Comparison between Gram stain and culture for the characterization of vaginal microflora: definition of a distinct grade that resembles grade I microflora and revised categorization of grade I microflora

VIBES: A consensus subtyping of the vaginal microbiota reveals novel classification criteria

This study aimed to develop a robust classification scheme for stratifying patients based on vaginal microbiome. By employing consensus clustering analysis, we identified four distinct clusters using a cohort that includes individuals diagnosed with Bacterial Vaginosis (BV) as well as control participants, each characterized by unique patterns of microbiome species abundances. Notably, the consistent distribution of these clusters was observed across multiple external cohorts, such as SRA022855, SRA051298, PRJNA208535, PRJNA797778, and PRJNA302078 obtained from public repositories, demonstrating the generalizability of our findings. We further trained an elastic net model to predict these clusters, and its performance was evaluated in various external cohorts. Moreover, we developed VIBES, a user-friendly R package that encapsulates the model for convenient implementation and enables easy predictions on new data. Remarkably, we explored the applicability of this new classification scheme in providing valuable insights into disease progression, treatment response, and potential clinical outcomes in BV patients. Specifically, we demonstrated that the combined output of VIBES and VALENCIA scores could effectively predict the response to metronidazole antibiotic treatment in BV patients. Therefore, this study's outcomes contribute to our understanding of BV heterogeneity and lay the groundwork for personalized approaches to BV management and treatment selection.

Key aspects of papillomavirus infection influence the host cervicovaginal microbiome in a preclinical murine papillomavirus (MmuPV1) infection model

Human papillomaviruses (HPVs) are the most common sexually transmitted infection in the United States and are a major etiological agent of cancers in the anogenital tract and oral cavity. Growing evidence suggests changes in the host microbiome are associated with the natural history and ultimate outcome of HPV infection. We sought to define changes in the host cervicovaginal microbiome during papillomavirus infection, persistence, and pathogenesis using the murine papillomavirus (MmuPV1) cervicovaginal infection model. Cervicovaginal lavages were performed over a time course of MmuPV1 infection in immunocompetent female FVB/N mice and extracted DNA was analyzed by qPCR to track MmuPV1 viral copy number. 16S ribosomal RNA (rRNA) gene sequencing was used to determine the composition and diversity of microbial communities throughout this time course. We also sought to determine whether specific microbial communities exist across the spectrum of MmuPV1-induced neoplastic disease. We, therefore, performed laser-capture microdissection to isolate regions of disease representing all stages of neoplastic disease progression (normal, low- and high-grade dysplasia, and cancer) from female reproductive tract tissue sections from MmuPV1-infected mice and performed 16S rRNA sequencing. Consistent with other studies, we found that the natural murine cervicovaginal microbiome is highly variable across different experiments. Despite these differences in initial microbiome composition between experiments, we observed that MmuPV1 persistence, viral load, and severity of disease influenced the composition of the cervicovaginal microbiome. These studies demonstrate that papillomavirus infection can alter the cervicovaginal microbiome.IMPORTANCEHuman papillomaviruses (HPVs) are the most common sexually transmitted infection in the United States. A subset of HPVs that infect the anogenital tract (cervix, vagina, anus) and oral cavity cause at least 5% of cancers worldwide. Recent evidence indicates that the community of microbial organisms present in the human cervix and vagina, known as the cervicovaginal microbiome, plays a role in HPV-induced cervical cancer. However, the mechanisms underlying this interplay are not well-defined. In this study, we infected the female reproductive tract of mice with a murine papillomavirus (MmuPV1) and found that key aspects of papillomavirus infection and disease influence the host cervicovaginal microbiome. This is the first study to define changes in the host microbiome associated with MmuPV1 infection in a preclinical animal model of HPV-induced cervical cancer. These results pave the way for using MmuPV1 infection models to further investigate the interactions between papillomaviruses and the host microbiome.

A molecular view on the interference established between vaginal Lactobacilli and pathogenic Candida species: Challenges and opportunities for the development of new therapies

Vaginal infectious diseases caused by viruses and bacteria have been linked to the occurrence of dysbiosis, that is, a reduction in the abundance of the normally dominating vaginal Lactobacillus species. Mucosal infections in the vagina and/or vulva caused by Candida species, usually known as vulvovaginal candidiasis (or VVC), are among the leading causes of diseases in the vaginal tract. The existence of a clear link between the occurrence of dysbiosis and the development of VVC is still unclear, although multiple observations point in that direction. Based on the idea that vaginal health is linked to a microbiota dominated by lactobacilli, several probiotics have been used in management of VVC, either alone or in combination with antifungals, having obtained different degrees of success. In most cases, the undertaken trials resorted to lactobacilli species other than those indigenous to the vaginal tract, although in vitro these vaginal species were shown to reduce growth, viability and virulence of Candida. In this paper we overview the role of lactobacilli and Candida in the vaginal micro- and myco-biomes, while discussing the results obtained in what concerns the establishment of interference mechanisms in vivo and the environmental factors that could determine that. We also overview the molecular mechanisms by which lactobacilli species have been shown to inhibit pathophysiology of Candida, including the description of the genes and pathways determining their ability to thrive in the presence of each other. In a time where concerns are increasing with the emergence of antifungal resistance and the slow pace of discovery of new antifungals, a thorough understanding of the molecular mechanisms underneath the anti-Candida effect prompted by vaginal lactobacilli is of utmost importance to assure a knowledge-based design of what can be a new generation of pharmaceuticals, eventually focusing therapeutic targets other than the usual ones.

Screening and characterization of thermostable enzyme-producing bacteria from selected hot springs of Ethiopia

Hot springs are potential sources of diverse arrays of microbes and their thermostable hydrolytic enzymes. Water and sediment samples were collected from three hot springs of Ethiopia and enriched on nutrient and thermus agar media to isolate pure cultures of potential microbes. A total of 252 bacterial isolates were screened and evaluated for the production of amylase, protease, cellulase, and lipase. About 95.23%, 84.12%, 76.58%, and 65.07% of the isolates displayed promising amylase, proteases, cellulase, and lipase activities, respectively. Based on the diameter of the clear zone formed, 45 isolates were further screened and identified to species level using matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry analysis and 16S rRNA gene sequencing. Five of the 45 isolates showed significantly high (P < 0.05) clear zone ratios as compared to others. The identified isolates were categorized under five bacterial species, namely, Bacillus licheniformis, Bacillus cereus, Paenibacillus thiaminolyticus, Paenibacillus dendritiformis, and Brevibacillus borstelensis. The most dominant species (66.7%) was B. licheniformis. It could be concluded that hot springs of Ethiopia are potential sources of thermostable extracellular hydrolytic enzymes for various industrial applications. Further optimization of the growth conditions and evaluation for better productivity of the desired products is recommended before attempting for large-scale production of the hydrolytic enzymes.

IMPORTANCE

Thermostable microbial enzymes play an important role in industries due to their stability under harsh environmental conditions, including extreme temperatures. Despite their huge application in different industries, however, the thermostable enzymes of thermophilic microorganism origin have not yet been fully explored in Ethiopia. Here, we explored thermophilic bacteria and their enzymes from selected hot spring water and sediment samples. Accordingly, thermophilic bacteria were isolated and screened for the production of extracellular hydrolytic enzymes. Promising numbers of isolates were found as producers of the enzymes. The potent enzyme producers were further identified using matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry analysis and 16S rRNA gene sequencing. The findings revealed the presence of potential hydrolytic enzyme-producing thermophilic bacteria in hot springs of Ethiopia and necessitate further comprehensive study involving other extreme environments. Our findings also revealed the potential of Ethiopian hot springs in the production of thermostable enzymes of significant application in different industries, including food industries.

SERS-PLSR Analysis of Vaginal Microflora: Towards the Spectral Library of Microorganisms

The accurate identification of microorganisms belonging to vaginal microflora is crucial for establishing which microorganisms are responsible for microbial shifting from beneficial symbiotic to pathogenic bacteria and understanding pathogenesis leading to vaginosis and vaginal infections. In this study, we involved the surface-enhanced Raman spectroscopy (SERS) technique to compile the spectral signatures of the most significant microorganisms being part of the natural vaginal microbiota and some vaginal pathogens. Obtained data will supply our still developing spectral SERS database of microorganisms. The SERS results were assisted by Partial Least Squares Regression (PLSR), which visually discloses some dependencies between spectral images and hence their biochemical compositions of the outer structure. In our work, we focused on the most common and typical of the reproductive system microorganisms (Lactobacillus spp. and Bifidobacterium spp.) and vaginal pathogens: bacteria (e.g., Gardnerella vaginalis, Prevotella bivia, Atopobium vaginae), fungi (e.g., Candida albicans, Candida glabrata), and protozoa (Trichomonas vaginalis). The obtained results proved that each microorganism has its unique spectral fingerprint that differentiates it from the rest. Moreover, the discrimination was obtained at a high level of explained information by subsequent factors, e.g., in the inter-species distinction of Candida spp. the first three factors explain 98% of the variance in block Y with 95% of data within the X matrix, while in differentiation between Lactobacillus spp. and Bifidobacterium spp. (natural flora) and pathogen (e.g., Candida glabrata) the information is explained at the level of 45% of the Y matrix with 94% of original data. PLSR gave us insight into discriminating variables based on which the marker bands representing specific compounds in the outer structure of microorganisms were found: for Lactobacillus spp. 1400 cm⁻¹, for fungi 905 and 1209 cm⁻¹, and for protozoa 805, 890, 1062, 1185, 1300, 1555, and 1610 cm⁻¹. Then, they can be used as significant marker bands in the analysis of clinical subjects, e.g., vaginal swabs.

Microbial Diversity and Pathogenic Properties of Microbiota Associated with Aerobic Vaginitis in Women with Recurrent Pregnancy Loss

Recurrent pregnancy loss (RPL) is a major reproductive problem that affects approximately 5% of couples. The objective of this study was to assess vaginal flora dysbiosis in women suffering from unexplained RPL and to investigate the pathogenic properties of the microbiota associated with aerobic vaginitis (AV). The study included one hundred fifteen women, 65 with RPL and 50 controls. The diversity of vaginal microbiota isolated was evaluated by molecular sequencing. Then, pathogenic factors, such as acid-resistance, antibiotics susceptibility, and biofilm formation were evaluated. The prevalence of AV was five-fold higher in the RPL group than in the controls (64.6% vs. 12.0%). The most prevalent isolates in the case group were Enterococcus spp. (52%) and Staphylococcus spp. (26%). All bacterial strains tolerate low pH. The prevalence of multidrug resistance (MDR) among all bacteria was 47.7%. Of all strains, 91.0% were biofilm producers. The presence of MDR was found to be related to biofilm formation. The results provide evidence supporting an increased presence of dysbiosis of the vaginal flora, especially AV, in women with RPL in Tunisia. The viability of the AV-associated bacteria and their persistence in the genitals may be due to their ability to resist low pH and to produce a biofilm.

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

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.

Vaginal Microbiome in Reproductive Medicine

The human microbiome has been given increasing importance in recent years. The establishment of sequencing-based technology has made it possible to identify a large number of bacterial species that were previously beyond the scope of culture-based technologies. Just as microbiome diagnostics has emerged as a major point of focus in science, reproductive medicine has developed into a subject of avid interest, particularly with regard to causal research and treatment options for implantation failure. Thus, the vaginal microbiome is discussed as a factor influencing infertility and a promising target for treatment options. The present review provides an overview of current research concerning the impact of the vaginal microbiome on the outcome of reproductive measures. A non-Lactobacillus-dominated microbiome was shown to be associated with dysbiosis, possibly even bacterial vaginosis. This imbalance has a negative impact on implantation rates in assisted reproductive technologies and may also be responsible for habitual abortions. Screening of the microbiome in conjunction with antibiotic and/or probiotic treatment appears to be one way of improving pregnancy outcomes.

Diagnosis of bacterial vaginosis: Comparison of Nugent´s and novel microscopic method

Background/Aim. Bacterial vaginosis (BV) is a common cause of vaginal discomfort in women. The aim of this study was to compare Nugent?s scoring system and novel microscopy method, introduced in our laboratory and used in BV diagnosis. Methods. This study included 705 pregnant and asymptomatic women between 24 and 28 weeks of pregnancy. The degree of agreement between methods was determined by the kappa (?) index. The sensitivity, specificity, positive and negative predictive value of the novel microscopy method was compared to Nugent?s score as standard. Results. Based on the scoring system of both methods, Nugent?s and novel microscopy method, BV was diagnosed in 21% and 25% of women, respectively. Despite the disparities among diagnostic criteria, which mainly concerned classification of intermediary samples, the degree of agreement between categories, determined by ? index, was satisfactory: Nugent?s vs. novel microscopy method (? = 0.68; good agreement), and Nugent?s vs. novel microscopy method without intermediary results (? = 0.83; very good agreement). We also demonstrated that compared to Nugent?s method, as the golden standard, the novel microscopy method had high sensitivity and specificity (ranging from 75%?99.3%) and positive and negative predictive values (ranging from 88.8%?99.5%). Our method is based on a relative number of bacterial morphotypes, either rod forms (? 1.5 ?m, lactobacilli) or non-rod forms (< 1.5 ?m, bacterial vaginosis associated bacteria) under 200? magnification, which extends the surface of examined preparation, but without prolongation of observer?s working time. Conclusion. The novel microscopy method in diagnosing BV corresponded well with Nugent?s scoring system which allows it to be an alternative method in diagnosing BV. Further-more, the novel microscopy method is based on a relative number of bacterial morphotypes that appeared to be flexible and can be reorganized in the way to categorize findings into only two groups: normal and BV, which makes it comparable to dichotomous Amsel?s clinical criterion.

Impact of Dapivirine and Placebo Vaginal Rings on the Microbiota of Adolescent, Lactating, and Postmenopausal Females

BACKGROUND

A 25 mg dapivirine vaginal ring has been demonstrated to reduce risk of HIV acquisition in nonpregnant adult women. In this secondary analysis of studies conducted in US adolescent, lactating, and postmenopausal females, vaginal microbiota was assessed prior to and after ring use, and between dapivirine and placebo ring users.

METHODS

Vaginal fluid swabs were collected before and after product use for the evaluation of microbiota using Nugent's criteria, quantitative culture, and qPCR.

RESULTS

Vaginal ring use did not impact bacterial vaginosis prevalence among the three populations and was associated with minimal shifts in microbiota. Adolescents in both arms demonstrated an increased prevalence of Lactobacillus crispatus and a decrease in quantity of Megasphaera lornae. Postmenopausal active and placebo ring users demonstrated an increased prevalence of lactobacilli and non-albicans yeast while dapivirine ring users demonstrated an increased prevalence of Candida albicans, and increased quantity of Group B Streptococcus (GBS) and non-albicans yeasts. Prevotella species were increased in lactating women while P. timonensis increased in prevalence and concentration among adolescent and postmenopausal women and P. bivia increased in prevalence among adolescent dapivirine ring users.

CONCLUSIONS

Dapivirine vaginal ring use was associated with minimal changes in the vaginal microbiota that are likely not clinically significant.

Probiotic lactobacilli in formulas and hygiene products for the health of the urogenital tract

Lactobacilli are the predominant microorganisms of the healthy human vagina. A novel alternative for the prevention and treatment of female urogenital tract infections (UGTI) is the inclusion of these microorganisms as active pharmaceutical ingredients in probiotic formulas, and more recently in female hygienic products. Probiotics are defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” A list of requirements must be considered during the development of probiotic product/formula for the female urogenital tract (UGT). This review aims to resume the requirements, probiotic characteristics, and clinical trial applied to determine the effect of probiotic and potentially probiotic strains on different woman’s physiological and pathological conditions, and in preterm birth prevention. A revision of female hygienic products available in the world market is included, together with novel studies applying nanotechnology for Lactobacillus incorporation in hygienic products. Further studies and well‐designed clinical trials are urgently required to complement the current knowledge and applications of probiotics in the female UGT. The use of probiotic formulas and products will improve and restore the ecological equilibrium of the UGT microbiome to prevent and treat UGTI in women under different conditions.

The Vaginal Microbiota, Bacterial Biofilms and Polymeric Drug-Releasing Vaginal Rings

The diversity and dynamics of the microbial species populating the human vagina are increasingly understood to play a pivotal role in vaginal health. However, our knowledge about the potential interactions between the vaginal microbiota and vaginally administered drug delivery systems is still rather limited. Several drug-releasing vaginal ring products are currently marketed for hormonal contraception and estrogen replacement therapy, and many others are in preclinical and clinical development for these and other clinical indications. As with all implantable polymeric devices, drug-releasing vaginal rings are subject to surface bacterial adherence and biofilm formation, mostly associated with endogenous microorganisms present in the vagina. Despite more than 50 years since the vaginal ring concept was first described, there has been only limited study and reporting around bacterial adherence and biofilm formation on rings. With increasing interest in the vaginal microbiome and vaginal ring technology, this timely review article provides an overview of: (i) the vaginal microbiota, (ii) biofilm formation in the human vagina and its potential role in vaginal dysbiosis, (iii) mechanistic aspects of biofilm formation on polymeric surfaces, (iv) polymeric materials used in the manufacture of vaginal rings, (v) surface morphology characteristics of rings, (vi) biomass accumulation and biofilm formation on vaginal rings, and (vii) regulatory considerations.

Probiotics and the envisaged role in treating human infertility

Background

Considerable attention is being directed nowadays towards using probiotics as an alternative therapy in treating several human diseases including gastrointestinal tract diseases especially colorectal cancers, cardiovascular diseases, hyperlipidemia, and blood pressure cases. However, infertility as affected by the microbiome and the probable role of probiotics in alleviating infertility problems did not receive the deserved attention, especially in IVF patients with male or female factors.

Main body

In this review, we tried to draw the attention of researchers in the medical settings to the importance of the forthcoming role of probiotics use in elucidating the role of the microbiome in infertile patients. The hope is to attain the best performance of both male and female reproductive systems and to shed some light on infertility problems.

Conclusion

More in vivo experiments are still needed to address many aspects of probiotics like proper administration, exact functional strains, required dose, application method, duration of treatment, and combination with antibiotics before considering probiotics as an alternative treatment.

Bacterial Vaginosis: Current Diagnostic Avenues and Future Opportunities

A healthy female genital tract harbors a microbiome dominated by lactic acid and hydrogen peroxide producing bacteria, which provide protection against infections by maintaining a low pH. Changes in the bacterial compositions of the vaginal microbiome can lead to bacterial vaginosis (BV), which is often associated with vaginal inflammation. Bacterial vaginosis increases the risk of acquiring sexually transmitted infections (STIs) like human immunodeficiency virus (HIV) and affects women's reproductive health negatively. In pregnant women, BV can lead to chorioamnionitis and adverse pregnancy outcomes, including preterm premature rupture of the membranes and preterm birth. In order to manage BV effectively, good diagnostic procedures are required. Traditionally clinical and microscopic methods have been used to diagnose BV; however, these methods require skilled staff and time and suffer from reduced sensitivity and specificity. New diagnostics, including highly sensitive and specific point-of-care (POC) tests, treatment modalities and vaccines can be developed based on the identification of biomarkers from the growing pool of vaginal microbiome and vaginal metabolome data. In this review the current and future diagnostic avenues will be discussed.

In vitro characteristics of intravaginal Lactobacilli; why is L. iners detected in abnormal vaginal microbial flora?

PURPOSE

Our purpose is to investigate the reasons why Lactobacillus iners is detected in abnormal vaginal microbial flora.

METHODS

In this study, in vitro characteristics of four type strains (L. crispatus, L. iners, L. gasseri, and L. jensenii) were examined by measuring the growth speed by OD₆₆₀, and acid resistance, with gram stain and Live/Dead stain.

RESULTS

The growth speed was L. gasseri > L. jensenii > L. crispatus > L. iners. Bacterial counts of all Lactobacilli in MRS medium began to decrease at the middle of the log-phase of the growth curve. In addition, L. iners grew to 10⁶ CFU/mL and the others grew to 10⁸ CFU/mL. L. iners was mostly Gram-negative with very short rod, while the others were mostly Gram-positive rods. L. iners was completely killed in the pH 3 medium, however, the others grew (in pH 3 medium) in 1/100 order compared with those in the pH 6 medium.

CONCLUSION

L. iners was not a typical gram-positive long rod Lactobacilli and presented weak acid-resistance. The reasons why L. iners is detected in abnormal vaginal microbial flora were presumed to be due to the unique morphologic and microbiologic characteristics.

Complete Genome of Lactobacillus iners KY Using Flongle Provides Insight Into the Genetic Background of Optimal Adaption to Vaginal Econiche

Despite the importance of Lactobacillus iners and its unique characteristics for the study of vaginal adaption, its genome and genomic researches for identifying molecular backgrounds of these specific phenotypes are still limited. In this study, the first complete genome of L. iners was constructed using a cost-effective long-read sequencing platform, Flongle from Oxford Nanopore, and comparative genome analysis was conducted using a total of 1,046 strain genomes from 10 vaginal Lactobacillus species. Single-molecule sequencing using Flongle effectively resolved the limitation of the 2nd generation sequencing technologies in dealing with genomic regions of high GC contents, and comparative genome analysis identified three potential core genes (INY, ZnuA, and hsdR) of L. iners which was related to its specific adaption to the vaginal environment. In addition, we performed comparative prophage analysis for 1,046 strain genomes to further identify the species specificity. The number of prophages in L. iners genomes was significantly smaller than other vaginal Lactobacillus species, and one of the specific genes (hsdR) was suggested as the means for defense against bacteriophage. The first complete genome of L. iners and the three specific genes identified in this study will provide useful resources to further expand our knowledge of L. iners and its specific adaption to the vaginal econiche.

Changes of intravaginal microbiota and inflammation after self-replacement ring pessary therapy compared to continuous ring pessary usage for pelvic organ prolapse

AIM

Continuous usage of a ring pessary for pelvic organ prolapse may cause a disturbance of intravaginal microbiota and intravaginal mucosal damage. To avoid the side effects of continuous ring pessary therapy, daily self-replacement of the ring pessary is recommended. The purpose of this study is to evaluate the outcomes of self-replacement versus continuous ring usage, by analysing clinical findings and intravaginal microbiota.

METHODS

Thirty seven patients who managed self-replacement ring pessary therapy and 13 patients with continuous ring pessary therapy participated in this study. The clinical symptoms were checked at 1 month after the initial ring pessary insertion. The changes in the intravaginal microbiota were evaluated by conventional methods, i.e. pH in the vagina, Lactobacillary grade, Nugent score, inflammatory cell counts, and culture-based bacterial detection methods. In addition, our clone library method using 16S rRNA sequencing of vaginal fluid was performed.

RESULTS

Patients were divided into four groups: self-replacement pre/post-menopause and continuous and pre/post-menopause. Five patients of the self-replacement group (n = 37) and all patients of the continuous use group (n = 13) complained of increased discharge. However, both the conventional methods and the clone library method revealed that the number of the self-replacement group patients who had abnormal intravaginal microbiota were not significantly different from that of the continuous use group.

CONCLUSION

Daily self-replacement ring pessary therapy prevented adverse clinical symptoms. However, abnormal intravaginal microbiota was frequently observed during self-replacement of ring pessary therapy as with continuous usage. Regardless, pelvic examinations should be performed routinely.

Sexual practices have a significant impact on the vaginal microbiota of women who have sex with women

Women-who-have-sex-with-women (WSW) are at increased risk of bacterial vaginosis (BV). We investigated the impact of practices and past BV on the vaginal microbiota within a two-year longitudinal cohort of Australian WSW. Self-collected vaginal swabs were used to characterise the vaginal microbiota using 16S-rRNA gene sequencing. Hierarchical clustering defined community state types (CSTs). Bacterial diversity was calculated using the Shannon diversity index and instability of the vaginal microbiota was assessed by change of CST and Bray-Curtis dissimilarity. Sex with a new partner increased the bacterial diversity (adjusted-coefficient = 0.41, 95%CI: 0.21,0.60, p < 0.001) and instability of the vaginal microbiota, in terms of both change of CST (adjusted-odds-ratio = 2.65, 95%CI: 1.34,5.22, p = 0.005) and increased Bray-Curtis dissimilarity (adjusted-coefficient = 0.21, 95%CI: 0.11,0.31, p < 0.001). Women reporting sex with a new partner were more likely than women reporting no new partner to have a vaginal microbiota characterised by Gardnerella vaginalis (adjusted-relative-risk-ratio[aRRR] = 3.45, 95%CI: 1.42,8.41, p = 0.006) or anaerobic BV-associated bacteria (aRRR = 3.62, 95%CI: 1.43,9.14, p = 0.007) relative to a Lactobacillus crispatus dominated microbiota. Sex with a new partner altered the vaginal microbiota of WSW by increasing the diversity and abundance of BV-associated bacteria. These findings highlight the influence of practices on the development of a non-optimal vaginal microbiota and provide microbiological support for the sexual exchange of bacteria between women.

Comparative analysis of the vaginal microbiome of pregnant women with either Trichomonas vaginalis or Chlamydia trachomatis

Background

Although the significance of the human vaginal microbiome for health and disease is increasingly acknowledged, there is paucity of data on the differences in the composition of the vaginal microbiome upon infection with different sexually transmitted pathogens.

Method

The composition of the vaginal bacterial community of women with Trichomonas vaginalis (TV, N = 18) was compared to that of women with Chlamydia trachomatis (CT, N = 14), and to that of controls (N = 21) (women negative for TV, CT and bacterial vaginosis). The vaginal bacterial composition was determined using high throughput sequencing with the Ion 16S metagenomics kit of the variable regions 2, 4 and 8 of the bacterial 16S ribosomal RNA gene from the vaginal swab DNA extract of the women. QIIME and R package “Phyloseq” were used to assess the α- and β-diversity and absolute abundance of the 16S rRNA gene per sample in the three groups. Differences in taxa at various levels were determined using the independent T-test.

Results

A total of 545 operational taxonomic units (OTUs) were identified in all the three groups of which 488 occurred in all three groups (core OTUs). Bacterial α-diversity, by both Simpson’s and Shannon’s indices, was significantly higher, (p = 0.056) and (p = 0.001) respectively, among women with either TV or CT than among controls (mean α-diversity TV-infected > CT-infected > Controls). At the genus level, women infected with TV had a significantly (p < 0.01) higher abundance of Parvimonas and Prevotella species compared to both controls and CT-infected women, whereas women infected with CT had a significantly (p < 0.05) higher abundance of Anaerococcus, Collinsella, Corynebacterium and Dialister.

Conclusion

The vaginal microbiomes of TV and CT-infected women were markedly different from each other and from women without TV and CT. Future studies should determine whether the altered microbiomes are merely markers of disease, or whether they actively contribute to the pathology of the two genital infections.

The gut microbiota influences anticancer immunosurveillance and general health

Discoveries made in the past 5 years indicate that the composition of the intestinal microbiota has a major influence on the effectiveness of anticancer immunosurveillance and thereby contributes to the therapeutic activity of immune-checkpoint inhibitors that target cytotoxic T lymphocyte protein 4 (CTLA-4) or the programmed cell death protein 1 (PD-1)-programmed cell death 1 ligand 1 (PD-L1) axis, as well as the activity of immunogenic chemotherapies. Herein, we highlight some of the bacteria, such as Akkermansia muciniphila, Bacteroides fragilis, Bifidobacterium spp. and Faecalibacterium spp., that have been associated with favourable anticancer immune responses in both preclinical tumour models and patients with cancer. Importantly, these bacteria also seem to have a positive influence on general health, thus reducing the incidence of metabolic disorders and a wide range of chronic inflammatory pathologies. We surmise that a diverse and propitious microbial ecosystem favours organismal homeostasis, particularly at the level of the cancer-immune dialogue.

The genital tract and rectal microbiomes: their role in HIV susceptibility and prevention in women

INTRODUCTION

Young women in sub-Saharan Africa are disproportionately affected by HIV, accounting for 25% of all new infections in 2017. Several behavioural and biological factors are known to impact a young woman's vulnerability for acquiring HIV. One key, but lesser understood, biological factor impacting vulnerability is the vaginal microbiome. This review describes the vaginal microbiome and examines its alterations, its influence on HIV acquisition as well as the efficacy of HIV prevention technologies, the role of the rectal microbiome in HIV acquisition, advances in technologies to study the microbiome and some future research directions.

DISCUSSION

Although the composition of each woman's vaginal microbiome is unique, a microbiome dominated by Lactobacillus species is generally associated with a "healthy" vagina. Disturbances in the vaginal microbiota, characterized by a shift from a low-diversity, Lactobacillus-dominant state to a high-diversity non-Lactobacillus-dominant state, have been shown to be associated with a range of adverse reproductive health outcomes, including increasing the risk of genital inflammation and HIV acquisition. Gardnerella vaginalis and Prevotella bivia have been shown to contribute to both HIV risk and genital inflammation. In addition to impacting HIV risk, the composition of the vaginal microbiome affects the vaginal concentrations of some antiretroviral drugs, particularly those administered intravaginally, and thereby their efficacy as pre-exposure prophylaxis (PrEP) for HIV prevention. Although the role of rectal microbiota in HIV acquisition in women is less well understood, the composition of this compartment's microbiome, particularly the presence of species of bacteria from the Prevotellaceae family likely contribute to HIV acquisition. Advances in technologies have facilitated the study of the genital microbiome's structure and function. While next-generation sequencing advanced knowledge of the diversity and complexity of the vaginal microbiome, the emerging field of metaproteomics, which provides important information on vaginal bacterial community structure, diversity and function, is further shedding light on functionality of the vaginal microbiome and its relationship with bacterial vaginosis (BV), as well as antiretroviral PrEP efficacy.

CONCLUSIONS

A better understanding of the composition, structure and function of the microbiome is needed to identify opportunities to alter the vaginal microbiome and prevent BV and reduce the risk of HIV acquisition.

Bifidobacterial strains in the intestines of newborns originate from their mothers

The gastrointestinal tract is believed to be colonized rapidly with bacteria immediately from birth. The source of these intestinal microbes is an ongoing topic of interest because increasing evidence suggests that the composition of the initial intestinal bacterial colonization strongly affects health. In particular, the source of bifidobacteria has received marked attention because these bacteria are suggested to play a crucial role in protecting against susceptibility to diverse diseases later in life. However, the source of these microbes has remained unclear. Recently, it was confirmed that mothers transmit their unique bifidobacterial strains to their children shortly after birth. The transmitted strains predominate during early infancy, suggesting that maternal intestinal bifidobacteria are an important source of the infant gut microbiota. Accordingly, maintenance of a healthy, balanced gut microbiota during pregnancy has an important positive influence on the newborn gut microbiota.

Bifidobacteria isolated from vaginal and gut microbiomes are indistinguishable by comparative genomics

Bifidobacteria colonize the human gastrointestinal tract, vagina, oral cavity and breast milk. They influence human physiology and nutrition through health-promoting effects, play an important role as primary colonizers of the newborn gut, and contribute to vaginal microbiome homeostasis by producing lactic acid. Nevertheless, the mechanisms by which bifidobacteria are transmitted from mother to infant remains in discussion. Moreover, studies have suggested that Bifidobacterium spp. have specializations for gut colonization, but comparisons of strains of the same bifidobacteria species from different body sites are lacking. Here, our objective was to compare the genomes of Bifidobacterium breve (n = 17) and Bifidobacterium longum (n = 26) to assess whether gut and vaginal isolates of either species were distinguishable based on genome content. Comparison of the general genome features showed that vaginal and gut isolates did not differ in size, GC content, number of genes and CRISPR, either for B. breve or B. longum. Average nucleotide identity and whole genome phylogeny analysis revealed that vaginal and gut isolates did not cluster separately. Vaginal and gut isolates also had a similar COG (Cluster of Orthologous Group) category distribution. Differences in the accessory genomes between vaginal and gut strains were observed, but were not sufficient to distinguish isolates based on their origin. The results of this study support the hypothesis that the vaginal and gut microbiomes are colonized by a shared community of Bifidobacterium, and further emphasize the potential importance of the maternal vaginal microbiome as a source of infant gut microbiota.

Association of high-risk sexual behaviour with diversity of the vaginal microbiota and abundance of Lactobacillus

Objective

To compare the vaginal microbiota of women engaged in high-risk sexual behaviour (sex work) with women who are not engaged in high-risk sexual behaviour. Diverse vaginal microbiota, low in Lactobacillus species, like those in bacterial vaginosis (BV), are associated with increased prevalence of sexually transmitted infections (STIs) and human immunodeficiency virus (HIV) acquisition. Although high-risk sexual behaviour increases risk for STIs, the vaginal microbiota of sex workers is understudied.

Methods

A retrospective cross-sectional study was conducted comparing vaginal microbiota of women who are not engaged in sex work (non-sex worker controls, NSW, N = 19) and women engaged in sex work (female sex workers, FSW, N = 48), using Illumina sequencing (16S rRNA, V3 region).

Results

Bacterial richness and diversity were significantly less in controls, than FSW. Controls were more likely to have Lactobacillus as the most abundant genus (58% vs. 17%; P = 0.002) and composition of their vaginal microbiota differed from FSW (PERMANOVA, P = 0.001). Six microbiota clusters were detected, including a high diversity cluster with three sub-clusters, and 55% of women with low Nugent Scores fell within this cluster. High diversity was observed by 16S sequencing in FSW, regardless of Nugent Scores, suggesting that Nugent Score may not be capable of capturing the diversity present in the FSW vaginal microbiota.

Conclusions

High-risk sexual behaviour is associated with diversity of the vaginal microbiota and lack of Lactobacillus. These factors could contribute to increased risk of STIs and HIV in women engaged in high-risk sexual behaviour.

Lactobacillus iners, the unusual suspect

Lactobacillus iners is an unusual Lactobacillus species which does not grow on de Man Rogosa Sharpe agar, does not produce d-lactic acid, and only limited amounts of hydrogen peroxide. Its production of inerolysin, a cytotoxin, is also unusual for a lactobacillus. Epidemiological studies point to an ambiguous role for this species, which is quite often recovered in high numbers from vaginal dysbiosis and offers limited protection against vaginal dysbiosis and, subsequently, against sexually transmitted infections and adverse pregnancy outcome. Several data indicate that L. iners might even contribute to the onset and maintenance of vaginal dysbiosis and be a risk factor for adverse pregnancy outcome.

Characterization of vaginal Lactobacillus species by rplK -based multiplex qPCR in Russian women

We describe a multiplex qPCR assay for identification and quantitative assessment of a set of vaginal Lactobacillus species, including L. acidophilus, L. crispatus, L. gasseri, L. helveticus, L. iners, and L. jensenii. The assay extends the previously developed qPCR method for Lactobacillus detection and total quantification based on targeting the rplK gene. Both assays use only single pair of primers and a set of probes combined in three reactions, comprising a vaginal Lactobacillus diagnostic assay panel. The utility of the diagnostic panel was evaluated by analyzing of vaginal swab specimens from 145 patients with different status of vaginal health. Most frequently, only one Lactobacillus species was dominant (68,9%), mostly L. crispatus (18,6%) or L. iners (33,1%), but two or three Lactobacillus species were also being simultaneously detected (24,9%). The diagnostic panel will facilitate investigations of the role of Lactobacillus species in the health of the female reproductive system and promote studies of variability of the vaginal microbiota.

Lactobacillus iners: Friend or Foe?

The vaginal microbial community is typically characterized by abundant lactobacilli. Lactobacillus iners, a fairly recently detected species, is frequently present in the vaginal niche. However, the role of this species in vaginal health is unclear, since it can be detected in normal conditions as well as during vaginal dysbiosis, such as bacterial vaginosis, a condition characterized by an abnormal increase in bacterial diversity and lack of typical lactobacilli. Compared to other Lactobacillus species, L. iners has more complex nutritional requirements and a Gram-variable morphology. L. iners has an unusually small genome (ca. 1 Mbp), indicative of a symbiotic or parasitic lifestyle, in contrast to other lactobacilli that show niche flexibility and genomes of up to 3-4 Mbp. The presence of specific L. iners genes, such as those encoding iron-sulfur proteins and unique σ-factors, reflects a high degree of niche specification. The genome of L. iners strains also encodes inerolysin, a pore-forming toxin related to vaginolysin of Gardnerella vaginalis. Possibly, this organism may have clonal variants that in some cases promote a healthy vagina, and in other cases are associated with dysbiosis and disease. Future research should examine this friend or foe relationship with the host.

Identification of vaginal bacteria diversity and it's association with clinically diagnosed bacterial vaginosis by denaturing gradient gel electrophoresis and correspondence analysis

Bacterial vaginosis (BV) is a common complex associated with numerous adverse health outcomes, affecting women of different ages throughout the world. The etiology of BV remains poorly understood due to the difficulty of establishing a molecular genetic criterion to recognize the vaginal microbiota of BV-positive women from that of the normal women. We used techniques of broad-range PCR-DGGE and gel imaging analysis system cooperated with 16S rRNA gene sequencing and statistical analysis to investigate the community structure of the healthy and BV-affected vaginal microbial ecosystems. The community of vaginal bacteria detected in subjects with BV was far more luxuriant and diverse than in subjects without BV. The mean number of microbial species in 128 BV-positive women was nearly two times greater than in 68 subjects without BV(4.05±1.96 versus 2.59±1.14). Our sequencing efforts yielded many novel phylotypes (198 of our sequences represented 59 species), including several novel BV-associated bacteria (BVAB) and many belonging to opportunistic infections, which remain inexplicable for their roles in determining the health condition of vaginal microflora. This study identifies Algoriphagus aquatilis, Atopobium vaginae, Burkholderia fungorum, Megasphaera genomosp species as indicators to BV and subjects with BV harbor particularly taxon-rich and diverse bacterial communities. Maybe Bifidobacterium, Staphylococcus or even more alien species are commensal creatures in normal vaginal microbiota.

Lactobacillus crispatus strain SJ-3C-US induces human dendritic cells (DCs) maturation and confers an anti-inflammatory phenotype to DCs

Lactobacillus crispatus is one of the most predominant species in the healthy vagina microbiota. Nevertheless, the interactions between this commensal bacterium and the immune system are largely unknown. Given the importance of the dendritic cells (DCs) in the regulation of the immunity, this study was performed to elucidate the influence of vaginal isolated L. crispatus SJ-3C-US from healthy Iranian women on DCs, either directly by exposure of DCs to ultraviolet-inactivated (UVI) and heat-killed (HK) L. crispatus SJ-3C-US or indirectly to its cell-free supernatant (CFS), and the outcomes of immune response. In this work we showed that L. crispatus SJ-3C-US induced strong dose-dependent activation of dendritic cells and production of high levels of IL-10, whereas IL-12p70 production was induced at low level in an inverse dose-dependent manner. This stimulation skewed T cells polarization toward CD4(+) CD25(+) FOXP3(+) Treg cells and production of IL-10 in a dose-dependent manner in mixed leukocyte reaction (MLR) test. The mode of bacterial inactivation did not affect the DCs activation pattern, upon encounter with L. crispatus SJ-3C-US. Moreover, while DCs stimulated with CFS showed moderate phenotypic maturation and IL-10 production, it failed to skew T cells polarization toward CD4(+) CD25(+) FOXP3(+) regulatory T cells (Treg) and production of IL-10. This study showed that L. crispatus SJ-3C-US confers an anti-inflammatory phenotype to DCs through up-regulation of anti-inflammatory/regulatory IL-10 cytokine production and induction of CD4(+) CD25(+) FOXP3(+) T cells at optimal dosage. Our findings suggest that L. crispatus SJ-3C-US could be a potent candidate as protective probiotic against human immune-mediated pathologies, such as chronic inflammation, vaginitis or pelvic inflammatory disease (PID).

A DNA tool for early detection of vaginal dysbiosis in African women

A next-generation diagnostic tool for bacterial vaginosis, consisting of quantitative and/or qualitative molecular criteria, has not yet been identified. The optimal diagnostic tool should not only diagnose bacterial vaginosis in diverse populations, but should also detect early signs of transition to dysbiosis. We evaluated a tool based on log10-transformed qPCR data for Lactobacillus crispatus, Lactobacillus iners, Lactobacillus jensenii, Lactobacillus gasseri, Lactobacillus vaginalis, Lactobacillus genus, Atopobium vaginae and Gardnerella vaginalis in vaginal specimens of 426 African women to detect dysbiosis and predict transition to dysbiosis. G. vaginalis (p = 0.204) and A. vaginae (p = 0.001) were more commonly present in women who evolved to an intermediate (Nugent 4-6) or bacterial vaginosis score (Nugent 7-10) compared to women who continued to have a normal Nugent score. The combination of G. vaginalis, A. vaginae and Lactobacillus genus counts performed best for diagnostic accuracy for bacterial vaginosis--sensitivity 93.4% and specificity 83.6%; and for predictive accuracy for bacterial vaginosis--sensitivity 79% and specificity 52%. L. crispatus combinations did not perform well. We conclude that a triple-G. vaginalis-A. vaginae-Lactobacillus genus-qPCR tool holds promise for research in sub-Saharan Africa or when developed as a next-generation clinical diagnostic modality for bacterial vaginosis, ideally engineered as a rapid assay.

Impact of maternal bifidobacteria and the mode of delivery on Bifidobacterium microbiota in infants

The aim of this study is to examine the influence of maternal intestinal and vaginal bifidobacteria on the colonisation of bifidobacteria in the gut of infants. Faecal samples from 120 healthy pregnant mothers within 1 month of delivery and from their infants at 1 month of age and 98 vaginal swabs from the mothers at the time of delivery were collected at a maternity hospital in Chiang Mai, Thailand. The faecal and vaginal samples were assayed by real-time PCR assays to detect Bifidobacterium species and to estimate the bifidobacterial copy numbers. After adjusting for the numbers of each Bifidobacterium species, delivery mode, and antibiotic use in infants by the age of 1 month, total counts of bifidobacteria in the mothers' faeces were associated with increased copy numbers of bifidobacteria in the faeces of breastfed infants. A caesarean section was also significantly associated with a decrease in the copy numbers of bifidobacteria in the faeces of infants. No significant correlation was found between the bifidobacterial copies of the vaginal swabs and those of the infants' faeces. The intestinal bifidobacterial status of exclusively breastfed infants was significantly positive affected by vaginal delivery and high bifidobacterial copy numbers in their mothers' gut.

Bifidobacteria from the gastrointestinal tract of animals: differences and similarities

At present, the genus Bifidobacterium includes 48 species and subspecies, and this number is expected to increase. Bifidobacteria are found in different ecological niches. However, most were originally isolated from animals, mainly mammals, especially during the milk feeding period of life. Their presence in high numbers is associated with good health of the host. Moreover, bifidobacteria are often found in poultry and insects that exhibit a social mode of life (honeybees and bumblebees). This review is designed as a summary of currently known species of the genus Bifidobacterium, especially focused on their difference and similarities. The primary focus is on their occurrence in the digestive tract of animals, as well as the specificities of animal strains, with regard to their potential use as probiotics.

Lactobacillus species as biomarkers and agents that can promote various aspects of vaginal health

The human body is colonized by a vast number of microorganisms collectively referred to as the human microbiota. One of the main microbiota body sites is the female genital tract, commonly dominated by Lactobacillus spp., in approximately 70% of women. Each individual species can constitute approximately 99% of the ribotypes observed in any individual woman. The most frequently isolated species are Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus jensenii and Lactobacillus iners. Residing at the port of entry of bacterial and viral pathogens, the vaginal Lactobacillus species can create a barrier against pathogen invasion since mainly products of their metabolism secreted in the cervicovaginal fluid can play an important role in the inhibition of bacterial and viral infections. Therefore, a Lactobacillus-dominated microbiota appears to be a good biomarker for a healthy vaginal ecosystem. This balance can be rapidly altered during processes such as menstruation, sexual activity, pregnancy and various infections. An abnormal vaginal microbiota is characterized by an increased diversity of microbial species, leading to a condition known as bacterial vaginosis. Information on the vaginal microbiota can be gathered from the analysis of cervicovaginal fluid, by using the Nugent scoring or the Amsel's criteria, or at the molecular level by investigating the number and type of Lactobacillus species. However, when translating this to the clinical setting, it should be noted that the absence of a Lactobacillus-dominated microbiota does not appear to directly imply a diseased condition or dysbiosis. Nevertheless, the widely documented beneficial role of vaginal Lactobacillus species demonstrates the potential of data on the composition and activity of lactobacilli as biomarkers for vaginal health. The substantiation and further validation of such biomarkers will allow the design of better targeted probiotic strategies.

Vaginal microbiota of adolescent girls prior to the onset of menarche resemble those of reproductive-age women

Puberty is an important developmental stage wherein hormonal shifts mediate the physical and physiological changes that lead to menarche, but until now, the bacterial composition of vaginal microbiota during this period has been poorly characterized. We performed a prospective longitudinal study of perimenarcheal girls to gain insight into the timing and sequence of changes that occur in the vaginal and vulvar microbiota during puberty. The study enrolled 31 healthy, premenarcheal girls between the ages of 10 and 12 years and collected vaginal and vulvar swabs quarterly for up to 3 years. Bacterial composition was characterized by Roche 454 pyrosequencing and classification of regions V1 to V3 of 16S rRNA genes. Contrary to expectations, lactic acid bacteria, primarily Lactobacillus spp., were dominant in the microbiota of most girls well before the onset of menarche in the early to middle stages of puberty. Gardnerella vaginalis was detected at appreciable levels in approximately one-third of subjects, a notable finding considering that this organism is commonly associated with bacterial vaginosis in adults. Vulvar microbiota closely resembled vaginal microbiota but often exhibited additional taxa typically associated with skin microbiota. Our findings suggest that the vaginal microbiota of girls begin to resemble those of adults well before the onset of menarche.

IMPORTANCE

This study addresses longitudinal changes in vaginal and vulvar microbial communities prior to and immediately following menarche. The research is significant because microbial ecology of the vagina is an integral aspect of health, including resistance to infections. The physiologic changes of puberty and initiation of cyclic menstruation are likely to have profound effects on vaginal microbiota, but almost nothing is known about changes that normally occur during this time. Our understanding has been especially hampered by the lack of thorough characterization of microbial communities using techniques that do not rely on the cultivation of fastidious bacteria, as well as a dearth of studies on girls in the early to middle stages of puberty. This study improves our understanding of the normal development of vaginal microbiota during puberty and onset of menarche and may better inform clinical approaches to vulvovaginal care of adolescent girls.

Diagnosis of bacterial vaginosis by a new multiplex peptide nucleic acid fluorescence in situ hybridization method

Bacterial vaginosis (BV) is one of most common vaginal infections. However, its diagnosis by classical methods reveals low specificity. Our goal was to evaluate the accuracy diagnosis of 150 vaginal samples with research gold standard methods and our Peptide Nucleic Acid (PNA) probes by Fluorescence in situ Hybridization (FISH) methodology. Also, we described the first PNA-FISH methodology for BV diagnosis, which provides results in approximately 3 h. The results showed a sensitivity of 84.6% (95% confidence interval (CI), from 64.3 to 95.0%) and a specificity of 97.6% (95% CI [92.6-99.4%]), demonstrating the higher specificity of the PNA-FISH method and showing false positive results in BV diagnosis commonly obtained by the classical methods. This methodology combines the specificity of PNA probes for Lactobacillus species and G. vaginalis visualization and the calculation of the microscopic field by Nugent score, allowing a trustful evaluation of the bacteria present in vaginal microflora and avoiding the occurrence of misleading diagnostics. Therefore, the PNA-FISH methodology represents a valuable alternative for BV diagnosis.

Establishment of a sensitive system for analysis of human vaginal microbiota on the basis of rRNA-targeted reverse transcription-quantitative PCR

Ten specific primer sets, for Lactobacillus gasseri, Lactobacillus crispatus, Atopobium vaginae, Gardnerella vaginalis, Mobiluncus curtisii, Chlamydia trachomatis/muridarum, Bifidobacterium longum subsp. longum, Bifidobacterium longum subsp. infantis, Bifidobacterium adolescentis, and Bifidobacterium angulatum, were developed for quantitative analysis of vaginal microbiota. rRNA-targeted reverse transcription-quantitative PCR (RT-qPCR) analysis of the vaginal samples from 12 healthy Japanese volunteers using the new primer sets together with 25 existing primer sets revealed the diversity of their vaginal microbiota: Lactobacilli such as L. crispatus, L. gasseri, Lactobacillus jensenii, Lactobacillus iners, and Lactobacillus vaginalis, as the major populations at 10(7) cells/ml vaginal fluid, were followed by facultative anaerobes such as Streptococcus and strict anaerobes at lower population levels of 10(4) cells/ml or less. Certain bacterial vaginosis (BV)-related bacteria, such as G. vaginalis, A. vaginae, M. curtisii, and Prevotella, were also detected in some subjects. Especially in one subject, both G. vaginalis and A. vaginae were detected at high population levels of 10(8.8) and 10(8.9) cells/ml vaginal fluid, suggesting that she is an asymptomatic BV patient. These results suggest that the RT-qPCR system is effective for accurate analysis of major vaginal commensals and diagnosis of several vaginal infections.

Homogeneity of the vaginal microbiome at the cervix, posterior fornix, and vaginal canal in pregnant Chinese women

The vaginal microbiome is an emerging concern in prenatal health. Because the sampling process of vaginal microbiota may pose potential risks for pregnant women, the choice of sampling site should be carefully considered. However, whether the microbial diversity is different across various sampling sites has been controversial. In the present study, three repeated swabs were collected at the cervix (C), posterior fornix (P), and vaginal canal (V) from 34 Chinese women during different pregnancy stages, and vaginal species were determined using the Illumina sequencing of 16S rRNA tag sequences. The identified microbiomes were classified into four community state types (CSTs): CST I (dominated by L. crispatus), CST II (dominated by L. gasseri), CST III (dominated by L. iners), and CST IV-A (characterized by a low abundance of Lactobacillus, but with proportions of various species previously shown to be associated with bacterial vaginosis). All individuals had consistent CST at the three sampling sites regardless of pregnancy stage and CST group. In addition, there was little heterogeneity across community structures within each individual, as determined by LEfSe, indicating high vaginal microbiome homogeneity at the three sampling sites. The present study also revealed different beta diversity during pregnancy stages. The vaginal microbiome variation among women during trimester T1 (9 ± 2.6 weeks) is larger than that of non-pregnant women and women from other trimesters, as demonstrated by the UniFrac distance (P < 0.05). In particular, the present study is the first one that demonstrates the notably difference of vaginal microbiome of postpartum women compare to women in gestation. These results will be useful for future studies of the vaginal microbiota during pregnancy.

Comparative functional genomics of Lactobacillus spp. reveals possible mechanisms for specialization of vaginal lactobacilli to their environment

Lactobacilli are found in a wide variety of habitats. Four species, Lactobacillus crispatus, L. gasseri, L. iners, and L. jensenii, are common and abundant in the human vagina and absent from other habitats. These may be adapted to the vagina and possess characteristics enabling them to thrive in that environment. Furthermore, stable codominance of multiple Lactobacillus species in a single community is infrequently observed. Thus, it is possible that individual vaginal Lactobacillus species possess unique characteristics that confer to them host-specific competitive advantages. We performed comparative functional genomic analyses of representatives of 25 species of Lactobacillus, searching for habitat-specific traits in the genomes of the vaginal lactobacilli. We found that the genomes of the vaginal species were significantly smaller and had significantly lower GC content than those of the nonvaginal species. No protein families were found to be specific to the vaginal species analyzed, but some were either over- or underrepresented relative to nonvaginal species. We also found that within the vaginal species, each genome coded for species-specific protein families. Our results suggest that even though the vaginal species show no general signatures of adaptation to the vaginal environment, each species has specific and perhaps unique ways of interacting with its environment, be it the host or other microbes in the community. These findings will serve as a foundation for further exploring the role of lactobacilli in the ecological dynamics of vaginal microbial communities and their ultimate impact on host health.

Comparative biophysical properties of tenofovir-loaded, thiolated and nonthiolated chitosan nanoparticles intended for HIV prevention

AIM

This study is designed to test the hypothesis that tenofovir-loaded (an anti-HIV microbicide) chitosan-thioglycolic acid-conjugated (CS-TGA) nanoparticles (NPs) exhibit superior biophysical properties for mucoadhesion compared with those of native CS NPs.

MATERIALS & METHODS

The NPs are prepared by ionotropic gelation. The particle mean diameter, encapsulation efficiency and release profile are analyzed by dynamic light scattering and UV spectroscopy, respectively. The cytotoxicity, cellular uptake and uptake mechanism are assessed on VK2/E6E7 and End1/E6E7 cell lines by colorimetry/fluorimetry, and percentage mucoadhesion is assessed using porcine vaginal tissue.

RESULTS

The mean diameter of the optimal NP formulations ranges from 240 to 252 nm, with a maximal encapsulation efficiency of 22.60%. Tenofovir release from CS and CS-TGA NPs follows first-order and Higuchi models, respectively. Both NPs are noncytotoxic in 48 h. The cellular uptake, which is time dependent, mainly occurs via the caveolin-mediated pathway. The percentage of mucoadhesion of CS-TGA NPs is fivefold higher than that of CS NPs, and reached up to 65% after 2 h.

CONCLUSION

Collectively, CS-TGA NPs exhibit superior biophysical properties and can potentially maximize the retention time of a topical microbicide, such as tenofovir, intended for the prevention of HIV transmission.

Bacterial vaginosis diagnosed by analysis of first-void-urine specimens

Bacterial vaginosis (BV) is traditionally diagnosed using vaginal samples. The aim of this study was to investigate whether BV can be diagnosed from first-void urine (FVU). Self-collected vaginal smears, vaginal swabs, and FVU were obtained from 176 women. BV was diagnosed by Nugent's criteria. The FVU and vaginal swabs were analyzed by quantitative PCRs (qPCRs) for selected vaginal bacteria (Atopobium vaginae, Prevotella spp., Gardnerella vaginalis, bacterial vaginosis-associated bacterium 2, Eggerthella-like bacterium, "Leptotrichia amnionii," Megasphaera type 1), and all had an area under the receiver operating characteristic (ROC) curve of >85%, suggesting good prediction of BV according to the Nugent score. All seven bacteria in FVU were significantly associated with BV in univariate analysis. An accurate diagnosis of BV from urine was obtained in this population by a combination of qPCRs for Megasphaera type 1 and Prevotella spp. The same two bacteria remained significantly associated with BV in a multivariate model after adjusting for the other five species. There was no statistically significant difference between the sensitivities and specificities of BV diagnosis by molecular methods performed on swabs and FVU samples. A linear regression analysis showed good agreement between bacterial loads from swabs and FVU, but Prevotella spp. could be detected in high numbers in a few FVU samples without being present in swabs. This method will allow diagnosis of BV in studies where only urine has been collected and where detection of BV is considered relevant.

More than meets the eye: associations of vaginal bacteria with gram stain morphotypes using molecular phylogenetic analysis

Bacterial vaginosis (BV) is a highly prevalent condition associated with adverse health outcomes. Gram stain analysis of vaginal fluid is the standard for confirming the diagnosis of BV, wherein abundances of key bacterial morphotypes are assessed. These Lactobacillus, Gardnerella, Bacteroides, and Mobiluncus morphotypes were originally linked to particular bacterial species through cultivation studies, but no studies have systematically investigated associations between uncultivated bacteria detected by molecular methods and Gram stain findings. In this study, 16S-rRNA PCR/pyrosequencing was used to examine associations between vaginal bacteria and bacterial morphotypes in 220 women with and without BV. Species-specific quantitative PCR (qPCR) and fluorescence in Situ hybridization (FISH) methods were used to document concentrations of two bacteria with curved rod morphologies: Mobiluncus and the fastidious BV-associated bacterium-1 (BVAB1). Rank abundance of vaginal bacteria in samples with evidence of curved gram-negative rods showed that BVAB1 was dominant (26.1%), while Mobiluncus was rare (0.2% of sequence reads). BVAB1 sequence reads were associated with Mobiluncus morphotypes (p<0.001). Among women with curved rods, mean concentration of BVAB1 DNA was 2 log units greater than Mobiluncus (p<0.001) using species-specific quantitative PCR. FISH analyses revealed that mean number of BVAB1 cells was 2 log units greater than Mobiluncus cells in women with highest Nugent score (p<0.001). Prevotella and Porphyromonas spp. were significantly associated with the “Bacteroides morphotype,” whereas Bacteroides species were rare. Gram-negative rods designated Mobiluncus morphotypes on Gram stain are more likely BVAB1. These findings provide a clearer picture of the bacteria associated with morphotypes on vaginal Gram stain.

Vaginal microbiome in women from Greenland assessed by microscopy and quantitative PCR

BACKGROUND

Bacterial vaginosis (BV) is a common condition, although its aetiology remains unexplained. The aim of this study was to analyse the composition of vaginal microbiota in women from Greenland to provide a quantitative description and improve the understanding of BV.

METHODS

Self-collected vaginal smears and swabs were obtained from 177 women. The vaginal smears were graded for BV according to Nugent's criteria. The vaginal swab samples were analysed by 19 quantitative PCRs (qPCRs) for selected vaginal bacteria and by PCR for four sexually transmitted infections (STIs).

RESULTS

STIs were common: Mycoplasma genitalium 12%, Chlamydia trachomatis 7%, Neisseria gonorrhoeae 1%, and Trichomonas vaginalis 0.5%. BV was found in 45% of women, but was not associated with individual STIs. Seven of the 19 vaginal bacteria (Atopobium vaginae, Prevotella spp., Gardnerella vaginalis, BVAB2, Eggerthella-like bacterium, Leptotrichia amnionii, and Megasphaera type 1) had areas under the receiver operating characteristic (ROC) curve > 85%, suggesting they are good predictors of BV according to Nugent. Prevotella spp. had the highest odds ratio for BV (OR 437; 95% CI 82-2779) in univariate analysis considering only specimens with a bacterial load above the threshold determined by ROC curve analysis as positive, as well as the highest adjusted odds ratio in multivariate logistic regression analysis (OR 4.4; 95% CI 1.4-13.5). BV could be subdivided into clusters dominated by a single or a few species together.

CONCLUSIONS

BV by Nugent score was highly prevalent. Two of seven key species (Prevotella spp. and A. vaginae) remained significantly associated with BV in a multivariate model after adjusting for other bacterial species. G. vaginalis and Prevotella spp. defined the majority of BV clusters.

Relationship of selected bacterial vaginosis-associated bacteria to Nugent score bacterial vaginosis among urban women early in pregnancy

Among urban, primarily African American pregnant women, 74% were identified with Nugent score bacterial vaginosis (BV). All BV-associated bacteria were more prevalent among women with Nugent score BV. Bacterial vaginosis-associated bacteria 3 (BVAB3) had the highest positive predictive value, whereas Gardnerella vaginalis and Atopobium spp. had the highest sensitivity. Atopobium spp. levels had the most significant area under the curve.

The villain team-up or how Trichomonas vaginalis and bacterial vaginosis alter innate immunity in concert

Objectives

Complex interactions of vaginal microorganisms with the genital tract epithelium shape mucosal innate immunity, which holds the key to sexual and reproductive health. Bacterial vaginosis (BV), a microbiome-disturbance syndrome prevalent in reproductive-age women, occurs commonly in concert with trichomoniasis, and both are associated with increased risk of adverse reproductive outcomes and viral infections, largely attributable to inflammation. To investigate the causative relationships among inflammation, BV and trichomoniasis, we established a model of human cervicovaginal epithelial cells colonised by vaginal Lactobacillus isolates, dominant in healthy women, and common BV species (Atopobium vaginae, Gardnerella vaginalis and Prevotella bivia).

Methods

Colonised epithelia were infected with Trichomonas vaginalis (TV) or exposed to purified TV virulence factors (membrane lipophosphoglycan (LPG), its ceramide-phosphoinositol-glycan core (CPI-GC) or the endosymbiont Trichomonas vaginalis virus (TVV)), followed by assessment of bacterial colony-forming units, the mucosal anti-inflammatory microbicide secretory leucocyte protease inhibitor (SLPI), and chemokines that drive pro-inflammatory, antigen-presenting and T cells.

Results

TV reduced colonisation by Lactobacillus but not by BV species, which were found inside epithelial cells. TV increased interleukin (IL)-8 and suppressed SLPI, likely via LPG/CPI-GC, and upregulated IL-8 and RANTES, likely via TVV as suggested by use of purified pathogenic determinants. BV species A vaginae and G vaginalis induced IL-8 and RANTES, and also amplified the pro-inflammatory responses to both LPG/CPI-GC and TVV, whereas P bivia suppressed the TV/TVV-induced chemokines.

Conclusions

These molecular host–parasite–endosymbiont–bacteria interactions explain epidemiological associations and suggest a revised paradigm for restoring vaginal immunity and preventing BV/TV-attributable inflammatory sequelae in women.

Lactobacillus species isolated from vaginal secretions of healthy and bacterial vaginosis-intermediate Mexican women: a prospective study

Background

Lactobacillus jensenii, L. iners, L. crispatus and L. gasseri are the most frequently occurring lactobacilli in the vagina. However, the native species vary widely according to the studied population. The present study was performed to genetically determine the identity of Lactobacillus strains present in the vaginal discharge of healthy and bacterial vaginosis (BV) intermediate Mexican women.

Methods

In a prospective study, 31 strains preliminarily identified as Lactobacillus species were isolated from 21 samples collected from 105 non-pregnant Mexican women. The samples were classified into groups according to the Nugent score criteria proposed for detection of BV: normal (N), intermediate (I) and bacterial vaginosis (BV). We examined the isolates using culture-based methods as well as molecular analysis of the V1–V3 regions of the 16S rRNA gene. Enterobacterial repetitive intergenic consensus (ERIC) sequence analysis was performed to reject clones.

Results

Clinical isolates (25/31) were classified into four groups based on sequencing and analysis of the 16S rRNA gene: L. acidophilus (14/25), L. reuteri (6/25), L. casei (4/25) and L. buchneri (1/25). The remaining six isolates were presumptively identified as Enterococcus species. Within the L. acidophilus group, L. gasseri was the most frequently isolated species, followed by L. jensenii and L. crispatus. L. fermentum, L. rhamnosus and L. brevis were also isolated, and were placed in the L. reuteri, L. casei and L. buchneri groups, respectively. ERIC profile analysis showed intraspecific variability amongst the L. gasseri and L. fermentum species.

Conclusions

These findings agree with previous studies showing that L. crispatus, L. gasseri and L. jensenii are consistently present in the healthy vaginal ecosystem. Additional species or phylotypes were detected in the vaginal microbiota of the non-pregnant Mexican (Hispanic-mestizo) population, and thus, these results further our understanding of vaginal lactobacilli colonisation and richness in this particular population.