New Techniques to characterise the vaginal microbiome in pregnancy (original) (raw)

The vaginal microbiota during pregnancy

Records of Pharmaceutical and Biomedical Sciences

Fetal development is considered to occur inside the microbiotafree intrauterine environment. Depending on recently published data resources, it is anticipated that the neonatal microbiome is established primarily throughout the amniotic membrane rupture, with extra microbiota introduced by the passage of he t fetus through the vaginal birth canal. Upon delivery, the neonate has been familiarized with the maternal microbiota of the vaginal ecosystem. Since the fetus is introduced to numerous bacterial environments during the early neonatal interval such as the vaginal canal, skin, and rectum, it is important to describe the potential influence of the maternal vaginal microbial community on neonates. Dynamic changes in the vaginal microbiome during the pregnancy including decreased vaginal diversity and Lactobacillus-dominance contribute to diminished risk of preterm birth as well as other adverse pregnancy outcomes. This minireview summarizes the composition of the vaginal microbiota during normal pregnancy as revealed by culture-independent highthroughput sequencing-based techniques such as 16S rRNA nextgeneration sequencing and metagenomic shotgun sequencing techniques.

A metagenomic approach to characterization of the vaginal microbiome signature in pregnancy

2012

While current major national research efforts (i.e., the NIH Human Microbiome Project) will enable comprehensive metagenomic characterization of the adult human microbiota, how and when these diverse microbial communities take up residence in the host and during reproductive life are unexplored at a population level. Because microbial abundance and diversity might differ in pregnancy, we sought to generate comparative metagenomic signatures across gestational age strata. DNA was isolated from the vagina (introitus, posterior fornix, midvagina) and the V5V3 region of bacterial 16S rRNA genes were sequenced (454FLX Titanium platform). Sixty-eight samples from 24 healthy gravidae (18 to 40 confirmed weeks) were compared with 301 non-pregnant controls (60 subjects). Generated sequence data were quality filtered, taxonomically binned, normalized, and organized by phylogeny and into operational taxonomic units (OTU); principal coordinates analysis (PCoA) of the resultant beta diversity measures were used for visualization and analysis in association with sample clinical metadata. Altogether, 1.4 gigabytes of data containing .2.5 million reads (averaging 6,837 sequences/ sample of 493 nt in length) were generated for computational analyses. Although gravidae were not excluded by virtue of a posterior fornix pH .4.5 at the time of screening, unique vaginal microbiome signature encompassing several specific OTUs and higher-level clades was nevertheless observed and confirmed using a combination of phylogenetic, nonphylogenetic, supervised, and unsupervised approaches. Both overall diversity and richness were reduced in pregnancy, with dominance of Lactobacillus species (L. iners crispatus, jensenii and johnsonii, and the orders Lactobacillales (and Lactobacillaceae family), Clostridiales, Bacteroidales, and Actinomycetales. This intergroup comparison using rigorous standardized sampling protocols and analytical methodologies provides robust initial evidence that the vaginal microbial 16S rRNA gene catalogue uniquely differs in pregnancy, with variance of taxa across vaginal subsite and gestational age.

Methods of investigation of human microbiome in obstetrics and gynecology

Romanian Biotechnological Letters, 2019

Microbiota of the vaginal epithelium undergoes significant changes associated with hormonal status, each change being characterized by a specific prevalence of Lactobacillus species. Because the vaginal microbiome varies, a systemic analysis of its metagenomics combined with integrated multi'omics, will help to determine the microbial profile (including the uncultured microorganisms) associated with normal and pathological conditions. A plethora of bacterial species with proinflammatory characteristics can induce vaginosis, preterm birth and other adverse outcomes in pregnancy. In order to improve health by manipulating the microbiome, all the factors involved in its plasticity have to be known. New technologies allow to examine the microbiome, highlighting the interaction between its components and the host epithelium. Data brought by next generation sequencing technique will open new perspectives on the role of microorganisms in the pathology of the female genital tract, in association with host genetic factors and different physiological conditions.

The vaginal microbiome during pregnancy and the postpartum period in a European population

Scientific reports, 2015

The composition and structure of the pregnancy vaginal microbiome may influence susceptibility to adverse pregnancy outcomes. Studies on the pregnant vaginal microbiome have largely been limited to Northern American populations. Using MiSeq sequencing of 16S rRNA gene amplicons, we characterised the vaginal microbiota of a mixed British cohort of women (n = 42) who experienced uncomplicated term delivery and who were sampled longitudinally throughout pregnancy (8-12, 20-22, 28-30 and 34-36 weeks gestation) and 6 weeks postpartum. We show that vaginal microbiome composition dramatically changes postpartum to become less Lactobacillus spp. dominant with increased alpha-diversity irrespective of the community structure during pregnancy and independent of ethnicity. While the pregnancy vaginal microbiome was characteristically dominated by Lactobacillus spp. and low alpha-diversity, unlike Northern American populations, a significant number of pregnant women this British population had ...

Racioethnic diversity in the dynamics of the vaginal microbiome during pregnancy

Nature Medicine

rowing evidence suggests that the impact of the vaginal microbiome extends to the health of pregnant women and their neonates in utero and beyond. The vaginal microbiome consists of a finite number of discrete microbial communities dominated by different bacterial taxa or combinations thereof 1,2. A vaginal microbiome with microbial communities dominated by species of Lactobacillus has been associated with adverse conditions of health of the female reproductive tract, whereas a microbiome dominated by complex microbial communities of Gardnerella, Atopobium, Dialister, Peptoniphilus, Lachnospiraceae members (bacterial vaginosis (BV)-associated bacterium 1 (BVAB1)) and other anaerobes 3-5 has been associated with a higher risk. A complex vaginal microbiome is associated with BV, the most common gynecological condition of women of reproductive age 6 , as well as a higher risk of sexually transmitted infection, pelvic inflammatory disease and adverse pregnancy outcomes including preterm birth (PTB) 3,5,7. More than 10% of neonates in the United States are delivered preterm (<37 weeks' gestation), and certain racial and ethnic groups have even higher rates 8-10. Women of African ancestry in the United States are significantly more likely than women of European ancestry to have a premature birth or experience very preterm delivery (<32 weeks' gestation). This health disparity could be due to differences in the vaginal microbiomes of these women as the population attributable risk of BV for spontaneous PTB at <32 weeks' gestation has been estimated to be ~40% 11. Although environmental factors, including socioeconomic status (for example, household income, access to care and so on) are known to contribute to these differences, genetic factors also play a role 12-14. Recent studies 1,2,15-23 show that the vaginal microbiomes of women of African ancestry are less likely to be dominated by species of Lactobacillus, and more likely to comprise primarily Gardnerella vaginalis, Atopobium vaginae, Sneathia amnii, BVAB1 and other anaerobes. Independent of the

Influence of Pregnancy History on the Vaginal Microbiome of Pregnant Women in their First Trimester

Scientific Reports

Pregnancy permanently alters maternal anatomy, physiology and immunity. We evaluated if the vaginal microbiome differed between women with a first or subsequent conception. Relative abundance of bacteria in the vaginal microbiome in first trimester pregnant women, 52 with their first known conception, 26 with a prior spontaneous or induced abortion but no deliveries and 77 with at least one prior birth, was determined by classifying DNA sequences from the V1-V3 region of bacterial 16 S rRNA genes. Lactobacillus crispatus was the numerically most abundant bacterium in 76.4% of women with a first conception, 50.0% with only a prior spontaneous or scheduled abortion and 22.2% with a prior birth (p ≤ 0.01). L. iners was the most abundant bacterium in 3.8% of women with a first conception as compared to 19.2% (p = 0.03) and 20.8% (p = 0.03) in those with a prior abortion or birth, respectively. Gardnerella as the most abundant bacterial genus increased from 3.8% in women with a first conception to 15.4% and 14.3% in those with a prior abortion or birth, respectively (p > 0.05). L. iners dominance was also associated with a history of spontaneous abortion (p ≤ 0.02). The composition of the vaginal microbiome and its influence on pregnancy outcome varies with pregnancy history.

Vaginal microbiota in pregnancy: Role in induction of labor and seeding the neonate’s microbiota?

Journal of Biosciences, 2019

Compared to other human microbiota, vaginal microbiota is fairly simple with low bacterial diversity and high relative abundance of Lactobacillus species. Lactobacillus dominance is even more pronounced during pregnancy. Genetic factors, such as ethnicity, along with environmental, individual and lifestyle factors all have an impact on vaginal microbiota composition. The composition of the vaginal microbiota appears to play an important role in pregnancy as recent studies have linked it to adverse obstetric outcomes such as preterm birth, a leading cause of neonatal morbidity and mortality worldwide. However, the same vaginal microbiota does not seem to cause the same response in all women, calling for future research to fully understand the complex host-microbiota interplay in normal and complicated pregnancies.