Prevalence of Gardnerella vaginalis in Male Sexual Partners of Women With and Without Bacterial Vaginosis

Infectious Vaginitis, Cervicitis, and Pelvic Inflammatory Disease

Vaginal symptoms are one of the most common reasons women consult with physicians and can significantly impact quality of life. The differential diagnosis of vaginal discharge includes physiologic discharge, vaginitis, cervicitis, and pelvic inflammatory disease (PID). Vaginitis is inflammation of the vagina, most commonly caused by bacterial vaginosis (BV), vulvovaginal candidiasis, and trichomoniasis infections. Cervicitis is an inflammation of the cervix and typically caused by Chlamydia trachomatis and Neisseria gonorrhoeae. PID is infection of the female upper genital tract, involving the uterus, fallopian tubes, ovaries, and/or pelvic peritoneum and usually caused by Chlamydia trachomatis, Neisseria gonorrhoeae, and bacterial vaginosis-associated pathogens. A pelvic exam should be performed for any woman presenting with vaginal discharge to confirm the diagnosis and rule out an upper tract infection. BV and vulvovaginal candidal infections only require treatment if symptomatic and do not require partner therapy, whereas treatment and partner therapy is recommended for sexually transmitted illnesses, such as trichomoniasis, chlamydia and gonorrhea. Vaginitis may be uncomfortable, but rarely leads to serious long-term consequence, but pelvic inflammatory disease can lead to serious long-term sequelae, including increased risk for ectopic pregnancy, infertility, and chronic pelvic pain.

Connecting the Dots: Translating the Vaginal Microbiome Into a Drug

A Lactobacillus-dominated vaginal microbiota (VMB) has been associated with health and considered an important host defense mechanism against urogenital infections. Conversely, depletion of lactobacilli and increased microbial diversity, amplifies the risk of adverse gynecologic and obstetric outcomes. A common clinical condition that exemplifies dysbiosis is bacterial vaginosis (BV). BV is currently treated with antibiotics, but frequently recurs, due in part to persistent dysbiosis and failure of lactobacilli to repopulate the vagina. New treatment options are needed to address BV. The VMB is relatively simple and optimally dominated by one or several species of Lactobacillus. Lactobacillus crispatus is strongly associated with vaginal health and depleted in dysbiosis. Replenishing the dysbiotic VMB with protective L. crispatus CTV-05 is a promising approach to prevent recurrent infections and improve women's health. Here we discuss confirmation of this approach with the microbiome-based biologic drug, LACTIN-V (L. crispatus CTV-05), focusing on prevention of BV recurrence.

Bacterial vaginosis: controversial issues

The purpose of the review. Consideration of the most controversial issues regarding the possibility of sexual transmission of BV-associated microorganisms (bacterias) in women and men. Basic provisions. Bacterial vaginosis (BV) is a common disease associated with an increased risk of contracting sexually transmitted infections (including human papillomavirus and human immunodeficiency virus) in women and their male sexual partners. BV is characterized by polymicrobial transformations caused by Gardnerella vaginalis, which is the main etiological microorganism of this disease. G. vaginalis has a proven ability to form microbial biofilms on the mucosal surface. As a rule, from 10 to 12 different G. vaginalis genotypes can simultaneously reside in one biofilm, which provides it with a longer lifespan and viability. It has been shown that microorganisms in the biofilm acquire properties that reduce sensitivity to standard etiotropic therapy even at high doses of antibiotics. It was found that the cause of BV is a polymicrobial gardnerella biofilm, all components of which are transferred as a whole (for example, with the help of key cells), including during sexual contact. In this regard, the article discusses the possibility of using a new term biofilm gardnerellosis, which more accurately reflects the essence of this problem. Microbial biofilms organized by G. vaginalis are found in a significant number of women with BV and their sexual partners.

"It's just an issue and you deal with it… you just deal with it, you move on and you do it together.": Men's experiences of bacterial vaginosis and the acceptability of male partner treatment

Bacterial vaginosis (BV) is a common vaginal infection among women of reproductive age. Increasing evidence suggests BV may be sexually transmitted indicating a potential role for the treatment of sexual partners. If partner treatment reduces BV recurrence in women, real-world success will depend on sexual partners’ willingness to accept it. However, a lack of data exists on the acceptability of partner treatment among sexual partners, and no data exists on male partners’ experience of BV specifically. The aim of this study was to explore male partners’ views and experience of BV and their attitudes toward associated partner treatment. A social constructionist approach informed the framework of this study. Semi structured interviews were conducted with eleven men who participated in a BV partner treatment trial. Interviews were transcribed verbatim and analysed thematically. In the absence of symptoms in themselves, BV had little impact on men beyond their concerns for their partner’s health and self-esteem. Acceptance of treatment was largely a demonstration of care and support. While all participants had accepted treatment, men surmised the primary reasons other men may reject treatment as being: if they felt BV had “nothing to do with them”, which was related to not wanting to be viewed as having a ‘problem’ and exacerbated by norms of masculinity and STI-related stigma; lack of a diagnostic test to indicate if a male “had BV”; and a casual or less established relationship. Men’s attitudes to BV and partner treatment were primarily influenced by the nature of their relationships. The ambiguous aetiology of BV appears to attenuate STI related stigma and questions of infidelity.

A Rare Cause of a Scrotal Abscess due to the Symbiotic Infection of Gardnerella vaginalis and Prevotella bivia in an Adult Male

Gardnerella vaginalis (G. vaginalis) is the major bacteria detected in women with bacterial vaginosis (BV). Prevotella bivia (P. bivia) has been demonstrated to show a symbiotic relationship with G. vaginalis. Some men have been shown to be colonized with G. vaginalis in their urogenital or anorectal tracts, however genitourinary infections in males, including balanitis and urethritis, due to this organism appear to be much less common. In this report, we summarize previous cases of men with G. vaginalis infection, and we present a rare and unusual case of a unilateral scrotal abscess caused by G. vaginalis in co-infection with P. bivia.

A reliable numerical analysis for stochastic gonorrhea epidemic model with treatment effect

The phenomena of disease spread are unpredictable in nature due to random mixing of individuals in a population. It is of more significance to include this randomness while modeling infectious diseases. Modeling epidemics including their stochastic behavior could be a more realistic approach in many situations. In this paper, a stochastic gonorrhea epidemic model with treatment effect has been analyzed numerically. Numerical solution of stochastic model is presented in comparison with its deterministic part. The dynamics of the gonorrhea disease is governed by a threshold quantity [Formula: see text] called basic reproductive number. If [Formula: see text], then disease eventually dies out while [Formula: see text] shows the persistence of disease in population. The standard numerical schemes like Euler Maruyama, stochastic Euler and stochastic Runge–Kutta are highly dependent on step size and do not behave well in certain scenarios. A competitive non-standard finite difference numerical scheme in stochastic setting is proposed, which is independent of step size and remains consistent with the corresponding deterministic model.

Differential sexual network connectivity offers a parsimonious explanation for population-level variations in the prevalence of bacterial vaginosis: a data-driven, model-supported hypothesis

BACKGROUND

The prevalence of bacterial vaginosis (BV) and vaginal microbiota types varies dramatically between different populations around the world. Understanding what underpins these differences is important, as high-diversity microbiotas associated with BV are implicated in adverse pregnancy outcomes and enhanced susceptibility to and transmission of sexually transmitted infections.

MAIN TEXT

We hypothesize that these variations in the vaginal microbiota can, in part, be explained by variations in the connectivity of sexual networks. We argue: 1) Couple-level data suggest that BV-associated bacteria can be sexually transmitted and hence high sexual network connectivity would be expected to promote the spread of BV-associated bacteria. Epidemiological studies have found positive associations between indicators of network connectivity and the prevalence of BV; 2) The relationship between BV prevalence and STI incidence/prevalence can be parsimoniously explained by differential network connectivity; 3) Studies from other mammals are generally supportive of the association between network connectivity and high-diversity vaginal microbiota.

CONCLUSION

To test this hypothesis, we propose a combination of empirical and simulation-based study designs.

Penile Inflammatory Skin Disorders and the Preventive Role of Circumcision

Penile inflammatory skin conditions such as balanitis and posthitis are common, especially in uncircumcised males, and feature prominently in medical consultations. We conducted a systematic review of the medical literature on PubMed, EMBASE, and Cohrane databases using keywords "balanitis," "posthitis," "balanoposthitis," "lichen sclerosus," "penile inflammation," and "inflammation penis," along with "circumcision," "circumcised," and "uncircumcised." Balanitis is the most common inflammatory disease of the penis. The accumulation of yeasts and other microorganisms under the foreskin contributes to inflammation of the surrounding penile tissue. The clinical presentation of inflammatory penile conditions includes itching, tenderness, and pain. Penile inflammation is responsible for significant morbidity, including acquired phimosis, balanoposthitis, and lichen sclerosus. Medical treatment can be challenging and a cost burden to the health system. Reducing prevalence is therefore important. While topical antifungal creams can be used, usually accompanied by advice on hygiene, the definitive treatment is circumcision. Data from meta-analyses showed that circumcised males have a 68% lower prevalence of balanitis than uncircumcised males and that balanitis is accompanied by a 3.8-fold increase in risk of penile cancer. Because of the high prevalence and morbidity of penile inflammation, especially in immunocompromised and diabetic patients, circumcision should be more widely adopted globally and is best performed early in infancy.

Bypassing the 'rapid-clearance-in-males-buffer': A fourth mechanism to explain how concurrency enhances STI spread

A number of sexually transmitted infections (STIs) persist for a considerably shorter period in the male urethra than the vagina. If the gap between sequential partnerships is longer than the duration of STI colonization in males, then this would protect future female partners from this STI in a setting of serial monogamy. If, however, males have more than one partner at a time (concurrency), then this would enable the STI to bypass this gap/buffer. We therefore propose bypassing the rapid-clearance-in-males-buffer as a fourth mechanism, whereby concurrency could enhance the spread of STIs.

The influence of sexual activity on the vaginal microbiota and Gardnerella vaginalis clade diversity in young women

OBJECTIVES

To examine the influence of sexual activity on the composition and consistency of the vaginal microbiota over time, and distribution of Gardnerella vaginalis clades in young women.

METHODS

Fifty-two participants from a university cohort were selected. Vaginal swabs were self-collected every 3-months for up to 12 months with 184 specimens analysed. The vaginal microbiota was characterised using Roche 454 V3/4 region 16S rRNA sequencing, and G.vaginalis clade typing by qPCR.

RESULTS

A Lactobacillus crispatus dominated vaginal microbiota was associated with Caucasian ethnicity (adjusted relative risk ratio[ARRR] = 7.28, 95%CI:1.37,38.57,p = 0.020). An L.iners (ARRR = 17.51, 95%CI:2.18,140.33,p = 0.007) or G.vaginalis (ARRR = 14.03, 95%CI:1.22,160.69, p = 0.034) dominated microbiota was associated with engaging in penile-vaginal sex. Microbiota dominated by L.crispatus, L.iners or other lactobacilli exhibited greater longitudinal consistency of the bacterial communities present compared to ones dominated by heterogeneous non-lactobacilli (p<0.030); sexual activity did not influence consistency. Women who developed BV were more likely to have clade GV4 compared to those reporting no sex/practiced non-coital activities (OR = 11.82, 95%CI:1.87,74.82,p = 0.009). Specimens were more likely to contain multiple G.vaginalis clades rather than a single clade if women engaged in penile-vaginal sex (RRR = 9.55, 95%CI:1.33,68.38,p = 0.025) or were diagnosed with BV (RRR = 31.5, 95%CI:1.69,586.87,p = 0.021).

CONCLUSIONS

Sexual activity and ethnicity influenced the composition of the vaginal microbiota of these young, relatively sexually inexperienced women. Women had consistent vaginal microbiota over time if lactobacilli were the dominant spp. present. Penile-vaginal sex did not alter the consistency of microbial communities but increased G.vaginalis clade diversity in young women with and without BV, suggesting sexual transmission of commensal and potentially pathogenic clades.

Managing Recurrent Bacterial Vaginosis: Insights for Busy Providers

INTRODUCTION

Bacterial vaginosis (BV) is a common clinical condition that affects millions of women annually. Serious sequelae exist from untreated infection. Recurrent BV (RBV) is also common with few approved clinical treatment modalities. Review of the current recommendations yields practical tips to aid busy professionals.

AIM

To review the current treatment recommendations for recurrent bacterial vaginosis.

METHODS

A literature review was conducted using the keywords: bacterial vaginosis, recurrent bacterial vaginosis, vaginal probiotics, vaginal reacidifiers, and trichomoniasis.

MAIN OUTCOME MEASURE

Patients with RBV should be treated with the approved suppressive antimicrobial regimen, but new modalities and adjuncts are currently under review and appear safe; however, rates of efficacy still need to be established.

RESULTS

There is no defined etiology of RBV, and thus, a curative treatment remains elusive. Sexual practices, hygiene practices, and the type of sexual partner all affect the rate of BV recurrence. Vaginal reacidifiers and probiotics may offer effective alternatives to the current antimicrobial regimens. Clinicians should obtain an in-depth history to have an accurate picture of the patient's pattern of infection, ensure they are using all clinical tools available to make the correct diagnosis, and educate the patient regarding simple behavioral changes they can make to prevent RBV.

CONCLUSION

More research is needed to explain and treat RBV. In the meantime, if clinicians maximize all current modalities, they will reduce the recurrence rate in certain patients. Marshall AO. Managing recurrent bacterial vaginosis: Insights for busy providers. Sex Med Rev 2015;3:88-92.

Making inroads into improving treatment of bacterial vaginosis - striving for long-term cure

Bacterial vaginosis (BV) is one of the great enigmas in women's health, a common condition of unknown aetiology, which is associated with significant morbidity and unacceptably high recurrence rates. While it remains unclear whether BV recurrence is predominantly due to failure of current antibiotic regimens to eradicate BV-associated bacteria (BVAB) and biofilm, a failure of some women to re-establish a resilient Lactobacillus-dominant vaginal microbiota, reinfection from sexual partners, or a combination of these factors, it is inherently challenging to make significant inroads towards this goal. In this review, we will outline why BV is such a clinical and epidemiologic conundrum, and focus on several key approaches that we believe merit discussion and clinical research, including strategies to: i) prevent reinfection (partner treatment trials), ii) boost favourable vaginal Lactobacillus species and promote a Lactobacillus-dominant vaginal microbiome (hormonal contraceptive and probiotic trials) and iii) disrupt vaginal BV-associated biofilm.

Recent progress in understanding the epidemiology of bacterial vaginosis

PURPOSE OF REVIEW

Bacterial vaginosis epidemiology has been transformed by new theoretical insights and methodologies, such as molecular sequencing. We summarize the progress made in these domains.

RECENT FINDINGS

The vaginal microbiome can be classified in five to eight clusters. Bacterial vaginosis-type clusters typically constitute one of these clusters, but in higher risk women, it can constitute up to three clusters. The vaginal microbiomes may be fairly stable or be subject to rapid changes in their constitutive makeup. Bacterial vaginosis does not appear to be a single entity. Certain bacterial communities are associated with particular symptoms of bacterial vaginosis that are paired with unique adverse outcomes. Biofilm-producing Gardnerella vaginalis are likely to play an important role in initiating the structured polymicrobial biofilm that is a hallmark of bacterial vaginosis.

SUMMARY

Longitudinal studies currently underway should help elucidate how to best define bacterial vaginosis and its subtypes. Risk factors and outcomes associated with particular bacterial vaginosis subtypes should also be further clarified through these studies.

Strong association between the prevalence of bacterial vaginosis and male point-concurrency

OBJECTIVE

The prevalence of bacterial vaginosis (BV) differs considerably between different populations, and individual-level risk factors such as number of sex partners seem unable to explain these differences. The effect of network-level factors, such as the prevalence of partner concurrency (the proportion of sexual partnerships that overlap in time as opposed to running sequentially) on BV prevalence has not hitherto been investigated.

STUDY DESIGN

We performed linear regression to assess the relationship between the prevalence of male concurrency and prevalence of BV in each of 11 countries for which we could obtain comparable data. The data for concurrency prevalence were taken from the WHO/Global Programme on AIDS (GPA) sexual behavioural surveys. BV prevalence rates were obtained from a systematic review of the global patterning of BV.

RESULTS

We found a strong relationship between the prevalence of male concurrency and BV prevalence (Pearson's R(2)=0.57; P=0.007).

CONCLUSIONS

The findings of a strong ecological-level association between BV and partner concurrency need to be replicated and augmented with different types of studies such as multilevel prospective studies tracking the incidence of BV and associated individual, partner and network level risk factors.

Recurrence of bacterial vaginosis is significantly associated with posttreatment sexual activities and hormonal contraceptive use

BACKGROUND

Bacterial vaginosis (BV) recurrence posttreatment is common. Our aim was to determine if behaviors were associated with BV recurrence in women in a randomized controlled trial (RCT).

METHODS

Symptomatic 18- to 50-year-old females with BV (≥3 Amsel criteria and Nugent score [NS] = 4-10) were enrolled in a 3-arm randomized double-blind RCT Melbourne Sexual Health Centre, Australia, in 2009-2010. All 450 participants received oral metronidazole (7 days) and were equally randomized to vaginal clindamycin, lactobacillus-vaginal probiotic or vaginal placebo. At 1, 2, 3, and 6 months, participants self-collected vaginal smears and completed questionnaires. Primary endpoint was NS = 7-10. Cox regression was used to estimate hazard ratios (HRs) for risk of BV recurrence associated with baseline and longitudinal characteristics.

RESULTS

Four hundred four (90%) women with postrandomization data contributed to analyses. Cumulative 6-month BV recurrence was 28% (95% confidence interval [CI], 24%-33%) and not associated with treatment. After stratifying for treatment and adjusting for age and sex frequency, recurrence was associated with having the same pre-/posttreatment sexual partner (adjusted HR [AHR] = 1.9; 95% CI, 1.2-3.0), inconsistent condom use (AHR = 1.9; 95% CI, 1.0-3.3), and being non-Australian (AHR = 1.5; 95% CI, 1.0-2.1), and halved with use of an estrogen-containing contraceptive (AHR = 0.5; 95% CI, .3-.8).

CONCLUSIONS

Risk of BV recurrence was increased with the same pre-/posttreatment sexual partner and inconsistent condom use, and halved with use of estrogen-containing contraceptives. Behavioral and contraceptive practices may modify the effectiveness of BV treatment.

CLINICAL TRIALS REGISTRATION

ACTRN12607000350426.

Understanding factors that modulate HIV infection at the female genital tract mucosae for the rationale design of microbicides

Women are now becoming the pivot of the epidemiological spread of HIV infection worldwide, especially in developing countries. Therefore, research to develop an efficient microbicide is now a priority for the prevention of HIV-1 acquisition in exposed women. However, recent disappointing failures in microbicide clinical trials revealed major gaps in basic and applied knowledge that hinder the development of effective microbicide formulations. Indeed, the inhibitory power of microbicide molecules may be affected by several physiological and immunological factors present in male and female genital tracts. Furthermore, mucosal crossing of HIV-1 to increase the ability to reach the submucosal target cells (macrophages, lymphocytes, and dendritic cells) may be modulated by supraepithelial factors such as seminal complement components (opsonized HIV-1), by epithelial factors released in the submucosal microenvironment such as antimicrobial soluble factors, cytokines, and chemokines, and by potent intraepithelial and submucosal innate immunity. The design of vaginal microbicide formulations should take into account an understanding of the intimate mechanisms involved in the crossing of HIV through the female genital mucosae, in the context of a mixture of both male and female genital fluids.

Susceptibility of Gardnerella vaginalis biofilms to natural antimicrobials subtilosin, ε-poly-L-lysine, and lauramide arginine ethyl ester

Bacterial vaginosis is a common vaginal infection associated with numerous gynecological and obstetric complications. This condition is characterized by the presence of thick adherent vaginal biofilms, composed mainly of Gardnerella vaginalis. This organism is thought to be the primary aetiological cause of the infection paving the way for various opportunists to colonize the niche. Previously, we reported that the natural antimicrobials subtilosin, ε-poly-L-lysine, and lauramide arginine ethyl ester selectively inhibit the growth of this pathogen. In this study, we used plate counts to evaluate the efficacy of these antimicrobials against established biofilms of G. vaginalis. Additionally, we validated and compared two rapid methods (ATP viability and resazurin assays) for the assessment of cell viability in the antimicrobial-treated G. vaginalis biofilms. Out of the tested antimicrobials, lauramide arginine ethyl ester had the strongest bactericidal effect, followed by subtilosin, with clindamycin and polylysine showing the weakest effect. In comparison to plate counts, ATP viability and resazurin assays considerably underestimated the bactericidal effect of some antimicrobials. Our results indicate that these assays should be validated for every new application.

Effect of sexual activity on vaginal colonization with hydrogen peroxide-producing lactobacilli and Gardnerella vaginalis

BACKGROUND

Bacterial vaginosis is associated with sexual activity, but mechanisms for this association are unclear.

STUDY DESIGN

Cross-sectional analysis of data from women reporting sex with women who provided information on sexual behaviors as part of a study of vaginal bacteria was conducted. Vaginal bacteria were detected by semiquantitative culture. Binomial regression with log-link evaluated associations between detection of bacteria and sexual behaviors reported to occur before enrollment. Linear regression evaluated associations between these behaviors and quantity of bacteria.

RESULTS

Of the 320 women, 216 (68%) were colonized with H2O2-producing lactobacilli and 142 (44%) with Gardnerella vaginalis. Colonization with G. vaginalis was associated with >20 digital-vaginal sex acts (risk ratio, 2.01; 1.22, 3.29) or >10 toy-vaginal acts in the past 3 months (risk ratio, 1.76; 1.32, 2.36). Quantity of H2O2-producing lactobacilli was 1.3 log lower in colonized women reporting >10 acts of insertive vaginal sex-toy use in the past 3 months (95% confidence interval: -2.04, -0.56), 1.19 log lower with toy-vaginal sex in past 7 days (-1.75, -0.62), and 0.78 log lower in women sharing toys with a partner (-1.25, -0.31).

CONCLUSIONS

Vaginal insertive use and sharing of sex toys were associated with decreased quantities of H2O2-producing lactobacilli and higher risk of colonization with G. vaginalis.

[Bacterial vaginosis in 2011: a lot of questions remain]

Bacterial vaginosis is one of the most frequent vaginal affections. It results from a deep imbalance of the vaginal ecosystem whose mechanisms remain mysterious, even if recent progress were accomplished in their comprehension: if the flora implied in the bacterial vaginosis is recognized like polymorphic, it appears that Gardnerella vaginalis plays a major part with two genomically different forms: a commensal form (slightly adhesive to the epithelial cells), and a pathogenic one (strongly adhesive to the epithelial cells); the changes in lactobacilli are also to take into account: L. iners could be a marker of the vaginal flora imbalance whereas L. crispatus is generally met in the normal vaginal flora. These findings could influence the composition of coming probiotics; it is recognized that bacterial vaginosis is involved in the risk of prematurity but molecular quantification of G. vaginalis (and of Atopobium vaginae) is more sensitive for the diagnosis of BV what could improve the detection of high-risk pregnant women. The isolated antibiotic treatments are not very effective on the prevention of recurrences. The rebalancing of the vaginal flora is essential. In this field, the local estrogens showed some effectiveness. The use of probiotics is promising and can be recommended in complement of the antibiotic treatment even if the results of the clinical studies are still too heterogeneous to lead to precise indications.

[Current knowledge of bacterial vaginosis]

Bacterial vaginosis, earlier termed nonspecific vaginitis (anaerobic vaginosis) because of the absence of recognized pathogens, is most common vaginal syndrome of women of childbearing age affecting 15-30%. This syndrome, whose aetiology and pathogenesis remains unknown, is characterized by significant changes in the vaginal ecosystem. These changes consist of a decrease in the number of lactobacilli and a large increase in the number of anaerobic organisms. The bacteria adhere to desquamated epithelial cells with a distinctive appearance of clue cells The main complaints of women with symptomatic bacterial vaginosis include vaginal discharge and odour. However, a significant number of all women who have bacterial vaginosis deny symptoms. Bacterial vaginosis is associated with a number of gynaecologic and obstetric complications including cervicitis, cervical neoplasia, pelvic inflammatory disease, postoperative infections, and preterm labour.The diagnosis is most frequently made based on vaginal smear stained according to Gram (Nugent scoring method). Metronidazole and clindamycin are the drugs of choice for treatment of women with bacterial vaginosis. Which women should undergo treatment? According to the prevailing attitude, it should include women with symptoms. Symptomatic women with frequent relapses of bacterial vaginosisas, as a rule, have poor response to the applied therapy. To achieve better efficiency in the treatment of such women, it is necessary to have more extensive understanding of all factors in the pathogenesis of the syndrome.

Interpreting the epidemiology and natural history of bacterial vaginosis: are we still confused?

Bacterial vaginosis (BV) is a common cause of vaginitis and increases women's risk of pelvic inflammatory disease, adverse pregnancy outcomes, and risk of STD/HIV acquisition. The etiology of BV is unclear, though it is believed to involve loss of vaginal hydrogen peroxide-producing lactobacilli and acquisition of complex bacterial communities that include many fastidious BV-associated bacteria (BVAB) that have recently been detected using PCR methods. Treatment failure (persistence) is common, and may be facilitated by unprotected sex. Potential contributions to BV and BV persistence include (1) sexual partners as a reservoir for BVAB; (2) specific sexual practices, including male partners' condom use; and (3) the composition of the vaginal microbiota involved in BV. Specific BVAB in the Clostridiales order may predict BV persistence when detected pre-treatment, and have been detected in men whose female partners have BV. BVAB may be associated with unprotected sexual behavior and failure of BV to resolve in women, supporting the hypothesis that BVAB colonization of male genitalia may serve as a reservoir for re-infection of female partners. Moreover, specific sexual practices may favor vaginal colonization with certain BVAB that have been associated with persistence. This review provides background on BV, and discusses the epidemiologic and microbiologic data to support a role for acquisition of BVAB and how this process might differ among subsets of women.

New concepts in the etiology of bacterial vaginosis

Bacterial vaginosis (BV) is the most common vaginal infection worldwide. It has been linked to serious public health consequences including preterm birth, postoperative infections, and the acquisition and transmission of sexually transmitted diseases including HIV. The etiology of BV remains unknown. In this article, controversies about sexual transmission, microbial pathogens, and heterogeneity of BV as a disease entity are discussed.

The epidemiology of bacterial vaginosis in relation to sexual behaviour

BACKGROUND

Bacterial vaginosis (BV) has been most consistently linked to sexual behaviour, and the epidemiological profile of BV mirrors that of established sexually transmitted infections (STIs). It remains a matter of debate however whether BV pathogenesis does actually involve sexual transmission of pathogenic micro-organisms from men to women. We therefore made a critical appraisal of the literature on BV in relation to sexual behaviour.

DISCUSSION

G. vaginalis carriage and BV occurs rarely with children, but has been observed among adolescent, even sexually non-experienced girls, contradicting that sexual transmission is a necessary prerequisite to disease acquisition. G. vaginalis carriage is enhanced by penetrative sexual contact but also by non-penetrative digito-genital contact and oral sex, again indicating that sex per se, but not necessarily coital transmission is involved. Several observations also point at female-to-male rather than at male-to-female transmission of G. vaginalis, presumably explaining the high concordance rates of G. vaginalis carriage among couples. Male antibiotic treatment has not been found to protect against BV, condom use is slightly protective, whereas male circumcision might protect against BV. BV is also common among women-who-have-sex-with-women and this relates at least in part to non-coital sexual behaviours. Though male-to-female transmission cannot be ruled out, overall there is little evidence that BV acts as an STD. Rather, we suggest BV may be considered a sexually enhanced disease (SED), with frequency of intercourse being a critical factor. This may relate to two distinct pathogenetic mechanisms: (1) in case of unprotected intercourse alkalinisation of the vaginal niche enhances a shift from lactobacilli-dominated microflora to a BV-like type of microflora and (2) in case of unprotected and protected intercourse mechanical transfer of perineal enteric bacteria is enhanced by coitus. A similar mechanism of mechanical transfer may explain the consistent link between non-coital sexual acts and BV. Similar observations supporting the SED pathogenetic model have been made for vaginal candidiasis and for urinary tract infection.

SUMMARY

Though male-to-female transmission cannot be ruled out, overall there is incomplete evidence that BV acts as an STI. We believe however that BV may be considered a sexually enhanced disease, with frequency of intercourse being a critical factor.

3-hydroxyphthalic anhydride-modified chicken ovalbumin exhibits potent and broad anti-HIV-1 activity: a potential microbicide for preventing sexual transmission of HIV-1

Heterosexual transmission is the primary route by which women acquire human immunodeficiency virus (HIV)/AIDS. Thus, development of woman-controlled topical microbicides for prevention of sexual transmission of HIV is urgently needed. Here we report that 3-hydroxyphthalic anhydride-modified chicken ovalbumin (HP-OVA) exhibits potent antiviral activity against a broad spectrum of human immunodeficiency virus type 1 (HIV-1) isolates with different genotypes and biotypes. Its antiviral activity is correlated with the percentages of the chemically modified and unmodified lysines and arginines in OVA. HP-OVA inhibits HIV-1 fusion and entry through multiple mechanisms of action, including (i) blocking gp120 binding to CD4 and (ii) interfering with gp41 six-helix bundle formation. Because of the widespread availability and established safety profile of OVA, HP-OVA has good potential to be developed as an effective, safe, and affordable microbicide for prevention of HIV sexual transmission.

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.

Antibody-based detection and inhibition of vaginolysin, the Gardnerella vaginalis cytolysin

Bacterial vaginosis (BV) is the most common vaginal infection worldwide and is associated with significant adverse sequelae. We have recently characterized vaginolysin (VLY), the human-specific cytotoxin produced by Gardnerella vaginalis and believed to play a critical role in the pathogenesis of BV and its associated morbidities. We hypothesize that novel antibody-based strategies may be useful for detection of VLY and for inhibition of its toxic effects on human cells. Using purified toxin as an immunogen, we generated polyclonal rabbit immune serum (IS) against VLY. A western blot of G. vaginalis lysate was probed with IS and a single band (57 kD) identified. Immunofluorescence techniques using IS detected VLY production by G. vaginalis. In addition, we have developed a sandwich ELISA assay capable of VLY quantification at ng/ml concentrations in the supernatant of growing G. vaginalis. To investigate the potential inhibitory role of IS on VLY-mediated cell lysis, we exposed human erythrocytes to VLY or VLY pretreated with IS and determined the percent hemolysis. Pretreatment with IS resulted in a significant reduction in VLY-mediated lysis. Similarly, both human cervical carcinoma cells and vaginal epithelial cells exhibited reduced cytolysis following exposure to VLY with IS compared to VLY alone. These results confirm that antibody-based techniques are an effective means of VLY detection. Furthermore, VLY antiserum functions as an inhibitor of VLY–CD59 interaction, mitigating cell lysis. These strategies may have a potential role in the diagnosis and treatment of BV.