Enhanced Trapping of HIV-1 by Human Cervicovaginal Mucus Is Associated with Lactobacillus crispatus-Dominant Microbiota

ABSTRACTCervicovaginal mucus (CVM) can provide a barrier that precludes HIV and other sexually transmitted virions from reaching target cells in the vaginal epithelium, thereby preventing or reducing infections. However, the barrier properties of CVM differ from woman to woman, and the causes of these variations are not yet well understood. Using high-resolution particle tracking of fluorescent HIV-1 pseudoviruses, we found that neither pH nor Nugent scores nor total lactic acid levels correlated significantly with virus trapping in unmodified CVM from diverse donors. Surprisingly, HIV-1 was generally trapped in CVM with relatively high concentrations ofd-lactic acid and aLactobacillus crispatus-dominant microbiota. In contrast, a substantial fraction of HIV-1 virions diffused rapidly through CVM with low concentrations ofd-lactic acid that had aLactobacillus iners-dominant microbiota or significant amounts ofGardnerella vaginalis, a bacterium associated with bacterial vaginosis. Our results demonstrate that the vaginal microbiota, including specific species ofLactobacillus, can alter the diffusional barrier properties of CVM against HIV and likely other sexually transmitted viruses and that these microbiota-associated changes may account in part for the elevated risks of HIV acquisition linked to bacterial vaginosis or intermediate vaginal microbiota.IMPORTANCEVariations in the vaginal microbiota, especially shifts away fromLactobacillus-dominant microbiota, are associated with differential risks of acquiring HIV or other sexually transmitted infections. However, emerging evidence suggests thatLactobacillus inersfrequently colonizes women with recurring bacterial vaginosis, raising the possibility thatL. inersmay not be as protective as otherLactobacillusspecies. Our study was designed to improve understanding of how the cervicovaginal mucus barrier against HIV may vary between women along with the vaginal microbiota and led to the finding that the vaginal microbiota, including specific species ofLactobacillus, can directly alter the diffusional barrier properties of cervicovaginal mucus. This work advances our understanding of the complex barrier properties of mucus and highlights the differential protective ability of different species ofLactobacillus, withLactobacillus crispatusand possibly other species playing a key role in protection against HIV and other sexually transmitted infections. These findings could lead to the development of novel strategies to protect women against HIV.

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Efficacy of Rifaximin Vaginal Tablets in Treatment of Bacterial Vaginosis: a Molecular Characterization of the Vaginal Microbiota

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00061-12 ◽

2012 ◽

Vol 56 (8) ◽

pp. 4062-4070 ◽

Cited By ~ 21

Author(s):

Federica Cruciani ◽

Patrizia Brigidi ◽

Fiorella Calanni ◽

Vittoria Lauro ◽

Raffaella Tacchi ◽

...

Keyword(s):

Bacterial Vaginosis ◽

Denaturing Gradient Gel Electrophoresis ◽

Vaginal Microbiota ◽

Controlled Study ◽

Double Blind ◽

Content Type ◽

Sexually Transmitted ◽

Gradient Gel Electrophoresis ◽

Adverse Pregnancy ◽

The Impact

ABSTRACTBacterial vaginosis (BV) is a common vaginal disorder characterized by an alteration of the vaginal bacterial morphotypes, associated with sexually transmitted infections and adverse pregnancy outcomes. The purpose of the present study was to evaluate the impact of different doses of rifaximin vaginal tablets (100 mg/day for 5 days, 25 mg/day for 5 days, and 100 mg/day for 2 days) on the vaginal microbiota of 102 European patients with BV enrolled in a multicenter, double-blind, randomized, placebo-controlled study. An integrated molecular approach based on quantitative PCR (qPCR) and PCR-denaturing gradient gel electrophoresis (PCR-DGGE) was used to investigate the effects of vaginal tablets containing the antibiotic. An increase in members of the genusLactobacillusand a decrease in the BV-related bacterial groups after the antibiotic treatment were demonstrated by qPCR. PCR-DGGE profiles confirmed the capability of rifaximin to modulate the composition of the vaginal microbial communities and to reduce their complexity. This molecular analysis supported the clinical observation that rifaximin at 25 mg/day for 5 days represents an effective treatment to be used in future pivotal studies for the treatment of BV.

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Detection of Fastidious Vaginal Bacteria in Women with HIV Infection and Bacterial Vaginosis

Infectious Diseases in Obstetrics and Gynecology ◽

10.1155/2009/236919 ◽

2009 ◽

Vol 2009 ◽

pp. 1-6 ◽

Cited By ~ 16

Author(s):

Caroline Mitchell ◽

Carla Moreira ◽

David Fredricks ◽

Kathleen Paul ◽

Angela M. Caliendo ◽

...

Keyword(s):

Hiv Infection ◽

Bacterial Vaginosis ◽

Quantitative Pcr ◽

Vaginal Microbiota ◽

Lactobacillus Crispatus ◽

Vaginal Ph ◽

Pcr Assays ◽

Women With Hiv ◽

Cervicovaginal Lavage ◽

Hiv 1

Background. Fastidious bacteria have been associated with bacterial vaginosis (BV) using PCR methods. We assessed the prevalence of these bacteria in HIV-1 infected women and their relationship with vaginal pH and shedding of HIV-1 RNA.Methods. 64 cervicovaginal lavage (CVL) samples were collected from 51 women. Vaginal microbiota were characterized using 8 bacterium-specific quantitative PCR assays.Results. Women with the fastidious bacteria Bacterial Vaginosis Associated Bacterium (BVAB) 1, 2, and 3 showed a trend to increased HIV-1 shedding (OR 2.59–3.07,P=.14–.17). Absence ofLactobacillus crispatus(P<.005) and presence of BVAB2 (P<.001) were associated with elevated vaginal pH. BVAB1, 2, and 3 were highly specific indicators of BV in HIV-infected women, with specificities of 89%–93%.Conclusions. Fastidious bacteria (BVAB 1, 2, and 3) remain specific indicators of BV in HIV-infected women, and BVAB2 may contribute to the elevated vaginal pH that is a hallmark of this syndrome.

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Effect of metronidazole on vaginal microbiota associated with asymptomatic bacterial vaginosis

Access Microbiology ◽

10.1099/acmi.0.000226 ◽

2021 ◽

Vol 3 (5) ◽

Author(s):

Daniel Ruiz-Perez ◽

Makella S. Coudray ◽

Brett Colbert ◽

Karl Krupp ◽

Hansi Kumari ◽

...

Keyword(s):

Bacterial Vaginosis ◽

Anaerobic Bacteria ◽

Vaginal Microbiota ◽

Effective Treatment Option ◽

Content Type ◽

Sexually Transmitted ◽

Link Type ◽

Increased Risk ◽

Oral Metronidazole

Vaginal dysbiosis-induced by an overgrowth of anaerobic bacteria is referred to as bacterial vaginosis (BV). The dysbiosis is associated with an increased risk for acquisition of sexually transmitted infections. Women with symptomatic BV are treated with oral metronidazole (MET), but its effectiveness remains to be elucidated. This study used whole-genome sequencing (WGS) to determine the changes in the microbiota among women treated with MET. WGS was conducted on DNA obtained from 20 vaginal swabs collected at four time points over 12 months from five randomly selected African American (AA) women. The baseline visit included all women who were diagnosed with asymptomatic BV and were untreated. All subjects were tested subsequently once every 2 months and received a course of MET for each BV episode during the 12 months. The BV status was classified according to Nugent scores (NSs) of vaginal smears. The microbial and resistome profiles were analysed along with the sociodemographic metadata. Despite treatment, none of the five participants reverted to normal vaginal flora — two were consistently positive for BV, and the rest experienced episodic cases of BV. WGS analyses showed Gardnerella spp. as the most abundant organism. After treatment with MET, there was an observed decline of Lactobacillus and Prevotella species. One participant had a healthy vaginal microbiota based on NS at one follow-up time point. Resistance genes including tetM and lscA were detected. Though limited in subjects, this study shows specific microbiota changes with treatment, presence of many resistant genes in their microbiota, and recurrence and persistence of BV despite MET treatment. Thus, MET may not be an effective treatment option for asymptomatic BV, and whole metagenome sequence would better inform the choice of antibiotics.

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HIV Inhibition by Lactobacilli: Easier in a Test Tube Than in Real Life

mBio ◽

10.1128/mbio.01485-15 ◽

2015 ◽

Vol 6 (5) ◽

Cited By ~ 6

Author(s):

Steven S. Witkin ◽

Iara M. Linhares

Keyword(s):

Lactic Acid ◽

Hiv Transmission ◽

Real Life ◽

Test Tube ◽

Vaginal Microbiota ◽

Carboxyl Groups ◽

Content Type ◽

Relative Inability ◽

Cervicovaginal Mucus

ABSTRACT A lactobacillus-dominant vaginal microbiota has been shown to decrease heterosexual HIV transmission. Nunn et al. now report that a vaginal microbiota dominated by Lactobacillus crispatus is associated with a relative inability of HIV pseudoviral particles to transverse cervicovaginal mucus (CVM) in vitro [mBio 6(5):e01084-15, 2015, doi:10.1128/mBio.01084-15]. The purported inhibitory mechanism is the interaction between carboxyl groups present on HIV and in CVM that occurred only under acidic conditions when carboxyl groups were protonated. L. crispatus produces high levels of lactic acid and results in the lowest vaginal pH when it is the dominant vaginal bacterium. In addition, high levels of lactic acid inhibit the proliferation of other bacteria that might negatively affect CVM structure. The utility of enhancing L. crispatus dominance to inhibit HIV transmission awaits assessment of the influence of ejaculated semen on this property and investigations on the role of Lactobacillus products such as d-lactic acid in this property.

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The cervicovaginal mucus barrier to HIV-1 is diminished in bacterial vaginosis

PLoS Pathogens ◽

10.1371/journal.ppat.1008236 ◽

2020 ◽

Vol 16 (1) ◽

pp. e1008236 ◽

Cited By ~ 8

Author(s):

Thuy Hoang ◽

Emily Toler ◽

Kevin DeLong ◽

Nomfuneko A. Mafunda ◽

Seth M. Bloom ◽

...

Keyword(s):

Bacterial Vaginosis ◽

Mucus Barrier ◽

Cervicovaginal Mucus ◽

Hiv 1

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Comparative Genome Analyses of Lactobacillus crispatus Isolates from Different Ecological Niches Reveal an Adaptation of This Species to the Human Vaginal Environment

Applied and Environmental Microbiology ◽

10.1128/aem.02899-20 ◽

2021 ◽

Vol 87 (8) ◽

Cited By ~ 1

Author(s):

Leonardo Mancabelli ◽

Walter Mancino ◽

Gabriele Andrea Lugli ◽

Christian Milani ◽

Alice Viappiani ◽

...

Keyword(s):

Pathogenic Bacteria ◽

Vaginal Microbiota ◽

Microbial Consortia ◽

Microbial Composition ◽

Vaginal Infections ◽

Shotgun Metagenomics ◽

Content Type ◽

Lactobacillus Crispatus ◽

Vaginal Tract

ABSTRACT The vaginal microbiota is defined as the community of bacteria residing in the human vaginal tract. Recent studies have demonstrated that the vaginal microbiota is dominated by members of the Lactobacillus genus, whose relative abundance and microbial taxon composition are dependent on the healthy status of this human body site. Particularly, among members of this genus, the high prevalence of Lactobacillus crispatus is commonly associated with a healthy vaginal environment. In the current study, we assessed the microbial composition of 94 healthy vaginal microbiome samples through shotgun metagenomics analyses. Based on our results, we observed that L. crispatus was the most representative species and correlated negatively with bacteria involved in vaginal infections. Therefore, we isolated 15 L. crispatus strains from different environments in which this species abounds, ranging from vaginal swabs of healthy women to chicken fecal samples. The genomes of these strains were decoded and their genetic content was analyzed and correlated with their physiological features. An extensive comparative genomic analysis encompassing all publicly available genome sequences of L. crispatus and combined with those decoded in this study revealed a genetic adaptation of strains to their respective ecological niche. In addition, in vitro growth experiments involving all isolated L. crispatus strains, together with a synthetic vaginal microbiota, reveal how this species is able to modulate the composition of the vaginal microbial consortia at the strain level. Overall, our findings suggest that L. crispatus plays an important ecological role in reducing the complexity of the vaginal microbiota by depleting pathogenic bacteria. IMPORTANCE The vaginal microbiota is defined as the community of bacteria residing in the human vaginal tract. Recent studies have demonstrated that the high prevalence of Lactobacillus crispatus strains is commonly associated with a healthy vaginal environment. In the current study, we assessed the microbial composition of 94 public healthy vaginal samples through shotgun metagenomics analyses. Results showed that L. crispatus was the most representative species and correlated negatively with bacteria involved in vaginal infections. Moreover, we isolated and sequenced the genomes of new L. crispatus strains from different environments, and the comparative genomics analysis revealed a genetic adaptation of strains to their ecological niche. In addition, in vitro growth experiments display the capability of this species to modulate the composition of the vaginal microbial consortia. Overall, our findings suggest an ecological role exploited by L. crispatus in reducing the complexity of the vaginal microbiota toward a depletion of pathogenic bacteria.

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Lactic acid-containing products for bacterial vaginosis and their impact on the vaginal microbiota: A systematic review

PLoS ONE ◽

10.1371/journal.pone.0246953 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0246953 ◽

Cited By ~ 1

Author(s):

Erica L. Plummer ◽

Catriona S. Bradshaw ◽

Michelle Doyle ◽

Christopher K. Fairley ◽

Gerald L. Murray ◽

...

Keyword(s):

Systematic Review ◽

Lactic Acid ◽

Bacterial Vaginosis ◽

Vaginal Microbiota ◽

Diagnostic Methods ◽

Control Group ◽

Microbiota Composition ◽

Randomised Trials ◽

High Quality Evidence ◽

Study Results

Objective The vaginal microbiota in bacterial vaginosis (BV) typically has low abundance of lactic acid producing lactobacilli. Lactic acid has properties that may make it effective for treating BV and/or restoring an optimal lactobacillus-dominated vaginal microbiota. We conducted a systematic review to describe the effect of intravaginal lactic acid-containing products on BV cure, and their impact on vaginal microbiota composition (PROSPERO registration: CRD42018115982). Methods PubMed, Embase and OVID were searched from inception to November 2019 to identify eligible studies. Included studies evaluated an intravaginal lactic acid-containing product and reported BV cure using established diagnostic methods, and/or vaginal microbiota composition using molecular methods. Studies were independently screened and assessed, and the proportion of women cured post-treatment was calculated. Study results were described in a qualitative manner. Results We identified 1,883 articles and assessed 57 full-texts for eligibility. Seven different lactic acid-containing products were evaluated and differed with respect to excipients, lactic acid concentration and pH. Most studies had medium or high risk of bias. Three trials compared the efficacy of a lactic acid-containing product to metronidazole for BV cure. One study found lactic acid to be equivalent to metronidazole and two studies found lactic acid to be significantly inferior to metronidazole. Two studies included a control group receiving a placebo or no treatment. One reported lactic acid to be superior than no treatment and the other reported lactic acid to be equivalent to placebo. Lactic acid-containing products did not significantly impact the vaginal microbiota composition. Conclusion There is a lack of high-quality evidence to support the use of lactic acid-containing products for BV cure or vaginal microbiota modulation. However, adequately powered and rigorous randomised trials with accompanying vaginal microbiota data are needed to evaluate the efficacy of lactic acid as a BV treatment strategy.

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Antimicrobial and immune modulatory effects of lactic acid and short chain fatty acids produced by vaginal microbiota associated with eubiosis and bacterial vaginosis

Frontiers in Physiology ◽

10.3389/fphys.2015.00164 ◽

2015 ◽

Vol 6 ◽

Cited By ~ 94

Author(s):

Muriel Aldunate ◽

Daniela Srbinovski ◽

Anna C. Hearps ◽

Catherine F. Latham ◽

Paul A. Ramsland ◽

...

Keyword(s):

Fatty Acids ◽

Lactic Acid ◽

Bacterial Vaginosis ◽

Short Chain Fatty Acids ◽

Vaginal Microbiota ◽

Short Chain ◽

Chain Fatty Acids

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Metatranscriptome Analysis of the Vaginal Microbiota Reveals Potential Mechanisms for Protection against Metronidazole in Bacterial Vaginosis

mSphere ◽

10.1128/mspheredirect.00262-18 ◽

2018 ◽

Vol 3 (3) ◽

Cited By ~ 22

Author(s):

Zhi-Luo Deng ◽

Cornelia Gottschick ◽

Sabin Bhuju ◽

Clarissa Masur ◽

Christoph Abels ◽

...

Keyword(s):

Antibiotic Therapy ◽

Bacterial Vaginosis ◽

Bactericidal Effect ◽

Vaginal Microbiota ◽

Gardnerella Vaginalis ◽

Vaginal Fluid ◽

Content Type ◽

Production Of Hydrogen ◽

Cas Genes

ABSTRACT Bacterial vaginosis (BV) is a prevalent multifactorial disease of women in their reproductive years characterized by a shift from the Lactobacillus species-dominated microbial community toward a taxonomically diverse anaerobic community. For unknown reasons, some women do not respond to therapy. In our recent clinical study, among 37 women diagnosed with BV, 31 were successfully treated with metronidazole, while 6 still had BV after treatment. To discover possible reasons for the lack of response in those patients, we performed a metatranscriptome analysis of their vaginal microbiota, comparing them to the patients who responded. Seven of 8 clustered regularly interspaced short palindromic repeat (CRISPR)-associated (Cas) genes of Gardnerella vaginalis were highly upregulated in nonresponding patients. Cas genes, in addition to protecting against phages, might be involved in DNA repair, thus mitigating the bactericidal effect of DNA-damaging agents such as metronidazole. In the second part of our study, we analyzed the vaginal metatranscriptomes of four patients over 3 months and showed high in vivo expression of genes for pore-forming toxins in L. iners and of genes encoding enzymes for the production of hydrogen peroxide and d-lactate in L. crispatus. IMPORTANCE Bacterial vaginosis is a serious issue for women in their reproductive years. Although it can usually be cured by antibiotics, the recurrence rate is very high, and some women do not respond to antibiotic therapy. The reasons for that are not known. Therefore, we undertook a study to detect the activity of the complete microbiota in the vaginal fluid of women who responded to antibiotic therapy and compared it to the activity of the microbiota in women who did not respond. We found that one of the most important pathogens in bacterial vaginosis, Gardnerella vaginalis, has activated genes that can repair the DNA damage caused by the antibiotic in those women that do not respond to therapy. Suppressing these genes might be a possibility to improve the antibiotic therapy of bacterial vaginosis.

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