bacterial cause of cancer theory, which was in fact abandoned over 100 years ago. This review will introduce some of the recent findings that exemplify the roles of breast-tumor-resident microbes in breast carcinogenesis and metastasis and provide mechanistic explanations for these phenomena. Such information would be able to justify the utility of breast-tumor-resident microbes as biomarkers for disease progression and therapeutic targets.

The Impact of Gestational Diabetes Mellitus (GDM) on the Development and Composition of the Neonatal Gut Microbiota: A Systematic Review

Gestational diabetes mellitus (GDM) is an important health issue, as it is connected with adverse effects to the mother as well as the fetus. A factor of essence for the pathology of this disorder is the gut microbiota, which seems to have an impact on the development and course of GDM. The role of the gut microbiota on maternal reproductive health and all the changes that happen during pregnancy as well as during the neonatal period is of high interest. The correct establishment and maturation of the gut microbiota is of high importance for the development of basic biological systems. The aim of this study is to provide a systematic review of the literature on the effect of GDM on the gut microbiota of neonates, as well as possible links to morbidity and mortality of neonates born to mothers with GDM. Systematic research took place in databases including PubMed and Scopus until June 2024. Data that involved demographics, methodology, and changes to the microbiota were derived and divided based on patients with exposure to or with GDM. The research conducted on online databases revealed 316 studies, of which only 16 met all the criteria and were included in this review. Research from the studies showed great heterogeneity and varying findings at the level of changes in α and β diversity and enrichment or depletion in phylum, gene, species, and operational taxonomic units in the neonatal gut microbiota of infants born to mothers with GDM. The ways in which the microbiota of neonates and infants are altered due to GDM remain largely unclear and require further investigation. Future studies are needed to explore and clarify these mechanisms.

Updates and Current Challenges in Reproductive Microbiome: A Comparative Analysis between Cows and Women

The microbiota plays an important role in numerous physiological processes, pathogenesis, development, and metabolism in different animal species. In humans, several studies have demonstrated an association between the vaginal microbiota and fertility rates, and even success in assisted reproduction techniques. In the context of cattle reproduction, although few studies have addressed the microbiota in a healthy state (which is not associated with diseases that affect the reproductive tract of cows), changes in its composition also seem to influence fertility. This review aims to explain the importance of the reproductive microbiota in female bovines and what is available in the literature regarding its possible role in increasing fertility. What are the challenges involved in this process? Future perspectives on its use and manipulation as a selection or intervention tool. Will it be possible to one day extrapolate the findings to reality and apply them in the field? In short, understanding the role of the reproductive microbiota of female bovines can signal the prospect of increasing production, whether of milk or meat, from the same number of animals, as it can optimize reproductive efficiency and perhaps become an allied tool for the economic profitability and sustainability of livestock farming.

The vaginal microbial signatures of preterm birth woman

To explore the differences of vaginal microbes in women with preterm birth (PTB), and to construct prediction model. We searched for articles related to vaginal microbiology in preterm women and obtained four 16S rRNA-sequence datasets. We analyzed that for species diversity and differences, and constructed a random forest model with 20 differential genera. We introduce an independent whole genome-sequencing (WGS) data for validation. In addition, we collected vaginal and cervical swabs from 33 pregnant women who delivered spontaneously full-term and preterm infants, performed WGS in our lab to further validate the model. Compared to term birth (TB) samples, PTB women vagina were characterized by a decrease in Firmicutes, Lactobacillus, and an increase in diversity accompanied by the colonization of pathogenic bacteria such as Gardnerella, Atopobium and Prevotella. Twenty genus markers, including Lactobacillus, Prevotella, Streptococcus, and Gardnerella performed well in predicting PTB, with study-to-study transfer validation and LODO validation, different gestation validation showing good results, and in two independent cohorts (external WGS cohorts and woman samples WGS cohorts) in which the accuracy was maintained. PTB women have unique vaginal microbiota characteristics. A predictive model of PTB was constructed and its value validated from multiple perspectives.

Anti-chlamydial activity of vaginal fluids: new evidence from an in vitro model

Introduction

We assessed the in vitro anti-chlamydial activity of fresh vaginal secretions, deciphering the microbial and metabolic components able to counteract Chlamydia trachomatis viability.

Methods

Forty vaginal samples were collected from a group of reproductive-aged women and their anti-chlamydial activity was evaluated by inhibition experiments. Each sample underwent 16S rRNA metabarcoding sequencing to determine the bacterial composition, as well as 1H-NMR spectroscopy to detect and quantify the presence of vaginal metabolites.

Results

Samples characterized by a high anti-chlamydial activity were enriched in Lactobacillus, especially Lactobacillus crispatus and Lactobacillus iners, while not-active samples exhibited a significant reduction of lactobacilli, along with higher relative abundances of Streptococcus and Olegusella. Lactobacillus gasseri showed an opposite behavior compared to L. crispatus, being more prevalent in not-active vaginal samples. Higher concentrations of several amino acids (i.e., isoleucine, leucine, and aspartate; positively correlated to the abundance of L. crispatus and L. jensenii) lactate, and 4-aminobutyrate were the most significant metabolic fingerprints of highly active samples. Acetate and formate concentrations, on the other hand, were related to the abundances of a group of anaerobic opportunistic bacteria (including Prevotella, Dialister, Olegusella, Peptostreptococcus, Peptoniphilus, Finegoldia and Anaerococcus). Finally, glucose, correlated to Streptococcus, Lachnospira and Alloscardovia genera, emerged as a key molecule of the vaginal environment: indeed, the anti-chlamydial effect of vaginal fluids decreased as glucose concentrations increased.

Discussion

These findings could pave the way for novel strategies in the prevention and treatment of chlamydial urogenital infections, such as lactobacilli probiotic formulations or lactobacilli-derived postbiotics.

Effect of Postbiotics Derived from Lactobacillus rhamnosus PB01 (DSM 14870) on Sperm Quality: A Prospective In Vitro Study

Vaginally administered postbiotics derived from Lactobacillus were recently demonstrated to be effective in alleviating bacterial vaginosis and increasing pregnancy rates. However, their potential effect on sperm quality has not been well investigated. This controlled in vitro study aimed to assess the dose- and time-dependent effects of postbiotics derived from Lactobacillus rhamnosus PB01 (DSM 14870) on sperm quality parameters. The experiment was conducted in vitro to eliminate potential confounding factors from the female reproductive tract and vaginal microbiota. Sperm samples from 18 healthy donors were subjected to analysis using Computer-Aided Sperm Analysis (CASA) in various concentrations of postbiotics and control mediums at baseline, 60 min, and 90 min of incubation. Results indicated that lower postbiotic concentration (PB5) did not adversely affect sperm motility, kinematic parameters, sperm DNA fragmentation, and normal morphology at any time. However, concentrations exceeding 15% demonstrated a reduction in progressively motile sperm and a negative correlation with non-progressively motile sperm at all time points. These findings underscore the importance of balancing postbiotic dosage to preserve sperm motility while realizing the postbiotics' vaginal health benefits. Further research is warranted to understand the underlying mechanisms and refine practical applications in reproductive health.

Gut microbiota modulation: a narrative review on a novel strategy for prevention and alleviation of ovarian aging

The global rise in life expectancy corresponds with a delay in childbearing age among women. Ovaries, seen as the chronometers of female physiological aging, demonstrate features of sped up aging, evidenced by the steady decline in both the quality and quantity of ovarian follicles from birth. The multifaceted pathogenesis of ovarian aging has kindled intensive research interest from the biomedical and pharmaceutical sectors. Novel studies underscore the integral roles of gut microbiota in follicular development, lipid metabolism, and hormonal regulation, forging a nexus with ovarian aging. In this review, we outline the role of gut microbiota in ovarian function (follicular development, oocyte maturation, and ovulation), compile and present gut microbiota alterations associated with age-related ovarian aging. We also discuss potential strategies for alleviating ovarian aging from the perspective of gut microbiota, such as fecal microbiota transplantation and probiotics.

Microbiome in Female Reproductive Health: Implications for Fertility and Assisted Reproductive Technologies

The microbiome plays a critical role in the process of conception and the outcomes of pregnancy. Disruptions in microbiome homeostasis in women of reproductive age can lead to various pregnancy complications, which significantly impact maternal and fetal health. Recent studies have associated the microbiome in the female reproductive tract (FRT) with assisted reproductive technology (ART) outcomes, and restoring microbiome balance has been shown to improve fertility in infertile couples. This review provides an overview of the role of the microbiome in female reproductive health, including its implications for pregnancy outcomes and ARTs. Additionally, recent advances in the use of microbial biomarkers as indicators of pregnancy disorders are summarized. A comprehensive understanding of the characteristics of the microbiome before and during pregnancy and its impact on reproductive health will greatly promote maternal and fetal health. Such knowledge can also contribute to the development of ARTs and microbiome-based interventions.

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.

Vaginal microbiota transplantation is a truly opulent and promising edge: fully grasp its potential

Vaginal microbiota transplantation (VMT) is a cutting-edge treatment modality that has the potential to revolutionize the management of vaginal disorders. The human vagina is a complex and dynamic ecosystem home to a diverse community of microorganisms. These microorganisms play a crucial role in maintaining the health and well-being of the female reproductive system. However, when the balance of this ecosystem is disrupted, it can lead to the development of various vaginal disorders. Conventional treatments, such as antibiotics and antifungal medications, can temporarily relieve the symptoms of vaginal disorders. However, they often fail to address the underlying cause of the problem, which is the disruption of the vaginal microbiota. In recent years, VMT has emerged as a promising therapeutic approach that aims to restore the balance of the vaginal ecosystem. Several studies have demonstrated the safety and efficacy of VMT in treating bacterial vaginosis, recurrent yeast infections, and other vaginal conditions. The procedure has also shown promising results in reducing the risk of sexually transmitted infections and preterm birth in pregnant women. However, more research is needed to establish optimal donor selection, preparation, and screening protocols, as well as long-term safety and efficacy. VMT offers a safe, effective, and minimally invasive treatment option for women with persistent vaginal problems. It could improve the quality of life for millions of women worldwide and become a standard treatment option shortly. With further research and development, it could potentially treat a wide range of other health problems beyond the scope of vaginal disorders.

HPV-associated cervicovaginal microbiome and host metabolome characteristics

BACKGROUND

Cervicovaginal microbiome plays an important role in the persistence of HPV infection and subsequent disease development. However, cervicovaginal microbiota varied cross populations with different habits and regions. Identification of population-specific biomarkers from cervicovaginal microbiota and host metabolome axis may support early detection or surveillance of HPV-induced cervical disease at all sites. Therefore, in the present study, to identify HPV-specific biomarkers, cervicovaginal secretion and serum samples from HPV-infected patients (HPV group, n = 25) and normal controls (normal group, n = 17) in Xichang, China were collected for microbiome (16S rRNA gene sequencing) and metabolome (UHPLC-MS/MS) analysis, respectively.

RESULTS

The results showed that key altered metabolites of 9,10-DiHOME, α-linolenic acid, ethylparaben, glycocholic acid, pipecolic acid, and 9,12,13-trihydroxy-10(E),15(Z)-octadecadienoic acid, correlating with Sneathia (Sneathia_amnii), Lactobacillus (Lactobacillus_iners), Atopobium, Mycoplasma, and Gardnerella, may be potential biomarkers of HPV infection.

CONCLUSION

The results of current study would help to reveal the association of changes in cervicovaginal microbiota and serum metabolome with HPV infections.

Deciphering the role of female reproductive tract microbiome in reproductive health: a review

Relevant studies increasingly indicate that female reproductive health is confronted with substantial challenges. Emerging research has revealed that the microbiome interacts with the anatomy, histology, and immunity of the female reproductive tract, which are the cornerstone of maintaining female reproductive health and preventing adverse pregnancy outcomes. Currently, the precise mechanisms underlying their interaction and impact on physiological functions of the reproductive tract remain elusive, constituting a prominent area of investigation within the field of female reproductive tract microecology. From this new perspective, we explore the mechanisms of interactions between the microbiome and the anatomy, histology, and immunity of the female reproductive tract, factors that affect the composition of the microbiome in the female reproductive tract, as well as personalized medicine approaches in managing female reproductive tract health based on the microbiome. This study highlights the pivotal role of the female reproductive tract microbiome in maintaining reproductive health and influencing the occurrence of reproductive tract diseases. These findings support the exploration of innovative approaches for the prevention, monitoring and treatment of female reproductive tract diseases based on the microbiome.

Microbiota substances modulate dendritic cells activity: A critical view

Contemporary research in the field of microbiota shows that commensal bacteria influence physiological activity of different organs and systems of a human organism, such as brain, lungs, immune and metabolic systems. This influence is realized by various processes. One of them is trough modulation of immune mechanisms. Interactions between microbiota and the human immune system are known to be complex and ambiguous. Dendritic cells (DCs) are unique cells, which initiate the development and polarization of adaptive immune response. These cells also interconnect native and specific immune reactivity. A large set of biochemical signals from microbiota in the form of different microbiota associated molecular patterns (MAMPs) and bacterial metabolites that act locally and distantly in the human organism. As a result, commensal bacteria influence the maturity and activity of dendritic cells and affect the overall immune reactivity of the human organism. It then determines the response to pathogenic microorganisms, inflammation, associated with different pathological conditions and even affects the effectiveness of vaccination.

Composition and interaction of maternal microbiota with immune mediators during pregnancy and their outcome: A narrative review

The connection between maternal microbiota and infant health has been greatly garnered interest for therapeutic purposes. The early resident microbiota perpetually exhibits much more flexibility as compared to that of the adults, and therefore, constant need of understanding the infant as well as maternal microbiota and their implications however has increased. In this review, we focus mainly on the diversity of overall maternal microbiota including the gut, vaginal, colostrum microbiota and how inflammatory markers fluctuate throughout the normal pregnancy as well in pregnancy with complications. The maternal body undergoes a cascade of physiological changes including hormonal, immunological and metabolic events to support the fetal development. These changes at the time of pregnancy have been correlated with alteration in the composition and diversity of maternal microbiota. Along with alteration in microbiome, the levels of circulatory cytokines fluctuate by complex network of inflammation, in order to prevent the fetal allograft throughout the pregnancy. The dynamic relationship of gut microbiota with the host and its immune system allows one to have greater insights of their role in pregnancy and newborn's health. Emerging evidence suggests that the vertical transmission of bacterial community from mother to newborn may begin in-utero which contributes in developing the immune system and infant gut microbiota.

Vaginal Lactobacilli Supernatants Protect from Herpes Simplex Virus Type 1 Infection in Cell Culture Models

A healthy vaginal microbiota hosts Lactobacillus as the most predominant genus. Lactobacilli play a role in human health through the production of diverse antimicrobial substances that can act against human pathogens or modulate the immune system. Previous reports highlighted the ability of vaginal lactobacilli to counteract viruses causing STIs, e.g., HIV-1 and HSV-2. In this report, we analyze the activity of supernatants of vaginal lactobacilli against HSV-1 infection, which is becoming increasingly relevant as a STI. We show that the supernatants of two vaginal Lactobacillus species (i.e., L. crispatus and L. gasseri) were active at neutralizing HSV-1 infection in two different cell lines of human and simian origin. Specifically, we demonstrate that L. crispatus strains are the most effective in antiviral activity, as evidenced by the comparison with a vaginal pathogen taken as reference. The effect was specific and not attributable to the generic toxicity of the supernatants to the cells. Our results pave the way for the development of probiotics to limit the impact of HSV-1 infection on women's health.

Taxonomic and functional shifts of gut microbiome in immunoglobulin A vasculitis children and their mothers

Objectives

To examine the gut microbiota characteristics in children with immunoglobulin A vasculitis and their interrelationships with the host, while evaluate the vertical inheritance of microbiota in the development and progression of IgA vasculitis.

Methods

This study investigated the gut microbiome of 127 IgA vasculitis mother-child pairs and 62 matched healthy mother-child pairs, and compared the gut microbial composition of different groups. The pathway enrichment analysis evaluated potential gut microbiome-mediated pathways involved in the pathophysiology of IgA vasculitis. The Spearman correlation analysis illustrated the relationships between clinical variables and bacterial biomarkers.

Results

This study identified distinct intestinal microbiome in IgA vasculitis children compared to healthy children, and further pointed out the association in gut microbiota between IgA vasculitis children's and their mother's. The relative abundance of Megamonas and Lactobacillus in IgAV children was positively correlated with that in their mothers. The pathway enrichment analysis found microbial biosynthesis of vitamins and essential amino acids was upregulated in children with IgA vasculitis. Correlation analysis showed bacterial biomarkers were correlated with indicators of blood coagulation.

Conclusion

Children with IgA vasculitis have unique bacterial biomarkers and may affect coagulation function, and their gut microbiome was closely associated with that of their mothers. The observed association in gut microbiota between IgA vasculitis children and their mothers suggested a potential intergenerational influence of the maternal microbiota on the development or progression of IgA vasculitis in children.

Human papillomavirus and cervical cancer in the microbial world: exploring the vaginal microecology

The vaginal microbiota plays a crucial role in female reproductive health and is considered a biomarker for predicting disease outcomes and personalized testing. However, its relationship with human papillomavirus (HPV) infection and cervical cancer is not yet clear. Therefore, this article provides a review of the association between the vaginal microbiota, HPV infection, and cervical cancer. We discuss the composition of the vaginal microbiota, its dysbiosis, and its relationship with HPV infection, as well as potential mechanisms in the development of cervical cancer. In addition, we assess the feasibility of treatment strategies such as probiotics and vaginal microbiota transplantation to modulate the vaginal microbiota for the prevention and treatment of diseases related to HPV infection and cervical cancer. In the future, extensive replication studies are still needed to gain a deeper understanding of the complex relationship between the vaginal microbiota, HPV infection, and cervical cancer, and to clarify the role of the vaginal microbiota as a potential biomarker for predicting disease outcomes, thus providing a theoretical basis for personalized testing.

Shaping Microbiota During the First 1000 Days of Life

Given that the host-microbe interaction is shaped by the immune system response, it is important to understand the key immune system-microbiota relationship during the period from conception to the first years of life. The present work summarizes the available evidence concerning human reproductive microbiota, and also, the microbial colonization during early life, focusing on the potential impact on infant development and health outcomes. Furthermore, we conclude that some dietary strategies including specific probiotics and other-biotics could become potentially valuable tools to modulate the maternal-neonatal microbiota during this early critical window of opportunity for targeted health outcomes throughout the entire lifespan.

Vaginal microbial dynamics and pathogen colonization in a humanized microbiota mouse model

Vaginal microbial composition is associated with differential risk of urogenital infection. Although Lactobacillus spp. are thought to confer protection against infection, the lack of in vivo models resembling the human vaginal microbiota remains a prominent barrier to mechanistic discovery. Using 16S rRNA amplicon sequencing of C57BL/6J female mice, we found that vaginal microbial composition varies within and between colonies across three vivaria. Noting vaginal microbial plasticity in conventional mice, we assessed the vaginal microbiome of humanized microbiota mice (HMbmice). Like the community structure in conventional mice, HMbmice vaginal microbiota clustered into community state types but, uniquely, HMbmice communities were frequently dominated by Lactobacillus or Enterobacteriaceae. Compared to conventional mice, HMbmice were less susceptible to uterine ascension by urogenital pathobionts group B Streptococcus (GBS) and Prevotella bivia. Although Escherichia and Lactobacillus both correlated with the absence of uterine GBS, vaginal pre-inoculation with exogenous HMbmouse-derived E. coli, but not Ligilactobacillus murinus, reduced vaginal GBS burden. Overall, HMbmice serve as a useful model to elucidate the role of endogenous microbes in conferring protection against urogenital pathogens.

A citizen-science-enabled catalogue of the vaginal microbiome and associated factors

Understanding the composition and function of the vaginal microbiome is crucial for reproductive and overall health. Here we established the Isala citizen-science project to analyse the vaginal microbiomes of 3,345 women in Belgium (18-98 years) through self-sampling, 16S amplicon sequencing and extensive questionnaires. The overall vaginal microbiome composition was strongly tied to age, childbirth and menstrual cycle phase. Lactobacillus species dominated 78% of the vaginal samples. Specific bacterial taxa also showed to co-occur in modules based on network correlation analysis. Notably, the module containing Lactobacillus crispatus, Lactobacillus jensenii and Limosilactobacillus taxa was positively linked to oestrogen levels and contraceptive use and negatively linked to childbirth and breastfeeding. Other modules, named after abundant taxa (Gardnerella, Prevotella and Bacteroides), correlated with multiple partners, menopause, menstrual hygiene and contraceptive use. With this resource-rich vaginal microbiome map and associated health, life-course, lifestyle and dietary factors, we provide unique data and insights for follow-up clinical and mechanistic research.

A prospective randomized clinical trial to assess antibiotic pocket irrigation on tissue expander breast reconstruction

Bacterial infection is the most common complication following staged post-mastectomy breast reconstruction initiated with a tissue expander (TE). To limit bacterial infection, antibiotic irrigation of the surgical site is commonly performed despite little high-quality data to support this practice. We performed a prospective randomized control trial to compare the impact of saline irrigation alone to a triple antibiotic irrigation regimen (1 g cefazolin, 80 mg gentamicin, and 50,000 units of bacitracin in 500 mL of saline) for breast implant surgery. The microbiome in breasts with cancer (n = 16) was compared to those without (n = 16), as all patients (n = 16) had unilateral cancers but bilateral mastectomies (n = 32). Biologic and prosthetic specimens procured both at the time of mastectomy and during TE removal months later were analyzed for longitudinal comparison. Outcomes included clinical infection, bacterial abundance, and relative microbiome composition. No patient in either group suffered a reconstructive failure or developed an infection. Triple antibiotic irrigation administered at the time of immediate TE reconstruction did not reduce bacterial abundance or impact microbial diversity relative to saline irrigation at the time of planned exchange. Implanted prosthetic material adopted the microbial composition of the surrounding host tissue. In cancer-naïve breasts, relative to saline, antibiotic irrigation increased bacterial abundance on periprosthetic capsules (P = 0.03) and acellular dermal matrices (P = 0.04) and altered the microbiota on both. These data show that, relative to saline only, the use of triple antibiotic irrigation in TE breast reconstruction does impact the bacterial abundance and diversity of certain biomaterials from cancer-naïve breasts. IMPORTANCE The lifetime risk of breast cancer is ~13% in women and is treated with a mastectomy in ~50% of cases. The majority are reconstructed, usually starting with a tissue expander to help restore the volume for a subsequent permanent breast implant or the women's own tissues. The biopsychosocial benefits of breast reconstruction, though, can be tempered by a high complication rate of at least 7% but over 30% in some women. Bacterial infection is the most common complication, and can lead to treatment delays, patient physical and emotional distress and escalating health care cost. To limit this risk, plastic surgeons have tried a variety of strategies to limit bacterial infection including irrigating the pocket created after removing the breast implant with antibiotic solutions, but good-quality data are scarce. Herein, we study the value of antibiotics in pocket irrigation using a robust randomized clinical trial design and molecular microbiology approaches.

Exploring Immunome and Microbiome Interplay in Reproductive Health: Current Knowledge, Challenges, and Novel Diagnostic Tools

The dynamic interplay between the immunome and microbiome in reproductive health is a complex and rapidly advancing research field, holding tremendously vast possibilities for the development of reproductive medicine. This immunome-microbiome relationship influences the innate and adaptive immune responses, thereby affecting the onset and progression of reproductive disorders. However, the mechanisms governing these interactions remain elusive and require innovative approaches to gather more understanding. This comprehensive review examines the current knowledge on reproductive microbiomes across various parts of female reproductive tract, with special consideration of bidirectional interactions between microbiomes and the immune system. Additionally, it explores innate and adaptive immunity, focusing on immunoglobulin (Ig) A and IgM antibodies, their regulation, self-antigen tolerance mechanisms, and their roles in immune homeostasis. This review also highlights ongoing technological innovations in microbiota research, emphasizing the need for standardized detection and analysis methods. For instance, we evaluate the clinical utility of innovative technologies such as Phage ImmunoPrecipitation Sequencing (PhIP-Seq) and Microbial Flow Cytometry coupled to Next-Generation Sequencing (mFLOW-Seq). Despite ongoing advancements, we emphasize the need for further exploration in this field, as a deeper understanding of immunome-microbiome interactions holds promise for innovative diagnostic and therapeutic strategies for reproductive health, like infertility treatment and management of pregnancy.

Microenvironment of the Lower Reproductive Tract: Focus on the Cervical Mucus Plug

The female lower reproductive tract microbiota is a complex ecosystem comprising various microorganisms that play a pivotal role in maintaining women's reproductive well-being. During pregnancy, the vaginal microbiota undergoes dynamic changes that are important for a successful gestation. This review summarizes the implications of the cervical mucus plug microenvironment and its profound impact on reproductive health. Further, the symbiotic relationship between the vaginal microbiome and the cervical mucus plug is highlighted, with a special emphasis on how this natural barrier serves as a guardian against ascending infections. Understanding this complex host-microbes interplay could pave the way for innovative approaches to improve women's reproductive health and fertility.

Investigation of the vaginal microbiota of dairy cows through genetic sequencing of short (Illumina) and long (PacBio) reads and associations with gestational status

The vaginal microbiota has been shown to be important in local immune regulation and may play a role in reproduction and fertility. Next-generation sequencing (NGS) technologies have been used to characterize the bovine vaginal microbiota, mainly using short-read sequencing (Illumina). However, the main limitation of this technique is its inability to classify bacteria at the species level. The objective of this study was to characterize the bovine vaginal microbiota at the species level using long-read sequencing (PacBio) and to compare it with the results of short-read sequencing. In addition, the vaginal microbiota of cows that became pregnant after artificial insemination (AI) was compared with that of infertile animals. Thirteen Holstein cows had vaginal swabs collected prior to AI. DNA was extracted and subjected to Illumina and PacBio sequencing to characterize the V4 region and the entire 16S rRNA gene, respectively. PacBio sequencing yielded 366,509 reads that were assigned to 476 species from 27 phyla. However, none of the most abundant reads (>1%) could be classified at the species level. Illumina sequencing yielded more reads and consequently was able to detect a more observed species, but PacBio sequencing was able to detect more unique and rare species. The composition of the vaginal microbiota varies according to the sequencing method used, which might complicate the interpretation of results obtained in the majority of the current studies. The present study expands on the current knowledge of bovine microbiota, highlighting the need for further efforts to improve the current databanks.

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.

Gut microbiota short-chain fatty acids and their impact on the host thyroid function and diseases

Thyroid disorders are clinically characterized by alterations of L-3,5,3',5'-tetraiodothyronine (T4), L-3,5,3'-triiodothyronine (T3), and/or thyroid-stimulating hormone (TSH) levels in the blood. The most frequent thyroid disorders are hypothyroidism, hyperthyroidism, and hypothyroxinemia. These conditions affect cell differentiation, function, and metabolism. It has been reported that 40% of the world's population suffers from some type of thyroid disorder and that several factors increase susceptibility to these diseases. Among them are iodine intake, environmental contamination, smoking, certain drugs, and genetic factors. Recently, the intestinal microbiota, composed of more than trillions of microbes, has emerged as a critical player in human health, and dysbiosis has been linked to thyroid diseases. The intestinal microbiota can affect host physiology by producing metabolites derived from dietary fiber, such as short-chain fatty acids (SCFAs). SCFAs have local actions in the intestine and can affect the central nervous system and immune system. Modulation of SCFAs-producing bacteria has also been connected to metabolic diseases, such as obesity and diabetes. In this review, we discuss how alterations in the production of SCFAs due to dysbiosis in patients could be related to thyroid disorders. The studies reviewed here may be of significant interest to endocrinology researchers and medical practitioners.

The Female Reproductive Tract Microbiota: Friends and Foe

We do not seem to be the only owner of our body; it houses a large population of microorganisms. Through countless years of coevolution, microbes and hosts have developed complex relationships. In the past few years, the impact of microbial communities on their host has received significant attention. Advanced molecular sequencing techniques have revealed a remarkable diversity of the organ-specific microbiota populations, including in the reproductive tract. Currently, the goal of researchers has shifted to generate and perceive the molecular data of those hidden travelers of our body and harness them for the betterment of human health. Recently, microbial communities of the lower and upper reproductive tract and their correlation with the implication in reproductive health and disease have been extensively studied. Many intrinsic and extrinsic factors influences the female reproductive tract microbiota (FRTM) that directly affects the reproductive health. It is now believed that FRTM dominated by Lactobacilli may play an essential role in obstetric health beyond the woman's intimate comfort and well-being. Women with altered microbiota may face numerous health-related issues. Altered microbiota can be manipulated and restored to their original shape to re-establish normal reproductive health. The aim of the present review is to summarize the FRTM functional aspects that influence reproductive health.

Evaluating Current Molecular Techniques and Evidence in Assessing Microbiome in Placenta-Related Health and Disorders in Pregnancy

The microbiome is of great interest due to its potential influence on the occurrence and treatment of some human illnesses. It may be regarded as disruptions to the delicate equilibrium that humans ordinarily maintain with their microorganisms or the microbiota in their environment. The focus of this review is on the methodologies and current understanding of the functional microbiome in pregnancy outcomes. We present how novel techniques bring new insights to the contemporary field of maternal-fetal medicine with a critical analysis. The maternal microbiome in late pregnancy has been extensively studied, although data on maternal microbial changes during the first trimester are rare. Research has demonstrated that, in healthy pregnancies, the origin of the placental microbiota is oral (gut) rather than vaginal. Implantation, placental development, and maternal adaptation to pregnancy are complex processes in which fetal and maternal cells interact. Microbiome dysbiosis or microbial metabolites are rising as potential moderators of antenatal illnesses related to the placenta, such as fetal growth restriction, preeclampsia, and others, including gestational diabetes and preterm deliveries. However, because of the presence of antimicrobial components, it is likely that the bacteria identified in placental tissue are (fragments of) bacteria that have been destroyed by the placenta's immune cells. Using genomic techniques (metagenomics, metatranscriptomics, and metaproteomics), it may be possible to predict some properties of a microorganism's genome and the biochemical (epigenetic DNA modification) and physical components of the placenta as its environment. Despite the results described in this review, this subject needs further research on some major and crucial aspects. The phases of an in utero translocation of the maternal gut microbiota to the fetus should be explored. With a predictive knowledge of the impacts of the disturbance on microbial communities that influence human health and the environment, genomics may hold the answer to the development of novel therapies for the health of pregnant women.

Profiling the microbiome of oral and genital mucosal surfaces in Behçet's disease

Almost 90% of Behçet's patients present with oral and/or genital ulcers which influence the disease outcome. We hypothesised that the dysregulation of the oral and genital microbiome, coupled with dysregulation of the immune response, contributes to the aetiopathogenesis of Behçet's Disease (BD) and drives disease activation.

METHOD

152 BD patient samples; 70 matched oral and genital samples plus 12 unmatched samples (Female: Male, 58:12; mean age, 42 ± 13.9: 39.3 ± 10.3) to profile microbial community high-throughput sequencing of the microbiome using 16 s rRNA sequencing targeting the V1/V2 and V3/V4 hyper variable regions were used and results reviewed in relation to disease severity, Work and Social Adjustment Scale (WSAS) outcomes and medication.

RESULTS

Alpha and beta diversity were significantly decreased in genital compared to oral samples; p value<0.05. However, grouping the samples as to whether ulceration was present was not significant. Escherichia-Shigella was the only Amplicon Sequence Variants (ASVs) in the V1/V2 region that was shared between the oral mucosa with ulcer (O_U) and genital mucosa with ulcer (G_U) groups. This was in contrast to the V3/V4 region which indicated that Lachnospiraceae, Saccharimonadales, and Coriobacteriales were shared between the O_U and G_U groups. In addition, gender had no impact on the bacterial abundance in V1/V2 analysis of the oral and genital samples. V3/V4 analysis of genital samples demonstrated that Lactobacilli and Gardnerella were significantly increased in females (20 times) compared to the males in samples; p-adj <0.05. Interestingly in BD patients, Rothia which is commonly found in the mouth was present in both oral and genital samples. Streptococci were significantly increased while Veillonella significantly decreased in the presence of oral ulceration in the BD cohort. The clinical phenotype had no effect on V1/V2 and V3/V4 on the bacterial abundance of oral samples. However, medication e.g. colchicine had a significant effect on the oral microbial abundance (V1/V2; P = 0.020, V3/V4; P = 0.003). There was no relationship between colchicine and the presence/absence of genital ulcers. BD patients with active disease had higher WSAS scores, and their bacterial abundance differed significantly from the non-active BD patients (ADONIS, R2 = 0.05, p value =0.029).

CONCLUSION

The presence of the microbes Streptococcus, Veillonella, Gardnerella, Lactobacillus, Atopobium, Peptoniphilus, Corynebacterium and Staphylococcus may provide early evidence of BD patients are with active disease.

Possible Therapeutic Mechanisms and Future Perspectives of Vaginal Microbiota Transplantation

Microbial communities inhabiting the human body play a crucial role in protecting the host against pathogens and inflammation. Disruptions to the microbial composition can lead to various health issues. Microbial transfer therapy (MTT) has emerged as a potential treatment option to address such issues. Fecal microbiota transplantation (FMT) is the most widely used form of MTT and has been successful in treating several diseases. Another form of MTT is vaginal microbiota transplantation (VMT), which involves transferring vaginal microbiota from a healthy female donor to a diseased patient's vaginal cavity with the goal of restoring normal vaginal microbial composition. However, VMT has not been extensively studied due to safety concerns and a lack of research. This paper explores the therapeutic mechanisms of VMT and discusses future perspectives. Further research is necessary to advance the clinical applications and techniques of VMT.

The interplay between human papillomavirus and vaginal microbiota in cervical cancer development

Over the past few decades, we have grown accustomed to the idea that human papillomavirus can cause tumors. The genetic and environmental factors that make the difference between elimination of viral infection and the development of cancer are therefore an area of active investigation at present. Microbiota has emerged as an important factor that may affect this balance by increasing or decreasing the ability of viral infection to promote. The female reproductive system has its specific microbiota that helps to maintain health and prevent infection with pathogens. In contrast to other mucosal sites, the vaginal microbiota typically has low diversity and contains few Lactobacillus spp. which by using high-throughput 16s rRNA gene sequencing, classified into five different community state types. According to emerging information, increased diversity of vaginal microbiota and reduced abundance of Lactobacillus spp. contribute to HPV acquisition, persistence, and development of cervical cancer. In this review, the role of normal female reproductive tract microbiota in health, mechanisms which dysbiosis can cause diseases through interaction with microbes and several therapeutic approaches were addressed.

Alterations in vaginal microbiota in uterine fibroids patients with ultrasound-guided high-intensity focused ultrasound ablation

Introduction

Vaginal microbiota dysbiosis is closely related to diseases of the vagina and uterus. Uterine fibroids (UF) are the most common benign neoplasms of the uterus, and increased diversity in vaginal microbial of UF patients. High-intensity focused ultrasound (HIFU) is effective invasive treatment for fibroids in women who are not good surgical candidates. Whether HIFU of uterine fibroids will cause the change in vaginal microbiota has not been reported. We aimed to investigate the vaginal microbiota of UF patients with/without HIFU treatment using 16S rRNA gene sequencing.

Methods

Vaginal secretions were collected from 77 UF patients (pre-operative and post-operative) and were used for comparative composition, diversity, and richness analyses of microbial communities.

Results

The microbial α-diversity was significantly lower in the vaginal of UF patients with HIFU treatment. The relative abundance of some pathogenic bacteria of UF patients with HIFU treatment were significantly decreased in the bacterial phylum and genus level. Proteobacteria were found to be significantly upregulated as a biomarker in the HIFU treatment group in our study.

Conclusion

These findings might confirm the effectiveness of HIFU treatment from the point of view of microbiota.

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.

Antimicrobial Substances and Mechanisms of Lactobacillus rhamnosus against Gardnerella vaginalis

Bacterial vaginosis (BV) is a common vaginal disease associated with abnormal changes in the vaginal microbiome. Our previous study found that Lactobacillus rhamnosus has a good therapeutic effect on bacterial vaginosis by inhibiting the most prominent bacterium associated with BV, Gardnerella vaginalis. In this study, we show that acetic acid and lactic acid are the main substances in the cell-free supernatant (CFS) of L. rhamnosus that inhibit the growth of G. vaginalis. Further study on the mechanism showed that acetic acid and lactic acid alter the morphology of the G. vaginalis cells, eventually causing the cells to shrink or burst, resulting in exudation of their intracellular contents. In addition, these two organic acids also dissipate the membrane potential of bacterial cells, affecting their synthesis of ATP. A reduced activity of the Na⁺/K⁺-ATPase leads to abnormal ATP metabolism, and ultimately inhibits the growth and reproduction of G. vaginalis. Our study provides valuable information for the widespread application of L. rhamnosus in the treatment of bacterial vaginosis.

Menopausal Changes in the Microbiome-A Review Focused on the Genitourinary Microbiome

A balanced interaction between the host and its microbiome is crucial to health. Research regarding the significance of the gut and vaginal microbiomes in female health is substantial. However, less data regarding the urinary microbiome are available. Interactions between the gut, vaginal, and urinary microbiomes are also currently being researched. Hormone-induced dysbiosis after menopause is believed to have effects on physical changes and health consequences. Postmenopausal changes in the gut microbiome are associated with increased short-chain fatty acids and hydrogen sulfide levels. Increased vaginal pH caused by reduced estrogen alters the vaginal microbiome, resulting in reduced levels of Lactobacillus. Such changes influence the vaginal structure and functions, contributing to the onset of genitourinary syndrome of menopause. A dysbiosis of the urinary microbiome is associated with urgency and urinary incontinence and also related to interstitial cystitis/bladder pain syndrome and neuropathic bladder. As these diseases commonly affect postmenopausal women, hormone-induced changes in the microbiome may play a role. Menopause increases the alpha diversity of the urinary microbiome and lowers the percentage of Lactobacillus in urine, and such changes precede recurrent cystitis. More research regarding the effects of changes in the urinary microbiome due to menopause on urinary tract diseases is needed.

Is there a placental microbiota? A critical review and re-analysis of published placental microbiota datasets

The existence of a placental microbiota is debated. The human placenta has historically been considered sterile and microbial colonization was associated with adverse pregnancy outcomes. Yet, recent DNA sequencing investigations reported a microbiota in typical human term placentas. However, this detected microbiota could represent background DNA or delivery-associated contamination. Using fifteen publicly available 16S rRNA gene datasets, existing data were uniformly re-analyzed with DADA2 to maximize comparability. While Amplicon Sequence Variants (ASVs) identified as Lactobacillus, a typical vaginal bacterium, were highly abundant and prevalent across studies, this prevalence disappeared after applying likely  DNA contaminant removal to placentas from term cesarean deliveries. A six-study sub-analysis targeting the 16S rRNA gene V4 hypervariable region demonstrated that bacterial profiles of placental samples and technical controls share principal bacterial ASVs and that placental samples clustered primarily by study origin and mode of delivery. Contemporary DNA-based evidence does not support the existence of a placental microbiota.ImportanceEarly-gestational microbial influences on human development are unclear. By applying DNA sequencing technologies to placental tissue, bacterial DNA signals were observed, leading some to conclude that a live bacterial placental microbiome exists in typical term pregnancy. However, the low-biomass nature of the proposed microbiome and high sensitivity of current DNA sequencing technologies indicate that the signal may alternatively derive from environmental or delivery-associated bacterial DNA contamination. Here we address these alternatives with a re-analysis of 16S rRNA gene sequencing data from 15 publicly available placental datasets. After identical DADA2 pipeline processing of the raw data, subanalyses were performed to control for mode of delivery and environmental DNA contamination. Both environment and mode of delivery profoundly influenced the bacterial DNA signal from term-delivered placentas. Aside from these contamination-associated signals, consistency was lacking across studies. Thus, placentas delivered at term are unlikely to be the original source of observed bacterial DNA signals.

Transcriptomic and Proteomic Analysis of Gardnerella vaginalis Responding to Acidic pH and Hydrogen Peroxide Stress

Gardnerella vaginalis is the main pathogen that causes bacterial vaginosis. In the healthy vaginal microecological environment of a woman, the lactobacilli produce lactate and hydrogen peroxide to inhibit the growth of pathogens such as G. vaginalis. The lack of lactobacilli results in a high pH and low hydrogen peroxide in the vagina which facilitate G. vaginalis growth, leading to the imbalance of the vaginal microecology. In this study, lactate and hydrogen peroxide were added to a G. vaginalis culture medium to simulate the co-culture of the lactobacilli and G. vaginalis, and then the genes related to the stress response of G. vaginalis were identified using transcriptomics and proteomics. It was indicated that, among all the upregulated genes, most of them encoded transporters associated with the efflux of harmful substances, and the majority of the downregulated genes were related to the biofilm formation and epithelial cell adhesion. This study may help find new drug targets for G. vaginalis for the development of novel therapies for bacterial vaginosis.

Urogenital tract and rectal microbiota composition and its influence on reproductive outcomes in infertile patients

Introduction

Microbiota in the human body are closely related to human diseases. Female urogenital tract and rectal microbes have been considered as important factors affecting female pregnancy, but the mechanism is unknown.

Methods

Cervical, vaginal, urethral, and rectal swabs were collected from 22 infertile patients and 10 controls, and follicular fluid was extracted from 22 infertile patients. The microbial composition of different sampling sites of infertile patients was examined. By comparing the microbial composition difference between infertile patients and controls and combining bioinformatics methods to analyze the potential impact of the female urogenital tract (cervical, vaginal and urethral) and rectal microbial diversity on female infertility and pregnancy outcomes.

Results

Lactobacillus predominated in the female urogenital tract, but its abundance decreased in infertile patients, whereas the abundance of Gardnerella and Atopobium increased. The microbial changes in the urethra had the same trend as that in the vagina. Compared with healthy controls, the cervical and rectal microbial diversity of infertile patients were significantly increased and decreased, respectively. There might be interactions between microbes in different parts of female. Geobacillus thermogeniticans was enriched in the urogenital tract and rectum of infertile patients, and has a good predictive effect on infertility. Compared with infertile patients, L. johnsonii was enriched in the vagina, urethra, and intestine of the control group. L. acidophilus in follicular fluid might be associated with Non-pregnancy.

Conclusion

This study found that the microbial composition of infertile patients was changed compared with that of healthy people. The translocation of Lactobacillus between the rectum and urogenital tract might play a protective barrier role. The changes of Lactobacillus and Geobacillus might be related to female infertility or pregnancy outcome. The study provided a theoretical basis for the future treatment of female infertility from the perspective of microorganisms by detecting the microbial changes associated with female infertility.

Vaginal microbial dynamics and pathogen colonization in a humanized microbiota mouse model

Vaginal microbiota composition is associated with differential risk of urogenital infection. Although vaginal Lactobacillus spp. are thought to confer protection through acidification, bacteriocin production, and immunomodulation, lack of an in vivo model system that closely resembles the human vaginal microbiota remains a prominent barrier to mechanistic discovery. We performed 16S rRNA amplicon sequencing of wildtype C57BL/6J mice, commonly used to study pathogen colonization, and found that the vaginal microbiome composition varies highly both within and between colonies from three distinct vivaria. Because of the strong influence of environmental exposure on vaginal microbiome composition, we assessed whether a humanized microbiota mouse ( HMb mice) would model a more human-like vaginal microbiota. Similar to humans and conventional mice, HMb mice vaginal microbiota clustered into five community state types ( h mCST). Uniquely, HMb mice vaginal communities were frequently dominated by Lactobacilli or Enterobacteriaceae . Compared to genetically-matched conventional mice, HMb mice were less susceptible to uterine ascension by urogenital pathobionts group B Streptococcus (GBS) and Prevotella bivia , but no differences were observed with uropathogenic E. coli . Specifically, vaginal Enterobacteriaceae and Lactobacillus were associated with the absence of uterine GBS. Anti-GBS activity of HMb mice vaginal E. coli and L. murinus isolates, representing Enterobacteriaceae and Lactobacillus respectively, were characterized in vitro and in vivo . Although L. murinus reduced GBS growth in vitro , vaginal pre-inoculation with HMb mouse-derived E. coli , but not L. murinus , conferred protection against vaginal GBS burden. Overall, the HMb mice are an improved model to elucidate the role of endogenous microbes in conferring protection against urogenital pathogens.

IMPORTANCE

An altered vaginal microbiota, typically with little to no levels of Lactobacillus , is associated with increased susceptibility to urogenital infections, although mechanisms driving this vulnerability are not fully understood. Despite known inhibitory properties of Lactobacillus against urogenital pathogens, clinical studies with Lactobacillus probiotics have shown mixed success. In this study, we characterize the impact of the vaginal microbiota on urogenital pathogen colonization using a humanized microbiota mouse model that more closely mimics the human vaginal microbiota. We found several vaginal bacterial taxa that correlated with reduced pathogen levels but showed discordant effects in pathogen inhibition between in vitro and in vivo assays. We propose that this humanized microbiota mouse platform is an improved model to describe the role of the vaginal microbiota in protection against urogenital pathogens. Furthermore, this model will be useful in testing efficacy of new probiotic strategies in the complex vaginal environment.

The function and mechanism of action of uterine microecology in pregnancy immunity and its complications

The human microbiota influences physiology, disease, and metabolic reproduction. The origin of uterine bacteria is controversial. The main assumption is that the germs enter the uterine cavity from the vagina through the cervical canal, bloodstream, fallopian tubes, and gynecological surgical channels. Understanding the microbiota at various anatomical sites is critical to the female reproductive system and pregnancy. Today's study focuses on the role of uterine bacteria in pregnancy and embryo implantation. According to our findings, the uterine microbiome influences embryo implantation and pregnancy outcome. Pregnancy is a natural, evolutionarily selected approach to human reproduction. During pregnancy, the microbiota of the reproductive tract changes, facilitating the maintenance of pregnancy, and the human immune system undergoes a series of changes that recognize and adapt to the non-self. From the beginning of pregnancy, a non-self fetus must establish a placenta of embryonic origin to protect itself and promote growth; the VMB tends to be more stable and lactobacillus-dominated in late gestation than in early gestation. Any material that disrupts this connection, such as microbial changes, is associated with a higher risk of poor health and poor pregnancy outcomes in women (eclampsia). The presence of any material that disrupts this connection, such as microbial changes, is associated with a higher risk of poor health and poor pregnancy outcomes (preeclampsia, preterm birth, gestational diabetes, etc.). In this work, we review the last decade of relevant research to improve our understanding of the mechanisms by which the microbiota of the female reproductive tract influences female reproductive health. This work discusses the mechanisms associated with the reproductive tract microbiota and pregnancy immunity, as well as the impact of an abnormal microbiota on adverse pregnancy outcomes. Emphasis is placed on the characteristics and sources of the female vaginal, uterine, and placental microbiota and the importance of a well-stabilized local human microbiota and immune system for embryo implantation, placental development, fetal growth, and pregnancy outcome.

Vulvovaginal candidiasis and vaginal microflora interaction: Microflora changes and probiotic therapy

Vaginal microbiome is mutually beneficial to the host and has a significant impact on health and disease. Candida species, including Candida albicans, are part of the mucosal flora of most healthy women. Under suitable conditions, they can live in the vulvovaginal mucosa, resulting in symptomatic vulvovaginal candidiasis (VVC). Based on the analysis of 16S ribosomal RNA gene sequences, great progress has been made in exploring the composition and structure of vaginal bacterial community. Moreover, researchers have conducted several studies on whether vaginal microbiome will change during VVC infection. In addition, it has been reported that vaginal colonization of probiotics in vaginal microorganisms, especially Lactobacillus, can effectively reduce the risk of VVC and treat VVC. This review aims to summarize the changes of vaginal microflora during VVC infection, and further point out the possibility of using lactic acid bacteria as probiotics to treat VVC, so as to reduce the adverse consequences of VVC infection and reduce the expensive treatment cost.

Lactobacillus spp. in the reproductive system of female moths and mating induced changes and possible transmission

BACKGROUND

The microbiome in the insect reproductive tract is poorly understood. Our previous study demonstrated the presence of Lactobacillus spp. in female moths, but their distribution and function remain unclear. Lactobacillus spp. are known as the 'healthy' vaginal microbiome in humans.

RESULTS

Here, we studied the microbiome in the reproductive system (RS) and gut of Spodoptera frugiperda using 16S rDNA sequences. The obtained 4315 bacterial OTUs were classified into 61 phyla and 642 genera, with Proteobacteria, Firmicutes and Bacteroidota being the top three dominant phyla and Enterococcus and Asaia being dominant genera in most samples. Mating dramatically increased the abundance of pathogens or pathogenic functions in the gut, while in the RS, the change range was trivial. Taxonomy assignment identified thirteen Lactobacillus spp. in S. frugiperda, with Lactobacillus crustorum and Lactobacillus murinus showing high abundance. Three species found in S. frugiperda, namely L. reuteri, L. plantarum and L. brevis, have also been identified as human 'healthy' vaginal bacterial species. Lactobacillus spp. showed higher abundance in the RS of virgin females and lower abundance in the RS of virgin males and the gut of virgin females. Mating reduced their abundance in the RS of females but increased their abundance in the RS of males, especially in males mated with multiple females. The RS of virgin females and of multiple mated males were very similar in terms of composition and abundance of Lactobacillus species, with Lactobacillus crustorum showing much higher abundance in both tissues, potentially due to sexual transmission.

CONCLUSIONS

Lactobacillus spp. showed high abundance and diversity in the RS of female moths. The higher abundance of Lactobacillus spp. in the RS of female moths and the similarity of Lactobacillus species in female moths with human 'healthy' vaginal Lactobacillus spp. suggest that these bacterial strains are also an important microbiome in the RS of female moths.

The interplay between the gut microbiota and metabolism during the third trimester of pregnancy

The gut microbiota undergoes dynamic changes during pregnancy. The gut microbial and metabolic networks observed in pregnant women have not been systematically analyzed. The primary purpose of this study was to explore the alterations in the gut microbiota and metabolism during late pregnancy and investigate the associations between the gut microbiota and metabolism. A total of thirty healthy pregnant women were followed from 30 to 32 weeks of gestation to full term. Fecal samples were collected for microbiome analysis and untargeted metabolomic analysis. The characteristics of the gut microbiota were evaluated by 16S ribosomal RNA gene sequencing of the V3-V4 regions. The plasma samples were used for untargeted metabolomic analysis with liquid chromatography-tandem mass spectrometry. The interplay between the gut microbiota and metabolism was analyzed further by bioinformatics approaches. We found that the relative abundances of Sellimonas and Megamonas were higher at full term, whereas that of Proteobacteria was lower. The correlation network of the gut microbiota tended to exhibit weaker connections from 32 weeks of gestation to the antepartum timepoint. Changes in the gut microbiota during late pregnancy were correlated with the absorbance and metabolism of microbiota-associated metabolites, such as fatty acids and free amino acids, thereby generating a unique metabolic system for the growth of the fetus. Decreasing the concentration of specific metabolites in plasma and increasing the levels of palmitic acid and 20-hydroxyarachidonic acid may enhance the transformation of a proinflammatory immune state as pregnancy progresses.

Impacts of Menstruation, Community Type, and an Oral Yeast Probiotic on the Vaginal Microbiome

A healthy state of the vaginal microbiome can prevent vaginal disease and promote successful fertilization and healthy pregnancies. Little is known about the stability of the vaginal microbiome and the influence of factors such as diet and probiotics. While less explored, yeast probiotics have an interesting potential because of their immunomodulatory and pathogen inhibition capacities. In this study, we investigated the impact of the oral yeast probiotic Saccharomyces cerevisiae CNCM I-3856 on the vaginal microbiomes of 52 healthy women using 16S and internal transcribed spacer (ITS) amplicon sequencing and quantitative PCR (qPCR). The vaginal fungal loads remained low, even after oral yeast supplementation, complicating the analysis of the vaginal mycobiome. Lactobacillus crispatus and Lactobacillus iners were the most dominant species in our study population and were found to codominate in 23% of the baseline samples. Bifidobacterium, Streptococcus, and Prevotella were also frequently found. The microbiome profiles were dynamic: 69% of women showed a shift in the dominant community members at least once during the 42-day sampling period. In addition, lower Lactobacillus abundances were observed at the time points after menstruation. Higher relative abundances of Lactobacillus with more L. iners-dominated samples and a trend toward lower relative abundances of Prevotella were observed in the probiotic group, but analyses of the effects of the yeast probiotic were complicated by differences already present at the onset of the study. Thus, our findings especially highlighted that the impact of menstruation and the stratification of women based on the dominant vaginal taxa before randomization and inclusion is important for future research: while the impact of the yeast probiotic on vaginal microbiome in healthy women was limited. IMPORTANCE How to define and promote a healthy state of the vaginal microbiome is not well understood. Knowledge of which underlying factors shape the microbial community composition of the vagina and how to modulate them will contribute to vaginal disease prevention and improve fertility. Here, we found that taking the menstrual cycle into account when designing a microbiome study is highly recommended: menstruation also showed to be poses an interesting time point for intervention because of the drop in the abundance of L. crispatus. Furthermore, the early stratification of groups (e.g., placebo versus treatment) according to the dominant taxa can be of high added value since menstruation impacts vaginal taxa differently, i.e., L. iners remains stable, in contrast to L. crispatus.