Vaginal hydrolytic enzymes, immunoglobulin A against Gardnerella vaginalis toxin, and risk of early preterm birth among women in preterm labor with bacterial vaginosis or intermediate flora

Cracking the Code: Investigating the Correlation between Aerobic Vaginitis and Preterm Labor

Aerobic vaginitis (AV) is a distinct clinical entity characterized by inflammation and abnormal vaginal microflora. Often mistaken for bacterial vaginosis, AV remains relatively unknown and underdiagnosed. AV's understanding is evolving, with some experts suggesting it may primarily be an immunological disorder, the prevalence of which has a range of 7-13% in non-pregnant women and 4.1-8.3% during pregnancy. Pregnancy can affect susceptibility to vaginal infections, leading to adverse outcomes for the woman and the newborn. This review summarizes the correlation between AV and adverse pregnancy outcomes, particularly preterm birth, the leading cause of morbidity and mortality among neonates. An improved understanding of AV's impact on pregnancy outcomes can lead to early recognition, proper management, and effective interventions. While some studies support an association between AV and preterm labor, the existing knowledge of this relationship remains limited. The evidence suggests that AV may contribute to adverse pregnancy outcomes, mainly preterm birth, but further research is needed to establish a definitive link. Further studies are needed to investigate the underlying mechanisms and clarify AV's role in premature labor. A comprehensive understanding of AV's impact on pregnancy outcomes is crucial for early recognition, appropriate management, and effective interventions.

Ureaplasma parvum infection induces inflammatory changes in vaginal epithelial cells independent of sialidase

BACKGROUND

Ureaplasma, a genus of the order Mycoplasmatales and commonly grouped with Mycoplasma as genital mycoplasma is one of the most common microbes isolated from women with infection/inflammation-associated preterm labor (PTL). Mycoplasma spp. produce sialidase that cleaves sialic acid from glycans of vaginal mucous membranes and facilitates adherence and invasion of the epithelium by pathobionts, and dysregulated immune response. However, whether Ureaplasma species can induce the production of sialidase is yet to be demonstrated. We examined U. parvum-infected vaginal epithelial cells (VECs) for the production of sialidase and pro-inflammatory cytokines.

METHODS

Immortalized VECs were cultured in appropriate media and treated with U. parvum in a concentration of 1 × 10⁵ DNA copies/ml. After 24 h of treatment, cells and media were harvested. To confirm infection and cell uptake, immunocytochemistry for multi-banded antigen (MBA) was performed. Pro-inflammatory cytokine production and protein analysis for sialidase confirmed pro-labor pathways.

RESULTS

Infection of VECs was confirmed by the presence of intracellular MBA. Western blot analysis showed no significant increase in sialidase expression from U. parvum-treated VECs compared to uninfected cells. However, U. parvum infection induced 2-3-fold increased production of GM-CSF (p = 0.03), IL-6 (p = 0.01), and IL-8 (p = 0.01) in VECs compared to controls.

CONCLUSION

U. parvum infection of VECs induced inflammatory imbalance associated with vaginal dysbiosis but did not alter sialidase expression at the cellular level. These data suggest that U. parvum's pathogenic effect could be propagated by locally produced pro-inflammatory cytokines and, unlike other genital mycoplasmas, may be independent of sialidase.

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

The microbiome of the female reproductive tract defies the convention that high biodiversity is a hallmark of an optimal ecosystem. Although not universally true, a homogeneous vaginal microbiome composed of species of Lactobacillus is generally associated with health, whereas vaginal microbiomes consisting of other taxa are generally associated with dysbiosis and a higher risk of disease. The past decade has seen a rapid advancement in our understanding of these unique biosystems. Of particular interest, substantial effort has been devoted to deciphering how members of the microbiome of the female reproductive tract impact pregnancy, with a focus on adverse outcomes, including but not limited to preterm birth. Herein, we review recent research efforts that are revealing the mechanisms by which these microorganisms of the female reproductive tract influence gynecologic and reproductive health of the female reproductive tract.

Mechanistic Insights into Immune Suppression and Evasion in Bacterial Vaginosis

The immunological response to bacterial vaginosis (BV) remains poorly understood and recurrent BV is still a major public health burden especially in the pregnant population. This article reviews the potential mechanisms by which BV-associated bacteria suppress and circumvent the host and microbial defence responses, and propagate their survival/dominance without overt inflammation. We discuss the composition of cervicovaginal mucosal barrier and the mechanism by which BV circumvents host defence: the degradation of the mucosal barrier and immunoglobulin A (IgA); the BV-associated organism Gardnerella vaginalis haemolysin (vaginolysin); diminished IgA response against vaginolysin; mucosal sialic acid degradation, foraging and depletion; inhibition of IL-8-induced neutrophilic infiltration; and metabolite-induced incapacitation of neutrophil and monocyte chemotaxis. We also highlight the tolerance/resistance to both host and antimicrobial molecules mounted by BV-associated biofilms. A plausible role of sialic acid-binding immunoglobulin-like lectins (SIGLECS) was also suggested. Sialidase, which is often produced by G. vaginalis, is central to the immunosuppression, relapse and recurrence observed in BV, although it is supported by other hydrolytic enzymes, vaginolysin and immunomodulatory metabolites.

A specific bacterial DNA signature in the vagina of Australian women in midpregnancy predicts high risk of spontaneous preterm birth (the Predict1000 study)

BACKGROUND

Intrauterine infection accounts for a quarter of the cases of spontaneous preterm birth; however, at present, it is not possible to efficiently identify pregnant women at risk to deliver preventative treatments.

OBJECTIVE

This study aimed to establish a vaginal microbial DNA test for Australian women in midpregnancy that will identify those at increased risk of spontaneous preterm birth.

STUDY DESIGN

A total of 1000 women with singleton pregnancies were recruited in Perth, Australia. Midvaginal swabs were collected between 12 and 23 weeks' gestation. DNA was extracted for the detection of 23 risk-related microbial DNA targets by quantitative polymerase chain reaction. Obstetrical history, pregnancy outcome, and demographics were recorded.

RESULTS

After excluding 64 women owing to losses to follow-up and insufficient sample for microbial analyses, the final cohort consisted of 936 women of predominantly white race (74.3%). The overall preterm birth rate was 12.6% (118 births); the spontaneous preterm birth rate at <37 weeks' gestation was 6.2% (2.9% at ≤34 weeks' gestation), whereas the preterm premature rupture of the membranes rate was 4.2%. No single individual microbial target predicted increased spontaneous preterm birth risk. Conversely, women who subsequently delivered at term had higher amounts of Lactobacillus crispatus, Lactobacillus gasseri, or Lactobacillus jensenii DNA in their vaginal swabs (13.8% spontaneous preterm birth vs 31.2% term; P=.005). In the remaining women, a specific microbial DNA signature was identified that was strongly predictive of spontaneous preterm birth risk, consisting of DNA from Gardnerella vaginalis (clade 4), Lactobacillus iners, and Ureaplasma parvum (serovars 3 and 6). Risk prediction was improved if Fusobacterium nucleatum detection was included in the test algorithm. The final algorithm, which we called the Gardnerella Lactobacillus Ureaplasma (GLU) test, was able to detect women at risk of spontaneous preterm birth at <37 and ≤34 weeks' gestation, with sensitivities of 37.9% and 44.4%, respectively, and likelihood ratios (plus or minus) of 2.22 per 0.75 and 2.52 per 0.67, respectively. Preterm premature rupture of the membranes was more than twice as common in GLU-positive women. Adjusting for maternal demographics, ethnicity, and clinical history did not improve prediction. Only a history of spontaneous preterm birth was more effective at predicting spontaneous preterm birth than a GLU-positive result (odds ratio, 3.6).

CONCLUSION

We have identified a vaginal bacterial DNA signature that identifies women with a singleton pregnancy who are at increased risk of spontaneous preterm birth and may benefit from targeted antimicrobial therapy.

Mechanistic insights into the action of probiotics against bacterial vaginosis and its mediated preterm birth: An overview

The human body is a reservoir of numerous micro-creatures; whose role is substantial and indispensable in the overall development of human beings. The advances in omic approaches have offered powerful means to decipher the core microbiome and metabolome diversities in a specific organ system. The establishment of lactobacilli in the female reproductive tract is thought to be a paramount prerequisite that maintains homeostatic conditions for a sustainable and healthy pregnancy. Nevertheless, a plethora of such Lactobacillus strains of vaginal source revealed probiotic phenotypes. The plummeting in the occurrence of lactobacilli in the vaginal ecosystem is associated with several adverse pregnancy outcomes (APOs). One such pathological condition is "Bacterial Vaginosis" (BV), a pathogen dominated gynecological threat. In this scenario, the ascending traffic of notorious Gram-negative/variable BV pathogens to the uterus is one of the proposed pathways that give rise to inflammation-related APOs like preterm birth. Since antibiotic resistance is aggravating among urogenital pathogens, the probiotics intervention remains one of the alternative biotherapeutic strategies to overcome BV and its associated APOs. Perhaps, the increased inclination towards the safer and natural biotherapeutic strategies rather than pharmaceutical drugs for maintaining gestational and reproductive health resulted in the use of probiotics in pregnancy diets. In this context, the current review is an attempt to highlight the microbiome and metabolites signatures of BV and non-BV vaginal ecosystem, inflammation or infection-related preterm birth, host-microbial interactions, role and effectiveness of probiotics to fight against aforesaid diseased conditions.

The Vaginal Microenvironment: The Physiologic Role of Lactobacilli

In addition to being a passage for sperm, menstruum, and the baby, the human vagina and its microbiota can influence conception, pregnancy, the mode and timing of delivery, and the risk of acquiring sexually transmitted infections. The physiological status of the vaginal milieu is important for the wellbeing of the host as well as for successful reproduction. High estrogen states, as seen during puberty and pregnancy, promote the preservation of a homeostatic (eubiotic) vaginal microenvironment by stimulating the maturation and proliferation of vaginal epithelial cells and the accumulation of glycogen. A glycogen-rich vaginal milieu is a haven for the proliferation of Lactobacilli facilitated by the production of lactic acid and decreased pH. Lactobacilli and their antimicrobial and anti-inflammatory products along with components of the epithelial mucosal barrier provide an effective first line defense against invading pathogens including bacterial vaginosis, aerobic vaginitis-associated bacteria, viruses, fungi and protozoa. An optimal host-microbial interaction is required for the maintenance of eubiosis and vaginal health. This review explores the composition, function and adaptive mechanisms of the vaginal microbiome in health and those disease states in which there is a breach in the host-microbial relationship. The potential impact of vaginal dysbiosis on reproduction is also outlined.

Study on the effects of an oral lactobacilli and lactoferrin complex in women with intermediate vaginal microbiota

PURPOSE

In the vagina of healthy reproductive-aged women, several microbial species maintain a finely tuned mutualistic relationship with the host providing the first-line of defense against the colonization by opportunistic pathogens, which are the leading cause of dysbiosis or vaginal infections (bacterial vaginosis, vulvovaginal candidiasis, and aerobic vaginitis). The use of probiotic lactobacilli to prevent vaginal infections has a good rationale, and an excellent safety record, but so far only a few strains have been clinically proven to be effective, particularly to prevent BV. The aim of the clinical trial was to evaluate the changes in Nugent score in women with intermediate vaginal microbiota treated with oral Lactobacillus acidophilus GLA-14 and Lactobacillus rhamnosus HN001 mixture, in combination with bovine lactoferrin RCX™ (Respecta^®) or placebo, for 15 days.

METHODS

Vaginal swabs were collected from each woman at baseline and at the end of probiotic treatment and analyzed by RT-PCR. Both symptoms of abnormal vaginal micorbiota and adverse effects were assessed throughout the study.

RESULTS

The results showed that oral intake of lactobacilli/lactoferrin mixture led to significant vaginal colonization by L. acidophilus GLA-14 and L. rhamnosus HN001 showing that both strains can colonize vagina following oral ingestion. The effect of such colonization is correlated with the restoration of normal Nugent score (values 0-3) and an improvement of symptoms of abnormal vaginal micorbiota including itching and discharge.

CONCLUSIONS

Oral consumption of lactobacilli/lactoferrin complex corroborates the effectiveness of using lactobacilli for supporting vaginal health and provides a rational basis for future studies on vaginal infections.

Aerobic vaginitis: no longer a stranger

Aerobic vaginitis (AV) is the name given in 2002 to a vaginal infectious entity which was not recognized as such before. It is characterized by abnormal (dysbiotic) vaginal microflora containing aerobic, enteric bacteria, variable levels of vaginal inflammation and deficient epithelial maturation. Although AV and bacterial vaginosis (BV) share some characteristics, such as a diminished number or absence of lactobacilli, increased discharge (fishy smelling in BV, while in severe forms of AV, a foul, rather rotten smell may be present) and increased pH (often more pronounced in AV), there are also striking differences between the two. There is no inflammation in women with BV, whereas the vagina of women with AV often appears red and edematous, and may even display small erosions or ulcerations. The color of the discharge in BV is usually whitish or gray and of a watery consistency, whereas in AV it is yellow to green and rather thick and mucoid. Women with BV do not have dyspareunia, while some women with severe AV do. Finally, the microscopic appearance differs in various aspects, such as the presence of leucocytes and parabasal or immature epithelial cells in AV and the absence of the granular aspect of the microflora, typical of BV. Despite all these differences, the distinction between AV and BV was not recognized in many former studies, leading to incomplete and imprecise diagnostic workouts and erroneous management of patients in both clinical and research settings. The prevalence of AV ranges between 7 and 12%, and is therefore less prevalent than BV. Although still largely undiagnosed, many researchers and clinicians increasingly take it into account as a cause of symptomatic vaginitis. AV can co-occur with other entities, such as BV and candidiasis. It can be associated with dyspareunia, sexually transmitted infections (such as human papilloma virus, human immunodeficiency virus, Trichomonas vaginalis and Chlamydia trachomatis), chorioamnionitis, fetal infection, preterm birth and cervical dysplasia. Many other possible pathological associations are currently under investigation. The diagnosis of AV is made using wet mount microscopy, ideally using phase contrast. An AV score is calculated, according to: lactobacillary grade, presence of inflammation, proportion of toxic leucocytes, characteristics of the microflora and presence of immature epithelial cells. To circumvent the hurdle of microscopic investigation, some groups have begun to develop nucleic-acid-based and enzymatic diagnostic tests, but the detailed information obtained with phase contrast microscopy is irreplaceable. The best treatment is not yet fully determined, but it must be tailored according to the microscopic findings and the patient's needs. There is a role for local estrogen therapy, corticosteroids, antimicrobials and probiotics. Further research will reveal more precise data on diagnosis, pathogenesis, management and prevention.

Gardnerella vaginalis diversity and ecology in relation to vaginal symptoms

Gardnerella vaginalis was first described in 1953, and subsequently identified as the causative agent of a cluster of vaginal symptoms currently known as vaginosis. Research has so far failed to confirm whether and by which mechanism G. vaginalis initiates vaginosis, with, consequently, poor diagnostics and treatment outcomes. Recent molecular analyses of protein-coding genes demonstrate that the taxon G. vaginalis consists of at least four distinct species. This development may represent a critical turning point in clarifying ecological interactions and virulence factors contributing to symptoms and/or sequelae of vaginosis.

Cervicovaginal cytokines, sialidase activity and bacterial load in reproductive-aged women with intermediate vaginal flora

Studies have shown that not only bacterial vaginosis, but also intermediate vaginal flora has deleterious effects for women's reproductive health. However, literature still lacks information about microbiological and immunological aspects of intermediate flora.

OBJECTIVE

To characterize intermediate flora regarding levels of Interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor-alpha, interleukin 1 receptor antagonist (IL-1ra), IL-10, sialidase; loads of Gardnerella vaginalis, total bacteria and to verify whether it is closer related to normal flora or bacterial vaginosis. This cross-sectional study enrolled 526 non-pregnant reproductive-aged women distributed in 3 groups according to pattern of vaginal flora using Nugent's system in normal, intermediate and bacterial vaginosis. Cervicovaginal levels of cytokines, sialidases, loads of G. vaginalis and total bacteria were assessed by ELISA, conversion of MUAN and quantitative real-time PCR, respectively. A principal component analysis(PCA) using all measured parameters was performed to compare the three different types of flora. Results showed that intermediate flora is associated with increased cervicovaginal IL-1beta in relation to normal flora(P<0.0001). When compared to bacterial vaginosis, intermediate flora has higher IL-8 and IL-10 levels(P<0.01). Sialidases were in significantly lower levels in normal and intermediate flora than bacterial vaginosis(P<0.0001). Loads of G. vaginalis and total bacterial differed among all groups(P<0.0001), being highest in bacterial vaginosis. PCA showed that normal and intermediate flora were closely scattered, while bacterial vaginosis were grouped separately.

CONCLUSION

Although intermediate flora shows some differences in cytokines, sialidases and bacterial loads in relation to normal flora and bacterial vaginosis, when taken together, general microbiological and immunological pattern pattern of intermediate flora resembles the normal flora.

The Application of Magnetic Bead Selection to Investigate Interactions between the Oral Microbiota and Salivary Immunoglobulins

The effect of humoral immunity on the composition of the oral microbiota is less intensively investigated than hygiene and diet, in part due to a lack of simple and robust systems for investigating interactions between salivary immunoglobulins and oral bacteria. Here we report the application of an ex situ method to investigate the specificity of salivary immunoglobulins for salivary bacteria. Saliva collected from six volunteers was separated into immunoglobulin and microbial fractions, and the microbial fractions were then directly exposed to salivary immunoglobulins of "self" and "non-self" origin. Antibody-selected bacteria were separated from their congeners using a magnetic bead system, selective for IgA or IgG isotypes. The positively selected fractions were then characterized using gel-based eubacterial-specific DNA profiling. The eubacterial profiles of positively selected fractions diverged significantly from profiles of whole salivary consortia based on volunteer (P≤ 0.001%) and immunoglobulin origin (P≤ 0.001%), but not immunoglobulin isotype (P = 0.2). DNA profiles of separated microbial fractions were significantly (p≤ 0.05) less diverse than whole salivary consortia and included oral and environmental bacteria. Consortia selected using self immunoglobulins were generally less diverse than those selected with immunoglobulins of non-self origin. Magnetic bead separation facilitated the testing of interactions between salivary antibodies and oral bacteria, showing that these interactions are specific and may reflect differences in recognition by self and non-self immunoglobulins. Further development of this system could improve understanding of the relationship between the oral microbiota and the host immune system and of mechanisms underlying the compositional stability of the oral microbiota.

Vaginal Mucosal Homeostatic Response May Determine Pregnancy Outcome in Women With Bacterial Vaginosis: A Pilot Study

Bacterial vaginosis (BV) is considered as a trigger for an inflammatory response that could promote adverse pregnancy outcome (APO). We hypothesized that BV-related inflammation could be counterbalanced by anti-inflammatory and mucosal homeostatic responses that could participate in pregnancy outcomes.A total of 402 vaginal self-samples from pregnant women in their first trimester were screened by Nugent score. In this population, we enrolled 23 pregnant women with BV but without APO, 5 pregnant women with BV and developing APO, 21 pregnant women with intermediate flora, and 28 random control samples from pregnant women without BV or APO.BV without APO in pregnant women was associated with 28-fold interleukin-8, 5-fold interleukin-10, and 40-fold interleukin-22 increases in expression compared to controls. BV associated with APO in pregnant women shared 4-fold increase in tumor necrosis factor, 100-fold decrease in interleukin-10, and no variation in interleukin-22 expressions compared to controls. Next-generation sequencing of vaginal microbiota revealed a shift from obligate anaerobic bacteria dominance in BV without APO pregnant women to Lactobacillus dominance microbiota in BV with APO.Our results show that the anti-inflammatory and mucosal homeostatic responses to BV may determine outcome of pregnancy in the setting of BV possibly through effects on the vaginal microbiota.

Bacterial vaginosis in pregnant adolescents: proinflammatory cytokine and bacterial sialidase profile. Cross-sectional study

CONTEXT AND OBJECTIVE

Bacterial vaginosis occurs frequently in pregnancy and increases susceptibility to sexually transmitted infections (STI). Considering that adolescents are disproportionally affected by STI, the aim of this study was to evaluate the cervicovaginal levels of interleukin (IL)-1 beta, IL-6, IL-8 and bacterial sialidase in pregnant adolescents with bacterial vaginosis.

DESIGN AND SETTING

Cross-sectional study at mother and child referral units in Belém, Pará, Brazil.

METHODS

Vaginal samples from 168 pregnant adolescents enrolled were tested for trichomoniasis and candidiasis. Their vaginal microbiota was classified according to the Nugent criteria (1991) as normal, intermediate or bacterial vaginosis. Cervical infection due to Chlamydia trachomatisand Neisseria gonorrhoeae was also assessed. Cytokine and sialidase levels were measured, respectively, using enzyme-linked immunosorbent assays and MUAN conversion in cervicovaginal lavages. Forty-eight adolescents (28.6%) were excluded because they tested positive for some of the infections investigated. The remaining 120 adolescents were grouped according to vaginal flora type: normal (n = 68) or bacterial vaginosis (n = 52). Their cytokine and sialidase levels were compared between the groups using the Mann-Whitney test (P < 0.05).

RESULTS

The pregnant adolescents with bacterial vaginosis had higher levels of IL-1 beta, IL-6 and IL-8 (P < 0.05). Sialidase was solely detected in 35 adolescents (67.2%) with bacterial vaginosis.

CONCLUSIONS

Not only IL-1 beta and sialidase levels, but also IL-6 and IL-8 levels are higher in pregnant adolescents with bacterial vaginosis, thus indicating that this condition elicits a more pronounced inflammatory response in this population, which potentially increases vulnerability to STI acquisition.

Metabolic signatures of bacterial vaginosis. mBio. 2015;6:e00204-215. [PMID: 25873373 PMCID: PMC4453549 DOI: 10.1128/mbio.00204-15]

Bacterial vaginosis (BV) is characterized by shifts in the vaginal microbiota from Lactobacillus dominant to a microbiota with diverse anaerobic bacteria. Few studies have linked specific metabolites with bacteria found in the human vagina. Here, we report dramatic differences in metabolite compositions and concentrations associated with BV using a global metabolomics approach. We further validated important metabolites using samples from a second cohort of women and a different platform to measure metabolites. In the primary study, we compared metabolite profiles in cervicovaginal lavage fluid from 40 women with BV and 20 women without BV. Vaginal bacterial representation was determined using broad-range PCR with pyrosequencing and concentrations of bacteria by quantitative PCR. We detected 279 named biochemicals; levels of 62% of metabolites were significantly different in women with BV. Unsupervised clustering of metabolites separated women with and without BV. Women with BV have metabolite profiles marked by lower concentrations of amino acids and dipeptides, concomitant with higher levels of amino acid catabolites and polyamines. Higher levels of the signaling eicosanoid 12-hydroxyeicosatetraenoic acid (12-HETE), a biomarker for inflammation, were noted in BV. Lactobacillus crispatus and Lactobacillus jensenii exhibited similar metabolite correlation patterns, which were distinct from correlation patterns exhibited by BV-associated bacteria. Several metabolites were significantly associated with clinical signs and symptoms (Amsel criteria) used to diagnose BV, and no metabolite was associated with all four clinical criteria. BV has strong metabolic signatures across multiple metabolic pathways, and these signatures are associated with the presence and concentrations of particular bacteria.

Bacterial vaginosis (BV) is a common but highly enigmatic condition that is associated with adverse outcomes for women and their neonates. Small molecule metabolites in the vagina may influence host physiology, affect microbial community composition, and impact risk of adverse health outcomes, but few studies have comprehensively studied the metabolomics profile of BV. Here, we used mass spectrometry to link specific metabolites with particular bacteria detected in the human vagina by PCR. BV was associated with strong metabolic signatures across multiple pathways affecting amino acid, carbohydrate, and lipid metabolism, highlighting the profound metabolic changes in BV. These signatures were associated with the presence and concentrations of particular vaginal bacteria, including some bacteria yet to be cultivated, thereby providing clues as to the microbial origin of many metabolites. Insights from this study provide opportunities for developing new diagnostic markers of BV and novel approaches for treatment or prevention of BV.

Anaerobes and bacterial vaginosis in pregnancy: virulence factors contributing to vaginal colonisation

The aetiology and pathogenesis of bacterial vaginosis (BV) is unclear but it appears to be associated with factors that disrupt the normal acidity of the vagina thus altering the equilibrium between the normal vaginal microbiota. BV has serious implications for female morbidity, including reports of pelvic inflammatory disease, adverse pregnancy outcomes, increased susceptibility to sexually transmitted infections and infertility. This paper reviewed new available information regarding possible factors contributing to the establishment of the BV vaginal biofilm, examined the proposed role of anaerobic microbial species recently detected by new culture-independent methods and discusses developments related to the effects of BV on human pregnancy. The literature search included Pubmed (NLM), LISTA (EBSCO), and Web of Science. Because of the complexity and diversity of population groups, diagnosis and methodology used, no meta-analysis was performed. Several anaerobic microbial species previously missed in the laboratory diagnosis of BV have been revealed while taking cognisance of newly proposed theories of infection, thereby improving our understanding and knowledge of the complex aetiology and pathogenesis of BV and its perceived role in adverse pregnancy outcomes.

Basic vaginal pH, bacterial vaginosis and aerobic vaginitis: prevalence in early pregnancy and risk of spontaneous preterm delivery, a prospective study in a low socioeconomic and multiethnic South American population

Background

Bacterial vaginosis (BV) increases the risk of spontaneous preterm deliveries (PD) in developed countries. Its prevalence varies with ethnicity, socioeconomic conditions and gestational age. Aerobic vaginitis (AV) has also been implicated with spontaneous PD. The present study aimed to estimate the prevalence of asymptomatic BV, the accuracy of vaginal pH level to predict BV and to estimate the risk of spontaneous PD <34 and <37 weeks’ gestation of BV and AV.

Methods

Women attending prenatal public services in Rio de Janeiro were screened to select asymptomatic pregnant women, < 20 weeks’ gestation, with no indication for elective PD and without risk factors of spontaneous PD. Vaginal smears of women with vaginal pH > = 4.5 were collected to determine the Nugent score; a sample of those smears was also classified according to a modified Donders’ score. Primary outcomes were spontaneous PD < 34 and <37 weeks’ gestation and abortion.

Results

Prevalence of asymptomatic BV was estimated in 28.1% (n = 1699); 42.4% of the smears were collected before 14 weeks’ gestation. After an 8-week follow up, nearly 40% of the initially BV positive women became BV negative. The prevalence of BV among white and black women was 28.1% (95% CI: 24.6%-32.0%) and 32.5% (95% CI: 28.2%-37.2%), respectively. The sensitivity of vaginal pH= > 4.5 and = > 5.0 to predict BV status was 100% and 82%, correspondingly; the 5.0 cutoff value doubled the specificity, from 41% to 84%. The incidence of < 37 weeks’ spontaneous PDs among BV pregnant women with a pH= > 4.5 was 3.8%. The RR of spontaneous PD < 34 and <37 weeks among BV women with pH > =4.5, as compared with those with intermediate state, were 1.24 and 1.86, respectively (Fisher’s exact test, p value = 1; 0.52, respectively, both ns). No spontaneous case of PD or abortion was associated with severe or moderate AV.

Conclusions

A high prevalence of asymptomatic BV was observed without statistically significant difference between black and white women. The RRs of spontaneous PD < 34 and <37 weeks among women with BV, as compared with those with intermediate state were not statistically significant but were consistent with those found in the literature.

Sialidase activity in aerobic vaginitis is equal to levels during bacterial vaginosis

OBJECTIVE

To evaluate levels of proinflammatory cytokines and sialidase activity in aerobic vaginitis (AV) in relation to normal vaginal flora and bacterial vaginosis (BV).

STUDY DESIGN

In this cross-sectional study, a total of 682 consecutive non-pregnant women attending the gynecology service were assessed and 408 women were included. Vaginal rinsing samples were collected from 223 women with microscopic finding of BV (n=98), aerobic vaginitis (n=25) and normal flora (n=100). Samples were tested for interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)-α, and sialidase activity.

RESULTS

Compared to women with normal flora, vaginal levels of IL-1β were highly increased in both BV and AV (p<0.0001). Significantly higher vaginal IL-6 was detected in AV (p<0.0001) but not in BV, in relation to normal flora. Women with AV also presented increased IL-8 levels (p<0.001), while those with BV presented levels similar to normal flora. Sialidase was increased in BV and AV compared with the normal group (p<0.0001) but no difference in sialidase activity was observed between BV and AV.

CONCLUSION

A more intense inflammatory host response occurs for AV than for BV when compared with normal flora. Furthermore, the increased sialidase activity in AV and BV indicates that both abnormal vaginal flora types can be harmful to the maintenance of a healthy vaginal environment.

[Innate and adaptative immunity of the female genital tract]

Most of molecules and cells involved in both types, innate and adaptive immunity are present within the feminine genital tract. This article attempts to list some of the various actors involved in these immunities, essentially at the vaginal level and to illustrate their implications in the most frequent pathologies. Among these molecules: defensins, collectins lysozyme, lactoferrin, calprotectin, SLP1, HSP and many others as well as Toll receptors and immunoglobulins (IgG and IgA) play a major role. Epithelial cells, antigen presenting cells, lymphocytes T, B, NK also contribute efficiently to the defenses in a coordinated way partially under the influence of sex hormones. The therapeutic perspectives, of which vaccines are briefly mentioned.

High sialidase levels increase preterm birth risk among women who are bacterial vaginosis-positive in early gestation

OBJECTIVE

The purpose of this study was to assess whether vaginal sialidases level in early pregnancy is associated with preterm birth among women who are bacterial vaginosis-positive.

STUDY DESIGN

Of the 1806 women who were enrolled at < 20 weeks of gestation, 800 of the women were bacterial vaginosis-positive (Nugent score, 7-10); 707 of the women had birth outcome data; 109 of the women who were bacterial vaginosis-positive had an adverse preterm outcome, which included 53 spontaneous preterm births (19 births were early at 20-34 weeks, and 34 births were late at 34-37 weeks), and 14 of the women had late miscarriages (12-20 weeks). Sialidase levels were compared with 352 control subjects (term normal birthweight infants).

RESULTS

Sialidase levels at ≥ 5, ≥ 10, and ≥ 14 nmol (odds ratio [OR], 1.56; 95% confidence interval [CI], 1.01-2.41; OR, 2.14; 95% CI, 1.25-3.64; OR, 3.17; 95% CI, 1.64-6.10, respectively) was associated significantly with all adverse preterm outcomes. The ≥ 10 nmol and ≥ 14 nmol cut-points were associated strongly with early spontaneous preterm births (OR, 3.79; 95% CI, 1.42-10.10 and OR, 5.36; 95% CI, 1.77-16.23, respectively) and late miscarriages (OR, 4.87; 95% CI, 1.61-14.65; OR, 8.33; 95% CI, 2.57-26.9, respectively).

CONCLUSION

Elevated sialidase level that is measured at 12 weeks of gestation is associated strongly with early spontaneous preterm births and late miscarriage.

Randomized controlled trial of probiotics for the prevention of spontaneous preterm delivery associated with intrauterine infection: study protocol

BACKGROUND

Spontaneous preterm deliveries that occur before the 34th week of gestation, and particularly before the 32nd week of gestation, have been strongly associated to intrauterine infection, ascending from vagina, and represent the largest portion of neonatal deaths and neurological problems. Bacterial vaginosis, characterized by a diminished or absent flora of lactobacilli and increased colonization of several anaerobic or facultative microorganisms, increases two times the risk of preterm delivery before the 34th week. Trials of antibiotics failed to show efficacy and effectiveness against spontaneous preterm birth related to bacterial vaginosis. Some studies indicate benefit from selected probiotics to treat genitourinary infections, including bacterial vaginosis.

OBJECTIVE

The purpose of this study is to evaluate the effectiveness of the early administration of selected probiotics to pregnant women with asymptomatic bacterial vaginosis/intermediate degree infection to reduce the occurrence of spontaneous preterm delivery and related neonatal mortality and morbidity.

METHODS/DESIGN

Women attending public prenatal care services in Rio de Janeiro will be screened to select asymptomatic pregnant women, less than 20 weeks' gestation, with no indication of elective preterm delivery. Those with vaginal pH > = 4.5 and a Nugent score between 4 and 10 (intermediate degree infection or bacterial vaginosis) will be randomized to either the placebo or the intervention group, after written informed consent. Intervention consists in the use of probiotics, Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14, 2 capsules a day, each capsule containing more than one million bacilli of each strain, for 6-12 weeks, up to the 24th-25th wk of gestation. Ancillary analyses include quantification of selected cervicovaginal cytokines and genotyping of selected polymorphisms. The randomization process is stratified for history of preterm delivery and blocked. Allocation concealment was designed as well as blinding of women, caregivers and outcome evaluators. The study will be supervised by an independent monitoring committee. Outcomes under study are preterm delivery (< 34- < 32 weeks of gestation) and associated neonatal complications: early neonatal sepsis, bronchopulmonary dysplasia, periventricular leukomalacia, necrotizing enterocolitis, and prematurity-related retinopathy; definitions were adapted from those recommended by the 2002 version of the Vermont-Oxford Network. Trial registration at NIH register: NCT00303082.

Changes in the vaginal microenvironment with metronidazole treatment for bacterial vaginosis in early pregnancy

OBJECTIVE

Bacterial vaginosis (BV) is associated with preterm delivery, but there is little evidence that treatment improves pregnancy outcomes. We examined whether oral or vaginal metronidazole treatment for BV in early pregnancy was more effective in restoring the normal vaginal environment.

METHODS

This was a randomized controlled trial comparing oral and intravaginal metronidazole for treatment of BV in early pregnancy (<20 weeks). Vaginal samples collected at baseline and 4 weeks after treatment were evaluated using gram stain, culture, colorimetric detection of sialidase, and immunoassay for measurement of proinflammatory cytokines interleukins-1beta, -6, -8 (IL-1beta, IL-6, IL-8) and secretory leukocyte protease inhibitor (SLPI). We compared the effect of treatment between groups (using chi-square and t test) and within individuals (McNemar's test).

RESULTS

Of 126 subjects, 108 (86%) completed follow-up (55 oral, 53 intravaginal). Of the study population, 34% achieved therapeutic cure, and this was not different between treatment groups. BV-associated bacteria were significantly reduced in both groups, but few subjects regained colonization with protective lactobacilli. Among women who achieved therapeutic cure, the level of IL-1beta dropped significantly (p < 0.001) and SLPI increased (p = 0.003). More women in the vaginal treatment group had undetectable sialidase after treatment (p = 0.013).

CONCLUSIONS

Treatment with oral or intravaginal metronidazole in early pregnancy reduced colonization with BV-associated bacteria but was not effective in achieving therapeutic cure or in restoring healthy vaginal lactobacilli.

Vaginal and oral microbes, host genotype and preterm birth

Preterm birth (PTB) is a leading cause of infant mortality and morbidity in the US and across the globe. Infection and associated inflammation are important initiators for PTB pathways; an estimated 40% of PTBs are attributed to amniochorionic-decidual or systemic inflammation. Historically, intrauterine infections have been implicated in PTB; recent evidence suggests that infections remote from the fetal site may also be causative. There is strong epidemiological evidence that bacterial vaginosis and periodontitis--two syndromes characterized by perturbations in the normal vaginal and oral bacterial microflora, respectively--are linked to infection-associated PTB. Oral and vaginal environments are similar in their bacterial microbiology; identical bacterial species have been independently isolated in periodontitis and bacterial vaginosis. Periodontitis and bacterial vaginosis also share many behavioral and sociodemographic risk factors suggesting a possible common pathophysiology. Genetic polymorphisms in host inflammatory responses to infection are shared between bacterial vaginosis, periodontitis and PTB, suggesting common mechanisms through which host genotype modify the effect of abnormal bacterial colonization on preterm birth. We review the state of knowledge regarding the risk of PTB attributable to perturbations in bacterial flora in oral and vaginal sites and the role of host genetics in modifying the risk of infection-related PTB. We posit that bacterial species that are common in perturbed vaginal and oral sites are associated with PTB through their interaction with the host immune system.

Predictive value for preterm birth of abnormal vaginal flora, bacterial vaginosis and aerobic vaginitis during the first trimester of pregnancy

INTRODUCTION

Abnormal vaginal flora (AVF) before 14 gestational weeks is a risk factor for preterm birth (PTB). The presence of aerobic microorganisms and an inflammatory response in the vagina may also be important risk factors.

AIM

The primary aim of the study was to investigate the differential influences of AVF, full and partial bacterial vaginosis, and aerobic vaginitis in the first trimester on PTB rate. The secondary aim was to elucidate why treatment with metronidazole has not been found to be beneficial in previous studies.

SETTING

Unselected women with low-risk pregnancies attending the prenatal unit of the Heilig Hart General Hospital in Tienen, Belgium, were included in the study.

MATERIALS AND METHODS

At the first prenatal visit, 1026 women were invited to undergo sampling of the vaginal fluid for wet mount microscopy and culture, of whom 759 were fully evaluable. Abnormal vaginal flora (AVF; disappearance of lactobacilli), bacterial vaginosis (BV), aerobic vaginitis (AV), increased inflammation (more than ten leucocytes per epithelial cell) and vaginal colonisation with Candida (CV) were scored according to standardised definitions. Partial BV was defined as patchy streaks of BV flora or sporadic clue cells mixed with other flora, and full BV as a granular anaerobic-type flora or more than 20% clue cells. Vaginal fluid was cultured for aerobic bacteria, Mycoplasma hominis and Ureaplasma urealyticum. Outcome was recorded as miscarriage <or=13 weeks + 6 days [early miscarriage (EM), n = 8 (1.1%)], between 14 + 0 and 24 weeks + 6 days [late miscarriage (LM), n = 7 (0.9%)], delivery or miscarriage <or=34 weeks + 6 days n = 29 (3.8%)], <or=36 weeks + 6 days n = 70 (9.2%)]. PTB between 25 + 0 and 36 weeks + 6 days was further divided in severe PTB (SPTB, 25 + 0 to 34 weeks + 6 days) and mild PTB (MPTB, 35 + 0 to 36 weeks + 6 days).

RESULTS

Women without abnormalities of the vaginal flora in the first trimester had a 75% lower risk of delivery before 35 weeks compared with women with AVF [odds ratio (OR) 0.26; 95% confidence interval (CI) 0.12-0.56]. The absence of lactobacilli (AVF) was associated with increased risks of PTB (OR 2.4; 95% CI 1.2-4.8), EPTB (OR 6.2; 95% CI 2.7-14) and miscarriage (OR 4.9; 95% CI 1.4-17). BV was associated with increased risks of PTB (OR 2.4; 95% CI 1.1-4.7), EPTB (OR 5.3; 95% CI 2.1-12.9) and miscarriage (OR 6.6; 95% CI 2.1-20.9) and coccoid AV was associated with increased risks of EPTB (OR 3.2; 95% CI 1.2-9.1) and miscarriage (OR 5.2; 95% CI 1.5-17). In women with BV, partial BV had a detrimental effect on the risk of PTB for all gestational ages, but full BV did not. Preterm deliveries later than 24 weeks+ 6 days were more frequent when M. hominis was present (EPTB OR 13.3; 95% CI 3.2-55).

DISCUSSION

Bacterial vaginosis, AV and AVF are associated with PTB, especially LM and severe PTB between 25 and 35 weeks. The absence of lactobacilli (AVF), partial BV and M. hominis, but not full BV, were associated with an increased risk of preterm delivery after 24 weeks+ 6 days. As metronidazole effectively treats full BV, but is ineffective against other forms of AVF, the present data may help to explain why its use to prevent PTB has not been successful in most studies.

Among pregnant women with bacterial vaginosis, the hydrolytic enzymes sialidase and prolidase are positively associated with interleukin-1beta

OBJECTIVE

The objective of the study was to explore the mechanisms of local innate immunity induction and modulation in pregnant women with bacterial vaginosis (BV).

STUDY DESIGN

A total of 200 singleton pregnant women in early gestation (12 +/- 4 weeks) with BV (Nugent 7-10) without concurrent vaginal infections with Trichomonas vaginalis, Chlamydia trachomatis, Neisseria gonorrhoeae, syphilis, and yeast. Concentrations of vaginal interleukin (IL)-1beta and IL-8, the number of neutrophils, and the levels of sialidase and prolidase hydrolytic enzymes were determined in vaginal fluid.

RESULTS

Concentrations of vaginal IL-1beta had a strong positive correlation with levels of sialidase (P < .001) and prolidase (P < .001). Conversely, such enzymes were negatively correlated with the ratio of IL-8/IL-1beta (both P < .001) and were not significantly associated with concentrations of IL-8. Notably, the number of vaginal neutrophils had a negative correlation with sialidase (P = .007).

CONCLUSION

The strong induction of IL-1beta in BV-positive women appears to be associated with the production of the hydrolytic enzymes sialidase and prolidase by BV-associated bacteria. However, these 2 enzymes may inhibit the expected amplification of the proinflammatory IL-1beta cascade as evaluated by the down-regulation of the IL-8/IL-1beta ratio. A blunted response to IL-1beta signals may cause the poor rise of neutrophils, which is peculiar to BV. This impairment of local defense may contribute to increased susceptibility to adverse outcomes in BV-positive pregnant women.

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.

Effect of Lactobacillus challenge on Gardnerella vaginalis biofilms

Bacterial vaginosis (BV) is the most common infectious condition in women. It is caused primarily by anaerobic bacteria which rapidly form biofilms recalcitrant to antibiotic treatment, elevate vaginal pH, induce inflammatory processes and displace indigenous lactobacilli from the vault. Gardnerella vaginalis is commonly associated with these infections. Microscopy analysis showed that within 72 h, viable G. vaginalis covered a surface area of 567 microm(2), reached a depth of 16 microm and a density of approximately 104 microm(3). They maintained these levels for a further 3 days unless challenged with lactobacilli strains. Lactobacillus reuteri RC-14 produced the biggest displacement of Gardnerella. This was not due to pH, which remained between 4.7 and 5.1 for all experiments, nor by hydrogen peroxide which is produced in low amounts by strain L. reuteri RC-14, high amounts by L. crispatus 33820 and not at all by L. rhamnosus GR-1. Deconvolution microscopy showed changes in structure and viability of the biofilms, with loss of dense Gardnerella biofilm pods. For the first time, a strain of L. iners, the most commonly isolated vaginal Lactobacillus in healthy women, was tested for potential probiotic properties. It was found to disrupt Gardnerella biofilm surface area, density and depth, albeit to a lesser extent than L. reuteri RC-14. These studies help to provide insight into the clinical situation in which probiotic and indigenous vaginal lactobacilli can interfere with Gardnerella's presence and reduce the risk of bacterial vaginosis.

Preconceptional antibiotic treatment to prevent preterm birth in women with a previous preterm delivery

This article addresses the question of whether the uterine cavity is normally sterile and reviews the difficulties in conducting microbiologic studies of the endometrium, the limitations of conventional microbiologic techniques (cultivation-dependent), and the potential contribution of molecular microbiology to examine microbial diversity and burden of the endometrium. Issues pertaining to the diagnosis of chronic endometritis and the need for information about the prognostic value of this finding in subsequent pregnancies are discussed. The results of a randomized clinical trial of antibiotic administration versus placebo in women with a previous preterm birth are reviewed and commentary is provided. The emerging picture is that microbial-host interactions in the endometrial cavity are important for reproductive success. This is a US government work. There are no restrictions on its use.

Differences in inflammatory cytokine and Toll-like receptor genes and bacterial vaginosis in pregnancy

OBJECTIVE

This study was undertaken to estimate the frequency of inflammatory cytokine and Toll-like receptor gene polymorphisms in women with and without bacterial vaginosis (BV) in pregnancy.

STUDY DESIGN

A secondary analysis was performed of pregnant women at less than 30 weeks' gestation enrolled as part of 2 multicenter studies. Eight hundred eighty-five women were assessed for BV (defined as Nugent's vaginal Gram stain score 7-10 and a pH > 4.5). Comparisons were made between women with or without BV. Extracted maternal DNA was analyzed for 7 cytokine (interleukin [IL] 1beta-511, IL1beta Exon 5 +3954, IL6-174, IL8-845, IL10-1082, tumor necrosis factor alpha-238 [TNFalpha-238], TNFalpha-308) and 2 Toll-like receptor (TLR-4 299, TLR-4 399) gene polymorphisms.

RESULTS

BV was diagnosed in 497 women and 388 did not have BV. Genotype and allele frequency analyses revealed associations with BV and polymorphisms at the IL1beta Exon 5 +3954, IL6-174, IL10-1082, and TLR-4 399 loci. Women with BV were less likely to be homozygous (C/C) for IL1beta Exon 5 +3954 (P = .04). Women with BV were also less likely to have polymorphisms at the IL10-1082 (P = .03) and TLR-4 399 (P = .04) loci in the univariate analysis. Women with BV were more likely to be heterozygous (G/C) for the IL6-174 genotype (P < .0001). Multivariate analysis, controlling for maternal race, confirmed the following associations with BV: IL1beta Exon 5 +3954 (odds Ratio [OR] 0.5, 95% CI 0.3-0.9) and IL6-174 (OR 2.2, 95% CI 1.6-3.1). In addition, polymorphism at the IL8-845 locus was associated with a decreased risk for BV (OR 0.6, 95% CI 0.4-1.0).

CONCLUSION

After controlling for race, polymorphisms at the IL1beta Exon 5 +3954, IL6-174, and IL8-845 loci were associated with an altered rate of BV in pregnancy.

Variation in microbiologic profiles among pregnant women with bacterial vaginosis

OBJECTIVE

The purpose of this study was to determine if clinical findings and sociodemographic variables among bacterial vaginosis (BV)-positive pregnant women are associated with different microbiologic profiles.

STUDY DESIGN

Pregnant women were assessed for BV by Nugent criteria. BV+ women were separated into 6 mutually exclusive microbiologic groups. In unadjusted analyses, we compared (1) sociodemographic and behavioral characteristics, and (2) 3 clinical characteristics among BV+ women with and without Mobiluncus (M+ vs M-). Unadjusted data were analyzed using the chi-square test. Multiple logistic regression was used to assess the likelihood of having clinical signs of BV in women with and without Mobiluncus spp while controlling for confounders.

RESULTS

A total of 1756 BV+ pregnant women were followed. The M+ group (n=702) was significantly more likely than the M- group (n=1054) to be non-Hispanic black (80.9% vs 66.2%; P < .0001), older than 21 years (61.7% vs 48.7%; P < .0001), and to have had more than 3 lifetime sexual partners (66.4% vs 54.9%; P < .0001). The M+ group was also more likely to have clue cells on wet mount (63.9% vs 47.2%; P < .0001) and a positive amine odor after addition of KOH (57.2% vs 45.0%; P=.001). There was no difference in other demographic variables or physician diagnosis of abnormal vaginal discharge. In the adjusted analyses for each clinical outcome, all findings were consistent with the unadjusted analyses.

CONCLUSION

BV+ pregnant women with Mobiluncus spp are more likely to have clue cells present on wet mount, a positive amine odor after KOH preparation, and to be older, non-Hispanic black, and have had more lifetime sexual partners compared to BV+ women without any Mobiluncus species.

Evaluation of a point-of-care test, BVBlue, and clinical and laboratory criteria for diagnosis of bacterial vaginosis

Bacterial vaginosis (BV) remains the most common cause of abnormal vaginal discharge in women of reproductive age and is associated with increased susceptibility to human immunodeficiency virus and sexually transmitted infections and preterm delivery. Present diagnostic methods require access to microscopy and laboratory expertise; however, the majority of women, particularly those in populations with a high prevalence of BV, do not have access to clinical services with on-site microscopy capabilities. We evaluated a point-of-care test for the diagnosis of BV, the BVBlue test, with 288 women attending a sexual health service with symptoms of abnormal vaginal discharge and/or odor. The BVBlue test performed well compared with conventional diagnostic methods for the assessment of women with symptoms suggestive of BV at the bedside and significantly better than other simple tests, such as vaginal pH determination and the amine test, that do not require microscopy. The BVBlue test was sensitive (88%; 95% confidence interval [CI], 81 to 93%) and specific (95%; 95% CI, 91 to 98%) compared to the method of Nugent et al. (R. P. Nugent, M. A. Krohn, and S. L. Hillier, J. Clin. Microbiol. 29:297-301, 1991) and performed well compared with the method of Amsel et al. (R. Amsel, P. A. Totten, C. A. Spiegel, K. C. Chen, D. Eschenbach, and K. K. Holmes, Am. J. Med. 74:14-22, 1983), with a sensitivity of 88% (95% CI, 81 to 93%) and a specificity of 91% (95% CI, 85 to 94%). The BVBlue test is a simple, rapid, and objective test for the diagnosis of BV and has the potential to facilitate prompt diagnosis and appropriate treatment of BV in the absence of microscopy. The majority of women at the greatest risk for the sequelae of BV are not in settings where the conventional diagnostic methods are either practical or possible, and they would greatly benefit from access to rapid and reliable point-of-care tests to improve the diagnosis and management of BV.

Assessment of cervical antibody concentrations fails to enhance the value of cervical length as a predictor of preterm delivery

OBJECTIVE

The purpose of this study was to determine if cervical fluid antibody concentrations can enhance the value of cervical length in predicting risk of preterm delivery.

STUDY DESIGN

We obtained cervical fluid samples with preweighed cellulose wicks from a prospective cohort of women 23 to 32 weeks' gestation with signs and symptoms of preterm labor and intact membranes. Total immunoglobulin A and G (IgA and IgG) concentrations were determined by enzyme-linked immunosorbent assay. Bacterial vaginosis was diagnosed by Gram stain, and cervical length was measured with endovaginal ultrasound.

RESULTS

For subjects with term (n = 77) and preterm (n = 24) deliveries, median IgA and IgG concentrations were 736 vs 643 microg/mL (P = .33) and 1528 vs 1769 microg/mL (P = .85). For subjects with normal flora (n = 71), intermediate flora (n = 14), and bacterial vaginosis (n = 16), median IgA and IgG concentrations were 717, 624, and 774 microg/mL (P = .90) and 1383, 1553, and 2731 microg/mL (P = .02). In a forward stepwise logistic regression model, cervical length was the only factor associated with preterm delivery (P < .001).

CONCLUSION

Measuring the concentrations of IgA and IgG in cervical fluid does not enhance the value of cervical length in predicting risk of preterm delivery.

Bacterial vaginosis - a microbiological and immunological enigma. Review article

The development of bacterial vaginosis (BV) among women of childbearing age and the resulting quantitative and qualitative shift from normally occurring lactobacilli in the vagina to a mixture of mainly anaerobic bacteria is a microbiological and immunological enigma that so far has precluded the formulation of a unifying generally accepted theory on the aetiology and clinical course of BV. This critical review highlights some of the more important aspects of BV research that could help in formulating new basic ideas respecting the biology of BV, not least the importance of the interleukin mediators of local inflammatory responses and the bacterial shift from the normally occurring lactobacilli species: L. crispatus, L. gasseri, L. jensenii, and L. iners to a mixed flora dominated by anaerobic bacteria.

Combination of vaginal pH with vaginal sialidase and prolidase activities for prediction of low birth weight and preterm birth

OBJECTIVE

The purpose of this study was to assess if easy to measure vaginal fluid biomarkers are predictive for low birth weight (LBW, <2500 g), very LBW (VLBW, <1500 g), spontaneous preterm at <37 weeks' gestation, and total preterm deliveries (at <37, <35, <32 weeks' gestation).

STUDY DESIGN

Low and high cutoffs for vaginal fluid pH, sialidase, and prolidase activities were examined in a nested case-control study of 579 Danish women (from a study population of 2846 women) with samples collected at mean 17 weeks' gestation. One hundred sixteen LBW (17 VLBW), 117 preterm deliveries (85 spontaneous), and 418 normal term deliveries were analyzed.

RESULTS

Vaginal pH >/=4.7 or pH >/=5 by itself was not associated with LBW or prematurity. Conversely, combination of pH >/=5 and high sialidase activity demonstrated OR 17 (CI 1.8-150) for LBW; OR 31 (CI 1.8-516) for VLBW; along with OR 18 (CI 1.6-204) for preterm at <35 weeks'; and OR 31 (CI 1.9-542) for preterm at <32 weeks' gestation. The combination of pH >/=5 and high prolidase activity demonstrated OR 13 (CI 1.3-122) for LBW; OR 33 (CI 2.0-553) for VLBW, as well as OR 9.2 (CI 0.6-150) for preterm at <35 weeks'; and OR 35 (CI 2.0-586) for preterm at <32 weeks' gestation. In this population, no woman having high sialidase and high prolidase activity had a term birth, or a baby weighting >/=2500 g at birth.

CONCLUSION

In this Danish population, mid-gestation findings of vaginal fluid elevated pH with sialidase and/or prolidase were associated with LBW, VLBW, and early preterm at <35 or <32 weeks' gestation.

Cervical immunoglobulin A and altered vaginal flora in pregnant women with threatened preterm delivery

The aim of our study was to investigate the cervical immunoglobulin A concentration in women with threatened preterm delivery. Immunoglobulin A concentration in the cervical mucus of 80 women with symptoms of preterm delivery was measured using radial immunodiffusion. The results were compared with those of 60 healthy pregnant women. Concentrations of immunoglobulins in maternal serum were also measured. There was no significant difference of cervical immunoglobulin A (IgA) concentration between women with threatened preterm delivery and controls: 53.98 (0.0-189.7) mg/l vs. 61.7 (1.4-400.9; p<0.4) mg/l (median, range). The median of cervical IgA levels in the group of threatened preterm delivery did not differ significantly between patients delivered preterm (n=34) or at term (n=46): 38.3 (0.0-187.9) vs. 65.7 (1.4-189.7; p<0.2) mg/l. Women with a normal vaginal flora showed a significantly higher cervical IgA concentration than those with a pathological colonization: 72.7 (0.0-187.9) vs. 42.5 (0.0-189.7) mg/l. Patients with a pathological vaginal smear and preterm delivery had the lowest IgA levels (35.0; 0.0-187.9 mg/l). Measurement of cervical IgA concentration does not differentiate between women who deliver before or at term.

Gardnerella vaginalis-infected scalp hematoma associated with electronic fetal monitoring

Infections in the neonate caused by the vaginal commensal Gardnerella vaginalis are rare and mostly consist of bacteremia. A 4130-g term neonate developed an infection of a scalp hematoma with G. vaginalis. The infection developed in association with electronic fetal monitoring. The only clinical sign was an increase in size of the hematoma.

The potential for probiotics to prevent bacterial vaginosis and preterm labor

Infections of the urogenital tract in women represent a major burden on the quality of life of women and on the health care system of Canada and other countries. Complications arising from bacterial vaginosis (BV) include increased risk of sexually transmitted diseases including human immunodeficiency virus and elevated risk of preterm birth (PTB). Pharmaceutical interventions, such as antibiotics, have been suboptimally effective and have failed to reduce the incidence of PTB. The absence of lactobacilli in the vagina, a specific feature of BV, raises the question as to whether restoration of lactobacilli, by probiotic therapy, can restore the normal flora and improve the chances of having a healthy term pregnancy. The rationale for probiotic use in pregnant women is quite strong. Certain lactobacilli strains can safely colonize the vagina after oral and vaginal administration, displace and kill pathogens including Gardnerella vaginalis and Escherichia coli, and modulate the immune response to interfere with the inflammatory cascade that leads to PTB. Additional attributes of probiotics include their potential to degrade lipids and enhance cytokine levels, which promote embryo development. In a society that focuses on disease rather than health and drug therapy rather than natural preventive measures, it will take some effort to get remedies such as probiotics into mainstream care. Perhaps the escalating health care budgets and emergence of "superbugs" will provide the incentives to put in place clinical trials designed to evaluate how best to use the commensal organisms that, after all, make up more of our body than human cells, and without which none of us would survive.

Determination of immunoglobulin A against Gardnerella vaginalis hemolysin, sialidase, and prolidase activities in vaginal fluid: implications for adverse pregnancy outcomes

A nested case-control study of low birth weight and preterm delivery was performed with singleton women. Immunoglobulin A (IgA) against the Gardnerella vaginalis hemolysin (anti-Gvh IgA) and sialidase and prolidase activities were determined in vaginal fluid at 17 weeks of gestation. Sialidase positivity and bacterial vaginosis with high prolidase activity were associated with 2- and 11-fold increased risks for low birth weight, respectively. No woman with bacterial vaginosis plus a strong anti-Gvh IgA response had an adverse outcome.