Intermittent Lactobacilli-containing Vaginal Probiotic or Metronidazole Use to Prevent Bacterial Vaginosis Recurrence: A Pilot Study Incorporating Microscopy and Sequencing

The role of probiotics as adjunct treatment in the prevention and management of gynecological infections: An updated meta-analysis of 35 RCT studies

OBJECTIVE

The present study aims to conduct a comprehensive meta-analysis of randomized controlled trials (RCTs) investigating the efficacy of probiotics as an adjunct treatment for preventing and treating gynecological infections.

MATERIALS AND METHODS

The study adopted a systematic review of scientific databases including PubMed, Cochrane, and EMBASE, using defined MeSH terms. The inclusion and exclusion criteria were set to refine the search, with the data extraction and quality assessment being conducted by two independent investigators.

RESULTS

A total of 35 articles, comprising 3751 patients, were included in the meta-analysis. The application of probiotics demonstrated a notable increase in the cure rates of bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC) as compared to control groups. A significant BV cure rate (OR: 5.972; 95% CI: 2.62-13.59; p-value: 0.01) was noted with probiotic use, which was even more pronounced when used as an adjunctive treatment with antibiotics (OR: 2.504; 95% CI: 1.03-6.06; p-value: 0.04). Additionally, probiotic use significantly reduced the recurrence rates of BV (OR: 0.34; 95% CI: 0.167-0.71; p-value: 0.004). For VVC, a significant increase in the cure rate was observed in the probiotic group (OR: 3.425; 95% CI: 2.404-4.879; p-value: 0.01), along with a lower recurrence rate (OR: 0.325; 95% CI: 0.175-0.606; p-value: 0.01).

CONCLUSION

Our findings underscore the potential role of probiotics as a beneficial adjunctive treatment for gynecological infections, indicating an improved cure rate and decreased recurrence. However, additional well-designed studies are necessary to corroborate these findings.

Lacticaseibacillus rhamnosus TOM 22.8 (DSM 33500) is an effective strategy for managing vaginal dysbiosis, rising the lactobacilli population

AIM

The present study is a single-centre, randomized, controlled clinical trial aimed to evaluate the effectiveness of the probiotic Lacticaseibacillus rhamnosus TOM 22.8 (DSM 33500) strain, orally administrated, to treat vaginal dysbiosis.

METHODS AND RESULTS

Overall, 80 women, with signs and symptoms of vaginal dysbiosis, were enrolled and allocated to the treatment group (A, n=60), who took 1 capsule of the probiotic strain for 10 consecutive days, or the non-treatment group (B, n=20), who did not receive any treatment. Clinical (vaginal signs and symptoms; pH of the vaginal fluid; Amsel criteria; Nugent score; Lactobacillary grade) and microbiological examinations were performed at baseline (T0), 10 days (T1), and 30 (T2) days after the oral administration of the probiotic TOM 22.8 strain. The latter resulted in a restoration of the physiological pH, accompanied by remission or attenuation of clinical signs and symptoms as well as the improvement of the quality of life (QoL). Microbiological data revealed a significant reduction of potentially pathogenic bacteria.

CONCLUSION

The administration of the L. rhamnosus TOM 22.8 probiotic strain could be proposed as an effective strategy for the treatment of vaginal dysbiosis.

Effect of Metronidazole on Concentrations of Vaginal Bacteria Associated with Risk of HIV Acquisition

Several bacterial vaginosis (BV)-associated bacteria have been associated with elevated risk of HIV acquisition, however susceptibility of these bacteria to antibiotics is poorly understood. Vaginal samples were collected from 22 persons daily for two weeks following BV diagnosis. Metronidazole treatment was prescribed for 5-7 days. Changes in bacterial concentrations were measured with taxon-specific 16S rRNA gene quantitative PCR (qPCR) assays. A culture-based antimicrobial assay confirmed presence of antibiotics in vaginal swab samples. Bacterial DNA concentrations decreased during antibiotic administration for all thirteen bacterial taxa tested. Comparison of bacterial DNA concentrations in samples before administration of antibiotics to samples taken on the last day of antimicrobial assay-confirmed antibiotic presence showed a 2.3-4.5 log10-fold decrease across all taxa. Concentrations were frequently reduced to the qPCR assay's limit of detection, suggesting eradication of bacteria. Mean clearance time varied across taxa (1.2-8.6 days), with several bacteria (e.g., Gemella asaccharolytica, Sneathia spp., Eggerthella-like sp.) taking >7 days to suppress. Metronidazole reduces quantities of bacterial taxa associated with increased HIV acquisition risk. Eradication of high-risk vaginal bacteria using metronidazole is one promising avenue for reducing HIV acquisition risk. A 5-7-day treatment course may not be sufficient to suppress all bacteria.

Harnessing the power within: engineering the microbiome for enhanced gynecologic health

Graphical abstract

Abstract

Although numerous studies have demonstrated the impact of microbiome manipulation on human health, research on the microbiome's influence on female health remains relatively limited despite substantial disease burden. In light of this, we present a selected review of clinical trials and preclinical studies targeting both the vaginal and gut microbiomes for the prevention or treatment of various gynecologic conditions. Specifically, we explore studies that leverage microbiota transplants, probiotics, prebiotics, diet modifications, and engineered microbial strains. A healthy vaginal microbiome for females of reproductive age consists of lactic acid-producing bacteria predominantly of the Lactobacillus genus, which serves as a protective barrier against pathogens and maintains a balanced ecosystem. The gut microbiota's production of short-chain fatty acids, metabolism of primary bile acids, and modulation of sex steroid levels have significant implications for the interplay between host and microbes throughout the body, ultimately impacting reproductive health. By harnessing interventions that modulate both the vaginal and gut microbiomes, it becomes possible to not only maintain homeostasis but also mitigate pathological conditions. While the field is still working toward making broad clinical recommendations, the current studies demonstrate that manipulating the microbiome holds great potential for addressing diverse gynecologic conditions.

Lay summary

Manipulating the microbiome has recently entered popular culture, with various diets thought to aid the microbes that live within us. These microbes live in different locations of our body and accordingly help us digest food, modulate our immune system, and influence reproductive health. The role of the microbes living in and influencing the female reproductive tract remains understudied despite known roles in common conditions such as vulvovaginal candidiasis (affecting 75% of females in their lifetime), bacterial vaginosis (25% of females in their lifetime), cervical HPV infection (80% of females in their lifetime), endometriosis (6-10% of females of reproductive age), and polycystic ovary syndrome (10-12% of females of reproductive age). Here, we review four different approaches used to manipulate the female reproductive tract and gastrointestinal system microbiomes: microbiota transplants, probiotics, prebiotics, and dietary interventions, and the use of engineered microbial strains. In doing so, we aim to stimulate discussion on new ways to understand and treat female reproductive health conditions.

Interpretation of vaginal metagenomic characteristics in different types of vaginitis

Although vaginitis is closely related to vaginal microecology in females, the precise composition and functional potential of different types of vaginitis remain unclear. Here, metagenomic sequencing was applied to analyze the vaginal flora in patients with various forms of vaginitis, including cases with a clue cell proportion ranging from 1% to 20% (Clue1_20), bacterial vaginitis (BV), vulvovaginal candidiasis (VVC), and BV combined with VVC (VVC_BV). Our results identified Prevotella as an important biomarker between BV and Clue1_20. Moreover, a gradual decrease was observed in the relative abundance of shikimic acid metabolism associated with bacteria producing indole as well as a decline in the abundance of Gardnerella vaginalis in patients with BV, Clue1_20, and healthy women. Interestingly, the vaginal flora of patients in the VVC_BV group exhibited structural similarities to that of the VVC group, and its potentially functional characteristics resembled those of the BV and VVC groups. Finally, Lactobacillus crispatus was found in high abundance in healthy samples, greatly contributing to the stability of the vaginal environment. For the further study of L. crispatus, we isolated five strains of L. crispatus from healthy samples and evaluated their capacity to inhibit G. vaginalis biofilms and produce lactic acid in vitro to select the potential probiotic candidate for improving vaginitis in future clinical studies. Overall, we successfully identified bacterial biomarkers of different vaginitis and characterized the dynamic shifts in vaginal flora between patients with BV and healthy females. This research advances our understanding and holds great promise in enhancing clinical approaches for the treatment of vaginitis.

IMPORTANCE

Vaginitis is one of the most common gynecological diseases, mostly caused by infections of pathogens such as Candida albicans and Gardnerella vaginalis. In recent years, it has been found that the stability of the vaginal flora plays an important role in vaginitis. Furthermore, the abundant Lactobacillus-producing rich lactic acid in the vagina provides a healthy acidic environment such as Lactobacillus crispatus. The metabolites of Lactobacillus can inhibit the colonization of pathogens. Here, we collected the vaginal samples of patients with bacterial vaginitis (BV), vulvovaginal candidiasis (VVC), and BV combined with VVC to discover the differences and relationships among the different kinds of vaginitis by metagenomic sequencing. Furthermore, because of the importance of L. crispatus in promoting vaginal health, we isolated multiple strains from vaginal samples of healthy females and chose the most promising strain with potential probiotic benefits to provide clinical implications for treatment strategies.

Genome-wide association study in Estonia reveals importance of vaginal epithelium associated genes in case of recurrent vaginitis

Recurrent vaginitis is a leading reason for visiting a gynaecologist, with bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC) being the most common diagnoses. Reasons and mechanisms behind their recurrent nature are poorly understood. We conducted a genome-wide association study (GWAS) to find possible genetic risk factors for recurrent vaginitis using data from a large population-based biobank, the Estonian Biobank. The study included 6870 cases (at least two episodes of vaginitis) and 5945 controls (no vaginitis episodes). GWAS approach included single marker and gene-based analyses, followed by functional annotation of associated variants and candidate gene mapping.In single marker analysis, one statistically significant (P = 7.8 × 10-9) variant rs1036732378 was identified on chromosome 10. The gene-based association analysis identified one gene, KRT6A, that exceeded the recommended significance threshold (P = 2.6 × 10-6). This is a member of the keratin protein family and is expressed during differentiation in epithelial tissues.Functional mapping and annotation of genetic associations by using adjusted significance level identified 22 potential risk loci that may be associated with recurrent vaginitis phenotype. Comparison of our results with previous studies provided nominal support for LBP (associated with immune response to vaginal bacteria) and PRKCH genes (possible role in keratinocyte differentiation and susceptibility to candidiasis).In conclusion, this study is the first highlighting a potential role of the vaginal epithelium in recurrent vaginitis.

Genital tract infections, the vaginal microbiome and gestational age at birth among pregnant women in South Africa: a cohort study protocol

INTRODUCTION

Preterm birth complications are the most common cause of death in children under 5 years. The presence of multiple microorganisms and genital tract inflammation could be the common mechanism driving early onset of labour. South Africa has high levels of preterm birth, genital tract infections and HIV infection among pregnant women. We plan to investigate associations between the presence of multiple lower genital tract microorganisms in pregnancy and gestational age at birth.

METHODS AND ANALYSIS

This cohort study enrols around 600 pregnant women at one public healthcare facility in East London, South Africa. Eligible women are ≥18 years and at <27 weeks of gestation, confirmed by ultrasound. At enrolment and 30-34 weeks of pregnancy, participants receive on-site tests for Chlamydia trachomatis and Neisseria gonorrhoeae, with treatment if test results are positive. At these visits, additional vaginal specimens are taken for: PCR detection and quantification of Trichomonas vaginalis, Candida spp., Mycoplasma genitalium, M. hominis, Ureaplasma urealyticum and U. parvum; microscopy and Nugent scoring; and for 16S ribosomal RNA gene sequencing and quantification. Pregnancy outcomes are collected from a postnatal visit and birth registers. The primary outcome is gestational age at birth. Statistical analyses will explore associations between specific microorganisms and gestational age at birth. To explore the association with the quantity of microorganisms, we will construct an index of microorganism load and use mixed-effects regression models and classification and regression tree analysis to examine which combinations of microorganisms contribute to earlier gestational age at birth.

ETHICS AND DISSEMINATION

This protocol has approvals from the University of Cape Town Research Ethics Committee and the Canton of Bern Ethics Committee. Results from this study will be uploaded to preprint servers, submitted to open access peer-reviewed journals and presented at regional and international conferences.

TRIAL REGISTRATION NUMBER

NCT06131749; Pre-results.

Under conditions closely mimicking vaginal fluid, Lactobacillus jensenii strain 62B produces a bacteriocin-like inhibitory substance that targets and eliminates Gardnerella species

Within the vaginal ecosystem, lactobacilli and Gardnerella spp. likely interact and influence each other's growth, yet the details of this interaction are not clearly defined. Using medium simulating vaginal fluid and a two-chamber co-culturing system to prevent cell-to-cell contact between the bacteria, we examined the possibility that Lactobacillus jensenii 62B (Lj 62B) and/or G. piotii (Gp) JCP8151B produce extracellular factors through which they influence each other's viability. By 24 h post-inoculation (hpi) in the co-culture system and under conditions similar to the vaginal environment - pH 5.0, 37 °C, and 5% CO2, Lj 62B viability was not affected but Gp JCP8151B had been eliminated. Cell-free supernatant harvested from Lj 62B cultures (Lj-CFS) at 20 hpi, but not 16 hpi, also eliminated Gp JCP8151B growth. Neither lactic acid nor H2O2 production by Lj 62B was responsible for this effect. The Lj-CFS did not affect viability of three species of lactobacilli or eight species of Gram-positive and Gram-negative uropathogens but eliminated viability of eight different strains of Gardnerella spp. Activity of the inhibitory factor within Lj-CFS was abolished by protease treatment and reduced by heat treatment suggesting it is most likely a bacteriocin-like protein; fractionation revealed that the factor has a molecular weight within the 10-30 kDa range. These results suggest that, in medium mimicking vaginal fluid and growth conditions similar to the vaginal environment, Lj 62B produces a potential bacteriocin-like inhibitory substance (Lj-BLIS) that clearly targets Gardnerella spp. strains. Once fully characterized, Lj-BLIS may be a potential treatment for Gardnerella-related BV that does not alter the vaginal microflora.

Antibiotics therapy combined with probiotics administered intravaginally for the treatment of bacterial vaginosis: A systematic review and meta-analysis

The objective was to examine the pooled effects of antibiotic-probiotic combinations by examining the cure rate and recurrence rate for bacterial vaginosis (BV). A systematic literature search was conducted from electronic databases. All parallel randomized controlled trials (RCTs) that focused on the effects of antibiotics combined with intravaginal probiotics were included. Cure rate and recurrence rate were the primary and secondary outcomes to be analyzed. Meta-analysis was conducted following the Cochrane handbook for Systematic Reviews of Interventions. As a result, of 923 studies identified, 11 articles involving 1,493 BV patients met the inclusion criteria and nine were available for meta-analysis. A meta-analysis of two studies evaluated the recurrence rate 12-16 weeks after treatment. Results showed a statistically significant difference favoring the antibiotics plus probiotics group vs the antibiotics plus placebo group (relative risk 0.62, 95% confidence interval [CI]: 0.45-0.85). The narrative review in one study indicated that the cure rate was higher in the antibiotics plus probiotics group, giving a significant HR ratio of 0.73 (95% CI 0.54-0.98) (p = 0.042). In conclusion, vaginal application of Lactobacillus in combination with antibiotics for the treatment of BV could be a promising method for both reducing the recurrence rate and relieving symptoms of BV.

Effect of vaginal probiotics containing Lactobacillus casei rhamnosus (Lcr regenerans) on vaginal dysbiotic microbiota and pregnancy outcome, prospective, randomized study

The intermediate bacterial microbiota is a heterogeneous group that varies in the severity of the dysbiosis, from minor deficiency to total absence of vaginal Lactobacillus spp. We treated women with this vaginal dysbiosis in the first trimester of pregnancy using a vaginally applied lactobacilli preparation to restore the normal microbiota in order to delay the preterm delivery rate. Pregnant women with intermediate microbiota of the vagina and a Nugent score of 4 were enrolled in two groups: intermediate vaginal microbiota and a Nugent score of 4 with lactobacilli (IMLN4) and intermediate vaginal microbiota and a Nugent score of 4 without lactobacilli (IM0N4), with and without vaginal lactobacilli at baseline, respectively. Half of the women in each group received the treatment. Among women without lactobacilli (the IM0N4 group), the Nugent sore decreased by 4 points only in the women who received treatment, and gestational age at delivery and neonatal birthweight were both significantly higher in the treated subgroup than in the untreated subgroup (p = 0.047 and p = 0.016, respectively). This small study found a trend toward a benefit of treatment with vaginal lactobacilli during pregnancy.

Impact of Lactobacillus crispatus-containing oral and vaginal probiotics on vaginal health: a randomised double-blind placebo controlled clinical trial

Health of reproductive tract is tightly associated with balance of microbial communities in this area. Bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC) represent common disturbances of vaginal communities. Vaginal discharge due to BV or VVC is a very frequent reason for visiting gynaecologist. We aimed to evaluate the impact of the novel evidence-based probiotics on BV and VVC patients. The study group included 89 BV and 93 VVC patients (aged 18-50 years) who were recruited into randomised double-blind placebo-controlled two-arm parallel trial. The patients of each diagnosis group received oral or vaginal probiotic capsules, or placebo capsules during 3 months. A probiotic capsule contained two (DSM32717 and DSM32720, in case of BV) or three (DSM32720, DSM32718 and DSM32716, in case of VVC) Lactobacillus crispatus strains. Vaginal, intestinal and general health was monitored weekly by questionnaire. Blood analyses were done in the beginning and at the end of trial. Vaginal samples were collected monthly, microscopic and molecular analyses were performed. The study revealed that both oral and vaginal capsules reduced the signs and symptoms in BV patients. Remarkable improvement was noted in Nugent score, amount and smell of discharge, but also in itching/irritation. Consumption of vaginal probiotics significantly increased the lactobacilli counts in their vagina while mean proportion of some BV-related bacteria decreased. In VVC patients, both oral and vaginal capsules lowered the combined score of two most important symptoms, amount of discharge and itching/irritation. In conclusion, the novel formulations of evidence-based well-focused probiotic L. crispatus strains are effective against BV and VVC being suitable for both vaginal and oral administration. Clinical trial registration: ISRCTN34840624, BioMed Central.

Evaluation of the efficacy of Lactobacillus-containing feminine hygiene products on vaginal microbiome and genitourinary symptoms in pre- and postmenopausal women: A pilot randomized controlled trial

As estrogen level decreases with aging, the vaginal mucosa gets thinner, and collagen amount decreases. In addition, the population of Lactobacillus in the vagina declines, increasing the risk of atrophic vaginitis, bacterial vaginosis, and genitourinary symptoms in the postmenopausal women. In this study, we evaluated the effects of Lactobacillus-containing feminine hygiene products on vaginal microbiome and genitourinary symptoms in pre- and postmenopausal women. This was a pilot randomized controlled trial in 35 premenopausal and 35 postmenopausal healthy women. For 4 weeks, treatment 1 group (14 premenopausal and 16 postmenopausal women) used the Lactobacillus-containing feminine soap and cream, and treatment 2 group (15 premenopausal and 14 postmenopausal women) used Lactobacillus-containing feminine gel in addition to soap and cream. The remaining 6 premenopausal and 5 postmenopausal women served as controls without using any products. We then compared the changes in the vaginal microbiota, genitourinary symptoms, and other related biomarkers after completion of treatment. Vaginal pH and pathogenic flora were reduced in both treatment groups compared to control group, which was more significant in the treatment 2 group of postmenopausal women. Genitourinary symptoms significantly improved in 60% of premenopausal women in treatment 1 group and 81.3% of postmenopausal women in treatment 2 group, compared to control group (0%, p = 0.043 and p<0.01 respectively). Overactive bladder symptom scores were significantly improved after using the products in eleven out of twelve postmenopausal women suspected of having overactive bladder. The use of Lactobacillus-containing feminine products was associated with improved vaginal ecosystem and urogenital health compared to control group, especially in those women using feminine gel.

Assessment of the Performance of the Aptima Bacterial Vaginosis Assay Over a 3-Month Period in a French Hospital

Bacterial vaginosis (BV) is the most common cause of abnormal vaginal discharge. BV represents a dysbiosis with the acquisition of a diverse community of anaerobic bacteria and a reduction in lactobacilli burden. Our objective was to evaluate the Aptima BV assay kit for the diagnosis of BV. From May to August 2019, we enrolled outpatients and inpatients, including nonpregnant women above 18 with vaginosis symptoms, consulting at Nantes University hospital. The Aptima BV assay measures the loads of Gardnerella vaginalis, Atopobium vaginae, and Lactobacillus species in relation to overall bacterial load. The Aptima BV assay was compared to Nugent scoring (NS). A total of 456 women were enrolled, and 347 patients met the inclusion criteria with data available for the analysis. NS was used to classify the samples and 144 (41.5%) samples were classified as normal (NS = 0-3), 45 (13%) as BV (NS = 7-10), 38 (11%) presented an intermediate vaginal microbiota (3 < NS < 7), 79 (22.7%) had various bacteria (excluding vaginal flora), 29 (8.3%) had insufficient bacterial density, and 12 (3.5%) had a predominance of yeasts. The Aptima BV kit displayed a sensitivity of 91.1% and specificity of 94.4% with a positive predictive value (PPV) of 83.7% and a negative predictive (NPV) value of 97.1%. The results of this monocentric retrospective study show that Aptima BV kit has a good diagnostic correlation compared to standard of care for dysbiotic diagnosis cases. IMPORTANCE The possibility exists of the involvement of a new molecular test in the routine algorithm of bacterial vaginosis diagnosis in microbiology laboratories. This manuscript reports on our experience, and we propose an organization combining Nugent scoring and molecular testing, especially for intermediate Nugent scores.

Impacts of Menstruation, Community Type, and an Oral Yeast Probiotic on the Vaginal Microbiome

How to define and promote a healthy state of the vaginal microbiome is not well understood. Knowledge of which underlying factors shape the microbial community composition of the vagina and how to modulate them will contribute to vaginal disease prevention and improve fertility.

Inhibitory effect of Lactobacillus gasseri CCFM1201 on Gardnerella vaginalis in mice with bacterial vaginosis

Gardnerella vaginalis is the core pathogen of bacterial vaginosis (BV), the most common vaginal infection in women. G. vaginalis exerts pathogenicity through various factors, such as biofilm formation and the local host immune response stimulation. Therefore, this study aimed to evaluate the inhibitory effect of Lactobacillus gasseri CCFM1201 on G. vaginalis using experimental BV models. We evaluated L. gasseri in vitro to inhibit pathogen biofilm formation and adhesion capacity in HeLa cells using crystal violet staining. Further in vivo studies were conducted to assess the inhibitory effects of L. gasseri CCFM1201 on BV induced by G. vaginalis. L. gasseri exhibited strain-specific adhesion and inhibition of pathogen biofilm formation in vitro. L. gasseri CCFM1201 significantly reduced G. vaginalis in mice (p < 0.05), inhibited sialidase activity, modulated tumor necrosis factor-α and interleukin-1β expression, and reduced myeloperoxidase activity (p < 0.05). Histopathological examination indicated that L. gasseri CCFM1201 improved inflammatory cell infiltration of vaginal tissue and restored its structure. Vaginal epithelial cell exfoliation, the main clinical feature of BV, was significantly improved by L. gasseri CCFM1201 intervention (p < 0.05). Thus, L. gasseri CCFM1201 is a potential candidate for treating G. vaginalis-induced vaginal diseases.

The contribution of bacteriophages to the aetiology and treatment of the bacterial vaginosis syndrome

Bacteriophages are obligate intracellular viruses that parasitize bacteria, making use of the host biosynthetic machinery. Bacterial vaginosis (BV) causes serious adverse sequelae, such as sexually transmitted infections, seroconversion to HIV positivity, and preterm birth. The aetiology of BV is multifactorial, and the vaginal microbiota, the response to antibiotics, and the phenotypic outcomes differ between cases. The choice of antibiotics to treat BV depends on the clinician’s personal experience, which contributes to the poor outcome of BV treatment and high recurrence rate. In this review, we classify BV into two subtypes based on whether or not the BV case is sexually associated (potentially phage-related). An appropriate antibiotic can be selected on the basis of this BV-typing to optimise the short- and long-term effects of treatment. Not all Lactobacillus spp. are helpful or protective and some may sequestrate metronidazole, which mitigates its therapeutic efficacy. Phages, used therapeutically, could contribute to eubiosis by sparing beneficial species of Lactobacilli. However, Lactobacilli have an important role in maintaining vaginal eubiosis, so conventional wisdom has been that treatment of BV may benefit from metronidazole that conserves lactobacilli rather than clindamycin, which destroys lactobacilli. Furthermore, if the quality and quantity of vaginal lactobacilli are compromised by phage colonisation, as in the sexually transmitted subtype, eradication of lactobacilli with clindamycin followed by replacement by probiotics may be better therapeutically than metronidazole and reduce recurrence rates. Accordingly, the subtype of BV may provide a more scientific approach to antibiotic selection, which is absent in current clinical guidelines. We provide support for the role of bacteriophages in the aetiology, recurrence or failure to cure BV following treatment, through parasitic colonisation of lactobacilli that may be sexually transmitted and may be enhanced by other risk factors like smoking, a factor associated with BV.

Identification, Biochemical Characterization, and Safety Attributes of Locally Isolated Lactobacillus fermentum from Bubalus bubalis (buffalo) Milk as a Probiotic

The demand of functional foods is on the rise, and researchers are trying to develop nutritious dairy products by using well-characterized strains of bacteria. In this study, we identified locally isolated strains of Lactobacillus fermentum from Bubalus bubalis (Nilli Ravi buffalo) milk and evaluated their potential as probiotics in food products like fermented milk. Fifteen Lactobacillus strains were initially isolated, and only four strains (NMCC-2, NMCC-14, NMCC-17, and NMCC-27) were examined for morphological and biochemical characterizations due to their ability of gas production in Durham tubes. Moreover, these strains were selected for further probiotic characterizations due to their extreme morphological resemblance with lactic acid bacteria for their antimicrobial activity, enzymatic potential, autoaggregation capability, hydrophobicity, and acid and bile tolerance. All selected isolates showed significant probiotic potential. However, NMCC-14 and NMCC-17 strains showed maximum probiotic potential. The isolates (NMCC-2, NMCC-14, NMCC-17, and NMCC-27) were identified as Lactobacillus fermentum utilizing 16S rRNA gene sequencing. The in vivo safety study of NMCC-14 (dose: 1010 CFU/day/mice; 21 days, orally) showed no histological dysfunctions in a mouse model. Pathogenic bacterial enzymes reduced the beneficial bacterial load in the host gastrointestinal tract. These results suggest that the NMCC-14 strain is safe and can be potentially used as a probiotic. Moreover, fermented milk was prepared by using the NMCC-14 strain. The results revealed that NMCC-14 strain-based fermented milk had significantly (p < 0.05) higher protein content (4.4 ± 0.06), water-holding capacity (WHC), and dynamic viscosity as compared to non-fermented milk. The results suggest that L. fermentum NMCC-14 is safe and nontoxic; hence, it can be a beneficial supplement to be used for the development of dairy products to be subjected to further clinical testing.

The Vaginal Microbiome: V. Therapeutic Modalities of Vaginal Microbiome Engineering and Research Challenges

OBJECTIVE

This series of articles, titled The Vaginal Microbiome (VMB), written on behalf of the International Society for the Study of Vulvovaginal Disease, aims to summarize the recent findings and understanding of the vaginal bacterial microbiota, mainly regarding areas relevant to clinicians specializing in vulvovaginal disorders.

MATERIALS AND METHODS

A search of PubMed database was performed, using the search terms "vaginal microbiome" with "treatment," "diagnosis," and "research." Full article texts were reviewed. Reference lists were screened for additional articles.

RESULTS

The currently available approaches for treating vaginitis or attempting to modulate the VMB are often insufficient. It has traditionally relied on the use of antibiotics, antiseptics, and antifungals. The fifth and last article of this series discusses the new and/or alternative therapeutic modalities. It addresses the role of probiotics, prebiotics and symbiotics, activated charcoal, biofilm disrupting agents, acidifying agents, phage therapy, and the concept of vaginal microbiome transplant. The challenges facing the research of VMB, including the clinical impact of microbiome manipulation, classification, and new diagnostic approaches are discussed.

CONCLUSIONS

Microbiome research has grown dramatically in recent years, motivated by innovations in technology and decrease in analysis costs. This research has yielded huge insight into the nature of microbial communities, their interactions, and effects with their hosts and other microbes. Further understanding of the bacterial, fungal, phage, and viral microbiomes in combination with host genetics, immunologic status, and environmental factors is needed to better understand and provide personalized medical diagnostics and interventions to improve women's health.

Effects of Pro/Prebiotics Alone over Pro/Prebiotics Combined with Conventional Antibiotic Therapy to Treat Bacterial Vaginosis: A Systematic Review

BACKGROUND

Bacterial vaginosis (BV), caused by an imbalance in the vaginal microbiota, can be treated and prevented by probiotics. Pregnant women with BV can experience premature labor and spontaneous abortions. Probiotics and prebiotics promote the proliferation of beneficial microorganisms, alter the composition of the vaginal microbiota, and prevent intravaginal infections in postmenopausal women. In addition to reducing infection symptoms, pre/probiotics can also help prevent vaginal infections.

MATERIALS AND METHODS

A systematic review was conducted on studies from 2010 to 2020 to determine the efficacy of pre/probiotics on the treatment of BV in pregnant and nonpregnant women. The databases Medline, Scopus, Embase, and Google Scholar were systematically searched using the following keywords: "bacterial vaginosis," "probiotics," "prebiotics," and "synbiotics."

RESULTS

A total of 1,871 articles were found in the initial search, and 24 clinical trials were considered eligible. In studies comparing the effects of pre/probiotics and placebos with or without antibiotic therapy in patients with BV, significant differences in clinical outcomes were observed. Probiotics reduced the levels of IL-1β and IL-6, as well as the overall Nugent score and Amsel's criteria for restitution of a balanced vaginal microbiota. In addition, probiotics can reduce the vaginal colonization of Group B streptococci among pregnant women. In subjects treated with probiotics, BV cure rates were higher than those in subjects treated with antibiotics. There were no additional adverse events.

CONCLUSION

Pre/probiotic regimens, when used for BV treatment, are usually safe and can exhibit long-term and short-term benefits. In order to prove the benefits of pre/probiotics in BV treatment, additional high-quality research is required.

Does probiotics work for bacterial vaginosis and vulvovaginal candidiasis

The different Lactobacillus strains of probiotics have been applied to the treatment and prevention of bacterial vaginosis and vulvovaginal candidiasis. The experimental data demonstrated that it works well via reducing the number of harmful bacteria, maintaining the acidic microenvironment, inhibiting the immune response, and so on, to restore the vaginal microecology. However, the clinical data indicated that it is not sufficient to support the use of probiotics in the intervention of vulvovaginal candidiasis rather than bacterial vaginosis. Hunting for novel probiotic strains and uncovering the precise mechanism of probiotics, especially with the new concept gut-vagina axis, to maintain the homeostasis of vaginal microbiota should be a great challenge in the future.

Probiotic Lacticaseibacillus rhamnosus GR-1 and Limosilactobacillus reuteri RC-14 as an Adjunctive Treatment for Bacterial Vaginosis Do Not Increase the Cure Rate in a Chinese Cohort: A Prospective, Parallel-Group, Randomized, Controlled Study

The purpose of this study was to evaluate the effectiveness of metronidazole and oral probiotics adjunct to metronidazole in the treatment of bacterial vaginosis (BV). One hundred and twenty-six Chinese women with BV were enrolled in this parallel, controlled trial, and were randomly assigned into two study arms: the metronidazole group, which was prescribed metronidazole vaginal suppositories for 7 days, and the adjunctive probiotic group, which received Lacticaseibacillus rhamnosus GR-1 and Limosilactobacillus reuteri RC-14 orally for 30 days as an adjunct to metronidazole. Clinical symptoms and Nugent scores at the initial visit, 30 days and 90 days were compared. There was no significant difference of the 30-day total cure rate between the adjunctive probiotic group (57.69%) and the metronidazole group (59.57%), with an odds ratio (OR) of 0.97 (95% confidence interval (CI), 0.70 to 1.35, p-value = 0.04), or of the 90-day total cure rate (36.54% vs. 48.94%, OR, 0.75; 95% CI, 0.47 to 1.19; p-value = 0.213). Also, no significant difference of the vaginal and faecal microbial diversity and structure between the two groups at 0, 30 or 90 days were shown based on 16S rRNA sequences. The probiotic species were rarely detected in either the vaginal microbiota or the faecal microbiota after administration which may revealed the cause of noneffective of oral probiotics. No serious adverse effects were reported in the trial. The study indicated that oral probiotic adjunctive treatment did not increase the cure rate of Chinese BV patients compared to metronidazole.

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.

Finding a Balance in the Vaginal Microbiome: How Do We Treat and Prevent the Occurrence of Bacterial Vaginosis?

Bacterial vaginosis (BV) has been reported in one-third of women worldwide at different life stages, due to the complex balance in the ecology of the vaginal microbiota. It is a common cause of abnormal vaginal discharge and is associated with other health issues. Since the first description of anaerobic microbes associated with BV like Gardnerella vaginalis in the 1950s, researchers have stepped up the game by incorporating advanced molecular tools to monitor and evaluate the extent of dysbiosis within the vaginal microbiome, particularly on how specific microbial population changes compared to a healthy state. Moreover, treatment failure and BV recurrence rate remain high despite the standard antibiotic treatment. Consequently, researchers have been probing into alternative or adjunct treatments, including probiotics or even vaginal microbiota transplants, to ensure successful treatment outcomes and reduce the colonization by pathogenic microbes of the female reproductive tract. The current review summarizes the latest findings in probiotics use for BV and explores the potential of vaginal microbiota transplants in restoring vaginal health.

Microbial mismanagement: how inadequate treatments for vaginal dysbiosis drive the HIV epidemic in women

Women and girls represent a key population driving new HIV infections and persistence of the HIV pandemic. A key determinant of HIV susceptibility is the composition of the vaginal microbiome, which can influence the local immune cell population, inflammation status, and HIV prevention drug levels. While a low-diversity composition dominated by Lactobacillus crispatus is associated with a decreased risk of HIV acquisition, high diversity environments associated with bacterial vaginosis increase risk of HIV. Given the important role of the vaginal microbiome in determining HIV susceptibility, altering the microbiome towards a Lactobacillus-dominated state is an attractive complementary strategy to reduce HIV incidence rates. Here, we provide an overview of the mechanisms by which the vaginal microbiome may contribute to HIV acquisition risk. Furthermore, we address the advantages and limitations of historical treatments and emerging technologies under investigation to modify the vaginal microbiome, including: antibiotics, bacteriophages, probiotics, topicals, and engineered bacteria. By addressing the current state of vaginal microbiome knowledge and strategies for manipulation, we hope to amplify the growing calls for increased resources and research into vaginal microbial health, which will be essential to accelerating preventative efforts amongst the world's most vulnerable populations.

Clinical research on traditional Chinese medicine treatment for bacterial vaginosis

Bacterial vaginosis (BV) is a common disease among women of reproductive age, with a serious impact on their daily life and health. At present, the most common treatment for BV is to take antibiotics, which results in good short-term treatment effects, but poor long-term effects. Traditional Chinese medicine (TCM) has been used to treat BV for over a millennium, with little risk of triggering drug resistance and adverse effects. Based on syndrome differentiation, there are three oral TCM treatment strategies for BV, including invigorating spleen, clearing dampness and heat, and nourishing kidney. The oral TCM prescriptions, such as Yi Huang decoction, Longdan Xiegan decoction, Zhibai Dihaung decoction, and so on are commonly used. Topical TCM treatment is also popular in China. According to the research results of pharmacological effects of active TCM ingredients, the most potential mechanisms of TCM for BV treatment are immune-enhancement effects, antibacterial activity, and estrogen-liked effects. Nonetheless, the multi-constituent of herbs may result in possible disadvantages to BV treatment, and the pharmacological mechanisms of TCM need further study. Here, we provide an overview of TCM compounds and their preparations used for BV, based on the pathogenesis and the potential therapeutic mechanisms, therefore providing a reference for further studies.

HIV susceptibility in women: The roles of genital inflammation, sexually transmitted infections and the genital microbiome

Given that heterosexual transmission of HIV across the genital mucosa is the most common route of infection in women, an in-depth understanding of the biological mechanisms associated with HIV risk in the female genital tract (FGT) is essential for effective control of the epidemic. Genital pro-inflammatory cytokines are well-described biological co-factors to HIV risk. Increased levels of pro-inflammatory cytokines in the FGT have been associated with a 3-fold higher-risk of acquiring HIV, presumably through involvement in barrier compromise and the recruitment of highly activated HIV target cells to the site of initial viral infection and replication. Sexually transmitted infections (STIs) and bacterial vaginosis (BV) are suggested possible contributors to genital inflammation in the FGT, and this, coupled with the relationship between genital inflammation and HIV risk, underscores the importance of effective treatment of STI and BV in the promotion of women's health. In most low- and middle-income countries, STIs are treated syndromically, a practice providing rapid treatment without identifying the infection source. However, this approach has been associated with over-diagnosis and the overuse of drugs. Further, because many women with STIs are asymptomatic, syndromic management also fails to treat a vast proportion of infected women. Although several studies have explored the role of STIs and the vaginal microbiome on genital inflammation and HIV risk, the impact of STI and BV management on genital inflammation remains poorly understood. This review aimed to collate the evidence on how BV and STI management efforts affect genital inflammation and the genital microbiome in women.

Feasibility and acceptability of frequent vaginal self-sampling at home by Rwandan women at high risk of urogenital tract infections

OBJECTIVES

To establish temporal links between vaginal microbiota (VMB) data and incident clinical events, frequent longitudinal vaginal sampling is required. Self-collection of swabs at the participant's home may be useful to avoid overburdening research clinics and participants. One-off vaginal self-sampling for STI or cervical cancer screening programmes has been shown to be feasible and acceptable to women in multiple studies, including in sub-Saharan Africa, but the feasibility and acceptability of frequent longitudinal vaginal sampling in the context of VMB sequencing studies is unknown.

METHODS

Twelve participants of a randomised clinical trial in Kigali, Rwanda, self-collected vaginal swabs three times a week for a month. We studied feasibility by comparing DNA concentrations, proportions of samples with >1000 16S rRNA amplicon sequencing reads and VMB composition outcomes of self-collected swabs with clinician-collected swabs. We evaluated the acceptability of self-collection using structured face-to-face interviews and a focus group discussion.

RESULTS

The participants collected vaginal swabs at 131 different time points. One woman stopped self-sampling after one try due to a social harm. All self-sampled swabs generated >1000 rRNA amplicon sequencing reads, and the DNA concentration of self-sampled swabs and clinician-sampled swabs did not differ significantly (Kruskal-Wallis p=0.484). Self-sampled and clinician-sampled swabs generated similar VMB composition data. Participants reported feeling very comfortable during self-sampling (11/12; 91.7%) and that self-sampling had become easier over time (12/12; 100%). They mentioned reduced travel time and travel costs as advantages of self-sampling at home.

CONCLUSIONS

Frequent longitudinal vaginal sampling at home is feasible and acceptable to participants, even in the context of a low-resource setting, as long as adequate counselling is provided.

TRIAL REGISTRATION NUMBER

NCT02459665.

Impact of vaginal microbiome communities on HIV antiretroviral-based pre-exposure prophylaxis (PrEP) drug metabolism

Despite the efficacy of antiretroviral-based pre-exposure prophylactics (PrEP) in men who have sex with men, studies in women have produced widely varying outcomes. Recent evidence demonstrates that vaginal microbial communities are associated with increased HIV acquisition risk and may impact PrEP efficacy. Here, we investigate the mechanisms underlying how vaginal bacteria alter PrEP drug levels and impact HIV infection rates ex vivo. Using cervicovaginal lavages (CVLs) from women with or without bacterial vaginosis (BV), we identified microbial metabolism of PrEP drugs in BV samples through LC-MS/MS analysis of soluble drug levels and metabolite formation in dual T-cell cultures. CVL samples were assessed for microbiome analysis using sequencing of bacterial 16S rRNA genes. We also observed non-Lactobacillus bacteria that are associated with BV may potentially impact PrEP efficacy through increased HIV infection rates in co-cultures containing Lactobacillus or BV bacteria, PrEP drugs, CEM-GFP cells, and HIV-1_LAI virus. Finally, we used these data to develop a novel predictive mathematical simulation modeling system to predict these drug interactions for future trials. These studies demonstrate how dysbiotic vaginal microbiota may impact PrEP drugs and provides evidence linking vaginal bacteria to PrEP efficacy in women.

HIV prevention strategies with antiretroviral drugs as pre-exposure prophylactics (PrEP) are not efficacious in women, in part due to biological factors such as the vaginal microbiome. Lactobacillus spp. prevent the colonization of dysbiotic bacteria (i.e. bacterial vaginosis), which is associated with increased HIV transmission. However, the role these microbes play in altering the pharmacokinetics of PrEP drugs is currently unknown. Here we show that primary bacteria from women with dysbiosis impact PrEP drug levels and kinetics. We found that dysbiotic microbes metabolize PrEP drugs faster than target cell uptake, and significantly alter HIV infection rates in vitro, and this can be predicted with novel computational modeling. Our results demonstrate that the vaginal microbiome may play a key role in HIV prevention through altering therapeutic drug levels via metabolism. Thus, better measurements and interventions for vaginal dysbiosis will be critical in improving the efficacy of HIV prevention efforts in women.

Vaginal microbiota and the potential of Lactobacillus derivatives in maintaining vaginal health

Human vagina is colonised by a diverse array of microorganisms that make up the normal microbiota and mycobiota. Lactobacillus is the most frequently isolated microorganism from the healthy human vagina, this includes Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus iners, and Lactobacillus jensenii. These vaginal lactobacilli have been touted to prevent invasion of pathogens by keeping their population in check. However, the disruption of vaginal ecosystem contributes to the overgrowth of pathogens which causes complicated vaginal infections such as bacterial vaginosis (BV), sexually transmitted infections (STIs), and vulvovaginal candidiasis (VVC). Predisposing factors such as menses, pregnancy, sexual practice, uncontrolled usage of antibiotics, and vaginal douching can alter the microbial community. Therefore, the composition of vaginal microbiota serves an important role in determining vagina health. Owing to their Generally Recognised as Safe (GRAS) status, lactobacilli have been widely utilised as one of the alternatives besides conventional antimicrobial treatment against vaginal pathogens for the prevention of chronic vaginitis and the restoration of vaginal ecosystem. In addition, the effectiveness of Lactobacillus as prophylaxis has also been well-founded in long-term administration. This review aimed to highlight the beneficial effects of lactobacilli derivatives (i.e. surface-active molecules) with anti-biofilm, antioxidant, pathogen-inhibition, and immunomodulation activities in developing remedies for vaginal infections. We also discuss the current challenges in the implementation of the use of lactobacilli derivatives in promotion of human health. In the current review, we intend to provide insights for the development of lactobacilli derivatives as a complementary or alternative medicine to conventional probiotic therapy in vaginal health.

The effect of probiotic supplementation during pregnancy on the interaction network of vaginal microbiome

AIM

To evaluate the effect of probiotic supplementation on the vaginal microbiome and provide the effective evidences for clinical management of pregnant women.

METHODS

A total of 28 healthy pregnant women at 32 weeks of gestation were enrolled. The women were divided randomly to the probiotic group where they were prescribed with 2 g combined probiotics daily (13 cases) during the third trimester of pregnancy or to the control group (15 cases) on a voluntary basis. Their vaginal samples were taken for analyzing microbiome with the 16S rDNA amplicon sequencing of V4 region.

RESULTS

There was no significant difference on the clinical characteristics between the probiotic and control groups. The complexity of vaginal microbial network increased from 32 weeks of gestation to antepartum. Lactobacillus was the dominant microbiota. The probiotic supplementation had no obvious influence on the structure of the vaginal microbiome, whereas the relationships of some pivotal vaginal microbiota at the genus level changed in the probiotic group.

CONCLUSION

The vaginal microbiome varied during the third trimester of pregnancy. The features of the vaginal microbiota after probiotic supplementation had shifted and the interaction network had the tendency to be loose. The probiotic supplementation may be useful in regulating the interaction network of vaginal microbiome.

Genital Micro-Organisms in Pregnancy

The microbiome of the female genital tract may undergo changes in pregnancy due to metabolic, endocrinological, and immunological alterations. These dysbiotic states may cause infections which may ascend upwards to the feto-placental unit or may be seeded hematogenously. These low grade and often low virulent infectious states lead to chronic inflammatory states and maybe associated with adverse maternal and neonatal outcome. Organisms have been isolated from amniotic fluid and placentae from women delivering pre-term; however the possibility of contamination cannot be conclusively ruled out. Common vaginal dysbiotic states often cause symptoms that are overlooked and often untreated. Vulvovaginal Candidiasis (VVC), Bacterial Vaginosis (BV), and Trichomonas Vaginitis (TV) are the commonly occurring dysbiotic states leading to vaginal infective states in pregnancy. With the advent of novel technologies like Next Generation sequencing (NGS), it will soon be possible to comprehensively map the vaginal microbiome and assess the interplay of each microbial state with their effects in pregnancy. This may open new avenues for antibiotic recommendations, probiotics and potential alternate therapies for dysbiotic states leading to pregnancy complications.

Vaginal probiotic adherence and acceptability in Rwandan women with high sexual risk participating in a pilot randomised controlled trial: a mixed-methods approach

OBJECTIVES

To evaluate adherence and acceptability of intermittent vaginal probiotic or antibiotic use to prevent bacterial vaginosis (BV) recurrence.

DESIGN

Repeated adherence and acceptability assessments using mixed methods within a pilot randomised controlled trial.

SETTING

Research clinic in Kigali, Rwanda.

PARTICIPANTS

Rwandan women with high sexual risk.

INTERVENTIONS

Women diagnosed with BV and/or trichomoniasis were randomised to four groups (n=17 each) after completing metronidazole treatment: behavioural counselling only, or behavioural counselling plus 2-month intermittent use of oral metronidazole, Ecologic Femi+ (EF+) vaginal capsule or Gynophilus LP (GynLP) vaginal tablet.

OUTCOME MEASURES

Adherence and acceptability were assessed by structured face-to-face interviews, semi-structured focus group discussions and in-depth interviews, daily diaries and counting of used/unused study products in randomised women (n=68). Vaginal infection knowledge was assessed by structured face-to-face interviews in randomised women and women attending recruitment sessions (n=131).

RESULTS

Most women (93%) were sex workers, 99.2% were unfamiliar with BV and none had ever used probiotics. All probiotic users (n=32) reported that insertion became easier over time. Triangulated adherence data showed that 17/17 EF+ users and 13/16 GynLP users used ≥80% of required doses (Fisher's exact p=0.103). Younger age (p=0.076), asking many questions at enrolment (p=0.116), having menses (p=0.104) and reporting urogenital symptoms (p=0.103) were non-significantly associated with lower perfect adherence. Women believed that the probiotics reduced BV recurrence, but reported that partners were sometimes unsupportive of study participation. Self-reported vaginal washing practices decreased during follow-up, but sexual risk behaviours did not. Most women (12/15) with an uncircumcised steady partner discussed penile hygiene with him, but many women found this difficult, especially with male clients.

CONCLUSIONS

High-risk women require education about vaginal infections. Vaginal probiotic acceptability and adherence were high in this cohort. Our results can be used to inform future product development and to fine-tune counselling messages in prevention programmes.

TRIAL REGISTRATION NUMBER

NCT02459665.

Randomized Trial of Lactin-V to Prevent Recurrence of Bacterial Vaginosis

BACKGROUND

Bacterial vaginosis affects 15 to 50% of women of reproductive age, and recurrence is common after treatment with an antibiotic agent. The high incidence of recurrence suggests the need for new treatments to prevent recurrent bacterial vaginosis.

METHODS

We conducted a randomized, double-blind, placebo-controlled, phase 2b trial to evaluate the ability of Lactobacillus crispatus CTV-05 (Lactin-V) to prevent the recurrence of bacterial vaginosis. Women 18 to 45 years of age who had received a diagnosis of bacterial vaginosis and who had completed a course of vaginal metronidazole gel as part of the eligibility requirements were randomly assigned, in a 2:1 ratio, to receive vaginally administered Lactin-V or placebo for 11 weeks; follow-up occurred through week 24. The primary outcome was the percentage of women who had a recurrence of bacterial vaginosis by week 12.

RESULTS

A total of 228 women underwent randomization: 152 to the Lactin-V group and 76 to the placebo group; of these participants, 88% in the Lactin-V group and 84% in the placebo group could be evaluated for the primary outcome. In the intention-to-treat population, recurrence of bacterial vaginosis by week 12 occurred in 46 participants (30%) in the Lactin-V group and in 34 participants (45%) in the placebo group (risk ratio after multiple imputation for missing responses, 0.66; 95% confidence interval [CI], 0.44 to 0.87; P = 0.01). The risk ratio for recurrence by week 24 (also calculated with multiple imputation for missing responses) was 0.73 (95% CI, 0.54 to 0.92). At the 12-week visit, L. crispatus CTV-05 was detected in 79% of participants in the Lactin-V group. The percentage of participants who had at least one adverse event related to Lactin-V or placebo by week 24 did not differ significantly between the groups. The percentage of participants with local or systemic adverse events was similar in the two groups.

CONCLUSIONS

The use of Lactin-V after treatment with vaginal metronidazole resulted in a significantly lower incidence of recurrence of bacterial vaginosis than placebo at 12 weeks. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT02766023.).

Pathobionts in the Vaginal Microbiota: Individual Participant Data Meta-Analysis of Three Sequencing Studies

Sequencing studies have shown that optimal vaginal microbiota (VMB) are lactobacilli-dominated and that anaerobes associated with bacterial vaginosis (BV-anaerobes) are commonly present. However, they overlooked a less prevalent but more pathogenic group of vaginal bacteria: the pathobionts that cause maternal and neonatal infections and pelvic inflammatory disease. We conducted an individual participant data meta-analysis of three VMB sequencing studies that included diverse groups of women in Rwanda, South Africa, and the Netherlands (2,044 samples from 1,163 women in total). We identified 40 pathobiont taxa but only six were non-minority taxa (at least 1% relative abundance in at least one sample) in all studies: Streptococcus (54% of pathobionts reads), Staphylococcus, Enterococcus, Escherichia/Shigella, Haemophilus, and Campylobacter. When all pathobionts were combined into one bacterial group, the VMB of 17% of women contained a relative abundance of at least 1%. We found a significant negative correlation between relative abundances (ρ = -0.9234), but not estimated concentrations (r = 0.0031), of lactobacilli and BV-anaerobes; and a significant positive correlation between estimated concentrations of pathobionts and BV-anaerobes (r = 0.1938) but not between pathobionts and lactobacilli (r = 0.0436; although lactobacilli declined non-significantly with increasing pathobionts proportions). VMB sequencing data were also classified into mutually exclusive VMB types. The overall mean bacterial load of the ≥20% pathobionts VMB type (5.85 log10 cells/μl) was similar to those of the three lactobacilli-dominated VMB types (means 5.13-5.83 log10 cells/μl) but lower than those of the four anaerobic dysbiosis VMB types (means 6.11-6.87 log10 cells/μl). These results suggest that pathobionts co-occur with both lactobacilli and BV-anaerobes and do not expand as much as BV-anaerobes do in a dysbiotic situation. Pathobionts detection/levels were increased in samples with a Nugent score of 4-6 in both studies that conducted Nugent-scoring. Having pathobionts was positively associated with young age, non-Dutch origin, hormonal contraceptive use, smoking, antibiotic use in the 14 days prior to sampling, HIV status, and the presence of sexually transmitted pathogens, in at least one but not all studies; inconsistently associated with sexual risk-taking and unusual vaginal discharge reporting; and not associated with vaginal yeasts detection by microscopy. We recommend that future VMB studies quantify common vaginal pathobiont genera.