Quantitative microbiologic models for preterm delivery

Association between serum carotenoids and bacterial vaginosis infection among American women

BACKGROUND

Bacterial vaginosis (BV) is a widely occurring vaginal inflammation in women of childbearing age caused by dysbiosis of the vaginal flora. Few studies have investigated the effect of serum carotenoids on the development and pathogenesis of BV. This study thus aimed to explore the correlation between serum carotenoids and BV in American women.

METHOD

The analysis included 1252 participants with BV from the National Health and Nutrition Examination Survey (NHANES) between 2001 and 2004. Multiple logistic regression was conducted to explore the correlation between BV and serum carotenoids, while smooth curve fitting was utilized to examine potential nonlinear correlations. Furthermore, stratified subgroup analyses and sensitivity analyses were conducted. ORs reflected the correlation between BV and serum carotenoids.

RESULT

Results of multiple logistic regression indicated that total serum carotenoids and BV had an inverse correlation. In the fully adjusted model II, the quartile with the highest levels of α-carotene and β-cryptoxanthin had a substantially lower incidence of BV. Smooth curve fitting revealed a significant negative linear correlation between serum carotenoids and the incidence of BV. The negative correlation between serum carotenoids and BV was relatively stable in stratified analyses. Moreover, in sensitivity analyses, the association between serum carotenoids and BV persisted, and β-carotene became significantly negatively correlated with BV.

CONCLUSION

This study found an inverse correlation between serum carotenoids and the prevalence of BV.

Matrix Metalloproteinases Expressed in Response to Bacterial Vaginosis Disrupt the Endocervical Epithelium, Increasing Transmigration of HIV

Bacterial vaginosis (BV), a disorder of the female reproductive tract (FRT) in which a healthy Lactobacillus-dominant microflora is replaced by BV-associated bacteria (BVAB), can significantly increase the incidence of human immunodeficiency virus (HIV) acquisition. Discerning the effect of BV on the mucosal epithelium of the FRT may yield novel preventatives and therapeutics for HIV infection. Here, we investigated barrier dysfunction of the endocervix by host-derived factors, secreted in response to BV, as a potential cause of HIV infection. Using a polarized endocervical cell culture system, we determined that conditioned media (CM) from endocervical cells cocultured with BVAB (endocervical+BVAB CM), as well as cervicovaginal fluid (CVF) from women with BV, disrupted epithelial polarization. We assessed host matrix metalloproteinases (MMPs) as the BV-associated secreted factors which disrupt the endocervical epithelium. MMPs were overexpressed in endocervical+BVAB CM and CVF from women with BV and were capable of disrupting endocervical epithelial polarization. When we cocultured polarized endocervical cells with HIV-1-infected lymphocyte-derived cells, we discovered endocervical+BVAB CM and MMPs significantly increased the transmigration of virus through the epithelium, and treatment with an MMP inhibitor decreased these effects. When we examined the effect of CVF on HIV-1 transmigration through endocervical epithelium, we demonstrated that CVF samples with greater concentrations of BV-associated MMPs increased viral transmigration. Our results suggest MMPs increase HIV-1 infection by disrupting the endocervical epithelium, permitting transmigration of virus through the epithelium to infect underlying target cells.

Association between increased antenatal vaginal pH and preterm birth rate: a systematic review

Background Worldwide, 14.9 million infants (11%) are born preterm each year. Up to 40% of preterm births (PTBs) are associated with genital tract infections. The vaginal pH can reflect changes in the vaginal milieu and, if elevated, indicates an abnormal flora or infection. Objective The aim of the study was to investigate whether an increased antenatal vaginal pH >4.5 in pre-labour pregnant women is associated with an increased PTB rate <37 completed weeks gestation. Search strategy Key databases included SCOPUS, EMBASE, MEDLINE, PsycInfo and the Cochrane Central Register of Controlled Trials, complemented by hand search, up to January 2017. Selection criteria Primary research reporting vaginal pH assessment in pre-labour pregnant women and PTB rate. Data collection and analysis Data extraction and appraisal were carried out in a pre-defined standardised manner, applying the Newcastle-Ottawa scale (NOS) and Cochrane risk of bias tool. Analysis included calculation of risk difference (RD) and narrative synthesis. It was decided to abstain from pooling of the studies due to missing information in important moderators. Main results Of 986 identified records, 30 were included in the systematic review. The risk of bias was considered mostly high (40%) or moderate (37%). Fifteen studies permitted a calculation of RD. Of these, 14 (93%) indicated a positive association between increased antenatal vaginal pH and PTB (RD range: 0.02-0.75). Conclusion An increased antenatal vaginal pH >4.5 may be associated with a higher risk for PTB. It is recommended to conduct a randomised controlled trial (RCT) to investigate the effectiveness of antenatal pH screening to prevent PTB. Tweetable abstract Pregnant women with an increased vaginal pH >4.5 may be at higher risk to experience preterm birth.

The Human Microbiome during Bacterial Vaginosis

Bacterial vaginosis (BV) is the most commonly reported microbiological syndrome among women of childbearing age. BV is characterized by a shift in the vaginal flora from the dominant Lactobacillus to a polymicrobial flora. BV has been associated with a wide array of health issues, including preterm births, pelvic inflammatory disease, increased susceptibility to HIV infection, and other chronic health problems. A number of potential microbial pathogens, singly and in combinations, have been implicated in the disease process. The list of possible agents continues to expand and includes members of a number of genera, including Gardnerella, Atopobium, Prevotella, Peptostreptococcus, Mobiluncus, Sneathia, Leptotrichia, Mycoplasma, and BV-associated bacterium 1 (BVAB1) to BVAB3. Efforts to characterize BV using epidemiological, microscopic, microbiological culture, and sequenced-based methods have all failed to reveal an etiology that can be consistently documented in all women with BV. A careful analysis of the available data suggests that what we term BV is, in fact, a set of common clinical signs and symptoms that can be provoked by a plethora of bacterial species with proinflammatory characteristics, coupled to an immune response driven by variability in host immune function.

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.

Prognostic models in obstetrics: available, but far from applicable

Health care provision is increasingly focused on the prediction of patients' individual risk for developing a particular health outcome in planning further tests and treatments. There has been a steady increase in the development and publication of prognostic models for various maternal and fetal outcomes in obstetrics. We undertook a systematic review to give an overview of the current status of available prognostic models in obstetrics in the context of their potential advantages and the process of developing and validating models. Important aspects to consider when assessing a prognostic model are discussed and recommendations on how to proceed on this within the obstetric domain are given. We searched MEDLINE (up to July 2012) for articles developing prognostic models in obstetrics. We identified 177 papers that reported the development of 263 prognostic models for 40 different outcomes. The most frequently predicted outcomes were preeclampsia (n = 69), preterm delivery (n = 63), mode of delivery (n = 22), gestational hypertension (n = 11), and small-for-gestational-age infants (n = 10). The performance of newer models was generally not better than that of older models predicting the same outcome. The most important measures of predictive accuracy (ie, a model's discrimination and calibration) were often (82.9%, 218/263) not both assessed. Very few developed models were validated in data other than the development data (8.7%, 23/263). Only two-thirds of the papers (62.4%, 164/263) presented the model such that validation in other populations was possible, and the clinical applicability was discussed in only 11.0% (29/263). The impact of developed models on clinical practice was unknown. We identified a large number of prognostic models in obstetrics, but there is relatively little evidence about their performance, impact, and usefulness in clinical practice so that at this point, clinical implementation cannot be recommended. New efforts should be directed toward evaluating the performance and impact of the existing models.

Gene Expression Profiling of Human Vaginal Cells In Vitro Discriminates Compounds with Pro-Inflammatory and Mucosa-Altering Properties: Novel Biomarkers for Preclinical Testing of HIV Microbicide Candidates

BACKGROUND

Inflammation and immune activation of the cervicovaginal mucosa are considered factors that increase susceptibility to HIV infection. Therefore, it is essential to screen candidate anti-HIV microbicides for potential mucosal immunomodulatory/inflammatory effects prior to further clinical development. The goal of this study was to develop an in vitro method for preclinical evaluation of the inflammatory potential of new candidate microbicides using a microarray gene expression profiling strategy.

METHODS

To this end, we compared transcriptomes of human vaginal cells (Vk2/E6E7) treated with well-characterized pro-inflammatory (PIC) and non-inflammatory (NIC) compounds. PICs included compounds with different mechanisms of action. Gene expression was analyzed using Affymetrix U133 Plus 2 arrays. Data processing was performed using GeneSpring 11.5 (Agilent Technologies, Santa Clara, CA).

RESULTS

Microarraray comparative analysis allowed us to generate a panel of 20 genes that were consistently deregulated by PICs compared to NICs, thus distinguishing between these two groups. Functional analysis mapped 14 of these genes to immune and inflammatory responses. This was confirmed by the fact that PICs induced NFkB pathway activation in Vk2 cells. By testing microbicide candidates previously characterized in clinical trials we demonstrated that the selected PIC-associated genes properly identified compounds with mucosa-altering effects. The discriminatory power of these genes was further demonstrated after culturing vaginal cells with vaginal bacteria. Prevotella bivia, prevalent bacteria in the disturbed microbiota of bacterial vaginosis, induced strong upregulation of seven selected PIC-associated genes, while a commensal Lactobacillus gasseri associated to vaginal health did not cause any changes.

CONCLUSIONS

In vitro evaluation of the immunoinflammatory potential of microbicides using the PIC-associated genes defined in this study could help in the initial screening of candidates prior to entering clinical trials. Additional characterization of these genes can provide further insight into the cervicovaginal immunoinflammatory and mucosal-altering processes that facilitate or limit HIV transmission with implications for the design of prevention strategies.

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.

Identification and characterization of bacterial vaginosis-associated pathogens using a comprehensive cervical-vaginal epithelial coculture assay

Bacterial vaginosis (BV) is the most commonly treated female reproductive tract affliction, characterized by the displacement of healthy lactobacilli by an overgrowth of pathogenic bacteria. BV can contribute to pathogenic inflammation, preterm birth, and susceptibility to sexually transmitted infections. As the bacteria responsible for BV pathogenicity and their interactions with host immunity are not understood, we sought to evaluate the effects of BV-associated bacteria on reproductive epithelia. Here we have characterized the interaction between BV-associated bacteria and the female reproductive tract by measuring cytokine and defensin induction in three types of FRT epithelial cells following bacterial inoculation. Four BV-associated bacteria were evaluated alongside six lactobacilli for a comparative assessment. While responses differed between epithelial cell types, our model showed good agreement with clinical BV trends. We observed a distinct cytokine and human β-defensin 2 response to BV-associated bacteria, especially Atopobium vaginae, compared to most lactobacilli. One lactobacillus species, Lactobacillus vaginalis, induced an immune response similar to that elicited by BV-associated bacteria, stimulating significantly higher levels of cytokines and human β-defensin 2 than other lactobacilli. These data provide an important prioritization of BV-associated bacteria and support further characterization of reproductive bacteria and their interactions with host epithelia. Additionally, they demonstrate the distinct immune response potentials of epithelial cells from different locations along the female reproductive tract.

Novel vaginal microflora colonization model providing new insight into microbicide mechanism of action

Several broad-spectrum microbicides, including cellulose sulfate (CS), have passed conventional preclinical and phase I clinical safety evaluation and yet have failed to protect women from acquiring HIV-1 in phase II/III trials. Concerns have been raised that current preclinical algorithms are deficient in addressing the complexity of the microflora-regulated vaginal mucosal barrier. We applied a novel microflora-colonized model to evaluate CS and hydroxyethylcellulose (HEC), which is used as a "universal placebo" in microbicide trials. Cervicovaginal epithelial cultures were colonized with normal vaginal microflora isolates representing common Lactobacillus species used as probiotics (L. acidophilus and L. crispatus) or Prevotella bivia and Atopobium vaginae, most prevalent in the disturbed microflora of bacterial vaginosis (BV). At baseline, all strains maintained constant epithelium-associated CFUs without inducing cytotoxicity and apoptosis. CS selectively reduced epithelium-associated CFUs and (to a lesser extent) planktonic CFUs, most significantly affecting L. crispatus. Inducing only minor changes in sterile epithelial cultures, CS induced expression of innate immunity mediators (RANTES, interleukin-8 [IL-8], and secretory leukocyte protease inhibitor [SLPI]) in microflora-colonized epithelia, most significantly potentiating effects of bacteria causing BV. In the absence of CS, all bacterial strains except L. acidophilus activated NF-κB, although IL-8 and RANTES levels were increased by the presence of BV-causing bacteria only. CS enhanced NF-κB activation in a dose-dependent manner under all conditions, including L. acidophilus colonization. HEC remained inert. These results offer insights into possible mechanisms of CS clinical failure. The bacterially colonized cervicovaginal model reveals unique aspects of microflora-epithelium-drug interactions and innate immunity in the female genital tract and should become an integral part of preclinical safety evaluation of anti-HIV microbicides and other vaginal formulations.

IMPORTANCE

This report provides experimental evidence supporting the concept that the vaginal microflora regulates the epithelial innate immunity in a species- and strain-specific manner and that topically applied microbicides may alter both the bacterial and epithelial components of this homeostatic interaction. Our data also highlight the importance of differentiating the effects of biomedical interventions on epithelium-associated versus conventional planktonic bacterial growth when assessing vaginal mucosal health and immunity.

Drawing the line between commensal and pathogenic Gardnerella vaginalis through genome analysis and virulence studies

Background

Worldwide, bacterial vaginosis (BV) is the most common vaginal disorder. It is associated with risk for preterm birth and HIV infection. The etiology of the condition has been debated for nearly half a century and the lack of knowledge about its cause and progression has stymied efforts to improve therapy and prevention. Gardnerella vaginalis was originally identified as the causative agent, but subsequent findings that it is commonly isolated from seemingly healthy women cast doubt on this claim. Recent studies shedding light on the virulence properties of G. vaginalis, however, have drawn the species back into the spotlight.

Results

In this study, we sequenced the genomes of a strain of G. vaginalis from a healthy woman, and one from a woman with bacterial vaginosis. Comparative analysis of the genomes revealed significant divergence and in vitro studies indicated disparities in the virulence potential of the two strains. The commensal isolate exhibited reduced cytotoxicity and yet the cytolysin proteins encoded by the two strains were nearly identical, differing at a single amino acid, and were transcribed at similar levels. The BV-associated strain encoded a different variant of a biofilm associated protein gene and demonstrated greater adherence, aggregation, and biofilm formation. Using filters with different pore sizes, we found that direct contact between the bacteria and epithelial cells is required for cytotoxicity.

Conclusions

The results indicated that contact is required for cytotoxicity and suggested that reduced cytotoxicity in the commensal isolate could be due to impaired adherence. This study outlines two distinct genotypic variants of G. vaginalis, one apparently commensal and one pathogenic, and presents evidence for disparate virulence potentials.

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.

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.

Association between Lactobacillus species and bacterial vaginosis-related bacteria, and bacterial vaginosis scores in pregnant Japanese women

Background

Bacterial vaginosis (BV), the etiology of which is still uncertain, increases the risk of preterm birth. Recent PCR-based studies suggested that BV is associated with complex vaginal bacterial communities, including many newly recognized bacterial species in non-pregnant women.

Methods

To examine whether these bacteria are also involved in BV in pregnant Japanese women, vaginal fluid samples were taken from 132 women, classified as normal (n = 98), intermediate (n = 21), or BV (n = 13) using the Nugent gram stain criteria, and studied. DNA extracted from these samples was analyzed for bacterial sequences of any Lactobacillus, four Lactobacillus species, and four BV-related bacteria by PCR with primers for 16S ribosomal DNA including a universal Lactobacillus primer, Lactobacillus species-specific primers for L. crispatus, L. jensenii, L. gasseri, and L. iners, and BV-related bacterium-specific primers for BVAB2, Megasphaera, Leptotrichia, and Eggerthella-like bacterium.

Results

The prevalences of L. crispatus, L. jensenii, and L. gasseri were significantly higher, while those of BVAB2, Megasphaera, Leptotrichia, and Eggerthella-like bacterium were significantly lower in the normal group than in the BV group. Unlike other Lactobacillus species, the prevalence of L. iners did not differ between the three groups and women with L. iners were significantly more likely to have BVAB2, Megasphaera, Leptotrichia, and Eggerthella-like bacterium. Linear regression analysis revealed associations of BVAB2 and Megasphaera with Nugent score, and multivariate regression analyses suggested a close relationship between Eggerthella-like bacterium and BV.

Conclusion

The BV-related bacteria, including BVAB2, Megasphaera, Leptotrichia, and Eggerthella-like bacterium, are common in the vagina of pregnant Japanese women with BV. The presence of L. iners may be correlated with vaginal colonization by these BV-related bacteria.

Asymptomatic bacterial vaginosis and intermediate flora as risk factors for adverse pregnancy outcome

We updated a previously published meta-analysis to evaluate bacterial vaginosis (BV) and intermediate vaginal flora as risk factors for adverse pregnancy outcome. Selection criteria were original, published, English-language reports of cohort studies or control groups of clinical trials including women <37 weeks' gestation with intact amniotic membranes. All women had to be screened for BV, diagnosed either by clinical criteria or by criteria based on Gram-stain findings. Outcomes were preterm delivery, late miscarriages, maternal or neonatal infections, and perinatal mortality. Fourteen new studies with results for 10,286 patients were included, so that results for 30,518 patients in 32 studies were available for this meta-analysis. BV more than doubled the risk of preterm delivery in asymptomatic patients (OR: 2.16, 95% CI: 1.56-3.00) and in patients with symptoms of preterm labor (OR: 2.38, 95% CI: 1.02-5.58). BV also significantly increased the risk of late miscarriages (OR: 6.32, 95% CI: 3.65-10.94) and maternal infection (OR: 2.53, 95% CI 1.26-5.08) in asymptomatic patients. No significant results were calculated for the outcomes of neonatal infection or perinatal mortality. Also, intermediate vaginal flora was not significantly associated with any outcome included. The results of this meta-analysis confirm that BV is a risk factor for preterm delivery and maternal infectious morbidity and a strong risk factor for late miscarriage.

Cultivation-independent analysis of changes in bacterial vaginosis flora following metronidazole treatment

PCR was used to survey bacterial vaginosis flora before and after metronidazole treatment. The species composition for pretreatment patients was variable. Lactobacillus iners was prominent in all patients posttreatment. Atopobium vaginae concentrations were highest for patients who failed or responded incompletely to treatment and lowest for patients who were cured.

Probiotics for women's health

GOALS

The goals of this research were 2-fold: (1) to determine whether a commercially available probiotic mixture (VSL-3) could survive and grow in a continuous culture system simulating the vaginal environment and (2) to determine whether the probiotic mixture was capable of suppressing the growth of a known vaginal vault pathogen, Gardnerella vaginalis.

BACKGROUND

An abnormal vaginal microflora, such as that associated with bacterial vaginosis (BV) is an important health issue for women. In addition, the association of this condition with preterm labor and delivery suggests that control of BV may impact the number of preterm births. Interventional trials with antibiotics have received mixed reviews and other interventional options, including the use of probiotics, are being considered.

STUDY

A well-documented continuous culture system has been used to determine whether VSL-3 can survive and grow in conditions simulating a vaginal environment. In addition, the ability of VSL-3 to inhibit the growth of a known vaginal vault pathogen, G. vaginalis, has been determined.

RESULTS

The probiotic mixture was shown to survive and maintain itself within the fermentation vessel of the continuous culture system over an extended period of time. This mixture, when challenged with a known pathogen, was also shown to suppress the growth of G. vaginalis.

CONCLUSIONS

It may be feasible to use probiotics as interventional therapy to suppress the growth of pathogens within the vaginal vault associated with BV.

Throwing the dice for the diagnosis of vaginal complaints?

BACKGROUND

Vaginitis is among the most common conditions women are seeking medical care for. Although these infections can easily be treated, the relapse rate is high. This may be due to inadequate use of the diagnostic potential.

METHODS

We evaluated the misjudgement rate of the aetiology of vaginal complaints. A total of 220 vaginal samples from women with a vaginal complaint were obtained and analysed for numbers of total lactobacilli, H2O2-producing lactobacilli, total aerobic cell counts and total anaerobic cell counts including bifidobacteria, Bacteroides spp., Prevotella spp. Additionally, the presence of Atopobium vaginae, Gardnerella vaginalis, Candida spp. and Trichomonas vaginalis was evaluated by DNA-hybridisation using the PCR and Affirm VPIII Microbial Identification Test, respectively.

RESULTS

The participating physicians diagnosed Bacterial vaginosis (BV) as origin of discomfort in 80 cases, candidiasis in 109 cases and mixed infections in 8 cases. However, a present BV, defined as lack of H2O2-lactobacilli, presence of marker organisms, such as G. vaginalis, Bacteroides spp. or Atopobium vaginae, and an elevated pH were identified in only 45 cases of the women examined. Candida spp. were detected in 46 cases. Interestingly, an elevated pH corresponded solely to the presence of Atopobium vaginae, which was detected in 11 cases.

CONCLUSION

Errors in the diagnosis of BV and candida vulvovaginitis (CV) were high. Interestingly, the cases of misjudgement of CV (77%) were more numerous than that of BV (61%). The use of Amsel criteria or microscopy did not reduce the number of misinterpretations. The study reveals that the misdiagnosis of vaginal complaints is rather high.

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

Background

The microbiological diagnosis of bacterial vaginosis is usually made using Nugent's criteria, a useful but rather laborious scoring system based on counting bacterial cell types on Gram stained slides of vaginal smears. Ison and Hay have simplified the score system to three categories and added a fourth category for microflora with a predominance of the Streptococcus cell type. Because in the Nugent system several cell types are not taken into account for a final score, we carried out a detailed assessment of the composition of the vaginal microflora in relation to standard Gram stain in order the improve the diagnostic value of the Gram stain. To this purpose we compared Gram stain based categorization of vaginal smears with i) species specific PCR for the detection of Gardnerella vaginalis and Atopobium vaginae and with ii) tDNA-PCR for the identification of most cultivable species.

Results

A total of 515 samples were obtained from 197 pregnant women, of which 403 (78.3%) were categorized as grade I microflora, 46 (8.9%) as grade II, 22 (4.3%) as grade III and 8 (1.6%) as grade IV, according to the criteria of Ison and Hay. Another 36 samples (7.0%) were assigned to the new category 'grade I-like', because of the presence of diphtheroid bacilli cell types. We found that 52.7% of the grade I-like samples contained Bifidobacterium spp. while L. crispatus was present in only 2.8% of the samples and G. vaginalis and A. vaginae were virtually absent; in addition, the species diversity of this category was similar to that of grade II specimens.

Based on the presence of different Lactobacillus cell types, grade I specimens were further characterized as grade Ia (40.2%), grade Iab (14.9%) and grade Ib (44.9%). We found that this classification was supported by the finding that L. crispatus was cultured from respectively 87.0% and 76.7% of grade Ia and Iab specimens while this species was present in only 13.3% of grade Ib specimens, a category in which L. gasseri and L. iners were predominant.

Conclusion

Further refinement of Gram stain based grading of vaginal smears is possible by distinguishing additional classes within grade I smears (Ia, Iab and Ib) and by adding a separate category, designated grade I-like. A strong correlation was found between grade Ia and the presence of L. crispatus and between grade I-like and the presence of bifidobacteria. This refinement of Gram stain based scoring of vaginal smears may be helpful to improve the interpretation of the clinical data in future studies, such as the understanding of response to treatment and recurrence of bacterial vaginosis in some women, and the relationship between bacterial vaginosis and preterm birth.

Association between vaginal 70-kd heat shock protein, interleukin-1 receptor antagonist, and microbial flora in mid trimester pregnant women

OBJECTIVE

This study investigated the association among the inducible 70-kd heat shock protein, cytokines, and microbial flora in the vagina in mid trimester pregnant women and subsequent preterm delivery.

STUDY DESIGN

Vaginal samples from 205 pregnant women, which were collected at 18 to 22 weeks of gestation, were analyzed for qualitative and quantitative vaginal microflora and for 70-kd heat shock protein, interleukin-1beta, interleukin-1 receptor antagonist, and tumor necrosis factor-alpha by enzyme-linked immunosorbent assay. Pregnancy outcome data were obtained subsequently.

RESULTS

The 70-kd heat shock protein was detected in 38 vaginal samples (18.5%). Its presence was associated with elevated vaginal pH, a diagnosis of bacterial vaginosis, and elevated interleukin-1 receptor antagonist levels (P < .001). Among women with bacterial vaginosis, 70-kd heat shock protein-positive subjects had a >80% increase in median vaginal concentration of interleukin-1 receptor antagonist (P < .05).

CONCLUSION

Vaginal 70-kd heat shock protein expression is associated with the down-regulation of the proinflammatory immune response to abnormal vaginal flora in mid trimester pregnant women.

Polymorphism in intron 2 of the interleukin-1 receptor antagonist gene, local midtrimester cytokine response to vaginal flora, and subsequent preterm birth

OBJECTIVE

This study investigated the association between polymorphism in intron 2 of the interleukin-1 receptor antagonist gene, midtrimester vaginal microflora, vaginal interleukin receptor antagonist and interleukin-1beta levels and subsequent spontaneous preterm birth.

STUDY DESIGN

Vaginal samples from 212 women, collected at 18-22 weeks' gestation, were analyzed for the polymorphism in intron 2 of the interleukin-1 receptor antagonist gene by polymerase chain reaction, qualitative and quantitative vaginal microflora, and interleukin-1beta and interleukin-1ra concentrations by enzyme-linked immunosorbent assay. Pregnancy outcome data were subsequently obtained.

RESULTS

Carriage of intron 2 of the interleukin-1 receptor antagonist allele 2 (IL1RN * 2) was associated with an elevated vaginal pH in black ( P < .001) and white ( P = .005) women, a reduced interleukin-1beta response to anaerobic Gram-negative rods and/or Gardnerella vaginalis ( P < .01), and a decreased rate of spontaneous preterm deliveries (6% versus 18%, P = .02). In black women, IL1RN * 2 carriage was associated with increased anaerobic Gram-negative rods, Mycoplasma, and Peptostreptococci and decreased Lactobacilli colonization.

CONCLUSION

IL1RN * 2 carriage was associated with a blunted proinflammatory interleukin-1beta response to abnormal vaginal flora. This property may decrease susceptibility to infection-related preterm birth.

Relationship between a toll-like receptor-4 gene polymorphism, bacterial vaginosis-related flora and vaginal cytokine responses in pregnant women

OBJECTIVE

The relationship between a single nucleotide polymorphism (TLR4 896 A > G) in the toll-like receptor-4 (TLR4) gene, qualitative and quantitative changes in vaginal micro-flora and vaginal interleukin (IL)-1beta and IL-1 receptor antagonist (IL-1ra) concentrations in pregnant women were evaluated.

STUDY DESIGN

Qualitative and quantitative microbial methods were used to characterize vaginal micro-flora of 238 women at 18-22 weeks gestation. Polymerase chain reaction was used to determine TLR4 genotype. IL-1beta and IL-1ra concentrations in vaginal lavage samples were measured by ELISA.

RESULTS

The TLR4 variant was identified in 10.3% of women. Carriage of this variant was associated with a median increase in vaginal pH (P = 0.05), a greater than 10-fold increase in vaginal Gardnerella vaginalis levels (P < 0.0001) and a 10-fold increase in the vaginal concentration of three species of anaerobic Gram-negative rods, Prevotella, Bacteroides, and Porphyromonas (P = 0.08 ). Colonization with G. vaginalis and/or the anaerobic Gram-negative rods resulted in elevated vaginal IL-1 (P = 0.01) and IL-1ra (P < 0.0002) concentrations in women who were TLR4 896A homozygotes, but not in TLR4 896G carriers.

CONCLUSION

The TLR4 896 A > G polymorphism contributes to inter-individual differences in the vaginal immune defense against G. vaginalis and anaerobic Gram-negative rods.

A disproportionate increase in IL-1beta over IL-1ra in the cervicovaginal secretions of pregnant women with altered vaginal microflora correlates with preterm birth

OBJECTIVE

This purpose of this study was to investigate the association between vaginal microflora, concentrations of interleukin-1beta (IL-1beta), and its natural receptor antagonist (IL-1ra) in the cervicovaginal discharge, and spontaneous preterm birth. Study design Vaginal samples collected at 18 to 22 weeks' gestation from 207 women were analyzed to study qualitative and quantitative microbiologic aspects of vaginal microflora and IL-1beta and IL-1ra concentrations.

RESULTS

Among women colonized with anaerobic Gram-negative rods and/or Gardnerella vaginalis, an elevated IL-1beta concentration, or a diminished IL-1ra:IL-1beta ratio were associated with preterm delivery. A cut-off IL-1ra:IL-1beta ratio of <8632:1 optimally discriminated the subjects with subsequent spontaneous preterm deliveries from subjects who delivered at term, with a sensitivity of 78%, specificity of 51%, positive predictive value of 21%, and negative predictive value of 95%.

CONCLUSION

A disproportionate increase in IL-1beta over IL-1ra in response to vaginal colonization with anaerobic Gram-negative rods and/or G. vaginalis at 18 to 22 weeks' gestation is associated with spontaneous preterm delivery.

Identification and H(2)O(2) production of vaginal lactobacilli from pregnant women at high risk of preterm birth and relation with outcome

Lactobacilli, principally the strains that are hydrogen peroxide (H(2)O(2)) producing, may have a protective effect against vaginal colonization by pathogenic species such as those that cause bacterial vaginosis. Previous reports have also suggested that H(2)O(2)-producing lactobacilli in the vagina may protect pregnant women against ascending infection of the chorioamniotic membranes and uterine cavity. We report the identification and H(2)O(2) production of lactobacilli isolated from vaginal swabs collected at 20 weeks' gestation from a population of pregnant women at high risk of preterm birth. We also report the correlation between identification and H(2)O(2) production in relation to the outcomes of chorioamnionitis and preterm birth. Lactobacilli were identified by partial 16S rRNA gene sequencing. H(2)O(2) production by isolates was determined by a semiquantitative method. The most commonly isolated species were L. crispatus, L. gasseri, L. vaginalis and L. jensenii. Amounts of H(2)O(2) produced by lactobacilli varied widely. The presence of lactobacilli producing high levels of H(2)O(2) in the vagina of this population of pregnant women was associated with a reduced risk of bacterial vaginosis at 20 weeks' gestation and subsequent chorioamnionitis. L. jensenii and L. vaginalis produced the highest levels of H(2)O(2). We postulate that H(2)O(2)-producing lactobacilli are able to reduce the incidence of ascending infections of the uterus and the subsequent production of proinflammatory molecules which are important in the pathogenesis of chorioamnionitis and preterm birth.