Dietary intake of selected nutrients affects bacterial vaginosis in women

Vaginal Microbiome and Its Relationship to Behavior, Sexual Health, and Sexually Transmitted Diseases

The vaginal microbiota has great significance in maintaining vaginal health and protecting the host from disease. Recent advances in molecular techniques and informatics allow researchers to explore microbial composition in detail and to compare the structure of vaginal microbial communities with behavior and health outcomes, particularly acquisition and transmission of sexually transmitted diseases (STDs) and poor birth outcomes. Vaginal flora have been found to cluster into a limited number of communities, although community structure is dynamic. Certain community types are more associated with poor reproductive outcomes and STDs; communities dominated by Lactobacillus species, particularly Lactobacillus crispatus, are most associated with vaginal health. Modifiable and nonmodifiable factors are strongly associated with community composition, including behavior, race or ethnicity, and hygiene. In this review, we describe the state of the science on the vaginal microbiome and its relationship to behavior, sexual health, and STDs, including determinants of the microbiome that go beyond an individual level.

Pathogenesis of Bacterial Vaginosis: Discussion of Current Hypotheses

In April 2015, the Division of Microbiology and Infectious Diseases of the National Institute of Allergy and Infectious Diseases hosted an experts technical consultation on bacterial vaginosis (BV), where data regarding controversies over the pathogenesis of BV were discussed. The discussion on the epidemiology and pathogenesis of BV is presented here, and several hypotheses on its pathogenesis are critiqued. Rigorous hypothesis-driven studies are needed to ultimately determine the cause of BV. This information is vital for the prevention and control of this important infection and its adverse public health consequences.

Impact of Health-Promoting Educational Intervention on Lifestyle (Nutrition Behaviors, Physical Activity and Mental Health) Related to Vaginal Health Among Reproductive-Aged Women With Vaginitis

Background

Vaginitis is one of the most common diseases in reproductive-aged women (15 - 49 years of age). Side effects of vaginitis can affect other aspects of health, which could be prevented by promoting a healthy lifestyle related to vaginal health.

Objectives

This study aimed at determining the impact of health-promoting educational intervention on lifestyle (nutrition behaviors, physical activities, and mental health) related to vaginal health among reproductive-aged women with vaginitis.

Methods

The data set was collected as part of an experimental study conducted on 350 reproductive-aged women with vaginitis. Participants were selected through a stratified two-stage clustered sampling and simple randomization from 10 attending health centers affiliated with Kermanshah University of Medical Sciences in five regions (North, South, East, West, and Center) of Kermanshah (a city in western Iran) in 2015. Two clinics in each region were selected; patients from the first center were chosen as the intervention group and patients from the second center made up the control group. To collect data, a questionnaire including socio-demographic and lifestyle questions was used. The questionnaire was designed and validated via the psychometric process. Educational intervention was performed over twenty sessions of 25 to 35 minutes. The intervention group was followed up with face-to-face education, a pamphlet, phone contact, and by social media. The control group continued the routine treatment without contacting the intervention group. Data were collected from both groups before the intervention and six months after the intervention. Data were analyzed using the SPSS-20 package, using the independent t-test, paired t-test, chi-square test, and analysis of covariance (ANCOVA) test. The confidence interval was 95% and P < 0.05 was considered statistically significant.

Results

ANCOVA showed that after adjusting for effects of pretest scores, the difference between mean scores on the scale of lifestyle related to vaginal health in the intervention group (28.48 ± 0.38) and control group (23.65 ± 1.23) was significant (P < 0.001). Intervention has a positive significant effect on increasing the mean scores of lifestyle in the intervention group (P < 0.001). Comparing mean differences between the two groups indicated significant difference between them (P < 0.001). Results of the paired t-test in the control group did not show significant changes in lifestyle scores after 6 months (P > 0.05). The independent t-test did not show significant statistical differences between the two groups in terms of demographic characteristics (P > 0.05).

Conclusions

According to the findings, educational intervention is beneficial in promoting three aspects of women's lifestyle related to vaginal health. Therefore, a health-promoting lifestyle seems essential for having a healthy vagina and for preventing vaginitis.

Determination of factors affecting relapse of vaginitis among reproductive-aged women: An experimental study

INTRODUCTION

Vaginitis is a common problem for women, especially in reproductive-aged women. It is a worldwide health problem with many side effects but could be prevented by a health-promoting lifestyle related to vagina health. The aim of this study was to determine the factors affecting relapse of vaginitis.

METHODS

In this experimental study, 350 reproductive-aged women with vaginitis were selected from 10 health centers in Kermanshah (Iran) during 2015 and were equally included in the intervention and control groups. To collect data, a researcher-created questionnaire, which included sociodemographic and health-promoting lifestyle questions, was used. The educational intervention was performed over 20 sessions, each lasting 25-35 minutes. An intervention group was educated by face-to-face education, pamphlets, phone contacts, text messages, and social media. Another group continued the routine clinic education and treatment without contacting the intervention group. Data were analyzed through chi-square and a logistics regression model using IBM-SPSS version 20.

RESULTS

The results of the study indicated a significant relation between sociodemographic characteristics such as women and their husbands' literacy, job, family size, income, area for each member of family, tendency of pregnancy, body mass index (BMI), and caesarean experience (p<0.001) and vaginitis. In addition, significant relationships between health-promoting lifestyle dimensions and prevention of vaginitis were identified. Relapse after intervention in the intervention group was 27.7% and 72.3% in the control group. According to the logistic regression analysis, chance for relapse of vaginitis in the group that did not receive intervention was more than the same chance in the intervention group (OR=5.14).

CONCLUSION

Health-promoting lifestyle intervention influences prevention of vaginitis. Health-promoting lifestyle, literacy promotion, prevention of caesarian, and obesity are beneficial to improvement in lifestyle dimensions associated with vagina health could be implemented as a successful prevention method. Therefore, it seems that applying a health-promoting lifestyle is essential for a healthy vagina and prevention of vaginitis.

Lactobacilli Dominance and Vaginal pH: Why Is the Human Vaginal Microbiome Unique?

The human vaginal microbiome is dominated by bacteria from the genus Lactobacillus, which create an acidic environment thought to protect women against sexually transmitted pathogens and opportunistic infections. Strikingly, lactobacilli dominance appears to be unique to humans; while the relative abundance of lactobacilli in the human vagina is typically >70%, in other mammals lactobacilli rarely comprise more than 1% of vaginal microbiota. Several hypotheses have been proposed to explain humans' unique vaginal microbiota, including humans' distinct reproductive physiology, high risk of STDs, and high risk of microbial complications linked to pregnancy and birth. Here, we test these hypotheses using comparative data on vaginal pH and the relative abundance of lactobacilli in 26 mammalian species and 50 studies (N = 21 mammals for pH and 14 mammals for lactobacilli relative abundance). We found that non-human mammals, like humans, exhibit the lowest vaginal pH during the period of highest estrogen. However, the vaginal pH of non-human mammals is never as low as is typical for humans (median vaginal pH in humans = 4.5; range of pH across all 21 non-human mammals = 5.4-7.8). Contrary to disease and obstetric risk hypotheses, we found no significant relationship between vaginal pH or lactobacilli relative abundance and multiple metrics of STD or birth injury risk (P-values ranged from 0.13 to 0.99). Given the lack of evidence for these hypotheses, we discuss two alternative explanations: the common function hypothesis and a novel hypothesis related to the diet of agricultural humans. Specifically, with regard to diet we propose that high levels of starch in human diets have led to increased levels of glycogen in the vaginal tract, which, in turn, promotes the proliferation of lactobacilli. If true, human diet may have paved the way for a novel, protective microbiome in human vaginal tracts. Overall, our results highlight the need for continuing research on non-human vaginal microbial communities and the importance of investigating both the physiological mechanisms and the broad evolutionary processes underlying human lactobacilli dominance.

Treatment of vitamin D deficiency is an effective method in the elimination of asymptomatic bacterial vaginosis: A placebo-controlled randomized clinical trial

Background & objectives:

Bacterial vaginosis (BV) is the most prevalent vaginal infection in women of reproductive age group which has been found to be associated with vitamin D deficiency. The purpose of this study was to investigate the effectiveness of the administration of 2000 IU/day edible vitamin D for 15 wk to eliminate asymptomatic BV among reproductive age women with vitamin D deficiency.

Methods:

A total of 208 women with asymptomatic BV, who were found to be eligible after interviews and laboratory tests, were randomly assigned to a control group (n=106) or an intervention group (n=105). They used vitamin D drops daily for 105 days. Vaginal and blood samples were taken before and after the second intervention using identical methods (Nugent score for BV diagnosis, serum 25-hydroxyvitamin D for vitamin D determination).

Results:

The cure rate of asymptomatic BV was 63.5 per cent in the intervention and 19.2 per cent in the control group (P <0.001). The results showed that being unmarried (P=0.02), being passive smoker (P<0.001), and being in the luteal phase of a menstrual cycle during sampling (P=0.01) were significantly associated with post-intervention BV positive results. After these elements were controlled, the odds of BV positive results in the control group was 10.8 times more than in the intervention group (P<0.001).

Interpretation & conclusions:

Among women in reproductive age group with vitamin D deficiency, the administration of 2000 IU/day edible vitamin D was effective in eliminating asymptomatic BV. This treatment could be useful in preventing the symptoms and side effects of BV.

Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE)

An increasing recognition has emerged of the complexities of the global health agenda—specifically, the collision of infections and noncommunicable diseases and the dual burden of over- and undernutrition. Of particular practical concern are both 1) the need for a better understanding of the bidirectional relations between nutritional status and the development and function of the immune and inflammatory response and 2) the specific impact of the inflammatory response on the selection, use, and interpretation of nutrient biomarkers. The goal of the Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE) is to provide guidance for those users represented by the global food and nutrition enterprise. These include researchers (bench and clinical), clinicians providing care/treatment, those developing and evaluating programs/interventions at scale, and those responsible for generating evidence-based policy. The INSPIRE process included convening 5 thematic working groups (WGs) charged with developing summary reports around the following issues: 1) basic overview of the interactions between nutrition, immune function, and the inflammatory response; 2) examination of the evidence regarding the impact of nutrition on immune function and inflammation; 3) evaluation of the impact of inflammation and clinical conditions (acute and chronic) on nutrition; 4) examination of existing and potential new approaches to account for the impact of inflammation on biomarker interpretation and use; and 5) the presentation of new approaches to the study of these relations. Each WG was tasked with synthesizing a summary of the evidence for each of these topics and delineating the remaining gaps in our knowledge. This review consists of a summary of the INSPIRE workshop and the WG deliberations.

Smoking, poor nutrition, and sexually transmitted infections associated with pelvic inflammatory disease in remote North Queensland Indigenous communities, 1998-2005

Background

Indigenous women in remote North Queensland have a high prevalence of unhealthy lifestyle behaviors and associated health conditions such as sexual transmitted infections (STI). The association of severe pelvic inflammatory disease (PID) with these factors has not been studied. The purpose of this study is to associate the factors with severe PID, as indicated by hospitalization in a high risk population in North Queensland Indigenous communities.

Methods

A cross-sectional association of 1445 Indigenous women using linked hospital separation and survey data during 1998–2005.

Results

The mean age of participating women was 37.4 years, 60% were of Aboriginal and 40% were Torres Strait Island (TSI) people. More than half of them (52.5%) were smokers, 9.3% had chlamydia and 2.6% had gonorrhoea with the overall prevalence of STI among those less than 25 years of age being 23.9%. Among the 47 participants diagnosed with PID in the study period, 42.5% were under 25 years and 95.7% (45 cases) were under 55 years (OR 2.5, 95% CI 1.2-4.1 among women younger than 25 compared to those 25 years and over). PID was strongly associated with smoking (OR 3.1, 95% CI 1.4-9.2) independent of age, ethnicity, STI and folate status. Low red cell folate increased PID hospitalization by 4 times (95% CI 1.5-13.2 of lowest quartile compared to the highest quartile) regardless of age. Having a STI significantly increased the likelihood of severe PID by 2.2 times (95% CI: 1.03-4.5) in Indigenous women younger than 45 years, independent of smoking and folate level. The risk of PID hospitalization was higher for gonorrheal infections (OR 3.2, 955 CI 1.1-9.6) compared to chlamydial infections (OR 1.5 95% CI 0.7-3.5).

Conclusions

Young Indigenous women in North Queensland communities are at very high risk for STI and PID. Smoking, low folate, and STI are clustered, and are associated with PID hospitalizations. Much of this can be prevented with improved nutrition and access to preventive services, especially tobacco control, regular STI screening and treatment, as well as more investment in sexual health education and awareness.

Electronic supplementary material

The online version of this article (doi:10.1186/s12905-015-0188-z) contains supplementary material, which is available to authorized users.

Bacterial vaginosis and season, a proxy for vitamin D status

BACKGROUND

Low serum vitamin D concentration has been associated with increased prevalence of bacterial vaginosis (BV) among pregnant women, but the few studies conducted in nonpregnant women have produced inconsistent results. Because serum vitamin D concentration is generally higher in the summer and fall than winter and spring, if vitamin D insufficiency causes BV, then BV would be expected to be more common during seasons with lower vitamin D concentrations.

METHODS

The Longitudinal Study of Vaginal Flora followed up women in Birmingham, Alabama (33.5° latitude), quarterly for up to 1 year. We used a case-crossover design with conditional logistic regression among women who attended visits in each season, to assess the adjusted association between season and BV. We compared each woman's BV status in summer, fall, and spring to her own status in winter.

RESULTS

Among the 3620 women in the parent study, 2337 attended visits in each season; BV prevalence was 40% in winter, 38% in spring, and 41% in summer and fall. One thousand three hundred thirty-five women had BV at some but not all visits and were therefore included in the case-crossover analysis. Season was not associated with BV in women who were BV negative at study entry (odds ratio vs. winter were 1.0 for spring, 1.0 for summer, and 0.9 for fall; P = 0.81). Among women BV positive at study entry, the corresponding odds ratios were 0.9, 1.4, and 1.4 (P < 0.001).

CONCLUSIONS

These results do not support an association between vitamin D, measured through the proxy variable of season, and BV.

Microbiota and pelvic inflammatory disease

Female genital tract microbiota play a crucial role in maintaining health. Disequilibrium of the microbiota has been associated with increased risk of pelvic infections. In recent years, culture-independent molecular techniques have expanded understanding of the composition of genital microbiota and the dynamic nature of the microbiota. There is evidence that upper genital tract may not be sterile and may harbor microflora in the physiologic state. The isolation of bacterial vaginosis-associated organisms in women with genital infections establishes a link between pelvic infections and abnormal vaginal flora. With the understanding of the composition of the microbiota in healthy and diseased states, the next logical step is to identify the function of the newly identified microbes. This knowledge will further expand our understanding of the causation of pelvic infections, which may lead to more effective prevention and treatment strategies.

A new era of the vaginal microbiome: advances using next-generation sequencing

Until recently, bacterial species that inhabit the human vagina have been primarily studied using organism-centric approaches. Understanding how these bacterial species interact with each other and the host vaginal epithelium is essential for a more complete understanding of vaginal health. Molecular approaches have already led to the identification of uncultivated bacterial taxa associated with bacterial vaginosis. Here, we review recent studies of the vaginal microbiome and discuss how culture-independent approaches, such as applications of next-generation sequencing, are advancing the field and shifting our understanding of how vaginal health is defined. This work may lead to improved diagnostic tools and treatments for women who suffer from, or are at risk for, vaginal imbalances, pregnancy complications, and sexually acquired infections. These approaches may also transform our understanding of how host genetic factors, physiological conditions (e.g., menopause), and environmental exposures (e.g., smoking, antibiotic usage) influence the vaginal microbiome.

Racial disparities in preterm birth: an overview of the potential role of nutrient deficiencies

OBJECTIVE

To give an overview of the literature for evidence of nutrient deficiencies as contributors to the disparity in preterm birth (PTB) between African-American and Caucasian women.

DESIGN

Structured literature survey.

METHODS

We searched MEDLINE to identify observational and experimental studies that evaluated the relation between nutrient intake and/or supplementation and PTB. For nutrients for which studies supported an association, we searched MEDLINE for studies of the prevalence of deficiency in the USA by race.

MAIN OUTCOME MEASURES

Summarized findings on nutrients for which there is both evidence of a role in PTB and variability in the prevalence of deficiency by race.

RESULTS

Nutrient deficiencies for which there are varying levels of evidence for an association with PTB and a greater burden among African-American compared with Caucasian women include deficiencies of iron, folic acid, zinc, vitamin D, calcium and magnesium, and imbalance of ω-3 and ω-6 polyunsaturated fatty acids. There are inadequate high-quality studies that investigate the role of nutrient deficiencies in PTB, their potential interaction with other risks, the proportion of excess risk for which they account, and whether supplementation can reduce the risk of, and racial disparities in, PTB in US populations.

CONCLUSION

Deficiencies of several nutrients have varying levels of evidence of association with PTB and are of greater burden among African-American compared with Caucasian women. Although further research is needed, strategies that improve the nutritional status of African-American women may be a means of addressing a portion of the racial disparity in PTB.

Maternal vitamin D, folate, and polyunsaturated fatty acid status and bacterial vaginosis during pregnancy

OBJECTIVE

To investigate associations among serum 25-hydroxy-vitamin D (25-OH-D), folate, omega-6/omega-3 fatty acid ratio and bacterial vaginosis (BV) during pregnancy.

METHODS

Biospecimens and data were derived from a random sample (N = 160) of women from the Nashville Birth Cohort. We compared mean plasma nutrient concentrations for women with and without BV during pregnancy (based on Nugent score ≥7) and assessed the odds of BV for those with 25-OH-D <12 ng/mL, folate <5 ug/L, and omega-6/omega-3 ratio >15.

RESULTS

The mean plasma 25-OH-D was significantly lower among women with BV during pregnancy (18.00±8.14 ng/mL versus 24.34±11.97 ng/mL, P = 0.044). The adjusted odds of BV were significantly increased among pregnant women with 25-OH-D <12 ng/mL (aOR 5.11, 95% CI: 1.19-21.97) and folate <5 ug/L (aOR 7.06, 95% CI: 1.07-54.05).

CONCLUSION

Vitamin D and folate deficiencies were strongly associated with BV (Nugent score ≥7) during pregnancy.

Vaginal microbiome and sexually transmitted infections: an epidemiologic perspective

Vaginal bacterial communities are thought to help prevent sexually transmitted infections. Bacterial vaginosis (BV) is a common clinical syndrome in which the protective lactic acid-producing bacteria (mainly species of the Lactobacillus genus) are supplanted by a diverse array of anaerobic bacteria. Epidemiologically, BV has been shown to be an independent risk factor for adverse outcomes including preterm birth, development of pelvic inflammatory disease, and acquisition of sexually transmitted infections. Longitudinal studies of the vaginal microbiome using molecular techniques such as 16S ribosomal DNA analysis may lead to interventions that shift the vaginal microbiota toward more protective states.

Maternal vitamin A and β-carotene supplementation and risk of bacterial vaginosis: a randomized controlled trial in rural Bangladesh

BACKGROUND

Bacterial vaginosis (BV) in pregnancy is linked to preterm birth, but its risk factors are not well understood. Micronutrient deficiencies may be associated with an increased risk of this condition.

OBJECTIVE

We assessed the effect of weekly vitamin A or β-carotene supplementation during pregnancy until 3 mo postpartum on BV risk in rural northeastern Bangladesh.

DESIGN

In this cluster-randomized, placebo-controlled trial, 33 clusters (n = 33) were randomly assigned to 3 groups. Women (n = 1812) were examined for BV by using self-administered swabs and the Nugent scoring method in early pregnancy, at 32 wk of gestation, and at 3 mo postpartum.

RESULTS

The prevalence of BV in early pregnancy, before supplementation, was 7.6% (95% CI: 6.3%, 9.1%) overall. Neither the prevalence nor the incidence of BV in the third trimester differed by supplement group. However, the prevalence (OR: 0.71; 95% CI: 0.52, 0.98) and incidence (RR: 0.58; 95% CI: 0.41, 0.81) of BV at 3 mo postpartum was lower among women in the vitamin A group (9.1% and 6.7%, respectively) than in the placebo group (12.4% and 11.8%, respectively), but not in the β-carotene group. Both vitamin A and β-carotene reduced the prevalence and incidence of BV at both time points (ie, third trimester and 3 mo postpartum) by 30-40% compared with placebo (all P < 0.05).

CONCLUSIONS

Weekly vitamin A supplementation reduced the risk of maternal BV in this rural Bangladeshi population. Enhancement of vitamin A status before and during pregnancy may reduce the risk of BV in areas with vitamin A deficiency. This trial is registered at clinicaltrials.gov as NCT00198822.

Bacterial vaginosis is associated with variation in dietary indices

Bacterial vaginosis (BV) is a common condition of unknown etiology and has been linked to adverse reproductive and obstetric health outcomes. Prior dietary research on BV has focused on specific macro- and micronutrients, but not dietary indices. We assessed the relationship between BV and selected dietary indicators among a cohort of 1735 nonpregnant women ages 15-44 y from Birmingham, Alabama. Annual intake was assessed with the Block98 FFQ, and the glycemic index, glycemic load (GL), and Healthy Eating Index were calculated by the Block Dietary Data System. The Naturally Nutrient Rich (NNR) score was also calculated. Vaginal flora was evaluated using Nugent Gram-stain criteria. Crude OR and adjusted OR were determined by multinomial and logistic regression in cross-sectional and prospective analyses, respectively. Participants were predominantly African American (85.5%) aged 25.3 ± 6.8 y (mean ± SD). Per 10-unit increase, GL was positively (adjusted OR = 1.01, 95% CI = 1.00-1.03) and NNR was negatively (adjusted OR = 0.93, 95% CI = 0.88-0.99) associated with BV compared to normal vaginal flora. In prospective analyses, only GL was associated with BV progression (adjusted OR = 1.03, 95% CI = 1.00-1.05) and persistence (adjusted OR = 1.02, 95% CI = 1.01-1.04) after adjustment. Both GL and NNR were associated with greater BV prevalence and GL was associated with an increase in BV persistence and acquisition. These results suggest that diet composition may contribute to vaginal flora imbalances and be important for elucidating the etiology of BV.

The association of HIV status with bacterial vaginosis and vitamin D in the United States

OBJECTIVE

To estimate the association between vitamin D deficiency and bacterial vaginosis (BV) among nonpregnant HIV-infected and uninfected women.

METHODS

In a substudy of the Women's Interagency HIV Study, including women from Chicago and New York, the association between BV and vitamin D deficiency, demographics, and disease characteristics was tested using generalized estimating equations. Deficiency was defined as <20 ng/mL 25 (OH) vitamin D and insufficiency as >20 and ≤30 ng/mL. BV was defined by the Amsel criteria.

RESULTS

Among 602 observations of nonpregnant women (480 HIV infected and 122 uninfected), BV was found in 19%. Vitamin D deficiency was found in 59.4%, and insufficiency was found in 24.4%. In multivariable analysis, black race was the most significant predictor of BV (adjusted odds ratio [AOR] 5.90, (95% confidence interval [CI] 2.52-13.8). Vitamin D deficiency was independently associated with BV among HIV-infected women (AOR 3.12, 95% CI 1.16-8.38) but not among HIV-uninfected women. There was a negative linear correlation between vitamin D concentration and prevalence of BV in HIV-infected women (r=-0.15, p=0.001).

CONCLUSIONS

Vitamin D deficiency was very common in this cohort and significantly associated with BV among HIV-infected women. These preliminary findings suggest that further epidemiologic and mechanistic exploration of the relationship between vitamin D and BV in HIV-infected women is warranted.

Molecular analysis of the diversity of vaginal microbiota associated with bacterial vaginosis

Background

Bacterial vaginosis (BV) is an ecological disorder of the vaginal microbiota that affects millions of women annually, and is associated with numerous adverse health outcomes including pre-term birth and the acquisition of sexually transmitted infections. However, little is known about the overall structure and composition of vaginal microbial communities; most of the earlier studies focused on predominant vaginal bacteria in the process of BV. In the present study, the diversity and richness of vaginal microbiota in 50 BV positive and 50 healthy women from China were investigated using culture-independent PCR-denaturing gradient gel electrophoresis (DGGE) and barcoded 454 pyrosequencing methods, and validated by quantitative PCR.

Results

Our data demonstrated that there was a profound shift in the absolute and relative abundances of bacterial species present in the vagina when comparing populations associated with healthy and diseased conditions. In spite of significant interpersonal variations, the diversity of vaginal microbiota in the two groups could be clearly divided into two clusters. A total of 246,359 high quality pyrosequencing reads was obtained for evaluating bacterial diversity and 24,298 unique sequences represented all phylotypes. The most predominant phyla of bacteria identified in the vagina belonged to Firmicutes, Bacteroidetes, Actinobacteria and Fusobacteria. The higher number of phylotypes in BV positive women over healthy is consistent with the results of previous studies and a large number of low-abundance taxa which were missed in previous studies were revealed. Although no single bacterium could be identified as a specific marker for healthy over diseased conditions, three phyla - Bacteroidetes, Actinobacteria and Fusobacteria, and eight genera including Gardnerella, Atopobium, Megasphaera, Eggerthella, Aerococcus, Leptotrichia/Sneathia, Prevotella and Papillibacter were strongly associated with BV (p < 0.05). These genera are potentially excellent markers and could be used as targets for clinical BV diagnosis by molecular approaches.

Conclusions

The data presented here have clearly profiled the overall structure of vaginal communities and clearly demonstrated that BV is associated with a dramatic increase in the taxonomic richness and diversity of vaginal microbiota. The study also provides the most comprehensive picture of the vaginal community structure and the bacterial ecosystem, and significantly contributes to the current understanding of the etiology of BV.

Race of male sex partners and occurrence of bacterial vaginosis

BACKGROUND

Whether bacterial vaginosis (BV) is sexually transmitted is uncertain. Also it is unknown why BV is approximately twice as prevalent among black as among white women. An association of BV with a characteristic of the male sex partner, such as race, might support sexual transmission as well as account for the observed ethnic disparity in BV.

METHODS

Three thousand six hundred twenty nonpregnant women 15 to 44 years of age were followed quarterly for 1 year. At each visit, extensive questionnaire data and vaginal swabs for Gram's staining were obtained. The outcome was transition from BV-negative to positive (Nugent's score > or =7) in an interval of 2 consecutive visits.

RESULTS

BV occurred in 12.8% of 906 sexually active intervals to white women-24.8% of intervals when the woman reported a black partner and 10.7% when all partners were white. Among white women, there was a 2-fold increased risk for BV incidence with a black, compared with a white partner (risk ratio [RR] 2.3, 95% confidence interval 1.6-3.4; adjusted RR 2.2, 95% confidence interval 1.5-3.4), but differed according to condom use. In the presence of consistent condom use, the adjusted RR was 0.7 (0.3-2.4); it was 2.4 (1.0-6.2) in the presence of inconsistent use; and 2.7 (1.7-4.2) in the absence of condom use. Black women could not be studied, as there were insufficient numbers who reported only white male sex partners.

CONCLUSION

The association of BV occurrence with partner's race, and its blunting by condom use, suggests that BV may have a core group component and may be sexually transmitted.

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.

Maternal vitamin D deficiency is associated with bacterial vaginosis in the first trimester of pregnancy

Bacterial vaginosis (BV) is a highly prevalent vaginal infection that is associated with adverse pregnancy outcomes. Vitamin D exerts an influence on the immune system and may play a role in BV. The objective of this study was to examine the association between maternal vitamin D status and the prevalence of BV in early pregnancy. Women (n = 469) enrolled in a pregnancy cohort study at <16 wk underwent a pelvic examination and provided a blood sample for determination of serum 25-hydroxyvitamin D [25(OH)D]. BV was diagnosed using Gram-stained vaginal smears interpreted using the method of Nugent. Approximately 41% of women had BV (Nugent score 7-10) and 52% had a serum 25(OH)D concentration <37.5 nmol/L. The mean unadjusted serum 25(OH)D concentration was lower among BV cases (29.5 nmol/L; 95% CI: 27.1, 32.0) compared with women with normal vaginal flora (40.1 nmol/L; 95% CI: 37.0, 43.5; P < 0.001). BV prevalence decreased as vitamin D status improved (P < 0.001). Approximately 57% of the women with a serum 25(OH)D concentration <20 nmol/L had BV compared with 23% of women with a serum 25(OH)D concentration >80 nmol/L. There was a dose-response association between 25(OH)D and the prevalence of BV. The prevalence declined as 25(OH)D increased to 80 nmol/L, then reached a plateau. Compared with a serum 25(OH)D concentration of 75 nmol/L, there were 1.65-fold (95% CI: 1.01, 2.69) and 1.26-fold (1.01, 1.57) increases in the prevalence of BV associated with a serum 25(OH)D concentration of 20 and 50 nmol/L, respectively, after adjustment for race and sexually transmitted diseases. Vitamin D deficiency is associated with BV and may contribute to the strong racial disparity in the prevalence of BV.

[Bacterial vaginosis]

Bacterial vaginosis is a widely spread health problem with multiple connotations. It has been the subject of many studies and work during decades and it still remains a polemic entity, with contradictory finding. The polymicrobian etiology, unsolved epidemiology, obstetrico-gynecological complications and high recurrence rate following treatment, make this infection a target for researchers. It is not an inflammatory process -yet an immune response exists. In this disorder, vaginal discharge increases, and it is associated with a high risk of developing sexually transmitted diseases.

Maternal vitamin D deficiency is associated with bacterial vaginosis in the first trimester of pregnancy

Bacterial vaginosis (BV) is a highly prevalent vaginal infection that is associated with adverse pregnancy outcomes. Vitamin D exerts an influence on the immune system and may play a role in BV. The objective of this study was to examine the association between maternal vitamin D status and the prevalence of BV in early pregnancy. Women (n = 469) enrolled in a pregnancy cohort study at <16 wk underwent a pelvic examination and provided a blood sample for determination of serum 25-hydroxyvitamin D [25(OH)D]. BV was diagnosed using Gram-stained vaginal smears interpreted using the method of Nugent. Approximately 41% of women had BV (Nugent score 7-10) and 52% had a serum 25(OH)D concentration <37.5 nmol/L. The mean unadjusted serum 25(OH)D concentration was lower among BV cases (29.5 nmol/L; 95% CI: 27.1, 32.0) compared with women with normal vaginal flora (40.1 nmol/L; 95% CI: 37.0, 43.5; P < 0.001). BV prevalence decreased as vitamin D status improved (P < 0.001). Approximately 57% of the women with a serum 25(OH)D concentration <20 nmol/L had BV compared with 23% of women with a serum 25(OH)D concentration >80 nmol/L. There was a dose-response association between 25(OH)D and the prevalence of BV. The prevalence declined as 25(OH)D increased to 80 nmol/L, then reached a plateau. Compared with a serum 25(OH)D concentration of 75 nmol/L, there were 1.65-fold (95% CI: 1.01, 2.69) and 1.26-fold (1.01, 1.57) increases in the prevalence of BV associated with a serum 25(OH)D concentration of 20 and 50 nmol/L, respectively, after adjustment for race and sexually transmitted diseases. Vitamin D deficiency is associated with BV and may contribute to the strong racial disparity in the prevalence of BV.