A prospective study of risk factors for bacterial vaginosis in HIV-1-seronegative African women

Changes in Vaginal Bacteria and Inflammatory Mediators From Periconception Through the Early Postpartum Period in a Cohort of Kenyan Women Without HIV

BACKGROUND

Women's increased risk of HIV acquisition during pregnancy and postpartum may be mediated by changes in vaginal microbiota and/or cytokines.

METHODS

A cohort of 80 Kenyan women who were HIV-1 seronegative contributed 409 vaginal samples at 6 pregnancy time points: periconception, positive pregnancy test result, first trimester, second trimester, third trimester, and postpartum. Concentrations of vaginal bacteria linked with HIV risk and Lactobacillus spp were measured using quantitative polymerase chain reaction. Cytokines were measured by immunoassay.

RESULTS

Based on Tobit regression, later pregnancy time points were associated with lower concentrations of Sneathia spp (P = .01), Eggerthella sp type 1 (P = .002), and Parvimonas sp type 2 (P = .02) and higher concentrations of Lactobacillus iners (P < .001), Lactobacillus crispatus (P < .001), Lactobacillus vaginalis (P < .001), interleukin 6 (P < .001), TNF (P = .004), C-X-C motif chemokine ligand 10 (CXCL10; P < .001), C-C motif ligand 3 (P = .009), C-C motif ligand 4 (P < .001), C-C motif ligand 5 (P = .002), interleukin 1β (P = .02), and interleukin 8 (P = .002). Most cervicovaginal cytokines and vaginal bacteria clustered separately in principal component analysis, except for CXCL10, which did not group with either cytokines or bacteria. The shift toward a Lactobacillus-dominated microbiota during pregnancy mediated the relationship between pregnancy time point and CXCL10.

CONCLUSIONS

Increases in proinflammatory cytokines, but not vaginal bacterial taxa linked with higher HIV risk, could provide an explanation for increased HIV susceptibility during pregnancy and postpartum.

Next generation sequencing to examine associations between vaginal washing and vaginal microbiota: A cohort study

BACKGROUND

The association between vaginal washing and HIV risk may be mediated by vaginal washing-associated changes in vaginal microbiota.

METHODS

Data from a cohort of HIV-negative US and Kenyan women enrolled in the Preventing Vaginal Infections trial were analyzed. Vaginal fluid samples and vaginal washing data were collected every 2 months for 12 months. Bacterial relative abundances were measured by broad-range 16S rRNA gene polymerase chain reaction with next generation sequencing. Generalized estimating equations were used to evaluate the association between vaginal washing and i) the Shannon Diversity Index (SDI); and ii) mean change in percent bacterial relative abundances, with application of a 10% false discovery rate (FDR).

RESULTS

Participants (N = 111) contributed 93/630 (14.8%) vaginal washing visits. Mean SDI was 0.74 points higher (95% CI 0.35, 1.14; p < 0.001) at washing visits among US participants (N = 26). Vaginal washing was not associated with SDI in Kenyan participants (N = 85). There were no associations between vaginal washing and vaginal bacterial relative abundances after applying the FDR.

CONCLUSIONS

The discordant results in Kenyan versus US women suggests the link between vaginal washing and sub-optimal vaginal microbiota may be context specific. Vaginal microbial shifts may not fully explain the association between vaginal washing and HIV acquisition.

Douching cessation and molecular bacterial vaginosis: a reanalysis of archived specimens

OBJECTIVES

Observational studies demonstrate an association between vaginal douching and bacterial vaginosis (BV) characterised by Gram stain. We sought to describe the effect of a douching cessation intervention on the composition and structure of the vaginal microbiota and molecular-BV, a state defined by low levels of Lactobacillus spp evaluated by molecular tools.

METHODS

33 women self-collected mid-vaginal swabs twice weekly (982 samples) during a douching observation phase (4 weeks) followed by a douching cessation phase (12 weeks) in a 2005 single crossover pilot study conducted in Baltimore, Maryland. Vaginal microbiota were characterised by 16S rRNA gene amplicon sequencing (V3-V4) and clustered into community state types (CSTs). Conditional logistic regression modelling allowed each participant to serve as their own control. Wilcoxon signed-rank tests were used to evaluate changes in microbiota between phases. Broad-range qPCR assays provided estimates of bacterial absolute abundance per swab in a subsample of seven participants before and after douching. A piecewise linear mixed effects model was used to assess rates of change in bacterial absolute abundance before and after douching.

RESULTS

There was no statistically significant change in the odds of molecular-BV versus Lactobacillus-dominated CSTs comparing the douching cessation interval to douching observation (adjusted OR 1.77, 95% CI 0.89 to 3.55). Removal of L. iners-dominated CST III from the outcome did not affect the results. There were no significant changes in the relative abundance of four Lactobacillus spp and no meaningful changes in other taxa investigated. There was no significant change in bacterial absolute abundance between a participant's sample collected 3 days prior to and following douching (p=0.46).

CONCLUSIONS

In this pilot study, douching cessation was not associated with major changes in vaginal microbiota. Douching cessation alone may not durably shift the vaginal microbiota and additional interventions may be needed to restore optimal vaginal microbiota among those who douche.

Hormonal contraceptive use and the risk of sexually transmitted infections: a systematic review and meta-analysis

There are 150 million women worldwide using combined or progestogen-only hormonal contraceptive methods who may be at risk of sexually transmitted infections (STIs). Previous systematic reviews that have sought to establish whether there is an aetiological association between hormonal contraceptive methods/use and STIs have been limited in their methods and have mixed findings. We sought to update these reviews using appropriate control groups. We undertook a systematic review following the PRISMA guidelines and meta-analysis to examine the association between the use of all hormonal contraceptive methods and the acquisition of STIs (Neisseria gonorrhoeae, syphilis/Treponema pallidum, Chlamydia trachomatis, herpes simplex virus, and Trichomonas vaginalis) and/or bacterial vaginosis in literature published between 2005 and 2020. We analysed the effect of hormonal contraceptive methods/use separately on the prevalence, incidence and recurrence of STIs. A total of 37 studies were included in this review that reported 61 associations, in which 27 prevalence, eight incidence and two recurrence studies provided 43, 16, and two associations, respectively. We observed a positive association between hormonal contraceptive methods/use and the risk of chlamydia and herpes but a negative association for trichomoniasis and vaginosis. A negative but statistically insignificant association was observed between hormonal contraceptive methods/use and gonorrhoea. Hormonal contraceptive methods/use influences a woman's risk of STIs/ bacterial vaginosis, but the risk may differ depending on the type of STI. These findings should be contextualized carefully, particularly when formulating practice guidelines and policy, as the effects of hormonal contraceptive methods/use on the risk of STIs varied in direction when analysed separately by STI.

Bacterial Vaginosis and Alcohol Consumption: A Cross-Sectional Retrospective Study in Baltimore, Maryland

BACKGROUND

Bacterial vaginosis (BV) is the most cited cause of vaginal complaints among women of reproductive age. Its etiology and associated risk factors are not entirely understood. Here we examined the association between BV and at-risk alcohol consumption in women attending 2 sexually transmitted infection (STI) clinics in Baltimore, MD.

METHODS

This was a retrospective cross-sectional analysis using data from first clinic visits from 2011-2016. At-risk alcohol use was defined as heavy episodic ("binge") drinking within the last 30 days or a self-report of having had vaginal or anal sex in the context of alcohol consumption. Pearson χ2 test and Student t test were used to assess baseline associations. Log binomial models were used to estimate prevalence ratios (PRs) before and after adjustments for potential confounding factors.

RESULTS

Of the 10,991 women included in the analysis, 2173 (19.7%) met the clinical diagnostic criteria for BV. Having had vaginal or anal sex in the context of alcohol consumption was associated with an increased risk of BV (PR, 1.25; 95% confidence interval, 1.13-1.37), as was binge drinking (PR, 1.15; 95% confidence interval, 1.04-1.27) after adjustment for confounders.

CONCLUSIONS

In this population, at-risk alcohol consumption was associated with an increased risk of BV. The mechanisms remain uncertain. Future prospective studies are needed to verify and evaluate causality in these associations.

Vaginal cytokine profile and microbiota before and after lubricant use compared with condomless vaginal sex: a preliminary observational study

BACKGROUND

Limited data suggest that personal lubricants may damage the vaginal mucosal epithelium, alter the vaginal microbiota, and increase inflammation. We compared vaginal cytokine profiles and microbiota before and after vaginal lubricant use and condomless vaginal sex.

METHODS

Reproductive-age women were recruited to a 10-week observational cohort study and were asked to self-collect vaginal samples and behavioral diaries daily. This nested case-control analysis utilized samples collected before and after self-reported condomless sexual activity with lubricants (22 case participants) and without lubricants (22 control participants). Controls were matched to cases on race/ethnicity. Microbiota composition was characterized by sequencing amplicons of the 16S rRNA gene V3-V4 regions. Cytokine concentrations were quantified using a magnetic bead 41-plex panel assay and read using a Bio-Plex 200 array reader. Wilcoxon signed-rank tests were used to assess baseline differences in vaginal cytokines between cases and controls as well as differences pre- and post-exposure. Linear mixed effects models were used to examine differences in relative post-to-pre change in each individual cytokine between matched cases and controls. Similar analyses were conducted for the microbiota data.

RESULTS

Mean age was 29.8 years (SD 6.8), and 63.6% were African American. There were few statistically significant changes in cytokines or microbiota before and after exposure in cases or controls. In mixed-effects modeling, the mean relative post-to-pre change of cytokines was higher in cases vs. controls for macrophage derived chemokine (MDC) (p = 0.03). The microbiota data revealed no significant changes when measured by similarity scores, diversity indexes and descriptive community state types (CST) transition analyses. However, post sexual activity, the mean relative abundance of L. crispatus decreased for those who used lubricants (particularly those who were L. iners-dominated prior to exposure).

CONCLUSIONS

Although there were overall few differences in the vaginal microbiota and cytokine profiles of lubricant users and controls before and after condomless vaginal sex, there was a trend toward decreases in relative abundance of L. crispatus following use of lubricant. Future larger studies that take into account osmolarity and composition of lubricants may provide additional insights.

Influence of Intramuscular Depot Medroxyprogesterone Acetate Initiation on Vaginal Microbiota in the Postpartum Period

BACKGROUND

The vaginal microbiome plays a key role in women's reproductive health. Use of exogenous hormones, such as intramuscular depot medroxyprogesterone acetate (DMPA-IM), may alter the composition of vaginal bacterial community.

METHODS

Vaginal swab samples were collected from postpartum Kenyan women initiating DMPA-IM or nonhormonal contraception (non-HC). Bacterial vaginosis was assessed by Nugent score (Nugent-BV) and bacterial community composition was evaluated using broad-range 16S ribosomal RNA gene polymerase chain reaction with high-throughput sequencing. Changes in Nugent score, alpha diversity (Shannon diversity index), and total bacterial load between contraceptive groups from enrollment to 3 months after initiation were estimated using multivariable linear mixed effects regression.

RESULTS

Among 54 human immunodeficiency virus-negative women, 33 choosing DMPA-IM and 21 choosing non-HC, Nugent-BV was more common among DMPA-IM users at enrollment. At follow-up, Nugent score had decreased significantly among DMPA-IM users (change, -1.89; 95% confidence interval [CI], -3.53 to -.25; P = .02) while alpha diversity remained stable (0.03; -.24 to .30; P = .83). Conversely, Nugent score remained relatively stable among non-HC users (change, -0.73; 95% CI, -2.18 to .73; P = .33) while alpha diversity decreased (-0.34; -.67 to -.001; P = .05). The total bacterial load decreased slightly in DMPA-IM users and increased slightly among non-HC users, resulting in a significant difference in change between the contraceptive groups (difference, -0.64 log10 gene copies per swab sample; 95% CI, -1.19 to -.08; P = .02). While significant changes in Nugent score and alpha diversity were observed within contraceptive groups, changes between groups were not significantly different.

CONCLUSIONS

Postpartum vaginal bacterial diversity did not change in DMPA-IM users despite a reduction in Nugent-BV, but it decreased significantly among women using non-HC. Choice of contraception may influence Lactobacillus recovery in postpartum women.

The Complex Link between the Female Genital Microbiota, Genital Infections, and Inflammation

The female genital tract microbiota is part of a complex ecosystem influenced by several physiological, genetic, and behavioral factors. It is uniquely linked to a woman's mucosal immunity and plays a critical role in the regulation of genital inflammation. A vaginal microbiota characterized by a high abundance of lactobacilli and low overall bacterial diversity is associated with lower inflammation. On the other hand, a more diverse microbiota is linked to high mucosal inflammation levels, a compromised genital epithelial barrier, and an increased risk of sexually transmitted infections and other conditions. Several bacterial taxa such as Gardnerella spp., Prevotella spp., Sneathia spp., and Atopobium spp. are well known to have adverse effects; however, the definitive cause of this microbial dysbiosis is yet to be fully elucidated. The aim of this review is to discuss the multiple ways in which the microbiota influences the overall genital inflammatory milieu and to explore the causes and consequences of this inflammatory response. While there is abundant evidence linking a diverse genital microbiota to elevated inflammation, understanding the risk factors and mechanisms through which it affects genital health is essential. A robust appreciation of these factors is important for identifying effective prevention and treatment strategies.

Vaginal microbiota evaluation and prevalence of key pathogens in ecuadorian women: an epidemiologic analysis

Vaginal infection is a gynecological problem in women of reproductive age with multiple health outcomes. The most common forms of infection include bacterial vaginosis (BV), vulvovaginal candidiasis (VC), and aerobic vaginitis (AV). Our main goals were to evaluate different types of vaginal infections in Ecuadorian women in a large urban area (Quito) and to characterize the vaginal microbiota colonization by opportunistic species. We collected vaginal swabs and epidemiological surveys from 414 women from June 2016 to July of 2017. We analyzed vaginal samples for the presence of any vaginal infection. The microbiological examination was done through Gram-stain, wet mount smears, and polymerase chain reaction (PCR) assays using primers for target genes, such as 16S rRNA (Atopobium vaginae, Mobiluncus mulieris, and Gardnerella species), ddl (Enterococcus faecalis), adk (Escherichia coli) and KER1 (Candida albicans) genes. Most women showed a healthy vaginal microbiota (66.7%). Nearly one-tenth (10.4%) of the participants had intermediate microbiota, and the remaining women (22.9%) had a single vaginal infection (BV, AV, or VC) or coinfections. From the 95 participants that had an infection, AV was the main diagnosed vaginal infection (51.6%), followed by BV (24.2%) and finally VC (7.4%). The remaining women (16.8%) showed coinfections, being BV and AV the most common coinfection. Using univariable logistic regression analyses we found an increased odds of healthy microbiota in women with a sexual partner (P = 0.02, OR = 1.64). Also, women in a free union relationship (P = 0.000, OR = 16.65) had an increased odds of having coinfections. On the other hand, the use of birth control (condom OR = 0.388 or other contraceptive method OR = 0.363) was associated with significantly lower odds of intermediate microbiota (P ≤ 0.05). We found no statistically significant differences between women with infection and a particular group age. Using multivariate logistic regression analyses we initially found an increased odds of having BV in women with M. mulieris (P = 0.020, OR = 4.98) and Gardnerella species (P = 0.010, OR = 4.16). Women with E. coli showed an increased odds of having AV (P = 0.009, OR = 2.81). The presence of C. albicans in women showed an increased odds of having VC (P = 0.007, OR = 17.94). Finally, women with M. mulieris showed a reverse odds of having healthy microbiota (P = 0.008, OR = 0.06). We found no statistically significant differences between women with symptomatic and asymptomatic infections or the presence of Enterococcus faecalis. We found using logistic regression analyses that M. mulieris was the most prevalent opportunistic pathogen among women with vaginal infection. Further studies should evaluate the possibility to use M. mulieris as a potential key predictor for vaginal infections.

Personal and Clinical Vaginal Lubricants: Impact on Local Vaginal Microenvironment and Implications for Epithelial Cell Host Response and Barrier Function

BACKGROUND

A majority of US women report past use of vaginal lubricants to enhance the ease and comfort of intimate sexual activities. Lubricants are also administered frequently in clinical practice. We sought to investigate if hyperosmolar lubricants are toxic to the vaginal mucosal epithelia.

METHODS

We tested a panel of commercially available lubricants across a range of osmolalities in human monolayer vaginal epithelial cell (VEC) culture and a robust 3-dimensional (3-D) VEC model. The impact of each lubricant on cellular morphology, cytotoxicity, barrier targets, and the induction of inflammatory mediators was examined. Conceptrol, containing nonoxynol-9, was used as a cytotoxicity control.

RESULTS

We observed a loss of intercellular connections, and condensation of chromatin, with increasing lubricant osmolality. EZ Jelly, K-Y Jelly, Astroglide, and Conceptrol induced cytotoxicity in both models at 24 hours. There was a strong positive correlation (r = 0.7326) between lubricant osmolality and cytotoxicity in monolayer VECs, and cell viability was reduced in VECs exposed to all the lubricants tested for 24 hours, except McKesson. Notably, select lubricants altered cell viability, barrier targets, and inflammatory mediators in 3-D VECs.

CONCLUSIONS

These findings indicate that hyperosmolar lubricants alter VEC morphology and are selectively cytotoxic, inflammatory, and barrier disrupting in the 3-D VEC model.

A cross-sectional pilot study of birth mode and vaginal microbiota in reproductive-age women

Recent studies suggest that birth mode (Cesarean section [C-section] or vaginal delivery) is an important event in the initial colonization of the human microbiome and may be associated with long-term health outcomes. We sought to determine the association between a woman's birth mode and her vaginal microbiota in adulthood. We re-contacted 144 adult women from two U.S. studies and administered a brief survey. Vaginal microbiota was characterized on a single sample by amplicon sequencing of the V3-V4 hypervariable regions of the 16S rRNA gene and clustered into community state types (CSTs). We evaluated the association between birth mode and a CST with low relative abundance of Lactobacillus spp. ("molecular bacterial vaginosis" [Molecular-BV]) compared to Lactobacillus-dominated CSTs in logistic regression modeling which adjusted for body mass index, a confounder in this analysis. Twenty-seven women (19%) reported C-section. Overall, C-section showed a non-significant trend towards increased odds of Molecular-BV (aOR = 1.22, 95% CI: 0.45, 3.32), and Prevotella bivia was the strongest single taxa associated with C-section. However, because the two archived studies had different inclusion criteria (interaction p = 0.048), we stratified the analysis by study site. In the study with a larger sample size (n = 88), women born by C-section had 3-fold higher odds of Molecular-BV compared to vaginally-delivered women (aOR = 3.55, p = 0.06, 95% CI: 0.97-13.02). No association was found in the smaller study (n = 56, aOR = 0.19, p = 0.14, 95% CI: 0.02-1.71). This pilot cross-sectional study suggests a possible association between C-section and Molecular-BV in adulthood. However, the analysis is limited by small sample size and lack of comparability in participant age and other characteristics between the study sites. Future longitudinal studies could recruit larger samples of women, address the temporal dynamics of vaginal microbiota, and explore other confounders, including maternal factors, breastfeeding history, and socioeconomic status, which may affect the relationship between birth mode and vaginal microbiota.

A Prospective Cohort Study of the Association Between Body Mass Index and Incident Bacterial Vaginosis

Some studies suggest that higher body mass index is associated with increased susceptibility to bacterial vaginosis (BV), but results are conflicting.

METHODS

Female sex workers aged 16 to 45 years and participating in an open, prospective cohort study in Mombasa, Kenya between 2000 and 2014 were included in this analysis. Up to 2 years of follow-up were included per woman. Body mass index (BMI) was categorized as underweight (≤18.5), normal (18.5-24.9), overweight (25-29.9), and obese (≥30). Bacterial vaginosis was assessed using Nugent scores. Generalized estimating equations were used to estimate relative risks of the association between BMI and BV.

RESULTS

At baseline, 32.1% (n = 625) of 1946 women had BV. Half of women were overweight (31.1%, n = 606) or obese (20.1%, n = 391). Participants contributed 14,319 follow-up visits. Adjusting for age, compared to women with normal BMI, overweight (adjusted relative risk, 0.91; 95% confidence interval, 0.81-1.02) and obese (adjusted relative risk, 0.82; 95% confidence interval, 0.71-0.94) women were at lower risk for BV (joint P = 0.03).

CONCLUSIONS

Obese women had a nearly 20% lower risk of BV compared with women with normal BMI. Potential mechanisms for this effect, including possible effects of diet, obesity-associated changes in the gut microbiome, and systemic estrogen levels, should be explored.

Lessons from Suppressive Therapy and Periodic Presumptive Treatment for Bacterial Vaginosis

PURPOSE OF REVIEW

Suppressive therapy and periodic presumptive treatment (PPT) are distinct but related strategies that have been used to reduce the incidence of bacterial vaginosis (BV). Here, we review clinical trial evidence of the effectiveness of suppressive therapy and PPT to reduce BV, and discuss their roles for women who frequently experience symptomatic or asymptomatic BV.

RECENT FINDINGS

Among women who were recently and successfully treated for symptomatic BV, suppressive therapy with twice-weekly metronidazole gel for 16 weeks reduces the likelihood of recurrent symptomatic BV and is currently recommended by the Centers for Disease Control and Prevention for prevention of recurrent BV. The premise of PPT is to provide regimens used to treat BV at regular intervals to reduce the overall frequency of BV, regardless of symptoms. Three PPT trials were conducted using different routes (oral or intravaginal), doses, and frequencies of administration. Each trial demonstrated a significant reduction in BV over the course 12 months, ranging from a 10 to 45% decrease. PPT regimens that substantially reduce the frequency of BV over time could be evaluated in clinical trials to assess whether a reduced frequency of BV leads to subsequent reductions in BV-associated sequelae. While both suppressive therapy and PPT reduce BV, their impact wanes following cessation of the regimen. Given the high prevalence of BV globally and burden of adverse reproductive health outcomes among women with BV, there is a critical need for more effective treatments that produce durable shifts in the microbiota towards vaginal health.

Effects of an over-the-counter lactic-acid containing intra-vaginal douching product on the vaginal microbiota

Background

Over-the-counter intra-vaginal lactic-acid containing douches are marketed as vaginal hygiene products that support optimal vaginal pH balance. We report the effect of a commercially available douche (Etos®) on the vaginal microbiota (VM) in a prospective study.

Results

Twenty-five healthy women were recruited through advertisements in 2015–2017 (ethical approval: METC-2014_413) and followed over three menstrual cycles. The participants had a median age of 24 years [IQR: 22–29], were mostly Dutch-Caucasian (88%), and 60% used combined oral contraceptives. All participants douched three times a week during the second cycle, starting on the first day of that cycle. Participants completed a questionnaire at baseline, kept a daily diary to report douching, menses, and sexual activity, self-collected vaginal swabs every other day during the first and third cycle and daily during the second cycle, and measured vaginal pH mid-cycle. A median of 44 vaginal swabs [inter-quartile range (IQR): 41–50] were assessed per participant by 16S rRNA gene (V3-V4 region) sequencing and a Candida albicans PCR was done at four time-points. At baseline, 21 participants (84%) had Lactobacillus-dominated VM (Lactobacillus crispatus (n = 14), L. iners (n = 6), or diverse Lactobacillus species (n = 1) and 4 participants (16%) had VM consisting of diverse anaerobes. In multinomial logistic regression models, a trend towards increased odds were observed for having diverse anaerobic VM in the second and third cycle, compared to the first cycle, after adjusting for menses [odds ratio (OR) = 1.4 (95% CI: 0.9–2.1) and OR = 1.7 (95% CI: 0.9–3.1), respectively] (p = 0.376). Douching did not affect vaginal pH. Menses increased the odds for having VM consisting of diverse anaerobes almost two-fold (OR = 1.7; 95% CI: 1.0–2.8), while douching during menses increased the odds 2.6 fold (OR = 2.6; 95% CI: 1.0–6.5), compared to not menstruating (p = 0.099). Participants were more likely to test positive for C. albicans after cycle 2, compared to cycle 1 [OR = 3.0 (95% CI: 1.2–7.2); p = 0.017].

Conclusion

The Etos® douche did not significantly affect the vaginal pH or VM composition, although increased odds for having diverse anaerobic VM was observed, especially when douching during menses. Furthermore, douching may promote C. albicans infections.

Electronic supplementary material

The online version of this article (10.1186/s12866-019-1545-0) contains supplementary material, which is available to authorized users.

Vaginal practices among women at risk for HIV acquisition in Soweto, South Africa

Background

Vaginal practices (VP) may adversely affect normal vaginal flora and mucosal integrity, and increase acquisition risk of HIV and other genital tract infections.

Objective

The aim of this study was to describe self-reported VP, changes in the reported number of VP over time and factors associated with VP in a cohort of young Sowetan women enrolled in the HVTN 915 observational study.

Method

We longitudinally assessed self-reported VP in 50 young women at risk of HIV acquisition aged 18-25 years in a prospective study over 3 months in Soweto, South Africa. Interviewer-administered HIV behavioural risk questionnaires were completed. No intervention to reduce VP was specified per protocol, but clinicians provided education at their discretion. The generalised estimating equation with inverse probability weights assessed VP over time.

Results

The mean age at screening was 22 years; women reported multiple sexual partnerships with a mean of one main and 2 casual partners in the last 30 days. Consistent condom use was 2% (n = 1), 25% (n = 12) and 43% (n = 3) with main, casual and new partners, respectively. Commonly reported VP included washing the vagina with water (44%) and using fingers (48%). VP decreased significantly over time (p < 0.001). Women who used condoms inconsistently or whose last sex was with a casual partner were 3 times more likely to report VP (p = 0.001).

Conclusion

Despite the high incidence of HIV in our setting, VP are still common and are associated with other behavioural risks for HIV. Further study is needed to assess whether clinician education may reduce VP and therefore should be included in HIV risk reduction counselling.

Does bacterial vaginosis modify the effect of hormonal contraception on HIV seroconversion

OBJECTIVES

A recent study of HIV serodiscordant couples found that depot medroxyprogesterone acetate (DMPA) and oral contraceptive pills (OCPs) were associated with increased HIV risk in the presence, but not in the absence, of bacterial vaginosis. We assessed whether bacterial vaginosis is an effect modifier of the association between hormonal contraception and HIV seroconversion in female sex workers (FSWs) in Mombasa, Kenya.

DESIGN

Prospective cohort study.

METHODS

Data collected from HIV-negative FSWs from 1993 to 2017 were analyzed. Cox proportional hazards models were used to assess the relationship between HIV seroconversion and use of DMPA, OCPs, or hormonal contraceptive implants (Norplant, Jadelle).

RESULTS

A total of 1985 women contributed 7127 person-years of follow-up; 307 women seroconverted to HIV (4.32/100 person-years). DMPA was significantly associated with elevated risk of HIV seroconversion in women with [aHR 1.56, 95% confidence interval (CI) 1.08-2.25; P = 0.02] and without (aHR 2.08, 95% CI 1.46-2.97; P < 0.001) bacterial vaginosis (interaction P = 0.4). Similarly, OCP use was associated with increased HIV risk both in the presence (aHR 1.50, 95% CI 0.94-2.39; P = 0.09) and absence (aHR 1.61, 95% CI 0.99-2.64; P = 0.06) of bacterial vaginosis (interaction P = 0.9), though neither stratum reached statistical significance. Implants were not associated with HIV seroconversion overall (aHR 0.99, 95% CI 0.40-2.45; P = 0.9), or in women with (aHR 0.65, 95% CI 0.16-2.72; P = 0.6) and without (aHR 1.39, 95% CI 0.43-4.46; P = 0.6) bacterial vaginosis (interaction P = 0.5).

CONCLUSION

Bacterial vaginosis had no effect on the associations between hormonal contraceptives and HIV seroconversion in this cohort. Contraceptive implants were not associated with increased HIV risk compared with no contraception.

Vaginal herb use and Chlamydia trachomatis infection: cross-sectional study among women of various ethnic groups in Suriname

OBJECTIVE

Vaginal steam baths with herb leaves (herb use) is practised by some Surinamese women. We assessed herb use among women from the five most prevalent ethnic groups, and if herb use is associated with Chlamydia trachomatis infection.

SETTING

Participants were recruited at a sexually transmitted infection (STI) clinic and a family planning clinic (FP) in Paramaribo, Suriname.

PARTICIPANTS

1040 women were included subsequently, comprising the following ethnic groups: Creole (26.7%), Hindustani (24.6%), Javanese (15.7%), Maroon (13.3%) and mixed descent (19.7%).

METHODS

Nurses collected a questionnaire and vaginal swabs for nucleic acid amplification C. trachomatis testing.

PRIMARY OUTCOMES

Determinants of vaginal herb use and C. trachomatis infection via univariable and multivariable logistic regression.

RESULTS

Herb use was most common among Maroon (68.8%) and Creole women (25.2%). In multivariable analysis including only Maroon and Creole women, determinants significantly associated with vaginal herb use were (OR; 95% CI): Maroon ethnic descent (5.33; 3.26 to 8.71 vs Creole), recruitment at the STI clinic (2.04; 1.24 to 3.36 vs FP), lower education levels (3.80; 1.68 to 8.57 lower vs higher, and 2.02; 0.90 to 4.51 middle vs higher). Lower age and recruitment at the STI clinic were associated with C. trachomatis infection, but not vaginal herb use.

CONCLUSION

In Suriname, vaginal herb use is common among Maroon and Creole women. Education, ethnic group and recruitment site were determinants for herb use. Vaginal herb use was not a determinant of C. trachomatis infection. Future research should focus on the effect of herb use on the vaginal microbiome and mucosal barrier.

The genital tract and rectal microbiomes: their role in HIV susceptibility and prevention in women

INTRODUCTION

Young women in sub-Saharan Africa are disproportionately affected by HIV, accounting for 25% of all new infections in 2017. Several behavioural and biological factors are known to impact a young woman's vulnerability for acquiring HIV. One key, but lesser understood, biological factor impacting vulnerability is the vaginal microbiome. This review describes the vaginal microbiome and examines its alterations, its influence on HIV acquisition as well as the efficacy of HIV prevention technologies, the role of the rectal microbiome in HIV acquisition, advances in technologies to study the microbiome and some future research directions.

DISCUSSION

Although the composition of each woman's vaginal microbiome is unique, a microbiome dominated by Lactobacillus species is generally associated with a "healthy" vagina. Disturbances in the vaginal microbiota, characterized by a shift from a low-diversity, Lactobacillus-dominant state to a high-diversity non-Lactobacillus-dominant state, have been shown to be associated with a range of adverse reproductive health outcomes, including increasing the risk of genital inflammation and HIV acquisition. Gardnerella vaginalis and Prevotella bivia have been shown to contribute to both HIV risk and genital inflammation. In addition to impacting HIV risk, the composition of the vaginal microbiome affects the vaginal concentrations of some antiretroviral drugs, particularly those administered intravaginally, and thereby their efficacy as pre-exposure prophylaxis (PrEP) for HIV prevention. Although the role of rectal microbiota in HIV acquisition in women is less well understood, the composition of this compartment's microbiome, particularly the presence of species of bacteria from the Prevotellaceae family likely contribute to HIV acquisition. Advances in technologies have facilitated the study of the genital microbiome's structure and function. While next-generation sequencing advanced knowledge of the diversity and complexity of the vaginal microbiome, the emerging field of metaproteomics, which provides important information on vaginal bacterial community structure, diversity and function, is further shedding light on functionality of the vaginal microbiome and its relationship with bacterial vaginosis (BV), as well as antiretroviral PrEP efficacy.

CONCLUSIONS

A better understanding of the composition, structure and function of the microbiome is needed to identify opportunities to alter the vaginal microbiome and prevent BV and reduce the risk of HIV acquisition.

Association between vaginal washing and vaginal bacterial concentrations

Vaginal washing is a common practice associated with adverse outcomes including bacterial vaginosis (BV) and HIV infection. Prior studies have not examined the associations between vaginal washing and individual vaginal bacteria, or whether these associations are independent of the effect of vaginal washing on BV. The purpose of this study was to characterize the association between vaginal washing and the presence and concentrations of vaginal bacteria associated with optimal and sub-optimal vaginal states. The analysis utilized data from participants in the placebo arm of the Preventing Vaginal Infections trial, which enrolled HIV-uninfected women from the United States and Kenya. Detection of bacterial taxa associated with BV was compared between visits with versus without reported vaginal washing. The effect of vaginal washing on a number of vaginal bacteria differed substantially (p<0.05) between the US and Kenya, so results were stratified by country. In US women, vaginal washing was associated with a significantly higher likelihood of detection of BV associated bacterium 1 (BVAB1) (relative risk [RR] 1.55, 95% confidence interval [CI] 1.15-2.09, p = 0.004), BVAB2 (RR 1.99, 95%CI 1.46-2.71, p<0.001), Mageeibacillus indolicus (RR 2.08, 95%CI 1.46-2.96, p<0.001), Atopobium vaginae (RR 1.34, 95%CI 1.13-1.59, p = 0.001), Leptotrichia/Sneathia species (RR 1.66, 95% CI 1.33-2.09, p<0.001), Megasphaera species (RR 1.78, 95%CI 1.34-2.37, p<0.001) and Gardnerella vaginalis (RR 1.08, 95%CI 1.01-1.16, p = 0.02). No significant association between vaginal washing and bacterial detection was found in Kenyan women. Adjustment for bacterial vaginosis diagnosed by Gram stain did not alter these results. This study provides evidence that the association between vaginal washing and detection of individual bacterial taxa can vary regionally. For some vaginal bacteria, the association with vaginal washing may be independent of the effect on Gram stain detection of BV. Larger prospective studies in diverse geographic settings should explore whether eliminating vaginal washing impacts the presence and concentrations of key vaginal bacteria.

Contraceptive use and the risk of sexually transmitted infection: systematic review and current perspectives

Purpose

Evidence on the association between contraceptive use and risk of sexually transmitted infections (STIs) and bacterial vaginosis (BV) is lacking, with few prospective studies. We systematically reviewed the last 10 years' evidence on the association between contraception and STI/BV, building on the most recent systematic reviews published in 2006 and 2009.

Methods

We searched the MEDLINE and POPLINE databases for peer-reviewed articles p ublished between January 1, 2008 and January 31, 2018 reporting prospective studies that assessed the association between contraceptive use and incident STI and/or incident or recurrent BV.

Results

We identified 33 articles that evaluated combined oral contraceptives (COC), depot medroxyprogesterone acetate (DMPA), the copper intrauterine device (Cu-IUD), the levonorgestrel intrauterine system (LNG-IUS) and other methods. The strength of the evidence for many specific contraceptive method/STI associations is limited by few prospective studies with comparably defined exposures and outcomes. Available data suggest no association of COCs and Neisseria gonorrhoeae, Trichomonas vaginalis, HSV-2 or syphilis, and mixed evidence on the association with HPV, Chlamydia trachomatis, and BV. For DMPA, none of the studies identified found an association with N. gonorrhoeae or syphilis, and data on C. trachomatis, T. vaginalis, HPV and BV were mixed. Two large studies showed a highly clinically significant increased risk of HSV-2 infection with DMPA use. Data on the effect of Cu-IUD and the LNG-IUS on the acquisition of C. trachomatis, N. gonorrhoeae and T. vaginalis are sparse, and data on HPV and BV are mixed.

Conclusion

Few data are available from prospective studies, including randomized trials, to draw strong conclusions about the relationships between contraceptive methods and specific STIs. The overall evidence on the association between contraceptive use and STI/BV risk is limited by the lack of any randomized trials, few published prospective studies designed to analyze these associations, wide variability in exposure definitions and comparator groups, potential for confounding due to inaccurate sexual behavior data, differential confounder adjustment and differences in study populations and sizes. Despite these limitations, new evidence is supportive of a significantly increased risk of HSV-2 infection among DMPA users which warrants additional research to better understand this association.

Incidence of unintended pregnancy among female sex workers in low-income and middle-income countries: a systematic review and meta-analysis

OBJECTIVES

To determine the incidence of unintended pregnancy among female sex workers (FSWs) in low-income and middle-income countries (LMICs).

DESIGN

We searched MEDLINE, PsychInfo, Embase and Popline for papers published in English between January 2000 and January 2016, and Web of Science and Proquest for conference abstracts. Meta-analysis was performed on the primary outcomes using random effects models, with subgroup analysis used to explore heterogeneity.

PARTICIPANTS

Eligible studies targeted FSWs aged 15-49 years living or working in an LMIC.

OUTCOME MEASURES

Studies were eligible if they provided data on one of two primary outcomes: incidence of unintended pregnancy and incidence of pregnancy where intention is undefined. Secondary outcomes were also extracted when they were reported in included studies: incidence of induced abortion; incidence of birth; and correlates/predictors of pregnancy or unintended pregnancy.

RESULTS

Twenty-five eligible studies were identified from 3866 articles. Methodological quality was low overall. Unintended pregnancy incidence showed high heterogeneity (I²>95%), ranging from 7.2 to 59.6 per 100 person-years across 10 studies. Study design and duration were found to account for heterogeneity. On subgroup analysis, the three cohort studies in which no intervention was introduced had a pooled incidence of 27.1 per 100 person-years (95% CI 24.4 to 29.8; I²=0%). Incidence of pregnancy (intention undefined) was also highly heterogeneous, ranging from 2.0 to 23.4 per 100 person-years (15 studies).

CONCLUSIONS

Of the many studies examining FSWs' sexual and reproductive health in LMICs, very few measured pregnancy and fewer assessed pregnancy intention. Incidence varied widely, likely due to differences in study design, duration and baseline population risk, but was high in most studies, representing a considerable concern for this key population. Evidence-based approaches that place greater importance on unintended pregnancy prevention need to be incorporated into existing sexual and reproductive health programmes for FSWs.

PROSPERO REGISTRATION NUMBER

CRD42016029185.

Sexual Quality of Life and Association With HIV and Sexually Transmitted Infections Among a Cohort of Heterosexual Couples in Kenya

INTRODUCTION

Sexual quality of life (SQoL) is a critical component of sexual health and is understudied in Sub-Saharan African settings with endemic HIV and sexually transmitted infection (STI).

AIM

We sought to assess SQoL among heterosexual couples in Kisumu, Kenya, and how this was associated with HIV status, STIs, and sexual practices.

METHODS

This was a prospective cohort study of community-recruited couples. SQoL, HIV status, herpes simplex virus (HSV)-2 status, bacterial vaginosis (BV), sexual practices, and sociodemographics were measured at baseline, 6 months, and 12 months. Multivariable linear regression with random intercept was fitted separately for females and males, accounting for partner characteristics.

MAIN OUTCOME MEASURE

SQoL was assessed with an 18-item female and 11-item male survey.

RESULTS

From April 2014 through July 2016, 252 couples were enrolled, and followed up through September 2017. At baseline, women were median age 23 years, 10% HIV positive, 53% HSV-2 seropositive, and 22% with BV. At baseline men were median age 26 years, 12% HIV positive, 47% HSV-2 seropositive, and 56% circumcised. Mean SQoL was higher for men (88) than women (78), with consistent scores over time. In multivariable analysis (P < .05 each), SQoL Questionnaire-Female (SQoL-F) score was reduced with: male partner report that sex felt rougher than he would have liked (9.5-point decrease), female HSV-2 seropositivity (5.15-point decrease), female reported having dry vaginal sex (5.27-point decrease); among women with BV, SQoL-F score declined with recent sexual activity (8.27-point decrease) and increasing age (0.75-point decrease per 1 year increase in age). Age and recent sex did not affect SQoL-F for women without BV. SQoL Questionnaire-Male score was decreased 4.99 points if male was employed, 4.52 points if male reported multiple recent sex partners, and 29.5 points for HIV positive men whose female partner reported having sex when not in the mood. Men's SQoL increased by 0.84 points for each 1-U increase in female partner body mass index and 17.6 points for HIV positive men whose female partner reported recent sex with him.

CLINICAL IMPLICATIONS

Within sexual partnerships, men had greater SQoL than women, and the adverse impact of BV and STIs on SQoL was greater for women than men.

STRENGTH & LIMITATIONS

Research is needed to ensure relevant domains are measured in settings where measure of SQoL has not been validated, along with robust measures of physiologic and psychologic correlates.

CONCLUSION

More attention to SQoL as an outcome may strengthen interventions aimed at preventing HIV and STIs and improving sexual health holistically. Mehta SD, Nordgren RK, Agingu W, et al. Sexual Quality of Life and Association With HIV and Sexually Transmitted Infections Among a Cohort of Heterosexual Couples in Kenya. J Sex Med 2018;15:1446-1455.

Evaluation of the association between the concentrations of key vaginal bacteria and the increased risk of HIV acquisition in African women from five cohorts: a nested case-control study

BACKGROUND

Disruptions of vaginal microbiota might increase women's susceptibility to HIV infection. Advances in molecular microbiology have enabled detailed examination of associations between vaginal bacteria and HIV acquisition. Therefore, this study aimed to evaluate the association between the concentrations of specific vaginal bacteria and increased risk of HIV acquisition in African women.

METHODS

We did a nested case-control study of participants from eastern and southern Africa. Data from five cohorts of African women (female sex workers, pregnant and post-partum women, and women in serodiscordant relationships) were used to form a nested case-control analysis between women who acquired HIV infection versus those who remained seronegative. Deep sequence analysis of broad-range 16S rRNA gene PCR products was applied to a subset of 55 cases and 55 controls. From these data, 20 taxa were selected for bacterium-specific real-time PCR assays, which were examined in the full cohort as a four-category exposure (undetectable, first tertile, second tertile, and third tertile of concentrations). Conditional logistic regression was used to generate odds ratios (ORs) and 95% CIs. Regression models were stratified by cohort, and adjusted ORs (aORs) were generated from a multivariable model controlling for confounding variables. The Shannon Diversity Index was used to measure bacterial diversity. The primary analyses were the associations between bacterial concentrations and risk of HIV acquisition.

FINDINGS

Between November, 2004, and August, 2014, we identified 87 women who acquired HIV infection (cases) and 262 controls who did not acquire HIV infection. Vaginal bacterial community diversity was higher in women who acquired HIV infection (median 1·3, IQR 0·4-2·3) than in seronegative controls (0·7, 0·1-1·5; p=0·03). Seven of the 20 taxa showed significant concentration-dependent associations with increased odds of HIV acquisition: Parvimonas species type 1 (first tertile aOR 1·67, 95% CI 0·61-4·57; second tertile 3·01, 1·13-7·99; third tertile 4·64, 1·73-12·46; p=0·005) and type 2 (first tertile 3·52, 1·63-7·61; second tertile 0·85, 0·36-2·02; third tertile 2·18, 1·01-4·72; p=0·004), Gemella asaccharolytica (first tertile 2·09, 1·01-4·36; second tertile 2·02, 0·98-4·17; third tertile 3·03, 1·46-6·30; p=0·010), Mycoplasma hominis (first tertile 1·46, 0·69-3·11; second tertile 1·40, 0·66-2·98; third tertile 2·76, 1·36-5·63; p=0·048), Leptotrichia/Sneathia (first tertile 2·04, 1·02-4·10; second tertile 1·45, 0·70-3·00; third tertile 2·59, 1·26-5·34; p=0·046), Eggerthella species type 1 (first tertile 1·79, 0·88-3·64; second tertile 2·62, 1·31-5·22; third tertile 1·53, 0·72-3·28; p=0·041), and vaginal Megasphaera species (first tertile 3·15, 1·45-6·81; second tertile 1·43, 0·65-3·14; third tertile 1·32, 0·57-3·05; p=0·038).

INTERPRETATION

Differences in the vaginal microbial diversity and concentrations of key bacteria were associated with greater risk of HIV acquisition in women. Defining vaginal bacterial taxa associated with HIV risk could point to mechanisms that influence HIV susceptibility and provide important targets for future prevention research.

FUNDING

National Institute of Child Health and Human Development.

Hyperosmolal vaginal lubricants markedly reduce epithelial barrier properties in a three-dimensional vaginal epithelium model

Most of the widely used vaginal lubricants in the U.S. and Europe are strongly hyperosmolal, formulated with high concentrations of glycerol, propylene glycol, polyquaternary compounds or other ingredients that make these lubricants 4 to 30 times the osmolality of healthy vaginal fluid. Hyperosmolal formulations have been shown to cause marked toxicity to human colorectal epithelia in vivo, and significantly increase vaginal transmission of genital herpes infections in the mouse/HSV model. They also cause toxicity to explants of vaginal epithelia, to cultured vaginal epithelial cells, and increase susceptibility to HIV in target cells in cell cultures. Here, we report that the osmolality of healthy vaginal fluid is 370 ± 40 mOsm/Kg in women with Nugent scores 0–3, and that a well-characterized three-dimensional human vaginal epithelium tissue model demonstrated that vaginal lubricants with osmolality greater than 4 times that of vaginal fluid (>1500 mOsm/Kg) markedly reduce epithelial barrier properties and showed damage in tissue structure. Four out of four such lubricants caused disruption in the parabasal and basal layers of cells as observed by histological analysis and reduced barrier integrity as measured by trans-epithelial electrical resistance (TEER). No epithelial damage to these layers was observed for hypo- and iso-osmolal lubricants with osmolality of <400 mOsm/Kg. The results confirm extensive reports of safety concerns of hyperosmolal lubricants and suggest the usefulness of reconstructed in vitro vaginal tissue models for assessing safety of lubricants in the absence of direct clinical tests in humans.

The Female Genital Tract Microbiome Is Associated With Vaginal Antiretroviral Drug Concentrations in Human Immunodeficiency Virus-Infected Women on Antiretroviral Therapy

Background

The female genital tract (FGT) microbiome may affect vaginal pH and other factors that influence drug movement into the vagina. We examined the relationship between the microbiome and antiretroviral concentrations in the FGT.

Methods

Over one menstrual cycle, 20 human immunodeficiency virus (HIV)-infected women virologically suppressed on tenofovir (TFV) disoproxil fumarate/emtricitabine and ritonavir-boosted atazanavir (ATV) underwent serial paired cervicovaginal and plasma sampling for antiretroviral concentrations using high-performance liquid chromatography-tandem mass spectrometry. Analysis of 16S ribosomal RNA gene sequencing of cervicovaginal lavage clustered each participant visit into a unique microbiome community type (mCT).

Results

Participants were predominantly African American (95%), with a median age of 38 years. Cervicovaginal lavage sequencing (n = 109) resulted in a low-diversity mCT dominated by Lactobacillus (n = 40), and intermediate-diversity (n = 28) and high-diversity (n = 41) mCTs with abundance of anaerobic taxa. In multivariable models, geometric mean FGT:plasma ratios varied significantly by mCT for all 3 drugs. For both ATV and TFV, FGT:plasma was significantly lower in participant visits with high- and low-diversity mCT groups (all P < .02). For emtricitabine, FGT:plasma was significantly lower in participant visits with low- vs intermediate-diversity mCT groups (P = .002).

Conclusions

Certain FGT mCTs are associated with decreased FGT antiretroviral concentrations. These findings are relevant for optimizing antiretrovirals used for biomedical HIV prevention in women.

From menarche to menopause: A population-based assessment of water, sanitation, and hygiene risk factors for reproductive tract infection symptoms over life stages in rural girls and women in India

Women face greater challenges than men in accessing water, sanitation, and hygiene (WASH) resources to address their daily needs, and may respond to these challenges by adopting unsafe practices that increase the risk of reproductive tract infections (RTIs). WASH practices may change as women transition through socially-defined life stage experiences, like marriage and pregnancy. Thus, the relationship between WASH practices and RTIs might vary across female reproductive life stages. This cross-sectional study assessed the relationship between WASH exposures and self-reported RTI symptoms in 3,952 girls and women from two rural districts in India, and tested whether social exposures represented by reproductive life stage was an effect modifier of associations. In fully adjusted models, RTI symptoms were less common in women using a latrine without water for defecation versus open defecation (Odds Ratio (OR) = 0.69; Confidence Interval (CI) = 0.48, 0.98) and those walking shorter distances to a bathing location (OR = 0.79, CI = 0.63, 0.99), but there was no association between using a latrine with a water source and RTIs versus open defecation (OR = 1.09; CI = 0.69, 1.72). Unexpectedly, RTI symptoms were more common for women bathing daily with soap (OR = 6.55, CI = 3.60, 11.94) and for women washing their hands after defecation with soap (OR = 10.27; CI = 5.53, 19.08) or ash/soil/mud (OR = 6.02; CI = 3.07, 11.77) versus water only or no hand washing. WASH practices of girls and women varied across reproductive life stages, but the associations between WASH practices and RTI symptoms were not moderated by or confounded by life stage status. This study provides new evidence that WASH access and practices are associated with self-reported reproductive tract infection symptoms in rural Indian girls and women from different reproductive life stages. However, the counterintuitive directions of effect for soap use highlights that causality and mechanisms of effect cannot be inferred from this study design. Future research is needed to understand whether improvements in water and sanitation access could improve the practice of safe hygiene behaviors and reduce the global burden of RTIs in women.

Pathogenesis of Bacterial Vaginosis: Discussion of Current Hypotheses

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

Women view key sexual behaviours as the trigger for the onset and recurrence of bacterial vaginosis

BACKGROUND

Bacterial vaginosis (BV) affects a third of women of reproductive age in the US and there is increasing evidence to suggest it may be sexually transmitted. This study aimed to extend and validate the findings of our earlier smaller qualitative study by exploring in detail women's views and experiences of the triggering factors associated with BV onset and recurrence.

METHODS

Women aged 20-49, who had experienced one or more symptomatic episode of BV within 6 months, were opportunistically recruited to complete a 38-item questionnaire on their experience of BV.

RESULTS

103 women completed the questionnaire. Women were significantly more likely to report sexual than lifestyle factors triggered BV onset and recurrence (p<0.001). The top 3 factors women attributed to both BV onset and recurrence were identical-and all sexual. They included, in order: 1) unprotected sex; 2) sex with a new male partner; and 3) sex in general. The main lifestyle factors nominated included stress, diet, menstruation and the use of feminine hygiene products. While many women felt their BV had been transmitted through sexual contact (54%) and developed as a result of sexual activity (59%), few considered BV a sexually transmitted infection (STI) (10%). Despite this 57% felt partners should also be treated for BV.

CONCLUSION

These data concur with our earlier qualitative findings that women believe BV is triggered by sexual activity. While many women felt BV was sexually transmitted and supported partner treatment, they did not consider BV an STI. This contradiction is likely due to information conveyed to women based on current guidelines. In the absence of highly effective BV treatments, this study highlights the need for guidelines to indicate there is scientific uncertainty around the pathogenesis of BV and to contain clear health messages regarding the evidence for practices shown to be associated with a reduced risk of BV (i.e. consistent condom use.

Recent Biomarker-Confirmed Unprotected Vaginal Sex, But Not Self-reported Unprotected Sex, Is Associated With Recurrent Bacterial Vaginosis

BACKGROUND

Self-reported unprotected vaginal sex seems to increase risk of bacterial vaginosis (BV). However, the validity of self-reports is questionable, given their inconsistency with more objective measures of recent semen exposure such as detection of prostate-specific antigen (PSA). We examined whether recent unprotected sex, as measured both by PSA detection on vaginal swabs and by self-report, was associated with increased BV recurrence.

METHODS

We analyzed randomized trial data from nonpregnant, BV-positive adult women recruited from a sexually transmitted disease clinic. Participants received BV therapy at enrollment and were scheduled to return after 4, 12, and 24 weeks. Bacterial vaginosis (by Nugent score) and PSA were measured at each visit. We used Cox proportional hazards models to examine the association between PSA positivity and recurrent BV. We also evaluated associations between self-reported unprotected sex (ever/never since the last visit and in the last 48 hours, analyzed separately) and recurrent BV.

RESULTS

Prostate-specific antigen and BV results were available for 96 women who contributed 226 follow-up visits. Prostate-specific antigen positivity was associated with increased BV recurrence (adjusted hazard ratio [aHR], 2.32; 95% confidence interval [CI], 1.28-4.21). In contrast, we observed no significant increase in BV recurrence among women self-reporting unprotected sex since the last visit (aHR, 1.63; 95% CI, 0.77-3.43) or in the last 48 hours (aHR, 1.28; 95% CI, 0.70-2.36).

CONCLUSIONS

Estimates from earlier studies linking self-reported unprotected sex and BV may be biased by misclassification. Biomarkers can improve measurement of unprotected sex, a critical exposure variable in sexual health research.

Changes in Vaginal Microbiota and Immune Mediators in HIV-1-Seronegative Kenyan Women Initiating Depot Medroxyprogesterone Acetate

BACKGROUND

Depot medroxyprogesterone acetate (DMPA) is associated with HIV acquisition. We studied changes in vaginal microbiota and inflammatory milieu after DMPA initiation.

METHODS

In a cohort of HIV-negative Kenyan women, we collected monthly vaginal swabs over 1 year before and after DMPA. Using quantitative polymerase chain reaction, we compared quantities of Lactobacillus crispatus, Lactobacillus jensenii, Lactobacillus iners, Gardnerella vaginalis, and total bacterial load (16S ribosomal RNA gene levels). Six vaginal immune mediators were measured with enzyme-linked immunosorbent assay. Trends in the detection and quantity of bacteria were estimated by logistic and linear mixed-effects regression.

RESULTS

From 2010 to 2012, 15 HIV-seronegative women initiated DMPA, contributing 85 visits (median, 6 visits/woman; range, 3-8 visits/woman). The median time of DMPA-exposed follow-up was 8.4 months (range, 1.5-11.6 months). Seven women (46%) had bacterial vaginosis within 70 days before DMPA start. L. iners was detected in 13 women (87%) before DMPA start, but other lactobacilli were rarely detected. Gardnerella vaginalis decreased by 0.21 log10 copies per swab per month after DMPA exposure (P = 0.01). Total bacterial load decreased by 0.08 log10 copies per swab per month of DMPA (P = 0.02). Sustained decreases in interleukin (IL)-6 (P = 0.03), IL-8 (P = 0.04), and IL-1 receptor antagonist (P < 0.001) were also noted. Nine women (60%) had L. crispatus detected post-DMPA, which significantly correlated with reduced IL-6 (P < 0.01) and IL-8 (P = 0.02).

CONCLUSIONS

Initiation of DMPA led to sustained shifts in vaginal bacterial concentrations and levels of inflammatory mediators. Further studies are warranted to outline components of the vaginal microbiota influenced by DMPA use and impact on HIV susceptibility.

The implications of post-coital intravaginal cleansing for the introduction of vaginal microbicides in South Africa

Post-coital intravaginal cleansing (IVC) could counteract the protective effect of a vaginal microbicide. IVC less than 1 h after sex is discouraged in most microbicide trials. During a microbicide trial in KwaZulu-Natal, we collected quantitative data on post-coital IVC. We discussed IVC during in-depth-interviews (IDIs) and focus-group discussions (FGDs) with women enrolled in the trial, and during FGDs with community members. Nearly one-third (336/1,143) of women reported IVC less than an hour after sex. In multivariate analysis, post-coital IVC was associated with younger age, larger household size, greater sexual activity, consistent gel use, and clinic of enrolment. During IDIs and FGDs, respondents described post-coital IVC as a common hygiene practice motivated by the need to remove semen, vaginal fluids and sweat, although this practice may be amenable to change in the context of microbicide use. We need to consider strategies for influencing post-coital IVC practices in future microbicide trials and delivery programmes.

Microbiome, sex hormones, and immune responses in the reproductive tract: challenges for vaccine development against sexually transmitted infections

The female and male reproductive tracts are complex eco-systems where immune cells, hormones, and microorganisms interact. The characteristics of the reproductive tract mucosa are distinct from other mucosal sites. Reproductive tract mucosal immune responses are compartmentalized, unique, and affected by resident bacterial communities and sex hormones. The female and male genital microbiomes are complex environments that fluctuate in response to external and host-associated stimuli. The female vaginal microbiota play an important role in preventing colonization by pathogenic organisms. Sex hormones and their duration of exposure affect the composition and stability of the microbiome as well as systemic and mucosal immune responses. In addition to the characteristics of the pathogen they are targeting, successful vaccines against sexually transmitted pathogens must take into account the differences between the systemic and mucosal immune responses, the compartmentalization of the mucosal immune responses, the unique characteristics of the reproductive tract mucosa, the role of the mucosal bacterial communities, the impact of sex hormones, and the interactions among all of these factors.

Hormonal contraception is associated with a reduced risk of bacterial vaginosis: a systematic review and meta-analysis

Objective

To examine the association between hormonal contraception (HC) and bacterial vaginosis (BV) by systematic review and meta-analysis.

Methods

Medline, Web of Science and Embase databases were searched to 24/1/13 and duplicate references removed. Inclusion criteria 1) >20 BV cases; 2) accepted BV diagnostic method; 3) measure of HC-use either as combined oestrogen-progesterone HC (combined), progesterone-only contraception (POC) or unspecified HC (u-HC); 4) ≥10% of women using HC; 5) analysis of the association between BV and HC-use presented; 6) appropriate control group. Data extracted included: type of HC, BV diagnostic method and outcome (prevalent, incident, recurrent), and geographical and clinic-setting. Meta-analyses were conducted to calculate pooled effect sizes (ES), stratified by HC-type and BV outcome. This systematic review is registered with PROSPERO (CRD42013003699).

Results

Of 1713 unique references identified, 502 full-text articles were assessed for eligibility and 55 studies met inclusion criteria. Hormonal contraceptive use was associated with a significant reduction in the odds of prevalent BV (pooled effect size by random-effects [reES] = 0.68, 95%CI0.63–0.73), and in the relative risk (RR) of incident (reES = 0.82, 95%CI:0.72–0.92), and recurrent (reES = 0.69, 95%CI:0.59–0.91) BV. When stratified by HC-type, combined-HC and POC were both associated with decreased prevalence of BV and risk of incident BV. In the pooled analysis of the effect of HC-use on the composite outcome of prevalent/incident/recurrent BV, HC-use was associated with a reduced risk of any BV (reES = 0.78, 95%CI:0.74–0.82).

Conclusion

HC-use was associated with a significantly reduced risk of BV. This negative association was robust and present regardless of HC-type and evident across all three BV outcome measures. When stratified by HC-type, combined-HC and POC were both individually associated with a reduction in the prevalence and incidence of BV. This meta-analysis provides compelling evidence that HC-use influences a woman’s risk of BV, with important implications for clinicians and researchers in the field.

Hormonal contraception decreases bacterial vaginosis but oral contraception may increase candidiasis: implications for HIV transmission

OBJECTIVE

A 2012 WHO consultation concluded that combined oral contraception (COC) does not increase HIV acquisition in women, but the evidence for depot medroxyprogesterone acetate (DMPA) is conflicting. We evaluated the effect of COC and DMPA use on the vaginal microbiome because current evidence suggests that any deviation from a 'healthy' vaginal microbiome increases women's susceptibility to HIV.

METHODS

We conducted a systematic review and reanalysed the Hormonal Contraception and HIV Acquisition (HC-HIV) study. Vaginal microbiome outcomes included bacterial vaginosis by Nugent scoring, vaginal candidiasis by culture or KOH wet mount and microbiome compositions as characterized by molecular techniques.

RESULTS

Our review of 36 eligible studies found that COC and DMPA use reduce bacterial vaginosis by 10-20 and 18-30%, respectively. The HC-HIV data showed that COC and DMPA use also reduce intermediate microbiota (Nugent score of 4-6) by 11% each. In contrast, COC use (but not DMPA use) may increase vaginal candidiasis. Molecular vaginal microbiome studies (n=4) confirm that high oestrogen levels favour a vaginal microbiome composition dominated by 'healthy' Lactobacillus species; the effects of progesterone are less clear and not well studied.

CONCLUSION

DMPA use does not increase HIV risk by increasing bacterial vaginosis or vaginal candidiasis. COC use may predispose for vaginal candidiasis, but is not believed to be associated with increased HIV acquisition. However, the potential role of Candida species, and vaginal microbiome imbalances other than bacterial vaginosis or Candida species, in HIV transmission cannot yet be ruled out. Further in-depth molecular studies are needed.

Behavioural and medical predictors of bacterial vaginosis recurrence among female sex workers: longitudinal analysis from a randomized controlled trial

Background

Data on risk factors of recurrent bacterial vaginosis (RBV) are still scarce. We used data from female sex workers (FSW) participating in a randomized controlled microbicide trial to examine predictors of BV recurrence.

Methods

Trial’s participants with at least an episode of BV which was treated and/or followed by a negative BV result and at least one subsequent visit offering BV testing were included in the analysis. Behavioural and medical data were collected monthly while laboratory testing for STI and genital tract infections were performed quarterly. The Andersen-Gill proportional hazards model was used to determine predictors of BV recurrence both in bivariate and multivariate analyses.

Results

440 women were included and the incidence rate for RBV was 20.8 recurrences/100 person-months (95% confidence interval (CI) =18.1–23.4). In the multivariate analysis controlling for the study site, recent vaginal cleansing as reported at baseline with adjusted hazard-ratio (aHR)=1.30, 95% CI = 1.02-1.64 increased the risk of BV recurrence, whereas consistent condom use (CCU) with the primary partner (aHR=0.68, 95% CI=0.49-0.93) and vaginal candidiasis (aHR=0.70, 95% CI=0.53-0.93), both treated as time-dependent variables, were associated with decreased risk of RBV.

Conclusion

This study confirms the importance of counselling high-risk women with RBV about the adverse effects of vaginal cleansing and the protective effects of condom use with all types of partners for the prevention of sexually transmitted infections, including BV. More prospective studies on risk factors of BV recurrence are warranted.

Trial registration

Trial registration: NCT00153777

Alcohol use, mycoplasma genitalium, and other STIs associated With HIV incidence among women at high risk in Kampala, Uganda

BACKGROUND

In 2008, the first clinic for women involved in high-risk sexual behavior was established in Kampala, offering targeted HIV prevention. This article describes rates, determinants, and trends of HIV incidence over 3 years.

METHODS

A total of 1027 women at high risk were enrolled into a closed cohort. At 3-monthly visits, data were collected on sociodemographic variables and risk behavior; biological samples were tested for HIV and other reproductive tract infections/sexually transmitted infections (RTI/STIs). Hazard ratios for HIV incidence were estimated using Cox proportional hazards regression among the 646 women HIV negative at enrolment.

RESULTS

HIV incidence was 3.66/100 person-years (pyr) and declined from 6.80/100 pyr in the first calendar year to 2.24/100 pyr and 2.53/100 pyr in the following years (P trend = 0.003). Sociodemographic and behavioral factors independently associated with HIV incidence were younger age, younger age at first sex, alcohol use (including frequency of use and binge drinking), number of paying clients in the past month, inconsistent condom use with clients, and not being pregnant. HIV incidence was also independently associated with Mycoplasma genitalium infection at enrolment [adjusted hazard ratio (aHR) = 2.28, 95% confidence interval (CI): 1.15 to 4.52] and with Neisseria gonorrhoeae (aHR = 5.91, 95% CI: 3.04 to 11.49) and Trichomonas vaginalis infections at the most recent visit (aHR = 2.72, 95% CI: 1.27 to 5.84). The population attributable fractions of HIV incidence for alcohol use was 63.5% (95% CI: 6.5 to 85.8) and for treatable RTI/STIs was 70.0% (95% CI: 18.8 to 87.5).

CONCLUSIONS

Alcohol use and STIs remain important risk factors for HIV acquisition, which call for more intensive control measures in women at high risk. Further longitudinal studies are needed to confirm the association between M. genitalium and HIV acquisition.

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.

Association between semen exposure and incident bacterial vaginosis

Objective. To identify correlates of incident bacterial vaginosis (BV) diagnosed with Nugent scoring among high-risk women. Study Design. We conducted both cohort and case-crossover analyses, stratified by HIV infection status, based on 871 HIV-infected and 439 HIV-uninfected participants in the HIV Epidemiology Research Study, conducted in 4 US sites in 1993–2000. Results. BV incidence was 21% and 19% among HIV-infected and -uninfected women, respectively. Fewer correlates of BV were found with case-crossover than with cohort design. Reporting frequent coitus (regardless of consistency of condom use) was correlated with BV in cohort analyses but not in case-crossover analyses. The sole correlate of BV in both types of analyses was the detection of spermatozoa on Gram stain, which is a marker of semen exposure. Conclusion. The inconsistent association between condom use and BV in prior studies could be from reporting bias. We found evidence of a relationship between semen exposure and incident BV.

Risks for acquisition of bacterial vaginosis among women who report sex with women: a cohort study

Background

Bacterial vaginosis (BV) is common in women who have sex with women. While cross-sectional data support a role for sexual transmission, risks for incident BV have not been prospectively studied in this group.

Methodology/Principal Findings

We studied risks for BV acquisition in a prospective cohort study of women (age 16–35 years) who reported sex with other women (≥1 partner, prior year). Women were followed for one year with examinations at quarterly visits and for genital symptoms at any time. Species-specific 16S rRNA gene PCRs for BV-associated bacteria (BVAB) were applied to vaginal fluid obtained at enrollment. Sexual behaviors were ascertained by computer-assisted interview. Of 335 participants, 239 had no BV at baseline; 199 were seen in follow-up (median follow-up 355 days, 4.0 visits/subject). Forty women experienced ≥1 BV episode. Risks for incident BV were presentation ≤14 days since onset of menses (hazard ratio (HR) 2.3 (95% CI, 1.2–4.7), report of new sex partner with BV history (HR 3.63 (1.1–11.9)), change in vaginal discharge (HR 2.6 (1.3–5.2)) and detection of any of several BVAB in vaginal fluid at enrollment, including BVAB1 (HR 6.3 (1.4–28.1)), BVAB2 (HR 18.2 (6.4–51.8)), BVAB3 (HR 12.6 (2.7–58.4)), G. vaginalis (HR 3.9 (1.5–10.4)), Atopobium vaginae (HR 4.2 (1.9–9.3)), Leptotrichia spp (9.3 (3.0–24.4)), and Megasphaera-1 (HR 11.5 (5.0–26.6)). Detection of Lactobacillus crispatus at enrollment conferred reduced risk for subsequent BV (HR 0.18 (0.08–0.4)). Detailed analysis of behavioral data suggested a direct dose-response relationship with increasing number of episodes of receptive oral-vulvovaginal sex (HR 1.02 (95% CI, 1.00–1.04).

Conclusions/Significance

Vaginal detection of several BVAB in BV-negative women predicted subsequent BV, suggesting that changes in vaginal microbiota precede BV by weeks or months. BV acquisition was associated with report of new partner with BV; associations with sexual practices – specifically, receptive oral sex – require further investigation.

Personal hygienic behaviors and bacterial vaginosis

BACKGROUND

Vaginal douching is consistently associated with bacterial vaginosis (BV), but whether it is a cause or result of BV remains unknown. The association between BV and other feminine hygienic behaviors is less studied; if BV symptoms caused behavior change then all hygiene behaviors might be more common among women with BV. Lack of association between nondouching hygiene behavior and BV would argue against reverse causation.

METHODS

In the Longitudinal Study of Vaginal Flora 3620 women had 13,517 visits where BV (Nugent score) was assessed. Associations between hygienic behavior and BV were assessed by Poisson regression.

RESULTS

After adjusting for demographic and sexual behavior factors, neither type of underwear (nylon vs. cotton prevalence ratio (PR) 1.05, 95% CI: 0.97-1.13), menstrual protection (tampons vs. pads; PR: 1.04, 95% CI: 0.95-1.12; pads and tampons vs. pads 1.00, 95% CI: 0.92-1.07), use of pads or panty liners when not menstruating (PR: 0.99, 95% CI: 0.95-1.05), nor weekly or greater use of hygiene spray (PR: 1.01, 95% CI: 0.94-1.09), powder (PR: 1.02, 95% CI: 0.96-1.07) or towlettes (PR: 1.03, 95% CI: 0.94-1.13) were strongly associated with BV. PR for daily versus less than daily bathing and showering were 1.06 (95% CI: 1.02-1.12) and 1.04 (95% CI: 1.00-1.09). Douching remained associated with BV (PR for weekly or greater vs. never 1.17, 95% CI: 1.09-1.26) and was not substantially impacted by adjustment for other hygienic behavior.

CONCLUSIONS

Douching, but not other feminine hygiene behaviors, is significantly associated with BV, providing additional evidence that douching may be causally associated with BV and is not simply a response to BV symptoms.

Intravaginal practices, vaginal infections and HIV acquisition: systematic review and meta-analysis

BACKGROUND

Intravaginal practices are commonly used by women to manage their vaginal health and sexual life. These practices could, however, affect intravaginal mucosal integrity. The objectives of this study were to examine evidence for associations between: intravaginal practices and acquisition of HIV infection; intravaginal practices and vaginal infections; and vaginal infections and HIV acquisition.

METHODOLOGY/PRINCIPAL FINDINGS

We conducted a systematic review of prospective longitudinal studies, searching 15 electronic databases of journals and abstracts from two international conferences to 31(st) January 2008. Relevant articles were selected and data extracted in duplicate. Results were examined visually in forest plots and combined using random effects meta-analysis where appropriate. Of 2120 unique references we included 22 publications from 15 different studies in sub-Saharan Africa and the USA. Seven publications from five studies examined a range of intravaginal practices and HIV infection. No specific vaginal practices showed a protective effect against HIV or vaginal infections. Insertion of products for sex was associated with HIV in unadjusted analyses; only one study gave an adjusted estimate, which showed no association (hazard ratio 1.09, 95% confidence interval, CI 0.71, 1.67). HIV incidence was higher in women reporting intravaginal cleansing but confidence intervals were wide and heterogeneity high (adjusted hazard ratio 1.88, 95%CI 0.53, 6.69, I(2) 83.2%). HIV incidence was higher in women with bacterial vaginosis (adjusted effect 1.57, 95%CI 1.26, 1.94, I(2) 19.0%) and Trichomonas vaginalis (adjusted effect 1.64, 95%CI 1.28, 2.09, I(2) 0.0%).

CONCLUSIONS/SIGNIFICANCE

A pathway linking intravaginal cleaning practices with vaginal infections that increase susceptibility to HIV infection is plausible but conclusive evidence is lacking. Intravaginal practices do not appear to protect women from vaginal infections or HIV and some might be harmful.

The vaginal bacterial communities of Japanese women resemble those of women in other racial groups

To determine whether different racial groups shared common types of vaginal microbiota, we characterized the composition and structure of vaginal bacterial communities in asymptomatic and apparently healthy Japanese women in Tokyo, Japan, and compared them with those of White and Black women from North America. The composition of vaginal communities was compared based on community profiles of terminal restriction fragments of 16S rRNA genes and phylogenetic analysis of cloned 16S rRNA gene sequences of the numerically dominant bacterial populations. The types of vaginal communities found in Japanese women were similar to those of Black and White women. As with White and Black women, most vaginal communities were dominated by lactobacilli, and only four species of Lactobacillus (Lactobacillus iners, Lactobacillus crispatus, Lactobacillus jensenii, and Lactobacillus gasseri) were commonly found. Communities dominated by multiple species of lactobacilli were common in Japanese and White women, but rare in Black women. The incidence, in Japanese women, of vaginal communities with several non-Lactobacillus species at moderately high frequencies was intermediate between Black women and White women. The limited number of community types found among women in different ethnic groups suggests that host genetic factors, including the innate and adaptive immune systems, may be more important in determining the species composition of vaginal bacterial communities than are cultural and behavioral differences.

In vitro evaluation of the viability of vaginal cells (VK2/E6E7) and probiotic Lactobacillus species in lemon juice

BACKGROUND

Women, especially in developing countries, most often bear the brunt of HIV infections. The continued lack of viable vaccines and microbicides has made some women resort to using natural products such as lemon or lime juice to avoid infection. Few in vitro studies have been done on the effect of lemon juice on vaginal cells and lactobacilli that constitute the major microbiota in healthy women.

OBJECTIVE

The objective of the present study was to evaluate in vitro the effect of lemon juice on the viability of vaginal cells (VK2/E6E7) and vaginal Lactobacillus species.

METHODS

Vaginal cells were exposed to different concentrations (0-30%) of lemon juice at pH 2.3 and 4.5 for 10 min. Viability was determined by staining the cells with propidium iodide and analysing them by flow cytometry. Lactobacillus organisms were dispensed into microplates with vaginally defined medium + peptone (VDMP) containing different concentrations of lemon juice ranging from 0 to 100%.

RESULTS

Lemon juice at pH 2.3 had a significant (P = 0.03) toxic effect on the vaginal cell line used. At 30% concentration, the vaginal cells were practically non-viable, typified by a 95% loss of viability, whereas at pH 4.5 there was only 5% cell loss. Lemon juice had varying growth inhibitory effects on the Lactobacillus species tested. At pH 4.5 and using 10-30% lemon juice, there was a stimulatory growth effect on certain Lactobacillus species.

CONCLUSIONS

Lemon juice (20-30%) at pH 2.3 was highly toxic to VK2/E6E7 cells, and at pH 4.5 there was no significant effect on the viability of the cells within 10 min. Lemon juice above 10% at pH 2.3 was found to be detrimental to the growth of vaginal lactobacilli. Although lemon juice may be useful in other applications, its use in the vaginal region should be discouraged.

Prospective study of correlates of vaginal Lactobacillus colonisation among high-risk HIV-1 seronegative women

OBJECTIVE

Vaginal colonisation with Lactobacillus species is characteristic of normal vaginal ecology. The absence of vaginal lactobacilli, particularly hydrogen peroxide (H(2)O(2))-producing isolates, has been associated with symptomatic bacterial vaginosis (BV) and increased risk for HIV-1 acquisition. Identification of factors associated with vaginal Lactobacillus colonisation may suggest interventions to improve vaginal health.

METHODS

We conducted a prospective cohort study of correlates of vaginal Lactobacillus colonisation among Kenyan HIV-1 seronegative female sex workers. At monthly follow-up visits, vaginal Lactobacillus cultures were obtained. Generalised estimating equations were used to examine demographic, behavioural and medical correlates of Lactobacillus isolation, including isolation of H(2)O(2)-producing strains.

RESULTS

Lactobacillus cultures were obtained from 1020 women who completed a total of 8896 follow-up visits. Vaginal washing, typically with water alone or with soap and water, was associated with an approximately 40% decreased likelihood of Lactobacillus isolation, including isolation of H(2)O(2)-producing strains. Recent antibiotic use, excluding metronidazole and treatments for vaginal candidiasis, reduced Lactobacillus isolation by approximately 30%. H(2)O(2)-producing lactobacilli were significantly less common among women with Trichomonas vaginalis infection and those who were seropositive for herpes simplex virus type 2. In contrast, H(2)O(2)-producing lactobacilli were significantly more common among women with concurrent vaginal candidiasis.

CONCLUSIONS

Modifiable biological and behavioural factors are associated with Lactobacillus colonisation in African women. Our results suggest intervention strategies to improve vaginal health in women at high risk for HIV-1.