Bacterial vaginosis (BV) and the risk of incident gonococcal or chlamydial genital infection in a predominantly black population

Multi-omics analysis identifies potential microbial and metabolite diagnostic biomarkers of bacterial vaginosis

BACKGROUND

Bacterial vaginosis (BV) is a common clinical manifestation of a perturbed vaginal ecology associated with adverse sexual and reproductive health outcomes if left untreated. The existing diagnostic modalities are either cumbersome or require skilled expertise, warranting alternate tests. Application of machine-learning tools to heterogeneous and high-dimensional multi-omics datasets finds promising potential in data integration and may aid biomarker discovery.

OBJECTIVES

The present study aimed to evaluate the potential of the microbiome and metabolome-derived biomarkers in BV diagnosis. Interpretable machine-learning algorithms were used to evaluate the utility of an integrated-omics-derived classification model.

METHODS

Vaginal samples obtained from reproductive-age group women with (n = 40) and without BV (n = 40) were subjected to 16S rRNA amplicon sequencing and LC-MS-based metabolomics. The vaginal microbiome and metabolome were characterized, and machine-learning analysis was performed to build a classification model using biomarkers with the highest diagnostic accuracy.

RESULTS

Microbiome-based diagnostic model exhibited a ROC-AUC (10-fold CV) of 0.84 ± 0.21 and accuracy of 0.79 ± 0.18, and important features were Aerococcus spp., Mycoplasma hominis, Sneathia spp., Lactobacillus spp., Prevotella spp., Gardnerella spp. and Fannyhessea vaginae. The metabolome-derived model displayed superior performance with a ROC-AUC of 0.97 ± 0.07 and an accuracy of 0.92 ± 0.08. Beta-leucine, methylimidazole acetaldehyde, dimethylethanolamine, L-arginine and beta cortol were among key predictive metabolites for BV. A predictive model combining both microbial and metabolite features exhibited a high ROC-AUC of 0.97 ± 0.07 and accuracy of 0.94 ± 0.08 with diagnostic performance only slightly superior to the metabolite-based model.

CONCLUSION

Application of machine-learning tools to multi-omics datasets aid biomarker discovery with high predictive performance. Metabolome-derived classification models were observed to have superior diagnostic performance in predicting BV than microbiome-based biomarkers.

The microbial revolution: Unveiling the benefits of vaginal probiotics and prebiotics

Vaginal health is essential to a woman's overall well-being, as abnormalities in vaginal health can lead to a variety of gynaecological disorders, such as urinary tract infections, yeast infections, and bacterial vaginosis. The vaginal microbiome is essential for the prevention of these infections. Disruptions in this microbial ecosystem can significantly impact vaginal health. The concept of utilizing probiotics and prebiotics to stimulate the growth of protective vaginal microbiota has gathered substantial interest in recent years. Probiotics are live micro-organisms that strengthen and restore vaginal microbial balance by lowering pH levels, production of bacteriocins, biofilm disruption, modulation of immune response, and production of hydrogen peroxide (H2O2), consequently combating the development of pathogens. Prebiotics are oligosaccharides that encourage the development of probiotics such as lactobacilli species. Probiotics and prebiotics also have some broader implications for vaginal health, including their role in minimizing the incidence of premature birth, optimizing fertility, managing menopausal symptoms, and preventing vaginal infections. Synbiotics are a combination of probiotics and prebiotics that deliver additional benefits by encouraging the development and activity of beneficial microbes. Furthermore, postbiotics are bioactive compounds derived from probiotic bacteria during fermentation that have immunomodulatory actions and provide an additional layer of protection against vaginal infections. The present study highlights the most prevalent vaginal infections and limitations of existing therapies that influence the vaginal microbiota. The profound consequences of probiotics and prebiotics in women's health, including their role in minimizing the prevalence of vaginal infections and promoting overall vaginal health, as well as advanced therapeutic strategies such as synbiotics and postbiotics, are also discussed. The literature offers significant insights into the mechanism, efficacy, and safety of probiotics and prebiotics to healthcare providers and researchers.

Sub-communities of the vaginal microbiota in pregnant and non-pregnant women

Diverse and non-Lactobacillus-dominated vaginal microbial communities are associated with adverse health outcomes such as preterm birth and the acquisition of sexually transmitted infections. Despite the importance of recognizing and understanding the key risk-associated features of these communities, their heterogeneous structure and properties remain ill-defined. Clustering approaches are commonly used to characterize vaginal communities, but they lack sensitivity and robustness in resolving substructures and revealing transitions between potential sub-communities. Here, we address this need with an approach based on mixed membership topic models. Using longitudinal data from cohorts of pregnant and non-pregnant study participants, we show that topic models more accurately describe sample composition, longitudinal changes, and better predict the loss of Lactobacillus dominance. We identify several non-Lactobacillus-dominated sub-communities common to both cohorts and independent of reproductive status. In non-pregnant individuals, we find that the menstrual cycle modulates transitions between and within sub-communities, as well as the concentrations of half of the cytokines and 18% of metabolites. Overall, our analyses based on mixed membership models reveal substructures of vaginal ecosystems which may have important clinical and biological associations.

Comparative Metagenome-Assembled Genome Analysis of "Candidatus Lachnocurva vaginae", Formerly Known as Bacterial Vaginosis-Associated Bacterium-1 (BVAB1)

Bacterial vaginosis-associated bacterium 1 (BVAB1) is an as-yet uncultured bacterial species found in the human vagina that belongs to the family Lachnospiraceae within the order Clostridiales. As its name suggests, this bacterium is often associated with bacterial vaginosis (BV), a common vaginal disorder that has been shown to increase a woman's risk for HIV, Chlamydia trachomatis, and Neisseria gonorrhoeae infections as well as preterm birth. BVAB1 has been further associated with the persistence of BV following metronidazole treatment, increased vaginal inflammation, and adverse obstetrics outcomes. There is no available complete genome sequence of BVAB1, which has made it difficult to mechanistically understand its role in disease. We present here a circularized metagenome-assembled genome (cMAG) of BVAB1 as well as a comparative analysis including an additional six metagenome-assembled genomes (MAGs) of this species. These sequences were derived from cervicovaginal samples of seven separate women. The cMAG was obtained from a metagenome sequenced with long-read technology on a PacBio Sequel II instrument while the others were derived from metagenomes sequenced on the Illumina HiSeq platform. The cMAG is 1.649 Mb in size and encodes 1,578 genes. We propose to rename BVAB1 to "Candidatus Lachnocurva vaginae" based on phylogenetic analyses, and provide genomic and metabolomic evidence that this candidate species may metabolize D-lactate, produce trimethylamine (one of the chemicals responsible for BV-associated odor), and be motile. The cMAG and the six MAGs are valuable resources that will further contribute to our understanding of the heterogeneous etiology of bacterial vaginosis.

Risk of Gonococcal Infection During Vaginal Exposure is Associated With High Vaginal pH and Active Menstruation

BACKGROUND

An understanding of the biological reasons why 25% to 35% of women resist infection during vaginal intercourse with a man infected with Neisseria gonorrhoeae could lead to novel control measures. We sought modifiable biological bases for infection resistance by comparing women in the same core-mixing group who did or did not become infected after sexual exposure.

METHODS

We enrolled 61 female contacts of index men with gonorrhea seen at Baltimore City Health Department clinics from January 2008 through May 2012. Exposure and sexual practices and histories, co-infections, physical signs on exam, patient symptom report, and menstrual history were collected.

RESULTS

Thirty-eight (62.3%) of the exposed women developed cervical infections. Multiple logistic regression found that a vaginal pH of 4.5 or higher at presentation to clinic was significantly associated with gonococcal infection (adjusted odds ratio, 5.5; P = 0.037) in women who presented within one menstrual cycle, 35 days. In this group of women, there was a significant association between acquiring an N. gonorrhoeae cervical infection and sexual exposure during menstruation (adjusted odds ratio 12.5; P = 0.05).

CONCLUSIONS

Modification of vaginal pH could be explored as novel strategy for reducing the risk of N. gonorrhoeae infections in women.

Noncandidal vaginitis: a comprehensive approach to diagnosis and management

Vaginitis is one of the most common causes of patient visits to gynecologists, primary care providers, and urgent care centers. However, many women leave without a clear diagnosis or experience recurrent symptoms despite treatment. The 3 most common etiologies of vaginitis are trichomonas, bacterial vaginosis, and vulvovaginal candidiasis, which account for an estimated 70% of cases. The remaining 30% may be related to other causes of vaginitis, including atrophic vaginitis, desquamative inflammatory vaginitis, and vaginal erosive disease. The purpose of this review is to describe the noncandidal causes of acute and recurrent vaginitis, with the goal of improving the likelihood of accurate diagnosis as well as efficient and effective therapy. We excluded candidal vaginitis from our review because there was a recently published review on this topic in the Journal. The clinical presentation and evaluation of patients with symptoms of vaginitis can be triaged into 1 of 2 diagnostic pathways: noninflammatory and inflammatory vaginitis. The most common noninflammatory cause is bacterial vaginosis. Features such as irritation, purulent discharge, and the presence of polymorphonuclear neutrophils are more suggestive of an inflammatory process. Trichomoniasis is the most common cause of inflammatory vaginitis. Other well-described forms of inflammatory vaginitis include atrophic vaginitis, desquamative inflammatory vaginitis, and erosive disease. We present a review of the pathogenesis, symptoms, examination findings, diagnostic testing, and treatment for each of these causes of noncandidal vaginitis.

Bacterial vaginosis-A brief synopsis of the literature

Bacterial vaginosis (BV) affects women of reproductive age and can either be symptomatic or asymptomatic. Approximately 50 % of women are symptomatic and experience vaginal malodor, discharge, itching and increased vaginal pH. BV can increase the risk of contracting many sexually transmitted infections (STIs) such as human immunodeficiency virus (HIV), Neisseria gonorrhea (NG), Chlamydia trachomatis (CT), Trichomonas vaginalis (TV) and herpes simplex virus-2 (HSV-2). Though effective treatment options do exist, metronidazole or clindamycin, these methods have proven not to be effective long term. The purpose of this review is to summarize current literature on the epidemiology of BV and highlight areas of deficiency in current clinical practice with respect to BV. BV recurrence rates are high, approximately 80 % three months after effective treatment. Furthermore, in some instances treatment is ineffective and BV persists. Literature also documents the relationship between BV and human papillomavirus (HPV). HPV is the most common sexually transmitted infection among young adult women while BV is the most common cause of vaginal symptoms among women of reproductive age. BV is associated with high levels of anaerobic organisms which can damage the vaginal epithelium and increase the risk of HPV infection. Recent research also highlights the role of the vaginal microbiome in BV. The results of this review warrant further exploration into the etiology of BV as well as exploration of more long-term effective treatment and the investigation of prognostic indicators. Additionally, the need for a standard definition of recurrent and persistent BV is recognized.

Perceived stress and incident sexually transmitted infections in a prospective cohort

PURPOSE

Psychosocial stress has been associated with susceptibility to many infectious pathogens. We evaluated the association between perceived stress and incident sexually transmitted infections (STIs; Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis genital infections) in a prospective study of women. Stress may increase vulnerability to STIs by suppressing immune function and altering the protective vaginal microbiota.

METHODS

Using the 1999 Longitudinal Study of Vaginal Flora (n = 2439), a primarily African American cohort of women, we fitted Cox proportional hazards models to examine the association between perceived stress and incident STIs. We tested bacterial vaginosis (measured by Nugent Score) and sexual behaviors (condom use, number of partners, and partner concurrence) as mediators using VanderWeele's difference method.

RESULTS

Baseline perceived stress was associated with incident STIs both before and after adjusting for confounders (adjusted hazard ratio = 1.015; 95% confidence interval, 1.005-1.026). Nugent score and sexual behaviors significantly mediated 21% and 65% of this adjusted association, respectively, and 78% when included together in the adjusted model.

CONCLUSIONS

This study advances understanding of the relationship between perceived stress and STIs and identifies high-risk sexual behaviors and development of bacterial vaginosis-both known risk factors for STIs-as mechanisms underlying this association.

Prevalence and associated factors of Chlamydia trachomatis and Neisseria gonorrhoeae among female commercial sex workers in Hawassa City, Southern Ethiopia

Background

Chlamydia trachomatis and Neisseria gonorrhoeae are the most common pathogens causing genital tract infections. Female commercial sex workers (FCSWs) are the key population to be affected by sexually transmitted infections (STIs). In Ethiopia, little is known about C. trachomatis and N. gonorrhoeae infections in most at risk population. Therefore, this study aimed to assess the prevalence of these bacterial STIs among FCSWs.

Methods

A cross-sectional study was conducted at the confidential clinic in Hawassa City, Southern Ethiopia from January to April, 2017. A total of 338 FCSWs were selected using systematic random sampling technique and enrolled in the study. Information about socio-demography and associated factors was collected using structured questionnaires. Endocervical swab samples were also collected from the study participants and tested for C. trachomatis using rapid immunochromatography assay. Samples were also cultured to isolate N. gonorrhoeae according to the standard bacteriological method.

Results

The prevalence of N. gonorrhoeae and C. trachomatis among FCSWs was 3.3% [95% confidence interval (CI): 1.5–5.3] and 6.8% (95% CI: 3.9–9.5), respectively. FCSWs who consistently practiced sex without condom in the last 6 months had 6.3 times (AOR 6.3; 95% CI 1.61–24.86, P = 0.008), and 4.0 times (AOR 4.0; 95% CI 1.06–15.31, p = 0.040) higher odds of acquiring N. gonorrhoeae and C. trachomatis infections, respectively.

Conclusion

The observed rates of C. trachomatis and N. gonorrhoeae infections among FCSWs warrant the need to strengthen intervention efforts. In this regard, screening FCSWs for the specified infections and improving the practice of condom use would be important.

Vaginal pH measured in vivo: lactobacilli determine pH and lactic acid concentration

Background

Lactic acid (protonated lactate) has broad antimicrobial activity. Vaginal lactobacilli produce lactic acid, and are known to confer protection against reproductive tract infections when they are predominant in the vaginal microbiota. Using novel ex vivo methods, we showed that cervicovaginal fluid (CVF) from women with a predominantly lactobacilli-morphotype microbiota contains significantly more lactic acid than previously thought, sufficient to inactivate reproductive tract pathogens.

Here, we measured vaginal pH in vivo in 20 women with a predominantly lactobacilli-morphotype (low Nugent score) microbiota. We also investigated the in vitro production of protons (as hydrogen ions) and lactate by vaginal lactobacilli.

Results

The average vaginal pH in these women was 3.80 ± 0.20, and the average lactate concentration was 0.79% ± 0.22% w/v, with pH and lactate concentration tightly correlated for each sample. In vitro, lactobacilli cultured from these CVF samples reached an average pH of 3.92 ± 0.22, but the average lactate concentration was only 0.14% ± 0.06% w/v, approximately five-fold less than in the corresponding CVF samples. When the pH of the cultures was raised, lactate and hydrogen ion production resumed, indicating that production of lactate and hydrogen ions by vaginal lactobacilli is limited primarily by their sensitivity to hydrogen ion concentration (low pH) not lactate concentration.

Conclusions

Some vaginal lactobacilli cultures have a lower limiting pH than others, and limiting pHs in vitro showed good correlation with pHs measured in vivo. The limiting pH of the lactobacilli predominant in a woman’s vaginal microbiota seems critical in determining the concentration of antimicrobial lactic acid protecting her.

How to Identify Exposed Women Who Are Infected with Neisseria gonorrhoeae

Treatment trials of antibiotics for Neisseria gonorrhoeae infections frequently enroll primarily men with urethritis, as the diagnosis of acute gonococcal infection in men with urethritis is easily made by Gram stain of the urethral exudate, followed by confirmatory culture or nucleic acid amplification tests (NAATs). Enrolling women in treatment trials is of great importance, but N. gonorrhoeae cervical infections cause nonspecific symptoms. This makes it difficult to conduct interventional trials, as large numbers of women with nonspecific symptoms need to be screened for infection. Gram stain of cervical secretions has a strikingly low sensitivity, and culture and/or NAAT results are not available at the time of screening. This necessitates recall and delayed treatment of infected women who may not return and who may spread the infection during the interval. In this chapter we present an algorithm, derived from a comparison of women who did, or did not, become infected during exposure, which identifies those women who are highly likely to be infected before culture and/or NAAT results are available. The algorithm provides an efficient way to conduct interventional trials in women without the problem of recall and delayed treatment.

Prevalence of bacterial vaginosis and factors associated among women who have sex with women

OBJECTIVE

to describe the prevalence of bacterial vaginosis and factors associated among women who have sex with women.

METHOD

cross-sectional, descriptive and analytical study with 150 women. The vaginal microbiota profile was analyzed by microscopic examination of vaginal swabs according to the Gram method. Endocervical samples were collected with cytobrush for the investigation of endocervicitis by Chlamydia trachomatis. The polymerase chain reaction was used to diagnosis Human Papillomavirus infection. Socio-demographic data, sexual behavior and clinical history were obtained through an interview. Logistic regression was performed to identify risk factors independently associated with bacterial vaginosis.

RESULTS

among the 150 participants, 71 (47.3%) presented some alteration in the vaginal microbiota, 54 (36.0%) bacterial vaginosis and 12 (8.0%) Flora II. The variable independently associated with bacterial vaginosis was the use of sexual accessories [2.37(1.13-4.97), p=0.022].

CONCLUSION

the high prevalence of bacterial vaginosis among women who have sex with women indicates the need for screening this population and association between use of sexual accessories and this disease suggests the possibility of transmission of sexual fluids between the partners during the sexual act, which demonstrates the need for educational actions on sexual and reproductive health.

Role of Lactobacilli and Lactoferrin in the Mucosal Cervicovaginal Defense

The innate defense system of the female mucosal genital tract involves a close and complex interaction among the healthy vaginal microbiota, different cells, and various proteins that protect the host from pathogens. Vaginal lactobacilli and lactoferrin represent two essential actors in the vaginal environment. Lactobacilli represent the dominant bacterial species able to prevent facultative and obligate anaerobes outnumber in vaginal microbiota maintaining healthy microbial homeostasis. Several mechanisms underlie the protection exerted by lactobacilli: competition for nutrients and tissue adherence, reduction of the vaginal pH, modulation of immunity, and production of bioactive compounds. Among bioactive factors of cervicovaginal mucosa, lactoferrin, an iron-binding cationic glycoprotein, is a multifunctional glycoprotein with antibacterial, antifungal, antiviral, and antiparasitic activities, recently emerging as an important modulator of inflammation. Lactobacilli and lactoferrin are largely under the influence of female hormones and of paracrine production of various cytokines. Lactoferrin is strongly increased in lower genital tract mucosal fluid of women affected by Neisseria gonorrheae, Chlamydia trachomatis, and Trichomonas vaginalis infections promoting both innate and adaptive immune responses. In vaginal dysbiosis characterized by low amounts of vaginal lactobacilli and increased levels of endogenous anaerobic bacteria, the increase in lactoferrin could act as an immune modulator assuming the role normally played by the healthy microbiota in vaginal mucosa. Then lactoferrin and lactobacilli may be considered as biomarkers of altered microbial homeostasis at vaginal level. Considering the shortage of effective treatments to counteract recurrent and/or antibiotic-resistant bacterial infections, the intravaginal administration of lactobacilli and lactoferrin could be a novel efficient therapeutic strategy and a valuable tool to restore mucosal immune homeostasis.

Lactobacillus iners-dominated vaginal microbiota is associated with increased susceptibility to Chlamydia trachomatis infection in Dutch women: a case-control study

INTRODUCTION

This prospective study aimed to study the composition and structure of the vaginal microbiota prior to Chlamydia trachomatis infection.

METHODS

A nested case-control study was performed in 122 women, half of which acquired C. trachomatis within a year after their first visit. At the first visit, the composition and structure of vaginal microbial communities were analysed using 16S rRNA sequencing in the context of the sociodemographic and sexual risk behaviour information using logistic regression.

RESULTS

Five vaginal community state types (CSTs) were identified. Four CSTs were dominated by Lactobacillus spp., of which L. crispatus (37%) and L. iners (33%) were the most common. One CST was characterised by the absence of Lactobacillus spp. (25%) and the presence of an array of strict and facultative anaerobes. Multivariate logistic regression analysis revealed that women with a L. iners-dominated CST had an increased risk of C. trachomatis infection (p=0.04; OR: 2.6, 95% CI 1.0 to 6.6).

CONCLUSIONS

The distribution of CSTs dominated by Lactobacillus spp. agreed with previous studies. However, the frequency of dysbiosis among Caucasian women was relatively high (24%). Having vaginal microbiota dominated by L. iners was associated with an increased risk for C. trachomatis infection. Therefore, we hypothesise that specific signatures of vaginal microbiota are indicative of increased host predisposition to acquiring STIs.

Association of Recent Bacterial Vaginosis With Acquisition of Mycoplasma genitalium

We assessed the association between recent bacterial vaginosis (BV) and incident Mycoplasma genitalium, a sexually transmitted bacterium associated with adverse female reproductive health outcomes. Female sex workers in Mombasa, Kenya, completed a monthly sexual behavior interview and clinical examination. During February 2005-February 2006, vaginal fluid specimens collected from women every other month were tested for M. genitalium by nucleic acid amplification testing. Vaginal microbiota were assessed monthly and categorized by Nugent score (0-3 = normal microbiota, 4-6 = intermediate microbiota disruption, and 7-10 = BV). A discrete failure time analysis for multiple events using logistic regression was employed to estimate the odds of incident M. genitalium infection at follow-up visits among women with BV (vs. normal microbiota) at the preceding visit. Among the 280 women, 54.3% were positive for human immunodeficiency virus. At baseline, 16.1% had prevalent M. genitalium infection and 40.4% had prevalent BV. There were 59 incident M. genitalium infections among 50 women, for an incidence rate of 34.6 cases per 100 person-years. Following adjustment for age, human immunodeficiency virus status, and time, prior BV was associated with a 3.5-fold increase in odds of incident M. genitalium (adjusted odds ratio = 3.49, 95% confidence interval: 1.86, 6.56). This strong association suggests that BV may enhance susceptibility to M. genitalium infection.

Is the role of human female reproductive tract microbiota underestimated?

An issue that is currently undergoing extensive study is the influence of human vaginal microbiota (VMB) on the health status of women and their neonates. Healthy women are mainly colonised with lactobacilli such as Lactobacillus crispatus, Lactobacillus jensenii, and Lactobacillus iners; however, other bacteria may be elements of the VMB, particularly in women with bacterial vaginosis. The implementation of culture-independent molecular methods in VMB characterisation, especially next-generation sequencing, have provided new information regarding bacterial diversity in the vagina, revealing a large number of novel, fastidious, and/or uncultivated bacterial species. These molecular studies have contributed new insights regarding the role of bacterial community composition. In this study, we discuss recent findings regarding the reproductive tract microbiome. Not only bacteria but also viruses and fungi constitute important components of the reproductive tract microbiome. We focus on aspects related to the impact of the maternal microbiome on foetal development, as well as the establishment of the neonatal microbiomes, including the placenta microbiome, and the haematogenous source of intrauterine infection. We also discuss whether the role of the vaginal microbiome is currently understood and appreciated.

High prevalence of curable sexually transmitted infections among pregnant women in a rural county hospital in Kilifi, Kenya

Background

Women attending antenatal care (ANC) in resource-limited countries are frequently screened for syphilis and HIV, but rarely for other sexually transmitted infections (STIs). We assessed the prevalence of curable STIs, defined as infection with either Chlamydia trachomatis or Neisseria gonorrhoeae or Trichomonas vaginalis, from July to September 2015.

Methods

In a cross-sectional study, women attending ANC at the Kilifi County Hospital, Kenya, had a urine sample tested for C. trachomatis/N. gonorrhoeae by GeneXpert^® and a vaginal swab for T. vaginalis by culture. Bacterial vaginosis (BV) was defined as a Nugent score of 7–10 of the Gram stain of a vaginal smear in combination with self-reported vaginal discharge. Genital ulcers were observed during collection of vaginal swabs. All women responded to questions on socio-demographics and sexual health and clinical symptoms of STIs. Predictors for curable STIs were assessed in multivariable logistic regression.

Results

A total of 42/202 (20.8%, 95% confidence interval (CI):15.4–27.0) women had a curable STI. The prevalence was 14.9% for C. trachomatis (95% CI:10.2–20.5), 1.0% for N. gonorrhoeae (95% CI: 0.1–3.5), 7.4% for T. vaginalis (95% CI:4.2–12.0), 19.3% for BV (95% CI: 14.1–25.4) and 2.5% for genital ulcers (95% CI: 0.8–5.7). Predictors for infection with curable STIs included women with a genital ulcer (adjusted odds ratio (AOR) = 35.0, 95% CI: 2.7–461.6) compared to women without a genital ulcer, women who used water for cleaning after visiting the toilet compared to those who used toilet paper or other solid means (AOR = 4.1, 95% CI:1.5–11.3), women who reported having sexual debut ≤ 17 years compared to women having sexual debut ≥18 years (AOR = 2.7, 95% CI:1.1–6.6), and BV-positive women (AOR = 2.7, 95% CI:1.1–6.6) compared to BV-negative women.

Conclusion

One in five women attending ANC had a curable STI. These infections were associated with genital ulcers, hygiene practices, early sexual debut and bacterial vaginosis.

Bacterial vaginosis: a synthesis of the literature on etiology, prevalence, risk factors, and relationship with chlamydia and gonorrhea infections

Bacterial vaginosis (BV) is a common vaginal disorder in women of reproductive age. Since the initial work of Leopoldo in 1953 and Gardner and Dukes in 1955, researchers have not been able to identify the causative etiologic agent of BV. There is increasing evidence, however, that BV occurs when Lactobacillus spp., the predominant species in healthy vaginal flora, are replaced by anaerobic bacteria, such as Gardenella vaginalis, Mobiluncus curtisii, M. mulieris, other anaerobic bacteria and/or Mycoplasma hominis. Worldwide, it estimated that 20-30 % of women of reproductive age attending sexually transmitted infection (STI) clinics suffer from BV, and that its prevalence can be as high as 50-60 % in high-risk populations (e.g., those who practice commercial sex work (CSW). Epidemiological data show that women are more likely to report BV if they: 1) have had a higher number of lifetime sexual partners; 2) are unmarried; 3) have engaged in their first intercourse at a younger age; 4) have engaged in CSW, and 5) practice regular douching. In the past decade, several studies have provided evidence on the contribution of sexual activity to BV. However, it is difficult to state that BV is a STI without being able to identify the etiologic agent. BV has also emerged as a public health problem due to its association with other STIs, including: human immunodeficiency virus (HIV), herpes simplex virus type 2 (HSV-2), Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG). The most recent evidence on the association between BV and CT/NG infection comes from two secondary analyses of cohort data conducted among women attending STI clinics. Based on these studies, women with BV had a 1.8 and 1.9-fold increased risk for NG and CT infection, respectively. Taken together, BV is likely a risk factor or at least an important contributor to subsequent NG or CT infection in high-risk women. Additional research is required to determine whether this association is also present in other low-risk sexually active populations, such as among women in the US military. It is essential to conduct large scale cross-sectional or population-based case-control studies to investigate the role of BV as a risk factor for CT/NG infections. These studies could lead to the development of interventions aimed at reducing the burden associated with bacterial STIs worldwide.

Home Screening for Bacterial Vaginosis to Prevent Sexually Transmitted Diseases

BACKGROUND

Longitudinal studies have consistently found a significant association between bacterial vaginosis (BV) and acquisition of sexually transmitted diseases. However, there are limited prospective data to confirm these findings.

METHODS

We conducted a prospective, randomized, open-label trial of home screening and treatment of young women with asymptomatic BV who were also at high risk for sexually transmitted diseases. These women were screened every 2 months for 12 months and randomized to treatment with oral metronidazole 500 mg twice daily for 7 days or observation alone. The primary outcome was the incidence of gonorrhea and/or chlamydia.

RESULTS

A total of 1365 subjects were enrolled in the study across 10 sites. Adherence with mailing specimens obtained at home was excellent in both groups (84%-88%). The incidence of gonorrhea and/or chlamydia was 19.1 per 100 person-years (95% confidence interval, 15.1-22.1) for the treatment group and 18.5 per 100 person-years (15.1-22.8) for the observation arm, a difference that was not statistically significant.

CONCLUSIONS

Young women were very amenable to home screening for BV, gonorrhea, and chlamydia. Treatment of asymptomatic BV with 1 week of oral metronidazole did not decrease the incidence of gonorrhea and/or chlamydia.

CLINICAL TRIALS REGISTRATION

NCT00667368.

Prevalent bacterial vaginosis infection - a risk factor for incident sexually transmitted infections in women in Durban, South Africa

The association between bacterial vaginosis (BV) and incident sexually transmitted infections (STIs) in a cohort of high-risk women from Durban, South Africa was investigated in this study. We undertook a secondary analysis of the Methods for Improving Reproductive Health in Africa trial that assessed effectiveness of the latex diaphragm and lubricant gel on HIV prevention among women. During study visits, urine specimens were collected for testing for Neisseria gonorrhoeae, Chlamydia trachomatis and Trichomonas vaginalis The presence of BV was based on vaginal pH and wet mount test assessments. The association between BV and the risk for incident STIs was determined using the Cox proportional hazards model. Prevalence of BV was 31% in a cohort of 435 women tested at baseline. Among these women, BV was significantly associated with incident Trichomonas vaginalis (14.6 per 100 PY, p = 0.03) and Chlamydia trachomatis infections (15.8 per 100 PY, p = 0.04). BV remained a significant predictor for Trichomonas vaginalis infections even after adjusting for potential confounders such as age and marital status (HR: 1.60, 95% CI: 1.00, 2.57, p = 0.04). Our study showed an association between baseline BV infections and incident Trichomonas vaginalis and Chlamydia trachomatis infections. Women with BV infections should be counselled on the use of condoms and the risk of new STIs.

The perinatal microbiome and pregnancy: moving beyond the vaginal microbiome

The human microbiome, the collective genome of the microbial community that is on and within us, has recently been mapped. The initial characterization of healthy subjects has provided investigators with a reference population for interrogating the microbiome in metabolic, intestinal, and reproductive health and disease states. Although it is known that bacteria can colonize the vagina, recent metagenomic studies have shown that the vaginal microbiome varies among reproductive age women. Similarly, the richness and diversity of intestinal microbiota also naturally fluctuate among gravidae in both human and nonhuman primates, as well as mice. Moreover, recent evidence suggests that microbiome niches in pregnancy are not limited to maternal body sites, as the placenta appears to harbor a low biomass microbiome that is presumptively established in early pregnancy and varies in association with a remote history of maternal antenatal infection as well as preterm birth. In this article, we will provide a brief overview on metagenomics science as a means to investigate the microbiome, observations pertaining to both variation and the presumptive potential role of a varied microbiome during pregnancy, and how future studies of the microbiome in pregnancy may lend to a better understanding of human biology, reproductive health, and parturition.

Cervicovaginal levels of proinflammatory cytokines are increased during chlamydial infection in bacterial vaginosis but not in lactobacilli-dominated flora

OBJECTIVE

The purpose of this study was to assess the cervicovaginal levels of proinflammatory cytokines in women with Chlamydia trachomatis (CT) infection in the presence of bacterial vaginosis (BV) and normal flora and to compare with those negative for CT.

MATERIALS AND METHODS

In this cross-sectional study, nonpregnant women were enrolled at 2 outpatient clinics and at 1 primary medical care unit in São Paulo State, Brazil. Cervicovaginal samples from 256 women with BV, of which 68 (26.6%) had concomitant CT infection and 188 (73.4%) were CT-negative, were measured for interleukin-1β (IL-1β), IL-6, and IL-8 by enzyme-linked immunosorbent assay. A matching number of samples from women with normal flora, CT-positive (n = 68) and negative (n = 188), were evaluated as control. Cytokine levels were compared by Mann-Whitney test and differences were considered significant at p < .05.

RESULTS

In CT-negative women, IL-1β was increased in BV (p < .001) when compared to normal flora, while the levels of IL-6 and IL8 were unchanged. The presence of CT infection was not associated with differences on cytokine levels in women with normal flora. However, women with BV had higher levels of IL-1β (p = .02), IL-6 (p = .02), and IL-8 (p = .03) in the presence of CT when compared to those who tested negative for CT.

CONCLUSIONS

Detection of endocervical CT is associated with increased cervicovaginal IL-1β, IL-6, and IL-8 levels in women with concomitant BV but not in those with normal flora.

Effects of bacterial vaginosis-associated bacteria and sexual intercourse on vaginal colonization with the probiotic Lactobacillus crispatus CTV-05

OBJECTIVE

Several fastidious bacteria have been associated with bacterial vaginosis (BV), but their role in lactobacilli recolonization failure is unknown. We studied the effect of 7 BV-associated bacterial species and 2 Lactobacillus species on vaginal colonization with Lactobacillus crispatus CTV-05 (LACTIN-V).

METHODS

Twenty-four women with BV were given a 5-day course of metronidazole vaginal gel and then randomized 3:1 to receive either LACTIN-V or placebo applied vaginally once daily for 5 initial consecutive days, followed by a weekly application over 2 weeks. Vaginal swabs for L. crispatus CTV-05 culture and 9 bacterium-specific 16S rRNA gene quantitative polymerase chain reaction assays were analyzed on several study visits for the 18 women receiving LACTIN-V.

RESULTS

Vaginal colonization with CTV-05 was achieved in 61% of the participants receiving LACTIN-V at either day 10 or day 28 visit and 44% at day 28. Participants not colonized with CTV-05 had generally higher median concentrations of BV-associated bacteria compared to those who colonized. Between enrollment and day 28, the median concentration of Gardnerella vaginalis minimally reduced from 10 to 10 16S rRNA gene copies per swab in women who colonized with CTV-05 but increased from 10 to 10 in those who failed to colonize (P = 0.19). Similarly, the median concentration of Atopobium spp. reduced from 10 16S rRNA gene copies per swab to below limit of detection in women who colonized with CTV-05, but increased from 10 to 10 in those who failed to colonize (P = 0.04). The presence of endogenous L. crispatus at enrollment was found to be significantly associated with a reduced odds of colonization with CTV-05 on day 28 (P = 0.003), and vaginal intercourse during the study significantly impaired successful CTV-05 colonization (P = 0.018).

CONCLUSION

Vaginal concentration of certain BV-associated bacteria, vaginal intercourse during treatment, and the presence of endogenous L. crispatus at enrollment predict colonization with probiotic lactobacilli.

Severity of bacterial vaginosis and the risk of sexually transmitted infection

OBJECTIVE

The purpose of this study was to determine whether the association between bacterial vaginosis (BV) and incident sexually transmitted infection (STI) varies with more extreme BV scores.

STUDY DESIGN

We analyzed the data from 535 women who were enrolled in a randomized trial to promote dual method contraceptive use. Incident STI was defined as any case of Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, or pelvic inflammatory disease. BV was defined by Gram stain (Nugent score). STI risk was estimated with the use of proportional hazards regression.

RESULTS

Binary (0-6 vs 7-10) and 3-level (negative 0-3, intermediate 4-6, or BV 7-10) categorizations were not associated with time to STI; however, women with the highest Nugent scores (9-10) had a 2.1-fold increased risk of STI (95% confidence interval, 1.05-4.28), compared with women with normal flora.

CONCLUSION

Nugent score>8 is associated with incident STI. More accurate classification of BV will allow clinicians to identify those women who are at greatest risk of STI.

Chlamydia trachomatis infection among women reporting sexual activity with women screened in Family Planning Clinics in the Pacific Northwest, 1997 to 2005

OBJECTIVES

We sought to define Chlamydia trachomatis positivity among women who report sexual activity with women, a population for which sparse data on this infection are available and for whom health disparities including challenged access to comprehensive sexual and reproductive health services, have been reported.

METHODS

We analyzed data from 9358 family planning clinic visits with C trachomatis tests among women aged 15 to 24 years who reported sexual activity within the past year exclusively with women (WSW) or with men and women (WSMW), in the Region X Infertility Prevention Project. Characteristics were compared with women who reported sexual activity exclusively with men (WSM). Results. C trachomatis positivity among both WSW and WSMW was 7.1%, compared with 5.3% among WSM. Behavioral risks were more commonly reported by WSW and WSMW, compared with reports by WSM. Risks for C trachomatis positivity were comparable across groups and included younger age, non-White race, behavioral risks, and clinical signs.

CONCLUSIONS

Higher C trachomatis positivity among women reporting same-sex sexual behavior supports investigation into potential explanatory factors, including sexual behaviors, biological susceptibility, routine C trachomatis screening disparities, sexual identity disclosure, and sexual network assessment.

Characteristic male urine microbiomes associate with asymptomatic sexually transmitted infection

BACKGROUND

The microbiome of the male urogenital tract is poorly described but it has been suggested that bacterial colonization of the male urethra might impact risk of sexually transmitted infection (STI). Previous cultivation-dependent studies showed that a variety of non-pathogenic bacteria colonize the urethra but did not thoroughly characterize these microbiomes or establish links between the compositions of urethral microbiomes and STI.

METHODOLOGY/FINDINGS

Here, we used 16S rRNA PCR and sequencing to identify bacteria in urine specimens collected from men who lacked symptoms of urethral inflammation but who differed in status for STI. All of the urine samples contained multiple bacterial genera and many contained taxa that colonize the human vagina. Uncultivated bacteria associated with female genital tract pathology were abundant in specimens from men who had STI.

CONCLUSIONS

Urine microbiomes from men with STI were dominated by fastidious, anaerobic and uncultivated bacteria. The same taxa were rare in STI negative individuals. Our findings suggest that the composition of male urine microbiomes is related to STI.

Bacterial vaginosis assessed by gram stain and diminished colonization resistance to incident gonococcal, chlamydial, and trichomonal genital infection

BACKGROUND

We sought to assess the relationship between bacterial vaginosis (BV) assessed by Gram stain and incident trichomonal, gonococcal, and/or chlamydial genital infection.

METHODS

This longitudinal study included 3620 nonpregnant women aged 15-44 years who presented for routine care at 12 clinics in Birmingham, Alabama. Participants were assessed quarterly for 1 year. Vaginal smears were categorized by the Nugent Gram stain score (0-3, normal; 4-6, intermediate state; 7-10, BV). Pooled logistic regression was used to estimate the hazard ratios for the comparison of trichomonal, gonococcal, and chlamydial infection incidence in participants by Nugent score at the prior visit. Participants were censored at their first visit with a positive test result for trichomonal, gonococcal, and/or chlamydial infection.

RESULTS

Of the 10,606 eligible visits, 37.96% were classified by BV and 13.3% by positive detection of trichomonal, gonococcal, and/or chlamydial infection. An intermediate state or BV at the prior visit was associated with a 1.5-2-fold increased risk for incident trichomonal, gonococcal, and/or chlamydial infection (adjusted hazard ratio [AHR] for intermediate state, 1.41 [95% confidence interval {CI}, 1.12-1.76]; AHR for BV, 1.73 [95% CI, 1.42-2.11]; P= .058 for trend). Estimates were similar for trichomonal-only, gonococcal-only, and chlamydial-only infection outcomes.

CONCLUSION

BV microbiota as gauged by Gram stain is associated with a significantly elevated risk for acquisition of trichomonal, gonococcal, and/or chlamydial genital infection.

Beyond douching: use of feminine hygiene products and STI risk among young women

INTRODUCTION

Use of feminine hygiene products (feminine wipes, sprays, douches, and yeast creams) by adolescent women is common, yet understudied.

AIM

We examine the association among these genital hygiene behaviors, condom use, and sexually transmitted infection (STI).

MAIN OUTCOME MEASURES

Using the interview as our unit of analysis, we examined associations between genital hygiene behaviors (use of feminine wipes, feminine sprays, douches, or yeast creams), STI risk factors, and infection with Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis.

METHODS

We recruited 295 adolescent women from primary care clinics as part of a larger longitudinal study of STI among high-risk adolescents. Participants completed face-to-face interviews every 3 months, and provided vaginal swabs for STI testing. Data were analyzed with repeated measures logistic models to control for multiple observations contributed by each participant.

RESULTS

Participants reported douching in 25% of interviews, feminine sprays in 29%, feminine wipes in 27%, and yeast creams in 19% of interviews. We observed a co-occurrence of douching, spraying, and wiping. A past STI (6 months or more prior) was associated with increased likelihood of yeast cream use, and a recent STI (3 months prior) was associated with increased likelihood of feminine wipe use. Condom use was modestly associated with increased likelihood of douching.

CONCLUSIONS

Young women frequently use feminine hygiene products, and it is important for clinicians to inquire about use as these products may mimic or mask STI. We found no associations between douching and STI, but instead modest associations between hygiene and STI prevention, suggesting motivation for self-care.

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Vaginal maturation index self-sample collection in mid-life women: acceptability and correlation with physician-collected samples

OBJECTIVE

During menopause, the ratio of the three vaginal epithelial cell types (parabasal, intermediate, and superficial) changes. The proportion of these vaginal cell types is categorized by the vaginal maturation index (VMI). The VMI provides an objective assessment of vaginal hormone response as well as overall hormonal environment. The aim of this study was to determine the concordance of self- and physician-collected samples for VMI and evaluate participant preference for self-collection.

DESIGN

Twenty women aged 42 to 67 years were enrolled. Each woman received instructions and self-collected a sample for VMI analysis from her posterior lateral vaginal walls. Next, she underwent a vaginal speculum examination for physician VMI sampling. Finally, she completed a survey regarding sampling preference, ease of self-sampling, and previous vaginal experience. Correlation between physician- and self-collected samples were calculated using Pearson's correlation coefficient and Cronbach's alpha. Participant characteristics, vaginal experiences, and sampling preferences were summarized using frequencies and measures of central tendencies. The relationships between preference for sampling method and previous vaginal experiences were examined using Fisher's exact test.

RESULTS

Average age of the 20 participants was 52.2 years (range, 42-67 y). Women had a variety of previous vaginal experiences ranging from tampon use (100%) to previous vaginal self-swabbing (15%). Average self-collected VMI was 48.4 (range, 13.8-83.5) and physician-collected VMI was 49.9 (range, 20.5-83.5) with a correlation of 0.97 (P < 0. 001), alpha = 0.94. The majority of women preferred self-collection (80%) to physician collection, and there was no difference in preference based on previous vaginal experiences. Nineteen women (95%) found the self-collection to be very easy, and one found it to be somewhat easy.

CONCLUSIONS

Women can reliably self-collect samples for VMI, and the majority of women in our study preferred self-collection to physician collection. Vaginal self-sampling allows this technique for measuring overall hormonal environment to be used in clinical and epidemiological research.

Bacterial vaginosis and HIV acquisition: a meta-analysis of published studies

OBJECTIVES

To assess and summarize the published literature on the extent to which bacterial vaginosis may increase the risk of HIV acquisition.

DESIGN

Meta-analysis of published studies.

METHODS

Medline and other electronic databases were systematically searched for eligible publications. The association between bacterial vaginosis and incident HIV was separately analyzed from that between bacterial vaginosis and prevalent HIV. The latter was further analyzed, stratified by bacterial vaginosis diagnostic method, HIV risk profile of the study population, and whether or not adjusted estimates were presented.

RESULTS

Twenty-three eligible publications were identified, including a total of 30,739 women. Bacterial vaginosis was associated with an increased risk of HIV acquisition in HIV-incidence studies (relative risk = 1.6, 95% confidence interval: 1.2, 2.1). All but one of 21 HIV-prevalence studies reported estimates above the null. The latter results were heterogeneous and showed some evidence of funnel plot asymmetry, precluding the estimation of a single summary measure. The association between bacterial vaginosis and HIV in prevalence studies appeared stronger for women without high-risk sexual behavior.

CONCLUSION

Bacterial vaginosis was consistently associated with an increased risk of HIV infection. High bacterial vaginosis prevalence may result in a high number of HIV infections being attributable to bacterial vaginosis. More prospective studies are needed to accurately evaluate the role of bacterial vaginosis in HIV acquisition in low-risk versus high-risk women. Furthermore, randomized clinical trials may be worth considering to determine the effect of bacterial vaginosis control measures on HIV acquisition.

Epidemiology of genital Chlamydia trachomatis infection among young women in Costa Rica

OBJECTIVE

To investigate Chlamydia trachomatis (Ct) epidemiology among 5829 women 18 to 25 years old, in Costa Rica.

METHODS

Data are from a community-based human papillomavirus 16/18 vaccine trial. Before randomization, eligible women who reported previous sexual activity were interviewed and tested for Ct DNA by Hybrid Capture 2 and polymerase chain reaction-based genotyping. Multivariate models were developed.

RESULTS

Overall prevalence was 14.2% (95% confidence interval, 13.3-15.1). Among Ct genotypes, serovar E was the most common (4.3%), followed by serovar F (3.0%), serovar D/Da (2.9%), and serovar I/Ia (2.1%).Ct increased with lifetime sexual partners of the women, and among women with 1 lifetime partner, with sexual partners of the partner. Current intrauterine device users had an increase in Ct detection [odds ratio (OR) 1.6, 1.1-2.5] but hormonal contraceptives or condom users did not. Miscarriages were associated with a reduction in Ct detection (OR 0.7, 0.5-1.0) while current regular smoking increased it (OR 1.7, 1.2-2.5). Vaginal discharge, reactive changes, ASCUS or LSIL and moderate to severe inflammation in the cytology were significantly more common among Ct positive women (P <0.001). Gonorrhea prevalence was 0.8%, and it was, as other STIs, highly correlated with Ct detection.

CONCLUSIONS

This is a high-prevalence population where we confirmed the strong link between Ct and sexual behavior of women and their partners. The establishment of a screening program in the age group included in this study should be considered. More studies are needed in developing countries to further investigate the role of intrauterine devices and the lack of protection by condoms, in addition to the interplay between Ct and other STIs, ectopy, inflammation, and epithelial abnormalities.