Bacterial vaginosis. Transmission, role in genital tract infection and pregnancy outcome: an enigma

MinION, a portable long-read sequencer, enables rapid vaginal microbiota analysis in a clinical setting

Background

It has been suggested that the local microbiota in the reproductive organs is relevant to women's health and may also affect pregnancy outcomes. Analysis of partial 16S ribosomal RNA (rRNA) gene sequences generated by short-read sequencers has been used to identify vaginal and endometrial microbiota, but it requires a long time to obtain the results, making it unsuitable for rapid bacterial identification from a small specimen amount in a clinical context.

Methods

We developed a simple workflow using the nanopore sequencer MinION that allows high-resolution and rapid differentiation of vaginal microbiota. Vaginal samples collected from 18 participants were subjected to DNA extraction and full-length 16S rRNA gene sequencing with MinION.

Results

The principal coordinate analysis showed no differences in the bacterial compositions regardless of the sample collection method. The analysis of vaginal microbiota could be completed with a total analysis time of approximately four hours, allowing same-day results. Taxonomic profiling by MinION sequencing revealed relatively low diversity of the vaginal bacterial community, identifying the prevailing Lactobacillus species and several causative agents of bacterial vaginosis.

Conclusions

Full-length 16S rRNA gene sequencing analysis with MinION provides a rapid means for identifying vaginal bacteria with higher resolution. Species-level profiling of human vaginal microbiota by MinION sequencing can allow the analysis of associations with conditions such as genital infections, endometritis, and threatened miscarriage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01218-8.

The expression of miR-17 and miR-29a in placenta-derived exosomes in LPS-induced abortion mice model: An experimental study

Background

The expression pattern of microRNAs in placenta-derived exosomes plays a crucial role in the regulation of immune responses and inflammation at the fetal–maternal interface.

Objective

Considering the immunomodulatory properties of miR-17 and miR-29a, we determined their expression levels in placenta-derived exosomes in a lipopolysaccharide (LPS)-induced abortion mice model.

Materials and Methods

A total of 14 pregnant BALB/c mice, aged 6–8 wk, were randomly divided into two groups (n = 7/each) on the gestational day 11.5. While the mice in the experimental group were treated with LPS, those in the control group were treated with Phosphate buffered saline; 5 hr after the treatment, the placental cells were isolated and cultured for 48 hr. Then, the cell culture supernatants were collected and used for isolation of exosomes. The isolated exosomes were confirmed by western blot and scanning electron microscopy. The miRNAs were then extracted from exosomes, and cDNA synthesized. The expression levels of miR-17 and miR-29a were evaluated by quantitative real-time PCR analysis.

Results

Our results showed that the expression levels of miR-29a in placenta-derived exosomes obtained from the experimental group increased significantly compared to the control group. Also, the expression levels of miR-17 in the placenta-derived exosomes obtained from the experimental group were found to decrease; however, it did not show significant changes compared with the control group (p > 0.05).

Conclusion

Inflammatory reactions at the fetal–maternal interface can alter miRNAs expression patterns in placenta-derived exosomes, especially miRNAs with immunomodulatory effects such as miR-29a.

When a Neonate Is Born, So Is a Microbiota

In recent years, the role of human microbiota as a short- and long-term health promoter and modulator has been affirmed and progressively strengthened. In the course of one’s life, each subject is colonized by a great number of bacteria, which constitute its specific and individual microbiota. Human bacterial colonization starts during fetal life, in opposition to the previous paradigm of the “sterile womb”. Placenta, amniotic fluid, cord blood and fetal tissues each have their own specific microbiota, influenced by maternal health and habits and having a decisive influence on pregnancy outcome and offspring outcome. The maternal microbiota, especially that colonizing the genital system, starts to influence the outcome of pregnancy already before conception, modulating fertility and the success rate of fertilization, even in the case of assisted reproduction techniques. During the perinatal period, neonatal microbiota seems influenced by delivery mode, drug administration and many other conditions. Special attention must be reserved for early neonatal nutrition, because breastfeeding allows the transmission of a specific and unique lactobiome able to modulate and positively affect the neonatal gut microbiota. Our narrative review aims to investigate the currently identified pre- and peri-natal factors influencing neonatal microbiota, before conception, during pregnancy, pre- and post-delivery, since the early microbiota influences the whole life of each subject.

Live Bacteria Supplementation as Probiotic for Managing Fishy, Odorous Vaginal Discharge Disease of Bacterial Vaginosis: An Alternative Treatment Option?

Bacterial vaginosis (BV) is a universally prevalent cause of genital discomfort in females belonging to the reproductive age group, rendering the vagina more susceptible to various other complications. The standard treatment of BV involves using metronidazole and clindamycin, which help eliminate the infection but play no role in re-flourishing the normal vaginal homeostasis, which is lactobacilli preponderant, thereby rendering the vagina more prone to re-infection. Hence, clinical research has been performed to increase vaginal lactobacillus count through oral or vaginal supplementation. This current study's main objective is to review the previously conducted research regarding the efficiency of probiotic supplementation in the prevention and treatment of BV.

Gardnerella and vaginal health: the truth is out there

The human vagina is a dynamic ecosystem in which homeostasis depends on mutually beneficial interactions between the host and their microorganisms. However, the vaginal ecosystem can be thrown off balance by a wide variety of factors. Bacterial vaginosis (BV) is the most common vaginal infection in women of childbearing age but its etiology is not yet fully understood, with different controversial theories being raised over the years. What is generally accepted is that BV is often characterized by a shift in the composition of the normal vaginal microbiota, from a Lactobacillus species dominated microbiota to a mixture of anaerobic and facultative anaerobic bacteria. During BV, a polymicrobial biofilm develops in the vaginal microenvironment, being mainly composed of Gardnerella species. The interactions between vaginal microorganisms are thought to play a pivotal role in the shift from health to disease and might also increase the risk of sexually transmitted infections acquisition. Here, we review the current knowledge regarding the specific interactions that occur in the vaginal niche and discuss mechanisms by which these interactions might be mediated. Furthermore, we discuss the importance of novel strategies to fight chronic vaginal infections.

The protective effect of berberine against lipopolysaccharide-induced abortion by modulation of inflammatory/immune responses

OBJECTIVE

Berberine is an isoquinoline derivative alkaloid with anti-inflammatory activity. In this study, we investigated the protective effects of berberine in prevention of LPS-induced abortion.

MATERIALS AND METHODS

On the gestation day (GD) 9.5, the pregnant mice were injected with low, medium, and high doses of berberine or with PBS. After 4 h, berberine or PBS-pretreated mice were injected with LPS. On GD 11.5, blood samples and uterine tissues were collected from treated mice and percentage of abortion and serum levels of NO, TNF-α, IL-10, and IL12p70 were measured by macroscopic examination and sandwich ELISA, respectively.

RESULTS

Our findings show that mice injected with berberine were resistant to LPS-induced abortion. We also found that this treatment prevents the reduction of IL-10 and the enhancement of NO, TNF-α, and IL-12p70 in LPS-treated pregnant mice.

CONCLUSIONS

Taken together, our results suggest that berberine as an anti-inflammatory agent has protective effects on LPS-induced abortion by modulation of inflammatory/immune responses.

Draft Genome Sequence of Gardnerella vaginalis Strain ATCC 49145 Associated with Bacterial Vaginosis

Gardnerella vaginalis is a Gram-variable bacterium associated with bacterial vaginosis, a common vaginal inflammation in women of reproductive age. This study reports the whole-genome sequencing for the clinical isolate strain ATCC 49145. The draft genome is composed of 21 contigs containing 1,325 protein-coding sequences, 45 tRNAs and a single tmRNA (SsrA).

Putative functions of tissue kallikrein-related peptidases in vaginal fluid

Cervical-vaginal fluid (CVF) is a complex biological fluid that hydrates the mucosa of the lower female reproductive system. In-depth proteomic and biochemical studies on CVF have revealed that it contains large amounts of endogenous proteases and protease inhibitors, including an abundance of several members of the tissue kallikrein-related peptidase (KLK) family. Despite their ubiquitous presence in human tissues and fluids, KLK expression levels vary considerably, with maximum expression observed in reproduction-related tissues and fluids. The roles of KLKs in the lower female reproductive system are not fully understood. The activation of KLKs in CVF is dependent on pH and various modes of KLK regulation in the vagina exist. KLKs have been postulated to have roles in physiological functions related to antimicrobial processes, vaginal and cervical epithelial desquamation, sperm transport, and the processing of fetal membranes as observed in preterm premature rupture of membranes. Increased understanding of the functional roles of KLKs in the lower female reproductive system could lead to new diagnostic and therapeutic modalities for conditions such as vaginal infections and vaginal atrophy.

Bacterial communities in penile skin, male urethra, and vaginas of heterosexual couples with and without bacterial vaginosis

BACKGROUND

The epidemiology of bacterial vaginosis (BV) suggests it is sexually transmissible, yet no transmissible agent has been identified. It is probable that BV-associated bacterial communities are transferred from male to female partners during intercourse; however, the microbiota of sexual partners has not been well-studied.

RESULTS

Pyrosequencing analysis of PCR-amplified 16S rDNA was used to examine BV-associated bacteria in monogamous couples with and without BV using vaginal, male urethral, and penile skin specimens. The penile skin and urethral microbiota of male partners of women with BV was significantly more similar to the vaginal microbiota of their female partner compared to the vaginal microbiota of non-partner women with BV. This was not the case for male partners of women with normal vaginal microbiota. Specific BV-associated species were concordant in women with BV and their male partners.

CONCLUSIONS

In monogamous heterosexual couples in which the woman has BV, the significantly higher similarity between the vaginal microbiota and the penile skin and urethral microbiota of the male partner, supports the hypothesis that sexual exchange of BV-associated bacterial taxa is common.

Lactocin 160, a Bacteriocin Produced by Vaginal Lactobacillus rhamnosus, Targets Cytoplasmic Membranes of the Vaginal Pathogen, Gardnerella vaginalis

Bacterial vaginosis (BV) is a commonly occurring vaginal infection that is associated with a variety of serious risks related to the reproductive health of women. Conventional antibiotic treatment for this condition is frequently ineffective because the antibiotics tend to inhibit healthy vaginal microflora along with the pathogens. Lactocin 160, a bacteriocin produced by healthy vaginal lactobacilli, is a promising alternative to antibiotics; this compound specifically inhibits the BV-associated vaginal pathogens such as Gardnerella vaginalis and Prevotella bivia without affecting the healthy microflora. This study investigates the molecular mechanism of action for lactocin 160 and reveals that this compound targets the cytoplasmic membrane of G. vaginalis, causing the efflux of ATP molecules and dissipation of the proton motive force.

Gardnerella vaginalis Subgroups Defined by cpn60 Sequencing and Sialidase Activity in Isolates from Canada, Belgium and Kenya

Increased abundance of Gardnerella vaginalis and sialidase activity in vaginal fluid is associated with bacterial vaginosis (BV), a common but poorly understood clinical entity associated with poor reproductive health outcomes. Since most women are colonized with G. vaginalis, its status as a normal member of the vaginal microbiota or pathogen causing BV remains controversial, and numerous classification schemes have been described. Since 2005, sequencing of the chaperonin-60 universal target (cpn60 UT) has distinguished four subgroups in isolate collections, clone libraries and deep sequencing datasets. To clarify potential clinical and diagnostic significance of cpn60 subgroups, we undertook phenotypic and molecular characterization of 112 G. vaginalis isolates from three continents. A total of 36 subgroup A, 33 B, 35 C and 8 D isolates were identified through phylogenetic analysis of cpn60 sequences as corresponding to four "clades" identified in a recently published study, based on sequencing 473 genes across 17 isolates. cpn60 subgroups were compared with other previously described molecular methods for classification of Gardnerella subgroups, including amplified ribosomal DNA restriction analysis (ARDRA) and real-time PCR assays designed to quantify subgroups in vaginal samples. Although two ARDRA patterns were observed in isolates, each was observed in three cpn60 subgroups (A/B/D and B/C/D). Real-time PCR assays corroborated cpn60 subgroups overall, but 13 isolates from subgroups A, B and D were negative in all assays. A putative sialidase gene was detected in all subgroup B, C and D isolates, but only in a single subgroup A isolate. In contrast, sialidase activity was observed in all subgroup B isolates, 3 (9%) subgroup C isolates and no subgroup A or D isolates. These observations suggest distinct roles for G. vaginalis subgroups in BV pathogenesis. We conclude that cpn60 UT sequencing is a robust approach for defining G. vaginalis subgroups within the vaginal microbiome.

Metagenomics: A New Way to Illustrate the Crosstalk between Infectious Diseases and Host Microbiome

Microbes have co-evolved with human beings for millions of years. They play a very important role in maintaining the health of the host. With the advancement in next generation sequencing technology, the microbiome profiling in the host can be obtained under different circumstances. This review focuses on the current knowledge of the alteration of complex microbial communities upon the infection of different pathogens, such as human immunodeficiency virus, hepatitis B virus, influenza virus, and Mycobacterium tuberculosis, at different body sites. It is believed that the increased understanding of the correlation between infectious disease and the alteration of the microbiome can contribute to better management of disease progression in the future. However, future studies may need to be more integrative so as to establish the exact causality of diseases by analyzing the correlation between microorganisms within the human host and the pathogenesis of infectious diseases.

Prevalence of the genital tract bacterial infections after vaginal reconstructive surgery

Due to frequent childbirth, heavy lifting and the structure of the lives of rural women in Shahrekord region, Iran, cystocele and rectocele are of the main medical problems of the women in this area and for its correction, vaginal reconstructive surgery is needed which causes infection. The purpose of this study was to identify the bacteria causing infection after vaginal reconstructive surgery and performing antibiogram to help these patients for faster recovery. Patients enrolled this study were 92 who had undergone previous vaginal reconstructive surgery and now had infection. After examination, the group of patients taking antibiotics (n = 26) were excluded and the remaining 66 completed the study questionnaire. A gynecologist performed sampling; related tests (aerobic and anaerobic culture using an anaerobic culture gas pack jar and type A which provides absolute anaerobic conditions) were performed; antimicrobial susceptibility testing using Disk Diffusion Method was carried out; and the results were recorded. All the positive samples were polymicrobial. Gardnerella vaginalis in 20 cases (31%), peptostreptococci and anaerobic cocci in 9 cases (13.6%), staphylococcus aureus in 8 cases (9.1%), bacteroides and fusobacterium in 7 cases (10.6%), streptococcus group B in 4 cases (6%), yeast cells in 11 cases (16.6%) and Trichomonas vaginalis in wet mount of 4 (6%) existed. Anaerobic bacteria showed 85% sensitivity to clindamycin, 82% to chloramphenicol, 85% sensitivity to ceftizoxime and 45% to penicillin. Facultative anaerobic bacteria showed a sensitivity rate of 90% to ceftizoxime, chloramphenicol and cephalothin. According to our findings, the rate of vaginal bacterial infection in women with vaginal reconstructive surgery has increased; from which, infections with anaerobic bacteria origins have increased dramatically. We recommend antibiotic prophylaxis prior to genital reconstructive surgeries.

Reproductive Tract Infections in Rural Vietnam, Women's Knowledge, and Health-Seeking Behavior: A Cross-Sectional Study

We interviewed 1,805 women in a rural setting in Vietnam with the aim of investigating women's knowledge regarding reproductive tract infections (RTIs) and their health-seeking behavior. We found that women's overall knowledge was poor. Furthermore, only one-third of the symptomatic women sought health care. RTIs affect millions of women globally each year. Most vulnerable are women in low- and middle-income countries where poverty and gender inequities affect their access to health care services. Findings from our study can be used in similar rural settings worldwide to understand and manage the widespread problem of RTIs.

Identification of vaginal lactobacilli with potential probiotic properties isolated from women in North Lebanon

The aim of this work was to study the diversity of vaginal lactobacilli in Lebanese women and to evaluate the antagonism, hydrophobicity, and safety characteristics of these strains. This study was performed on samples from 135 women who visited a gynecology clinic in the north of Lebanon, between September 2012 and January 2013. From these samples, 53 different isolates of vaginal lactobacilli were collected from vaginal swabs and identified using biochemical and molecular methods. The use of genotypic Rep-PCR fingerprinting allowed for the organization of these isolates into 23 different groups. Seven of the isolated lactobacilli were antagonistic against the following vaginal pathogens: Gardnerella vaginalis CIP7074T, Staphylococcus aureus ATCC33862, Escherichia coli CIP103982, and Candida albicans ATCC10231. The antagonistic lactobacilli strains were then identified using 16S rDNA sequence. The data of this study show that the antagonistic lactobacilli were non-hemolytic, sensitive to most antibiotic tests, free of plasmid DNA, and exhibited interesting hydrophobicity and autoaggregation properties positioning them as potential candidates for probiotic design.

The composition and stability of the vaginal microbiota of normal pregnant women is different from that of non-pregnant women

BACKGROUND

This study was undertaken to characterize the vaginal microbiota throughout normal human pregnancy using sequence-based techniques. We compared the vaginal microbial composition of non-pregnant patients with a group of pregnant women who delivered at term.

RESULTS

A retrospective case-control longitudinal study was designed and included non-pregnant women (n = 32) and pregnant women who delivered at term (38 to 42 weeks) without complications (n = 22). Serial samples of vaginal fluid were collected from both non-pregnant and pregnant patients. A 16S rRNA gene sequence-based survey was conducted using pyrosequencing to characterize the structure and stability of the vaginal microbiota. Linear mixed effects models and generalized estimating equations were used to identify the phylotypes whose relative abundance was different between the two study groups. The vaginal microbiota of normal pregnant women was different from that of non-pregnant women (higher abundance of Lactobacillus vaginalis, L. crispatus, L. gasseri and L. jensenii and lower abundance of 22 other phylotypes in pregnant women). Bacterial community state type (CST) IV-B or CST IV-A characterized by high relative abundance of species of genus Atopobium as well as the presence of Prevotella, Sneathia, Gardnerella, Ruminococcaceae, Parvimonas, Mobiluncus and other taxa previously shown to be associated with bacterial vaginosis were less frequent in normal pregnancy. The stability of the vaginal microbiota of pregnant women was higher than that of non-pregnant women; however, during normal pregnancy, bacterial communities shift almost exclusively from one CST dominated by Lactobacillus spp. to another CST dominated by Lactobacillus spp.

CONCLUSION

We report the first longitudinal study of the vaginal microbiota in normal pregnancy. Differences in the composition and stability of the microbial community between pregnant and non-pregnant women were observed. Lactobacillus spp. were the predominant members of the microbial community in normal pregnancy. These results can serve as the basis to study the relationship between the vaginal microbiome and adverse pregnancy outcomes.

Effects of probiotics for the treatment of bacterial vaginosis in adult women: a meta-analysis of randomized clinical trials

PURPOSE

The aim of this study was to evaluate the evidence for probiotic use in the treatment of bacterial vaginosis (BV) in adult women.

METHODS

The Cochrane Library, PubMed, CINAHL and EMBASE databases were searched to identify the relevant randomized controlled trials that investigated the effects of probiotics for the treatment of BV. Two independent authors used an Excel file to extract data and assessed trial quality. The primary outcome measure was the cure rate of BV. The meta-analysis was performed with the fixed-effects model or random-effects model according to heterogeneity.

RESULTS

A total of 1,304 patients from 12 trials were subjected to meta-analysis. The pooled result showed that probiotics supplementation can significantly improve the cure rate in adult BV patients [risk ratio (RR) 1.53; 95 % confidence interval (CI) 1.19-1.97]. Findings were slightly different when analyses were restricted to nine high-quality studies (RR 1.60; 95 % CI 1.16-2.22). In a subgroup meta-analysis, a statistically significant beneficial effect of probiotics was observed in Europe populations and short-term follow-up days.

CONCLUSION

Compared with the control arm, the limited evidence suggests that probiotics show a beneficial effect in patients who are suffering from BV. However, the results should be interpreted cautiously because of the heterogeneity among study designs. Further large-scale, well-designed RCTs on this topic are urgently needed.

Effects of feminine hygiene products on the vaginal mucosal biome

Background

Over-the-counter (OTC) feminine hygiene products come with little warning about possible side effects. This study evaluates in-vitro their effects on Lactobacillus crispatus, which is dominant in the normal vaginal microbiota and helps maintain a healthy mucosal barrier essential for normal reproductive function and prevention of sexually transmitted infections and gynecologic cancer.

Methods

A feminine moisturizer (Vagisil), personal lubricant, and douche were purchased OTC. A topical spermicide (nonoxynol-9) known to alter the vaginal immune barrier was used as a control. L. crispatus was incubated with each product for 2 and 24h and then seeded on agar for colony forming units (CFU). Human vaginal epithelial cells were exposed to products in the presence or absence of L. crispatus for 24h, followed by epithelium-associated CFU enumeration. Interleukin-8 was immunoassayed and ANOVA was used for statistical evaluation.

Results

Nonoxynol-9 and Vagisil suppressed Lactobacillus growth at 2h and killed all bacteria at 24h. The lubricant decreased bacterial growth insignificantly at 2h but killed all at 24h. The douche did not have a significant effect. At full strength, all products suppressed epithelial viability and all, except the douche, suppressed epithelial-associated CFU. When applied at non-toxic dose in the absence of bacteria, the douche and moisturizer induced an increase of IL-8, suggesting a potential to initiate inflammatory reaction. In the presence of L. crispatus, the proinflammatory effects of the douche and moisturizer were countered, and IL-8 production was inhibited in the presence of the other products.

Conclusion

Some OTC vaginal products may be harmful to L. crispatus and alter the vaginal immune environment. Illustrated through these results, L. crispatus is essential in the preservation of the function of vaginal epithelial cells in the presence of some feminine hygiene products. More research should be invested toward these products before they are placed on the market.

Selection, phenotyping and identification of acid and hydrogen peroxide producing bacteria from vaginal samples of Canadian and East African women

The common but poorly understood condition known as bacterial vaginosis (BV) increases vulnerability to HIV infection and is associated with the absence of H₂O₂-producing Lactobacillus. Vaginal lactic acid bacteria (LAB) produce anti-HIV factors such as organic acids and hydrogen peroxide (H₂O₂), and may bind and inactivate HIV particles during scavenging of mannose. These factors define potential criteria for initial selection of candidate probiotics to block heterosexual transmission of HIV. Therefore, the primary goal of this study was to characterize acid production on mannose and H₂O₂ production in vaginal isolates from Canadian adolescents (192 isolates, 16 individuals) and commercial sex workers in Nairobi, Kenya (576 isolates, 96 individuals). Selection of isolates from H₂O₂-detecting media suggested an idiosyncratic individual-level profile and extensive phenotypic diversity, including the identification of a subset of “double-strong” acid- and H₂O₂-producers with phenotypes similar to well-characterized probiotic strains. Molecular fingerprinting of all isolates by capillary electrophoresis of 16S-23S rRNA interspacer amplicons was coupled with chaperonin-60 universal target (cpn60 UT) sequencing in a subset, tentatively identifying 96% of isolates although only 19% were sequenced. Most isolates belonged to Lactobacillus, Streptococcus, Bifidobacterium or Gardnerella, with a total of 37 species in 15 genera, as well as 5 potentially novel organisms, identified in this study. This sensitivity was likely enhanced by phenotype-based selection on two chromogenic media formulations. Identification of double-strong isolates may provide a rational basis for selection and further characterization of vaginal probiotics, with potential application as part of HIV prevention initiatives in western Canada and East Africa.

The Microbiological Context of HIV Resistance: Vaginal Microbiota and Mucosal Inflammation at the Viral Point of Entry

Immune activation is increasingly recognized as a critical element of HIV infection and pathogenesis, causing expansion of virus founder populations at the mucosal port of entry and eventual exhaustion of cellular immune effectors. HIV susceptibility is well known to be influenced by concurrent sexually transmitted infections; however, the role of commensal vaginal microbiota is poorly characterized. Bacterial vaginosis (BV) is a risk factor for HIV acquisition in studies worldwide; however, the etiology of BV remains enigmatic, and the mechanisms by which BV increases HIV susceptibility are not fully defined. A model of how vaginal microbiota influences HIV transmission is considered in the context of a well-established cohort of HIV-exposed seronegative (HESN) commercial sex workers (CSW) in Nairobi, Kenya, many of whom have increased levels of anti-inflammatory factors in vaginal secretions and reduced peripheral immune activation (immune quiescence). Elucidation of the relationship between complex microbial communities and inflammatory mucosal responses underlying HIV infection should be a priority for future prevention-focussed research.

Bacterial vaginosis, HIV serostatus and T-cell subset distribution in a cohort of East African commercial sex workers: retrospective analysis

OBJECTIVE

Although bacterial vaginosis is a known correlate of HIV infection, no previous studies have investigated whether women defined as HIV-exposed seronegative (HESN) are less likely to have bacterial vaginosis. Little is known about the effects of bacterial vaginosis on systemic immune activation associated with HIV+ serostatus.

DESIGN

Cohort-based retrospective analysis of bacterial vaginosis in relation to HESN status, HIV+ serostatus and peripheral T-helper cells, with cross-sectional analysis of bacterial vaginosis in relation to peripheral T-regulatory cells (Tregs).

METHODS

Bacterial vaginosis diagnosis by Gram stain and determination of systemic CD4(+) and CD8(+) T-helper cell frequency by flow cytometry for 3504 vaginal samples from 988 commercial sex workers over 4 years. Treg phenotyping by FoxP3 staining and multiparameter flow cytometry in peripheral blood of 97 women at a single time-point.

RESULTS

No differences in bacterial vaginosis diagnosis were observed between HESN and other HIV-negative (HIV-N) controls; however, HIV+ women were more likely to be diagnosed with bacterial vaginosis compared to all HIV-negative women (HESN/HIV-N combined). HIV+ women with bacterial vaginosis had significantly higher CD4(+)/CD8(+) T-helper cell counts and a lower CD4/CD8 ratio, as well as fewer Tregs as a proportion of total T-helper cells, compared to bacterial vaginosis-negative women. The number of bacterial vaginosis diagnoses in this cohort has decreased significantly over time.

CONCLUSION

Bacterial vaginosis is associated with HIV serostatus and shifts in distribution of T-cell subsets. A concomitant reduction in bacterial vaginosis and HIV infections over time suggests that the elucidation of bacterial vaginosis-HIV interactions will be critical to further understanding of HIV pathogenesis and prevention in this high-risk group.

Exploring the diversity of Gardnerella vaginalis in the genitourinary tract microbiota of monogamous couples through subtle nucleotide variation

BACKGROUND

Bacterial vaginosis (BV) is an enigmatic disease of unknown origin that affects a large percentage of women. The vaginal microbiota of women with BV is associated with serious sequelae, including abnormal pregnancies. The etiology of BV is not fully understood, however, it has been suggested that it is transmissible, and that G. vaginalis may be an etiological agent. Studies using enzymatic assays to define G. vaginalis biotypes, as well as more recent genomic comparisons of G. vaginalis isolates from symptomatic and asymptomatic women, suggest that particular G. vaginalis strains may play a key role in the pathogenesis of BV.

METHODOLOGY/PRINCIPAL FINDINGS

To explore G. vaginalis diversity, distribution and sexual transmission, we developed a Shannon entropy-based method to analyze low-level sequence variation in 65,710 G. vaginalis 16S rRNA gene segments that were PCR-amplified from vaginal samples of 53 monogamous women and from urethral and penile skin samples of their male partners. We observed a high degree of low-level diversity among G. vaginalis sequences with a total of 46 unique sequence variants (oligotypes), and also found strong correlations of these oligotypes between sexual partners. Even though Gram stain-defined normal and some Gram stain-defined intermediate oligotype profiles clustered together in UniFrac analysis, no single G. vaginalis oligotype was found to be specific to BV or normal vaginal samples.

CONCLUSIONS

This study describes a novel method for investigating G. vaginalis diversity at a low level of taxonomic discrimination. The findings support cultivation-based studies that indicate sexual partners harbor the same strains of G. vaginalis. This study also highlights the fact that a few, reproducible nucleotide variations within the 16S rRNA gene can reveal clinical or epidemiological associations that would be missed by genus-level or species-level categorization of 16S rRNA data.

Self-collected vaginal swabs for the quantitative real-time polymerase chain reaction assay of Atopobium vaginae and Gardnerella vaginalis and the diagnosis of bacterial vaginosis

The aim of this study was to assess the feasibility of using self-collected vaginal specimens for the quantitative real-time polymerase chain reaction (qPCR) assays of bacterial vaginosis (BV)-associated bacteria versus practitioner-collected swabs. A cross-sectional study included 190 pregnant women enrolled before 20 weeks' gestation from September 2008 to November 2009. Self- and practitioner-collected swabs were taken during the same prenatal visit for each woman, qPCR assays performed for each, and the results compared. The quantification of the human albumin gene was used as an internal control to ensure sampling quality and accurate comparisons. The level of agreement of the qPCR assays for each microorganism was calculated with the Spearman product moment correlation coefficient and the kappa statistic. In all, 370 vaginal samples (185 self- and 185 practitioner-collected swabs) had a narrow range of values for the number of albumin gene copies and a significant correlation coefficient (Spearman's rho = 0.532; p < 0.001). The agreement between both sampling methods was excellent (Spearman's rho was 0.748 for Atopobium vaginae, 0.918 for Lactobacillus species, 0.940 for Gardnerella vaginalis; p < 0.001), especially for high concentrations of A. vaginae (≥10(8) copies/mL; kappa value = 0.973; p < 0.001) and G. vaginalis (≥10(9) copies/mL; kappa value = 0.903; p < 0.001). This study demonstrates the validity and reliability of self- versus practitioner-collected swabs for the molecular quantification of Lactobacillus species, G. vaginalis, and A. vaginae.

Molecular definition of vaginal microbiota in East African commercial sex workers

Resistance to HIV infection in a cohort of commercial sex workers living in Nairobi, Kenya, is linked to mucosal and antiinflammatory factors that may be influenced by the vaginal microbiota. Since bacterial vaginosis (BV), a polymicrobial dysbiosis characterized by low levels of protective Lactobacillus organisms, is an established risk factor for HIV infection, we investigated whether vaginal microbiology was associated with HIV-exposed seronegative (HESN) or HIV-seropositive (HIV(+)) status in this cohort. A subset of 44 individuals was selected for deep-sequencing analysis based on the chaperonin 60 (cpn60) universal target (UT), including HESN individuals (n = 16), other HIV-seronegative controls (HIV-N, n = 16), and HIV(+) individuals (n = 12). Our findings indicate exceptionally high phylogenetic resolution of the cpn60 UT using reads as short as 200 bp, with 54 species in 29 genera detected in this group. Contrary to our initial hypothesis, few differences between HESN and HIV-N women were observed. Several HIV(+) women had distinct profiles dominated by Escherichia coli. The deep-sequencing phylogenetic profile of the vaginal microbiota corresponds closely to BV(+) and BV(-) diagnoses by microscopy, elucidating BV at the molecular level. A cluster of samples with intermediate abundance of Lactobacillus and dominant Gardnerella was identified, defining a distinct BV phenotype that may represent a transitional stage between BV(+) and BV(-). Several alpha- and betaproteobacteria, including the recently described species Variovorax paradoxus, were found to correlate positively with increased Lactobacillus levels that define the BV(-) ("normal") phenotype. We conclude that cpn60 UT is ideally suited to next-generation sequencing technologies for further investigation of microbial community dynamics and mucosal immunity underlying HIV resistance in this cohort.

The aetiology of bacterial vaginosis

Bacterial vaginosis (BV) is the most common vaginal infection among women of childbearing age. This condition is notorious for causing severe complications related to the reproductive health of women. Five decades of intense research established many risk factors for acquisition of BV; however, because of the complexity of BV and lack of a reliable animal model for this condition, its exact aetiology remains elusive. In this manuscript, we use a historical perspective to critically review the development of major theories on the aetiology of BV, ultimately implicating BV-related pathogens, healthy vaginal microbiota, bacteriophages and the immune response of the host. None of these theories on their own can reliably explain the epidemiological data. Instead, BV is caused by a complex interaction of multiple factors, which include the numerous components of the vaginal microbial ecosystem and their human host. Many of these factors are yet to be characterized because a clear understanding of their relative contribution to the aetiology of BV is pivotal to the formulation of an effective treatment for and prophylaxis of this condition.

Recent advances in understanding the microbiology of the female reproductive tract and the causes of premature birth

Data derived from molecular microbiological investigations of the human vagina have led to the discovery of resident bacterial communities that exhibit marked differences in terms of species composition. All undergo dynamic changes that are likely due to intrinsic host and behavioral factors. Similar types of bacteria have been found in both amniotic fluid and the vagina, suggesting a potential route of colonization. Given that not all of the species involved in intrauterine infections are readily cultivated, it is important that culture-independent methods of analysis must be used to understand the etiology of these infections. Further research is needed to establish whether an ascending pathway from the vagina to the amniotic cavity enables the development of intrauterine infections.

Use of cervicovaginal fluid for the identification of biomarkers for pathologies of the female genital tract

Cervicovaginal fluid has an important function in the homeostasis and immunity of the lower female genital tract. Analysis of the cervicovaginal fluid proteome may therefore yield important information about the pathogenesis of numerous gynecological pathologies. Additionally, cervicovaginal fluid has great potential as a source of biomarkers for these conditions.

This review provides a detailed discussion about the human cervicovaginal proteome and the proteomics studies performed to characterize this biological fluid. Furthermore, infection-correlated pathological conditions of the female genital tract are discussed for which cervicovaginal fluid has been used in order to identify potential biomarkers. Recent years, numerous studies have analyzed cervicovaginal fluid samples utilizing antibody-based technologies, such as ELISA or Western blotting, to identify biomarkers for preterm birth, premature preterm rupture of membranes, bacterial vaginosis and cervical cancer. The present article will discuss the importance of proteomic technologies as alternative techniques to gain additional meaningful information about these conditions. In addition, the review focuses on recent proteomic studies on cervicovaginal fluid samples for the identification of potential biomarkers. We conclude that the use of proteomic technology for analysis of human cervicovaginal fluid samples is promising and may lead to the discovery of new biomarkers which can improve disease prevention and therapy development.

Diagnostic accuracy of quantitative real-time PCR assay versus clinical and Gram stain identification of bacterial vaginosis

The purpose of this investigation was to determine the diagnostic accuracy of quantitative real-time polymerase chain reaction (PCR) assay in diagnosing bacterial vaginosis versus the standard methods, the Amsel criteria and the Nugent score. The Amsel criteria, the Nugent score, and results from the molecular tool were obtained independently from vaginal samples of 163 pregnant women who reported abnormal vaginal symptoms before 20 weeks gestation. To determine the performance of the molecular tool, we calculated the kappa value, sensitivity, specificity, and positive and negative predictive values. Either or both of the Amsel criteria (≥3 criteria) and the Nugent score (score ≥7) indicated that 25 women (15%) had bacterial vaginosis, and the remaining 138 women did not. DNA levels of Gardnerella vaginalis or Atopobium vaginae exceeded 10(9) copies/mL or 10(8) copies/mL, respectively, in 34 (21%) of the 163 samples. Complete agreement between both reference methods and high concentrations of G. vaginalis and A. vaginae was found in 94.5% of women (154/163 samples, kappa value = 0.81, 95% confidence interval 0.70-0.81). The nine samples with discordant results were categorized as intermediate flora by the Nugent score. The molecular tool predicted bacterial vaginosis with a sensitivity of 100%, a specificity of 93%, a positive predictive value of 73%, and a negative predictive value of 100%. The quantitative real-time PCR assay shows excellent agreement with the results of both reference methods for the diagnosis of bacterial vaginosis.

Efficacy of vaginal probiotic capsules for recurrent bacterial vaginosis: a double-blind, randomized, placebo-controlled study

OBJECTIVE

We assessed the effectiveness of vaginal probiotic capsules for recurrent bacterial vaginosis (BV) prevention.

STUDY DESIGN

One hundred twenty healthy Chinese women with a history of recurrent BV were assigned randomly to daily vaginal prophylaxis with 1 capsule (Probaclac Vaginal; Nicar Laboratories, Inc, Blainville, Quebec, Canada) that contained 8 billion colony-forming units of Lactobacillus rhamnosus, L acidophilus, and Streptococcus thermophilus (n = 58 women) or 1 placebo capsule (n = 62 women) for 7 days on, 7 days off, and 7 days on.

RESULTS

Probiotic prophylaxis resulted in lower recurrence rates for BV (15.8% [9/57 women] vs 45.0% [27/60 women]; P < .001) and Gardnerella vaginalis incidence through 2 months (3.5% [2/57 women] vs 18.3% [11/60 women]; P = .02). Between the 2- and 11-month follow-up period, women who received probiotics reported a lower incidence of BV and G vaginalis. Aside from vaginal discharge and malodor, no adverse events were reported in either study group.

CONCLUSION

Short-term probiotic prophylaxis is well tolerated and reduces BV recurrence and G vaginalis risk through 11 months after treatment.

Lactic acid bacteria colonization and clinical outcome after probiotic supplementation in conventionally treated bacterial vaginosis and vulvovaginal candidiasis

This randomized double-blind placebo controlled study assessed the vaginal colonization of lactic acid bacteria and clinical outcome. Vaginal capsules containing L gasseri LN40, Lactobacillus fermentum LN99, L. casei subsp. rhamnosus LN113 and P. acidilactici LN23, or placebos were administered for five days to 95 women after conventional treatment of bacterial vaginosis and/or vulvovaginal candidiasis. Vulvovaginal examinations and vaginal samplings were performed before and after administration, after the first and second menstruation, and after six months. Presence of LN strains was assessed using RAPD analysis. LN strains were present 2-3 days after administration in 89% of the women receiving LN strains (placebo: 0%, p < 0.0001). After one menstruation 53% were colonized by at least one LN strain. Nine percent were still colonized six months after administration. Ninety-three percent of the women receiving LN strains were cured 2-3 days after administration (placebo: 83%), and 78% after one menstruation (placebo: 71%) (ns). The intervention group experienced less malodorous discharge 2-3 days after administration (p = 0.03) and after the second menstruation (p = 0.04), compared with placebo. In summary, five days of vaginal administration of LN strains after conventional treatment of bacterial vaginosis and/or vulvovaginal candidiasis lead to vaginal colonization, somewhat fewer recurrences and less malodorous discharge.

Quantitative PCR assessments of bacterial species in women with and without bacterial vaginosis

Knowledge of the abundance of bacterial species in vaginal communities will help us to better understand their role in health and disease. However, progress in this field has been limited because quantifying bacteria in natural specimens is an arduous process. We developed quantitative real-time PCR (qPCR) assays to facilitate assessments of bacterial abundance in vaginal specimens and evaluated the utility of these assays by measuring species abundance in patients whose vaginal floras were clinically described as normal, intermediate, or bacterial vaginosis (BV) as defined by Nugent's criteria. The qPCR measurements showed that Lactobacillus species were predominant in normal vaginal specimens and that high Lactobacillus crispatus and Lactobacillus jensenii abundance was specific to normal specimens, while Lactobacillus iners abundance was high in all categories including BV. The abundances of all non-Lactobacillus species were higher in BV specimens than in normal specimens. Prevotella species were prevalent in all specimens and represented a high percentage of total species in BV specimens. qPCR assays can be a useful tool for describing the structure of vaginal communities and elucidating their role in health and disease.

Analysis of adherence, biofilm formation and cytotoxicity suggests a greater virulence potential of Gardnerella vaginalis relative to other bacterial-vaginosis-associated anaerobes

Worldwide, bacterial vaginosis (BV) is the most common vaginal disorder in women of childbearing age. BV is characterized by a dramatic shift in the vaginal microflora, involving a relative decrease in lactobacilli, and a proliferation of anaerobes. In most cases of BV, the predominant bacterial species found is Gardnerella vaginalis. However, pure cultures of G. vaginalis do not always result in BV, and asymptomatic women are sometimes colonized with low numbers of G. vaginalis. Thus, there is controversy about whether G. vaginalis is an opportunistic pathogen and the causative agent of many cases of BV, or whether BV is a polymicrobial condition caused by the collective effects of an altered microbial flora. Recent studies of the biofilm-forming potential and cytotoxic activity of G. vaginalis have renewed interest in the virulence potential of this organism. In an effort to tease apart the aetiology of this disorder, we utilized in vitro assays to compare three virulence properties of G. vaginalis relative to other BV-associated anaerobes. We designed a viable assay to analyse bacterial adherence to vaginal epithelial cells, we compared biofilm-producing capacities, and we assessed cytotoxic activity. Of the BV-associated anaerobes tested, only G. vaginalis demonstrated all three virulence properties combined. This study suggests that G. vaginalis is more virulent than other BV-associated anaerobes, and that many of the bacterial species frequently isolated from BV may be relatively avirulent opportunists that colonize the vagina after G. vaginalis has initiated an infection.

Probiotics for the treatment of bacterial vaginosis

BACKGROUND

The dominance of lactobacilli in healthy vaginal microbiota and its depletion in bacterial vaginosis (BV) has given rise to the concept of oral or vaginal instillation of probiotic Lactobacillus strains for the management of this condition.

OBJECTIVES

To ascertain the efficacy of probiotics in the treatment of BV.

SEARCH STRATEGY

We searched electronic databases irrespective of publication status or language. These included: Cochrane Central Register of Controlled Trials (CENTRAL), the HIV/AIDS and STD Cochrane Review Groups' specialized registers, the Cochrane Complementary Medicine Field's Register of Controlled Trials, MEDLINE (1966 to 2008), EMBASE (1980 to 2007), ISI science citation index (1955 to 2007), CINAHL (Cumulative Index to Nursing & Allied Health Literature (1982 to 2007).We handsearched of specialty journals, conference proceedings and publications list on the website of the International Scientific Association of Probiotics and Prebiotics (http://www.isapp.net/default.asp).For unpublished studies or ongoing trials, we contacted authors from relevant publications, nutraceutical companies and probiotic-related scientific associations. We searched electronic databases on ongoing clinical trials.

SELECTION CRITERIA

Randomized controlled trials using probiotics for the treatment of women of any age diagnosed with bacterial vaginosis, regardless of diagnostic method used. The probiotic preparation could be single or "cocktail" of strains, any preparation type/dosage/route of administration. Studies comparing probiotics with placebo, probiotics used in conjunction with conventional antibiotics compared with placebo or probiotics alone compared with conventional antibiotics were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We screened titles and abstracts , obtained full reports of relevant trialsand independently appraised them for eligibility. A data extraction form was used to extract data from the four included studies. For dichotomous outcomes, odds ratios (OR) and 95% confidence intervals (CI) were derived for each study using RevMan (versions 4.2 and 5). We did not perform meta-analysis due to significant differences in the probiotic preparations and trial methodologies.

MAIN RESULTS

Analysis suggests beneficial outcome of microbiological cure with the oral metronidazole/probiotic regimen (OR 0.09 (95% CI 0.03 to 0.26)) and the probiotic/estriol preparation (OR 0.02, (95% CI 0.00 to 0.47)). For the probiotic/estriol preparation, the OR and 95% CI for physician-reported resolution of symptoms was OR 0.04 (95% CI 0.00 to 0.56).

AUTHORS' CONCLUSIONS

The results do not provide sufficient evidence for or against recommending probiotics for the treatment of BV. The metronidazole/probiotic regimen and probiotic/estriol perparation appear promising but well-designed randomized controlled trials with standardized methodologies and larger patient size are needed.

The clinical content of preconception care: infectious diseases in preconception care

A number of infectious diseases should be considered for inclusion as part of clinical preconception care. Those infections strongly recommended for health promotion messages and risk assessment or for the initiation of interventions include Chlamydia infection, syphilis, and HIV. For selected populations, the inclusion of interventions for tuberculosis, gonorrheal infection, and herpes simplex virus are recommended. No clear evidence exists for the specific inclusion in preconception care of hepatitis C, toxoplasmosis, cytomegalovirus, listeriosis, malaria, periodontal disease, and bacterial vaginosis (in those with a previous preterm birth). Some infections that have important consequences during pregnancy, such as bacterial vaginosis (in those with no history of preterm birth), asymptomatic bacteriuria, parvovirus, and group B streptococcus infection, most likely would not be improved through intervention in the preconception time frame.

Effect of semen on vaginal fluid cytokines and secretory leukocyte protease inhibitor

The presence of semen in vaginal fluid, as identified by an acid phosphatase spot test, does not influence vaginal proinflammatory cytokine concentrations.

OBJECTIVE

Determine whether semen, as detected by acid phosphatase, influences vaginal cytokines or secretory leukocyte protease inhibitor concentrations.

METHODS

138 pregnant women had vaginal fluid collected for Gram stain, acid phosphatase detection by colorimetric assay, and interleukin 1-Beta, interleukin-6, interleukin-8, and secretory leukocyte protease inhibitor measurement by enzyme immunoassay. Results for women with and without acid phosphatase were compared by Mann-Whitney test.

RESULTS

Of 138 subjects, 28 (20%) had acid phosphatase detected; of these, only 19 (68%) reported recent intercourse and 3 (11%) had sperm seen on Gram stain. There were no significant differences in proinflammatory cytokine concentrations; however, secretory leukocyte protease inhibitor concentrations were significantly higher among women with acid phosphatase.

CONCLUSIONS

Proinflammatory cytokine measurement does not appear to be affected by the presence of semen, but secretory leukocyte protease inhibitor is significantly higher when semen is present. Detection of semen by acid phosphatase was associated with higher vaginal SLPI concentrations, however, the presence of semen did not appear to influence vaginal proinflammatory cytokine concentrations.

The case for extrathymic development of vaginal T lymphocytes

The vaginal tract mucosa is populated by a small, yet phenotypically diverse and functionally significant, subset of T cells that plays a major role in local cell-mediated immunity. Although phenotypic and functional characteristics of vaginal T cells have received some attention in recent years, little is known about the development of this cell population. In this mini review, the developmental origins of vaginal T cells are traced from published work related to vaginal T cells, the vaginal mucosa environment and vaginal tract infection animal models. A CD3(+)TCR(+)CD2(+)CD5(+)B220(-) (CD3(+)B220(-)) subpopulation, which is mostly CD4(+), makes up 30-40% of vaginal T lymphocytes. This population consists of a TCRalphabeta(+) subset and TCRgammadelta(+) subset. While CD3(+)B220(-)TCRalphabeta(+) vaginal T cells exhibit phenotypic and functional properties consistent with that of peripheral T cells, CD3(+)B220(-)TCRgammadelta(+) vaginal T cells exhibit unique phenotypic and functional features that set them apart from other TCRgammadelta(+) T cell subsets populating the periphery or other mucosal areas. The vaginal mucosa is populated also by CD3(+)TCRalphabeta(+)CD4(-)/8(-)B220(+)CD2(-)CD5(-) T cells (CD3(+)B220(+)) whose relative predominance increases significantly in systemic T cell deficiency. This subset is generally unresponsive to TCR-mediated stimuli and expresses high levels of CD25, perhaps indicative of a regulatory role. Current data suggest that, while CD3(+)B220(-) vaginal T cells are mostly thymic in origin, CD3(+)TCRalphabeta(+)B220(+) cells are exclusively extrathymic.

Flow cytometric quantification of bacteria in vaginal swab samples self-collected by adolescents attending a gynecology clinic

Bacterial vaginosis (BV) is an important risk factor in reproductive health outcomes, such as pre-term birth and sexually transmitted infections including HIV. However, its etiology, diagnosis and treatment remain poorly defined. We evaluated flow cytometry as a tool to quantify total bacterial cells in vaginal specimens self-collected longitudinally by adolescents. BV was diagnosed by Gram-stain (criteria of Hay and Ison). Average flow cytometric counts of bacterial cell-units (BCU) was log(10) 8.04 per gram sample and was found to correlate with sample weight (p<0.0001). BV was frequently observed in this group, with 22 of 32 participants (69%) diagnosed with BV for at least one timepoint. Surprisingly, increased BCU was associated with normal Hay-Ison score (p=0.0003), even when adjusting for sample weight (p=0.02). Since presence and quantity of Lactobacillus defines normal vaginal microbiology (ie. absence of BV), this result indicates a possible bias towards dominance of Lactobacillus cells in measurements of "total" BCU. Increased BCU per gram was associated in multivariate analysis with longer self-reported time since last menstruation (p=0.004) and last sexual intercourse (p=0.007). Sperm was detected in 3 samples provided by those reporting sexual intercourse in the previous 24 h. Light-scattering profiles of bacteria and vaginal cells in samples collected over time from an individual were often identical and distinct from other individuals. To our knowledge, this is the first description of flow cytometry for analysis of commensal bacteria in vaginal specimens. Further development may help to illuminate the complex dynamics of vaginal microbial communities underlying BV.

Condom use and its association with bacterial vaginosis and bacterial vaginosis-associated vaginal microflora

BACKGROUND

Previous studies have been inconsistent with regard to whether condom use is associated with bacterial vaginosis. We evaluated this association using case-crossover analyses.

METHODS

A total of 871 women at high risk for sexually transmitted diseases were followed for a median of 3 years. At baseline and at 6, 12, 24, and 36 months thereafter, vaginal swabs were obtained for gram stain diagnosis of bacterial vaginosis, culture of microflora, and DNA amplification of Neisseria gonorrhoeae and Chlamydia trachomatis. Case-crossover analyses using incident and recurrent incident case periods were used to assess the associations among condom use, bacterial vaginosis, and vaginal microflora.

RESULTS

Consistent condom use (10 out of 10 sexual encounters) was associated with a decreased frequency of bacterial vaginosis (adjusted odds ratio = 0.55 [95% confidence interval 0.35-0.88]). When we excluded women with intermediate flora, consistent condom use was even more strongly protective against bacterial vaginosis (0.37 [0.20-0.70]). Consistent condom use was similarly protective against carriage of anaerobic gram-negative pigmented rods (0.58 [0.36-0.94]). Results were similar when analyses were repeated to capture only first occurrences of outcomes among women without bacterial vaginosis at baseline, suggesting a protective effect against the acquisition of bacterial vaginosis.

CONCLUSIONS

Consistent condom use was associated with a decrease in the risk for bacterial vaginosis and associated vaginal microflora.

Human lactobacilli as supplementation of clindamycin to patients with bacterial vaginosis reduce the recurrence rate; a 6-month, double-blind, randomized, placebo-controlled study

Background

The primary objective of this study was to investigate if supplementary lactobacilli treatment could improve the initial cure rate after vaginal clindamycin therapy, and secondly, if lactobacilli as repeated adjunct treatment during 3 menstrual cycles could lengthen the time to relapse after initial cure.

Methods

Women (n = 100) with bacterial vaginosis diagnosed by Amsel criteria were after informed consent offered vaginal clindamycin therapy followed by vaginal gelatine capsules containing either 10⁹ freeze-dried lactobacilli or identical placebo capsules for 10 days during 3 menstrual cycles in a double-blind, randomized, placebo-controlled trial.

Results

The initial intent to treat (ITT) analysis for the one-month cure rate was 64% in the lactobacilli group and 78% in the placebo group (p > 0.05). However, any patient with missing or unclassified smears at the initial visit who continued the study and whose next smear indicated a cure was included in the cured group; the study also excluded two of the patients in the lactobacilli group who reported that they did not take any vaginal capsules. With consideration to these population changes, the initial cure rate would be 77% in the lactobacilli group. The 76 cured women were followed for 6 menstrual cycles or until relapse within that time span. At the end of the study, 64.9% (24/37) of the lactobacilli treated women were still BV-free compared to 46.2% (18/39) of the placebo treated women. Comparison of the two groups regarding "Time from cure to relapse" was statistically significant (p = 0.027) in favour of the lactobacilli treatment. Adjuvant therapy with lactobacilli contributed significantly to avoidance of relapse with a proportional Hazard Risk ratio (HR) of 0.73 (0.54–0.98) (p < 0.05)

Conclusion

The study shows that supplementary treatment combining two different strains of probiotic lactobacilli does not improve the efficacy of BV therapy during the first month of treatment, but for women initially cured, adjunct treatment of lactobacilli during 3 menstrual cycles lengthens the time to relapse significantly in that more women remained BV free at the end of the 6-month follow up.

Trial registration number

ISRCTN62879834

Predisposing factors for bacterial vaginosis, treatment efficacy and pregnancy outcome among term deliveries; results from a preterm delivery study

Background

Bacterial vaginosis (BV) during pregnancy is associated with an increased risk of preterm delivery but little is known about factors that could predict BV. We have analyzed if it is possible to identify a category of pregnant women that should be screened for BV, and if BV would alter the pregnancy outcome at term; we have also studied the treatment efficacy of clindamycin.

Methods

Prospective BV screening and treatment study of 9025 women in a geographically defined region in southeast Sweden. BV was defined as a modified Nugent score of 6 and above. Data was collected from the Swedish Medical Birth Register. Women allocated to treatment were supplied with vaginal clindamycin cream. The main outcome goals were to identify factors that could predict BV.

Results

Vaginal smears were consistent with BV criteria in 9.3%. Logistic regression indicates a significant correlation between smoking and BV (p < 0.001) and a greater prevalence of BV in the lower age groups (p < 0.001). We found no correlation between BV and history of preterm deliveries, previous miscarriages, extra-uterine pregnancies, infertility problems or reported history of urinary tract infections–factors that earlier have been associated with BV. Treatment with clindamycin cream showed a cure rate of 77%. Less than 1% of women with a normal vaginal smear in early pregnancy will develop BV during the pregnancy. There was no association between BV and the obstetric outcome among women who delivered at term. Women with BV, both treated patients and nontreated, had the same obstetric outcome at term as women with normal vaginal flora.

Conclusion

BV is more than twice as common among smokers, and there is a higher prevalence in the younger age group. However these two markers for BV do not suffice as a tool for screening, and considering the lack of other risk factors associated with BV, screening of all pregnant women might be a strategy to follow in a program intended to reduce the number of preterm births.

Probiotics for the treatment of women with bacterial vaginosis

This review considers whether probiotics are effective agents for the treatment and/or prevention of bacterial vaginosis (BV). There seems to be an association between the absence of, or low concentrations of, vaginal lactobacilli and the development of BV. Many studies have suggested that the presence of H2O2-producing vaginal lactobacilli may protect against BV, although some studies do not support this hypothesis. In-vitro studies have suggested that certain specific strains of lactobacilli are able to inhibit the adherence of Gardnerella vaginalis to the vaginal epithelium and/or produce H2O2, lactic acid and/or bacteriocins, which inhibit the growth of bacteria causing BV. Clinical trials showed that intra-vaginal administration of Lactobacillus acidophilus for 6-12 days, or oral administration of L. acidophilus or Lactobacillus rhamnosus GR-1 and Lactobacillus fermentum RC-14 for 2 months, resulted in the cure of BV (defined as a 0-1 positive score according to Amsel's criteria), and/or reduced the recurrences of BV, and/or caused an increase in vaginal lactobacilli and restoration of a normal vaginal microbiota, significantly more frequently than did a placebo, acetic acid or no treatment. However, several trials have found no significant difference in the cure rate of BV and in the number of vaginal lactobacilli after intra-vaginal instillation of lactobacilli when compared with the effect of a placebo or oestrogen. Thus, although the available results concerning the effectiveness of the administration of lactobacilli for the treatment of BV are mostly positive, it cannot yet be concluded definitively that probiotics are useful for this purpose.

Parallel analysis of antimicrobial activities in microbial community by SSCP based on CE

Conventional antimicrobial activity analyses such as the broth dilution method and disk diffusion test are considerably demanding processes for new antimicrobial agent discovery and sensitive diagnosis of infectious diseases. Here, we developed a new antimicrobial activity analysis system using CE-based SSCP (CE-SSCP) combined with 16S rRNA gene-specific PCR (PCR/CE-SSCP). Using this method, the population change in the microbial community in response to specific antimicrobial agents could be quantified with a high sensitivity and accuracy from a small sample amount. Using a mixture of microorganisms comprising Escherichia coli, Corynebacterium glutamicum, Acinetobacter calcoaceticus, and Staphylococcus aureus as a model system, the linear correlation between the genomic DNA concentrations and peak areas in 16S rRNA gene-specific PCR/CE-SSCP was determined; consequently, quantification of cell concentrations could be demonstrated using this method. Compared to the minimum inhibitory concentration (MIC) values from the conventional broth dilution method, this new system provided almost the same MIC values for popular antimicrobial agents such as kanamycin, spectinomycin, and streptomycin. The results demonstrated that the newly developed method can be a substitute for the conventional antimicrobial analysis method and highlighted its high potential in the areas of new antimicrobial agent discovery and clinical diagnosis.

Prevotella bivia can invade human cervix epithelial (HeLa) cells

Prevotella bivia has been associated with female upper genital tract infections and an increased risk of preterm delivery. In this study, the adherence and invasion capacity of P. bivia was investigated using a cervix epithelial cell line. P. bivia was furthermore analysed for its ability to evoke a proinflammatory cytokine response in epithelial cells. The invasion capacity, defined as the number of bacteria recovered from lysed HeLa cells infected with P. bivia, varied considerably among five strains, all of which were isolates from women with bacterial vaginosis. One P. bivia strain (P47) gave rise to an approximately 120-fold higher number of intracellular bacteria (7 x 10(3) bacteria per 1 x 10(5) cells) compared with the least invasive strain. Three strains expressed an intermediate or low invasiveness, showing an approximately 3- to 40-fold higher number of intracellular bacteria per 1 x 10(5) cells compared with the least invasive strain. The intracellular localization of P47 in phagosome-like vesicles was confirmed by transmission electron microscopy. All P. bivia strains adhered to HeLa cells to the same extent (range 14-22 bacteria per cell) as analysed by interference microscopy. No correlation was found between adhesion and invasion capacity of the strains. Furthermore, no fimbriae-like structures were observed on P47 detected by scanning electron microscopy or negative staining. Analysis of TNF-alpha, IL-1alpha, IL-6, IL-8, and IL-18 in P. bivia-stimulated HeLa cells showed low levels of only IL-6 and IL-8 for the most invasive P. bivia strain P47. Thus, the induction of IL-6 or IL-8 secretion appeared to be associated with invasion capacity. This work provides evidence that some P. bivia isolates can invade human cervix epithelial. Thus, a strong capacity for invasion and a weak proinflammatory cytokine-inducing capacity in P. bivia are suggested to be virulence factors in establishing a low-grade upper genital tract infection.

Intermittent intravaginal antibiotic treatment of bacterial vaginosis in HIV-uninfected and -infected women: a randomized clinical trial

Objective:

Assess efficacy of intermittent intravaginal metronidazole gel treatment in reducing frequency of bacterial vaginosis (BV).

Design:

Randomized, double-masked, placebo-controlled phase 3 trial.

Setting:

Postnatal and family planning clinics of the Queen Elizabeth Central Hospital and two health centers in Blantyre, Malawi.

Participants:

Nonpregnant HIV-uninfected and -infected women.

Intervention:

Intravaginal metronidazole treatment and placebo gels provided at baseline and every 3 mo for 1 y.

Outcome measures:

Primary: Cross-sectional and longitudinal comparisons of BV frequency at baseline, 1 mo after product dispensation (post-treatment evaluation [PTE]), and every quarterly visit. Secondary: Effect of treatment on BV clearance and recurrence.

Results:

Baseline: 842 HIV-uninfected and 844 HIV-infected women were enrolled. The frequency of BV at baseline in treatment and placebo arms, respectively, was 45.9% and 46.8% among HIV-uninfected women, and 60.5% and 56.9% among HIV-infected women. Primary outcomes: At the PTEs the prevalence of BV was consistently lower in treatment than placebo arms irrespective of HIV status. The differences were statistically significant mainly in HIV-uninfected women. Prevalence of BV was also reduced over time in both treatment and placebo arms. In a multivariable analysis that controlled for other covariates, the effect of intravaginal metronidazole treatment gel compared with placebo was not substantial: adjusted relative risk (RR) 0.90, 95% confidence interval (CI) 0.83–0.97 in HIV-uninfected women and adjusted RR 0.95, 95% CI 0.89–1.01 in HIV-infected women. Secondary outcomes: Intravaginal metronidazole treatment gel significantly increased BV clearance (adjusted hazard ratio [HR] 1.34, 95% CI 1.07–1.67 among HIV-uninfected women and adjusted HR 1.29, 95% CI 1.06–1.58 among HIV-infected women) but was not associated with decreased BV recurrence. Safety: No serious adverse events were related to use of intravaginal gels.

Conclusion:

Intermittent microbicide treatment with intravaginal gels is an innovative approach that can reduce the frequency of vaginal infections such as BV.

Background: Bacterial vaginosis (BV) results from a change in the normal balance of bacteria in the vaginal tract, and is very common. In pregnant women, it is associated with poorer outcomes in pregnancy, and is also linked with HIV transmission (although it is not certain that BV actually increases the chance of getting HIV—just because these two occur together it does not necessarily follow that one causes the other). BV can be treated with metronidazole tablets, although these can cause gut symptoms and should not be taken repeatedly. The researchers wanted to carry out a multiclinic–based trial to find out whether a metronidazole gel applied intermittently to the vagina (for five nights every three months) would reduce the frequency of BV among women in Malawi. HIV-infected and HIV-uninfected women, recruited from postnatal and family planning clinics, were randomized to receive either metronidazole gels, or equivalent placebo gels, every three months and were then followed up for 12 months. The primary outcome for the trial was the proportion of women with BV at each quarterly follow-up visit, and the researchers intended to compare this outcome between treatment arms at each visit and also to look at the overall changes over time among women receiving either metronidazole or placebo, looking separately at HIV-infected and HIV-uninfected women.

What this trial shows: In total 1,686 women took part in the trial (842 not infected with HIV, and 844 infected with HIV). The proportion of HIV-uninfected women with BV dropped by around 20% over the course of the trial, both in women using metronidazole and in those using placebo. However, when comparing the proportion of HIV-uninfected women with BV between the two arms of the trial, there did not seem to be a consistent effect: differences were statistically significant at some time points and not others. Among HIV-infected women, there was also a drop over the course of the trial in the proportion of women with BV, irrespective of whether they used metronidazole or placebo. Again, when comparing the rate of BV among HIV-infected women between study arms (metronidazole versus placebo), the researchers did not see a consistent trend; differences were statistically significant at some time points but not others. Overall, when comparing metronidazole and placebo in an analysis that controlled for other factors, the metronidazole gel seemed to show a small effect in reduction of BV among HIV-uninfected women, but no obvious effect among HIV-infected women.

Strengths and limitations: Strengths in the design of this trial include the sample size, which was appropriate to detect an important effect of the metronidazole gel (versus placebo) had one existed, and the randomization and blinding procedures, which were designed to minimize the chance that the trialists or women being enrolled could anticipate to which arm of the trial they might be assigned. A key limitation of this study, as the researchers acknowledge, is the absence of a “no treatment” study arm. The frequency of BV dropped over the course of the trial in women using the placebo gel, raising the possibility that the placebo actually has some effect on bacteria in the vagina. However, a trial with a “no treatment” arm would pose its own problems, since trialists and participants would then not be fully blinded as to their treatment status.

Contribution to the evidence: This trial adds data on the efficacy of metronidazole gel when used intermittently, and among women in the community who may or may not actually have BV. Previous studies have evaluated treatment with metronidazole among women who already have symptoms or a diagnosis of BV. The findings of this trial rule out a substantial effect of metronidazole gel, as compared to placebo gel, in reducing the frequency of BV in this setting.

Preterm labour: update on prediction and prevention strategies

PURPOSE OF REVIEW

The incidence of preterm birth is increasing and continues to be a significant cause of neonatal mortality and morbidity. Techniques now exist that can accurately predict early birth. Prevention can therefore be targeted, although effective measures that improve outcome are yet to be established.

RECENT FINDINGS

Obtaining an accurate history is the first step in identifying high-risk women. Clinicians then rely on other predictors such as fetal fibronectin, cervical length assessment and biochemical markers. Research should focus on the combination of noninvasive markers targeted at high-risk women as a screening tool, determining not only appropriate diagnostic levels for positive tests, but also sufficiently large studies should be performed to determine the predictive values of these tests. Interventions to prevent delivery and improve neonatal outcome remain unsatisfactory, mainly comprising tocolysis, cerclage, progesterone and, in some cases, antibiotics. Women who would most benefit from these interventions are difficult to identify and an appreciation of the pathophysiology in an individual woman, such as the relevance of the inflammatory status of the endocervix, may be important in tailoring intervention.

SUMMARY

An improved understanding of the mechanisms underlying the pathological process in preterm birth will allow screening and interventions to be appropriately targeted.

Is the presence of Trichomonas on a Pap smear associated with an increased incidence of bacterial vaginosis?

OBJECTIVE

Bacterial vaginosis (BV) is associated with significant morbidity. Bacterial vaginosis is due to an overgrowth of anaerobic organisms in the vagina. It has been postulated that the presence of Trichomonas creates an anaerobic environment that favors BV. Thus, BV should be more frequent in the presence of Trichomonas if Trichomonas is creating a favorable anaerobic environment.

MATERIALS AND METHODS

A retrospective review of Pap test reports was performed for a diagnosis of coccobacilli consistent with shift in vaginal flora, that is, the presence of clue cells. Cases were Pap smears with Trichomonas identified. Controls were cases without Trichomonas. Results were analyzed using Fisher exact test.

RESULTS

Four hundred cases were reviewed; 200 with and 200 without Trichomonas. The incidence of BV was significantly higher in the Trichomonas group (46.5%) than in group without Trichomonas (24.5%) (p < .0001.).

CONCLUSION

The presence of Trichomonas on a Pap smear is associated with an increased incidence of BV. The report of Trichomonas on a Pap smear should prompt clinical consideration that BV may be present.