Speaker Abstracts - S618



Articles

Targeting Perinatal Pathogens in the Vaginal Microbiome


Identification: Ratner, Adam

Credits: None available.

 
Targeting Perinatal Pathogens in the Vaginal Microbiome
 
Adam J. Ratner, MD, MPH
Departments of Pediatrics and Microbiology, New York University School of Medicine, USA
 
Asymptomatic mucosal colonization is an initial and crucial step in a wide range of bacterial diseases. For example, the perinatal pathogens Streptococcus agalactiae (Group B Streptococcus; GBS) and Escherichia coli can colonize maternal lower genital and gastrointestinal tract mucosal surfaces in late pregnancy. Peripartum transmission of these species may begin a series of events culminating in life-threatening early-onset (EO) neonatal sepsis. Current preventive strategies for EO sepsis involve either intrapartum antibiotic prophylaxis (IAP) for GBS-colonized mothers or, in investigational settings, vaccination against specific bacterial species. Despite the importance of maternal colonization to EO sepsis pathogenesis, interactions between GBS or E. coli and the vaginal or gastrointestinal microbiomes are not yet well understood. Investigations of the role of maternal microbiomes in establishment and maintenance of GBS or E. coli colonization, changes in microbiome composition in the presence or absence of these species, and the impact of IAP or vaccination targeting perinatal pathogens on maternal microbiome structure are warranted. A more detailed understanding of such factors may allow for the development of microbiome-targeted (or at least “microbiome-aware”) strategies to reduce the risk of EO sepsis and minimize off-target effects. I will discuss the potential benefits and challenges of this approach and describe studies directed at understanding the interplay between perinatal pathogens and host microbiomes.
 


The Oral Contraceptive Pill Favorably Influences the Vaginal Microbiota but Sexual Activity Drives BV Recurrence


Identification: Vodstrcil, Lenka

Credits: None available.

 

The Oral Contraceptive Pill Favorably Influences the Vaginal Microbiota but Sexual Activity Drives BV Recurrence
 
Vodstrcil LA1,2, Ratten, LK1, Plummer EL1, Fairley CK1, Murray G3, Garland SM3, Tachedjian G4, Law M5, Hocking JS2, Danielewski J3, Chow EPF1, Bradshaw CS1,2
1Central Clinical School, Monash University & Melbourne Sexual Health Centre, Alfred Health; 2School of Population & Global Health, University of Melbourne; 3Royal Women's Hospital; 4Burnet Institute; 5Kirby Institute, UNSW Australia
      
We conducted an open-label RCT of oral contraceptive pill (OCP)-use to determine if it reduced BV recurrence. Women with BV were prescribed first-line antibiotics, randomized to OCP or current non-hormonal contraception, and returned vaginal swabs and questionnaires monthly for 6mo or until BV-recurrence. Modified intention-to-treat methods were used to determine cumulative recurrence rates. Cox regression analyses, adjusted for randomization, assessed factors associated with recurrence in all women. Specimens (N=449) underwent vaginal microbiota (VM) analysis by 16s rRNA V3V4 gene sequencing. Recurrence rates did not differ in women randomized to the OCP (10/100PY,95%CI:6,19) compared to controls (14/100PY,95%CI:9,21). However, increased risk of recurrence was associated with sex with an ongoing regular sexual partner (RSP;AHR=3.09,95%CI:1.40,6.87). Baseline pre-treatment specimens had a Gardnerella vaginalis dominant or highly diverse VM, while post-treatment specimens had a low diversity Lactobacillus dominated VM. OCP-exposure was associated with lower VM diversity (adj Shannon co-eff=-0.55,95%CI:-0.75,-0.36). Women with OCP-exposure were more likely than women without OCP-exposure to have a VM dominated by L. crispatus (RRR=3.12,95%CI:1.24,7.81) or L. iners (RRR=4.40,95%CI:1.90,10.18) than G. vaginalis. Exposure to an RSP was associated with increased diversity (adj Shannon co-eff=0.26, 95%CI:0.034,0.48) and a higher abundance of G. vaginalis (AOR=1.86,95%CI:1.07,3.23). While this RCT of OCP-use did not improve BV cure it did increase the likelihood of a Lactobacillus dominant VM. Importantly, RSP exposure increased the likelihood of a highly diverse or G. vaginalis dominant microbiota, highlighting the contribution of reinfection to post-treatment recurrence. These data have important implications for the development of BV treatment and prevention strategies.
 
Funds: Monash University (CB); Early Career Research Grant, University of Melbourne (LV)

 


Study of In Vivo Biofilms of the Female Genital Tract


Identification: Verstraelen, Hans

Credits: None available.

Study of In Vivo Biofilms of the Female Genital Tract
 
Hans Verstraelen1, Alexander Swidsinski2
1Ghent University & Ghent University Hospital, Belgium; 2Charité - Universitätsmedizin Berlin, Germany
      
Next-generation sequencing has significantly advanced our knowledge of community assembly patterns of the vaginal microbiota. Sequencing per se does however not inform on community architecture or spatial distribution of bacterial communities relative to host mucosal surfaces. A notable example of the biological significance of spatial community organization is the biofilm mode, characterized by spatially organized aggregates of bacteria surrounded by a polymer matrix, allowing sessile growth on a given surface. It is well-established for various ecological niches, that the biofilm phenotype represents a unique structure-function relationship, with emergent properties that have a profound impact on community ecology. From a clinical perspective, major hallmarks of in vivo biofilms include their marked resistance to host defense mechanisms as well as to high concentrations of antimicrobial agents even over prolonged periods of time. For over a decade, we have aimed to visualize spatial community organization of various vaginal microbiota community states. We typically perform spatial mapping of the microbiota on vaginal biopsy specimens collected to this purpose, either on desquamated vaginal epithelial cells recovered from urine sediment samples, through fluorescence-in-situ-hybridization with oligonucleotide probes that target bacterial 16S and 23S rRNA genes. A central finding to our research is that that lactobacilli, when dominant, are primarily dispersed in the cervicovaginal fluid layer in an unstructured distribution, while in case of bacterial vaginosis, Gardnerella vaginalis, and to a lesser extent, Atopobium vaginae and other taxa, constitute highly structured biofilm communities that adhere in their entirety to the vaginal epithelium, from which they may disperse.
 
 
 
 
 
 
 
 
 


Vaginal probiotics: Results of a randomized pilot trial and systematic review


Identification: van de Wijgert, Janneke

Credits: None available.

Vaginal Probiotics: Results of a Randomized Pilot Trial and Systematic Review
 
Janneke H.H.M. van de Wijgert1,2, Marijn C. Verwijs1, on behalf of the Rwanda VMB trial group
1 Institute of Infection and Global Health, University of Liverpool, Liverpool, UK; 2 Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
 
Background: Bacterial vaginosis (BV) is associated with adverse outcomes, and recurrence rates after treatment are high. Many intervention trials have been conducted but few incorporated molecular endpoints.
Methods: HIV-negative non-pregnant high-risk Rwandan women were randomized to four groups (n=17 per group) after successful metronidazole treatment of BV or Trichomonas vaginalis (TV): behavioral counseling only (control group) or behavioral counseling plus intermittent use of oral metronidazole, or one of two vaginal probiotics, for two months. Vaginal microbiota (VMB) assessments at all visits included Nugent scoring (7-10 is BV) and 16S rRNA gene qPCR and HiSeq sequencing.
Results: No safety concerns were identified for any of the products. During the intervention period, metronidazole users compared to controls had significantly lower BV incidence (1.41/person-year at risk (PY) versus 10.18/PY), and higher mean Lactobacillus concentration and relative abundance, and were less likely to have a dysbiotic VMB type consisting of BV-anaerobes. The two vaginal probiotics also outperformed 'counseling only', albeit with lower effect sizes than metronidazole (e.g. BV incidence rates were 3.58/PY and 5.36/PY), with some but not all effects reaching statistical significance, likely due to limited statistical power. Hormonal contraceptive use/pregnancy, consistent condom use, and sampling around menses also affected VMB composition. Some product-related protective effects persisted after adjustment for these in mixed effects models.
Conclusions: All three interventions were promising. Unlike antibiotics, vaginal probiotics will not affect other microbiota niches or cause antimicrobial resistance. Our results will be compared with those of other trials, and recommendations will be made for next steps, including the incorporation of molecular endpoints in trials.
 
Funding: This work was funded by the DFID/MRC/Wellcome Trust Joint Global Health Trials Scheme as a Development Project (grant reference MR/M017443/1; grant title: “Preparing for a clinical trial of interventions to maintain normal vaginal microbiota for preventing adverse reproductive health outcomes in Africa”). Vaginal probiotics for use in the trial were donated by the manufacturers (details will be presented).


Metabolic Signatures of Bacterial Vaginosis


Identification: Srinivasan, Sujatha

Credits: None available.

 
Metabolic Signatures of Bacterial Vaginosis
 
Sujatha Srinivasan
Fred Hutchinson Cancer Research Center, Seattle, WA
 
The vaginal microbiome can impact the health of women, their sex partners, and their neonates. A hallmark of bacterial vaginosis (BV) is the transformation of the bacterial community from primarily Lactobacillus species to diverse anaerobes, with a corresponding change in the composition of small molecule metabolites in vaginal fluid. These metabolites impact at least three of four clinical criteria that are presently used to diagnose BV including elevated pH, presence of an amine odor, and detection of an abnormal vaginal discharge. Importantly, metabolites in the vagina reflect the complex enzymatic and metabolic pathways that drive bacterial metabolism of human derived nutrients, and these metabolites may influence human cell function, inflammation, and disease susceptibility. In this lecture, I will review recent investigations of vaginal fluid using untargeted metabolomics approaches that have identified hundreds of metabolites, and coupled these assessments with systematic characterization of the vaginal microbiota using broad-range 16S rRNA gene PCR and sequencing, or targeted measurements of vaginal bacteria using quantitative PCR. BV has been associated with strong metabolic signatures across multiple pathways affecting amino acid, carbohydrate, and lipid metabolism, and these metabolites have been correlated to bacterial communities and individual bacterial species. Longitudinal measurements of metabolites and bacterial species within the same participant have illustrated that changes in the microbiota are associated with shifts in metabolites, while stability of the microbiota is associated with fewer changes in metabolites, supporting the notion that metabolites in vaginal fluid are products of bacterial metabolism. We will further discuss how microbiome studies that integrate both taxonomic profiling and metabolomics help to disentangle underlying metabolic networks of bacterial communities in BV, thereby providing opportunities for the development of new diagnostic markers and novel approaches for the treatment or prevention of BV.
Funded by NIH R01 AI061628 and HG005816
 
 


The Relationship between Vaginal Microbiota Composition and Poor Pregnancy Outcomes


Identification: MacIntyre, David

Credits: None available.

The Relationship between Vaginal Microbiota Composition and Poor Pregnancy Outcomes
 
David MacIntyre1
1Institute of Reproductive and Developmental Biology, Imperial College London, UK
      
Acending vaginal infection has long been considered a major cause of poor pregnancy outcomes including infection-induced preterm birth. However, culture independent characterisation of vaginal microbiota has provided new understanding of relationships between composition and outcome.  For example, we have shown that dominance of the pregnancy vaginal microbiota by L. crispatus confers protection against preterm birth whereas highly diverse communities void in L. crispatus are a risk factor for preterm premature rupture of membranes and subsequent development of early onset neonatal sepsis. Recent findings from our group also indicate that specific interventions during pregnancy can negatively impact reproductive tract microbial composition and increase risk of poor outcomes for both mother and baby. Finally, I will describe some of our recent efforts to apply novel analytical methods for rapid assessment of microbiota-maternal host interactions that could be used in a clinical setting for patient stratification and targeted treatment strategies.
 


Role of Lactobacillus iners in the Vaginal Microbiota


Identification: Petrova, Mariya

Credits: None available.

 

Role of Lactobacillus iners in the Vaginal Microbiota
 
Mariya I. Petrova
KU Leuven, Belgium
      
The vaginal microbial community is typically characterized by abundant lactobacilli. Lactobacillus iners, a fairly recently detected species, is frequently present in the vaginal niche. However, the role of this species in vaginal health is unclear, since it can be identified in normal conditions as well as during vaginal dysbiosis, such as bacterial vaginosis, a condition characterized by an abnormal increase in bacterial diversity and lack of typical lactobacilli. Compared to other Lactobacillus species, L. iners has more complex nutritional requirements and a Gram-variable morphology. L. iners has an unusually small genome, indicative of a symbiotic or parasitic lifestyle, in contrast to other lactobacilli that show niche flexibility and genomes of up to 3-4 Mbp. The presence of specific L. iners genes, such as those encoding iron-sulfur proteins and unique σ-factors, reflects a high degree of niche specification. The genome of L. iners strains also encodes inerolysin, a pore-forming toxin related to vaginolysin of Gardnerella vaginalis. Possibly, this organism may have clonal variants that in some cases promote a healthy vagina, and in other cases are associated with dysbiosis and disease. Future research should examine the exact role of this species and its relationship with the host.
 

 


Interplay between genital immunity and microbiota, relevant to HIV risk


Identification: Passmore, Jo-Ann

Credits: None available.

Interplay Between Genital Immunity and Microbiota, Relevant to HIV Risk
 
Jo-Ann S. Passmore, PhD1,2,3,4
1Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa; 2CAPRISA Centres of Excellence, University of Cape Town, Cape Town, South Africa; 3SA MRC-UCT Gynaecological Cancer Research Centre, University of Cape Town, Cape Town, South Africa; 4National Health Laboratory Service, Cape Town, South Africa
 
Young people living in sub-Saharan Africa continue to be most severely afflicted by HIV, and understanding factors that influence high HIV risk in this region are critical. Since heterosexual transmission is the predominant mode of new infections, both genital inflammation and alterations in the microbiome are likely to be important underlying causes. This talk will summarize our current understanding by which genital inflammation increases HIV infection risks - by attracting HIV target cells into the vaginal mucosa, or by damaging the mucosal barrier in ways that facilitate HIV penetration, in the context of bacterial vaginosis (BV) and sexually transmitted infections that contribute to increased HIV acquisition risks. Knowledge of the major drivers of HIV risk should directly inform future HIV risk-mitigation interventions in Africa. None of the present approaches to manage STIs or treat BV have demonstrated long-term efficacy and most have focused exclusively on females, including the use of Lactobacilli-containing probiotics and antibiotics that target anaerobic bacteria (such as metronidazole). Whereas most of the probiotics that are used to promote vaginal health do not contain the most common vaginal Lactobacilli spp., antibiotics used to treat BV also kill beneficial anaerobes. Despite our inability to effectively manage BV, in the context of preventing HIV transmission, it is essential that future studies direct us towards novel methods to improve the vaginal health of women as well as mitigate HIV risk in men.
 
 


Microbiota of the Female Upper Genital Tract


Identification: Mitchell, Caroline

Credits: None available.

Microbiota of the Female Upper Genital Tract
 
Caroline Mitchell, MD, MPH
Assistant Professor, Harvard Medical School, Vincent Center for Reproductive Biology, Massachusetts General Hospital, Boston, MA, USA
 
While dogma in the field of Obstetrics & Gynecology has long asserted that the uterus is sterile, studies spanning five decades have demonstrated the presence of microbes in the upper genital tract of ostensibly healthy women.  Recent application of next-generation sequencing technology to upper genital tract samples has expanded the description of the upper tract microbial community, and has suggested links between upper tract microbiota and reproductive health outcomes ranging from pregnancy implantation to endometrial cancer.  This presentation will review what is known about the origin, composition, and stability of uterine and fallopian tube microbiota, will outline specific challenges associated with evaluation of these sites, and will discuss the potential impact of the upper tract microbiome on reproductive health outcomes.


Metaproteomics Approaches to Understand Mucosal Inflammation and Target Cell Activation Associated with HIV Acquisition in African Women


Identification: Masson, Lindi

Credits: None available.

Metaproteomics Approaches to Understand Mucosal Inflammation and Target Cell Activation Associated with HIV Acquisition in African Women 
 
Arghavan Alisoltanidehkordi1, Matthys Potgieter1, Liam Bell2, Elizabeth Waldron2, Smritee Dabee1, Arash Iranzadeh1, Zac McDonald2, Imane Allali1, Shaun Barnabas1, Heather Jaspan1,3, Nicola Mulder1, David Tabb4, Jonathan Blackburn1, Linda-Gail Bekker5, Jo-Ann Passmore1,6,7, Lindi Masson1,6
1Institute of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa; 2Centre for Proteomic and Genomic Research (CPGR), Cape Town, South Africa; 3Seattle Children's Research Institute, University of Washington, Seattle, Washington, USA; 4Division of Molecular Biology and Human Genetics, University of Stellenbosch, Cape Town, South Africa; 5Desmond Tutu HIV Foundation, Cape Town, South Africa; 6Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa; 7National Health Laboratory Service, South Africa
 
Young South African women are at exceptionally high risk of HIV infection. Genital inflammatory markers, which are associated with increased HIV acquisition risk, are elevated in younger women and may partly explain their vulnerability to infection. We aimed to improve our understanding of causes of genital inflammation in young South African women. Liquid chromatography tandem mass spectrometry was used to evaluate metaproteomic profiles in vaginal swabs collected at two time-points from 109 women (16-22 years) from Cape Town. Proteins were identified using MaxQuant and a custom database generated using de novo sequencing. Bacterial vaginosis (BV) was assessed by Nugent scoring. To define genital inflammation, cytokines were measured using Luminex and women were grouped using bi-clustering. A total of 3,589 proteins and 17,774 peptides were identified. Protein expression differed substantially between BV positive and negative women, and women with high versus low inflammation. Both microbial populations and functions differed significantly between women with high versus low inflammation. Up-regulated microbial proteins in women with inflammation included BV-associated bacteria (Gardnerella vaginalis, Prevotella, Megasphaera) and fungi. Lactobacillus crispatus and L. jensenii were most abundant in women with low inflammation and L. iners in women with medium inflammation. Over-represented pathways associated with inflammation included chronic antigenic inflammatory response and alpha-beta T cell differentiation, while cell-cell junction organisation and epithelial barrier development were under-represented. In summary, both presence and function of bacteria and fungi were associated with genital inflammation, which may increase susceptibility to HIV infection by increasing HIV target cells and impairing epithelial barrier function.