Inferring stability and persistence in the vaginal microbiome: A stochastic model of ecological dynamics.

The interplay of stochastic and ecological processes that govern the establishment and persistence of host-associated microbial communities is not well understood. Here we illustrate the conceptual and practical advantages of fitting stochastic population dynamics models to multi-species bacterial time series data. We show how the stability properties, fluctuation regimes and persistence probabilities of human vaginal microbial communities can be better understood by explicitly accommodating three sources of variability in ecological stochastic models of multi-species abundances: 1) stochastic biotic and abiotic forces, 2) ecological feedback and 3) sampling error.

Inferring stability and persistence in the vaginal microbiome: A stochastic model of ecological dynamics.

The interplay of stochastic and ecological processes that govern the establishment and persistence of host-associated microbial communities is not well understood. Here we illustrate the conceptual and practical advantages of fitting stochastic population dynamics models to multi-species bacterial time series data. We show how the stability properties, fluctuation regimes and persistence probabilities of human vaginal microbial communities can be better understood by explicitly accommodating three sources of variability in ecological stochastic models of multi-species abundances: 1) stochastic biotic and abiotic forces, 2) ecological feedback and 3) sampling error.

The cervical microbiota of Hispanics living in Puerto Rico is nonoptimal regardless of HPV status.

The cervicovaginal microbiota is influenced by host physiology, immunology, lifestyle, and ethnicity. We hypothesized that there would be differences in the cervicovaginal microbiota among pregnant, nonpregnant, and menopausal women living in Puerto Rico (PR) with and without human papillomavirus (HPV) infection and cervical cancer. We specifically wanted to determine if the microbiota is associated with variations in cervical cytology.

Biofilms preserve the transmissibility of a multi-drug resistance plasmid.

Self-transmissible multidrug resistance (MDR) plasmids are a major health concern because they can spread antibiotic resistance to pathogens. Even though most pathogens form biofilms, little is known about how MDR plasmids persist and evolve in biofilms. We hypothesize that (i) biofilms act as refugia of MDR plasmids by retaining them in the absence of antibiotics longer than well-mixed planktonic populations and that (ii) the evolutionary trajectories that account for the improvement of plasmid persistence over time differ between biofilms and planktonic populations.

Insight into the ecology of vaginal bacteria through integrative analyses of metagenomic and metatranscriptomic data.

Background: Vaginal bacterial communities dominated by Lactobacillus species are associated with a reduced risk of various adverse health outcomes. However, somewhat unexpectedly, many healthy women have microbiota that are not dominated by lactobacilli. To determine the factors that drive vaginal community composition we characterized the genetic composition and transcriptional activities of vaginal microbiota in healthy women.

The vaginal Torquetenovirus titer varies with vaginal microbiota composition in pregnant women.

Torquetenovirus (TTV) is a nonpathogenic endogenous virus whose abundance varies with the extent of immune system activation. We determined if the TTV titer in the vagina of pregnant women was associated with vaginal microbiota composition and levels of compounds in vaginal secretions. Vaginal TTV and microbiota composition in 494 second trimester pregnant women were identified by gene amplification and analysis.

Contagious Antibiotic Resistance: Plasmid Transfer among Bacterial Residents of the Zebrafish Gut.

By characterizing the trajectories of antibiotic resistance gene transfer in bacterial communities such as the gut microbiome, we will better understand the factors that influence this spread of resistance. Our aim was to investigate the host network of a multidrug resistance broad-host-range plasmid in the culturable gut microbiome of zebrafish. This was done through and conjugation experiments with as the donor of the plasmid pB10:: When this donor was mixed with the extracted gut microbiome, only transconjugants of were detected.

Influence of Lactobacillus crispatus, Lactobacillus iners and Gardnerella vaginalis on bacterial vaginal composition in pregnant women.

Purpose: To investigate associations between bacterial species in the vagina in mid-trimester pregnant women from Brazil.

Methods: The vaginal microbiome in 613 subjects was identified by analysis of the V1-V3 region of bacterial 16S ribosomal RNA and the relative prevalence of individual bacteria were determined.

Results: The bacterial species present in the greatest number of women were Lactobacillus crispatus (306 women), L.

An exploratory study of associations with spontaneous preterm birth in primigravid pregnant women with a normal cervical length.

Background: Predictors of spontaneous preterm birth in primigravid women remain undetermined.

Aim: We evaluated whether biomarkers in vaginal secretions and/or differences in the dominant bacterium in the vaginal microbiome predicted the risk for spontaneous preterm birth in primigravid women with a cervical length >25mm.

Study Design: In a prospective study, 146 second trimester pregnant women with their first conception and a cervix >25mm were enrolled.

Changes in the Vaginal Microbiome during the Pregnancy to Postpartum Transition.

Substantial changes in the composition of the vaginal microbiome occur following the end of pregnancy. To identify potential drivers of microbiome changes in individual women during the pregnancy to postpartum transition, we evaluated vaginal samples from 48 pregnant women during their first and third trimesters and postpartum. We determined the species composition of vaginal communities and the vaginal fluid levels of compounds involved in mediating changes in host physiology and the immune system at each time point.

Amylases in the Human Vagina.

Dominance of species in vaginal communities is a hallmark of healthy conditions in the female genital tract. Key nutrients for lactobacilli include sugars produced when glycogen is degraded by α-amylase in the vagina. While α-amylase activity has been demonstrated in vaginal fluids, it is unclear whether α-amylases are produced solely by the host, bacteria in the vagina, or both.

The influence of race on cervical length in pregnant women in Brazil.

Objectives: Short cervical length is a predictor of preterm birth. We evaluated if there were racial differences in variables associated with cervical length in pregnant Brazilian women.

Methods: Cervical length was determined by vaginal ultrasound in 414 women at 21 weeks gestation.

Identification of bacteriophages in the vagina of pregnant women: a descriptive study.

Objective: To determine the presence and identity of extracellular bacteriophage (phage) families, genera and species in the vagina of pregnant women.

Design: Descriptive, observational cohort study.

Setting: São Paulo, Brazil.

Torquetenovirus Titer in Vaginal Secretions from Pregnant and Postpartum Women: Association with Absence of Lactobacillus crispatus and Levels of Lactic Acid and Matrix Metalloproteinase-8.

Vaginal samples from women with term deliveries were tested for torquetenovirus (TTV) by gene amplification, matrix metalloproteinase (MMP)-8 and D- and L-lactic acid by ELISA, and microbiome composition by analysis of the bacterial 16S ribosomal RNA gene. TTV was detected in 43.2%, 31.

Changes in the vaginal microbiota across a gradient of urbanization.

The vaginal microbiota of healthy women typically has low diversity, which increases after perturbations. Among these, lifestyle associated with certain sexual and antimicrobial practices may be associated with higher diversity. To test this hypothesis, we characterized the vaginal microbiota in the cervicovaginal and introital sites in sexually active Amerindians (N = 82) spanning urbanization, and in urban mestizos (N = 29), in the Venezuelan Amazonas.

High-fat diet-induced alterations to gut microbiota and gut-derived lipoteichoic acid contributes to the development of enteric neuropathy.

Background: High-fat diet, microbial alterations and lipopolysaccharide (LPS) are thought to cause enteric diabetic neuropathy and intestinal dysmotility. However, the role of the gut microbiota, lipoteichoic acid (LTA) from Gram-positive bacteria and short-chain fatty acids (SCFAs) in the development of diabetic enteric neuropathy and intestinal dysmotility is not well understood. Our aim was to examine the role of the gut microbiota, LTA and SCFAs in the development of diabetic enteric neuropathy and intestinal dysmotility.

Evolving Populations in Biofilms Contain More Persistent Plasmids.

Bacterial plasmids substantially contribute to the rapid spread of antibiotic resistance, which is a crisis in healthcare today. Coevolution of plasmids and their hosts promotes this spread of resistance by ameliorating the cost of plasmid carriage. However, our knowledge of plasmid-bacteria coevolution is solely based on studies done in well-mixed liquid cultures, even though biofilms represent the main way of bacterial life on Earth and are responsible for most infections.

Vaginal Biomarkers That Predict Cervical Length and Dominant Bacteria in the Vaginal Microbiomes of Pregnant Women.

In many impoverished regions of the world, it may not be possible to assess two major risk factors for preterm birth: a short cervical length and the depletion of vaginal lactobacilli. We determined whether measuring specific compounds in vaginal fluid might be a simple, noninvasive, and cost-effective way to predict the bacteria that dominate the vaginal microbiome and indicate the presence of a shortened cervix (<25 mm). Vaginal fluid samples were prospectively collected from mid-trimester pregnant women, and the concentrations of d- and l-lactic acid, tissue inhibitor of matrix metalloproteinases TIMP-1 and TIMP-2, matrix metalloproteinases MMP-2 and MMP-8, the 70-kDa heat shock protein, a2 isoform of vacuolar ATPase, and sequestrome-1 were quantified by an enzyme-linked immunosorbent assay (ELISA).

The Cervicovaginal Microbiota-Host Interaction Modulates Chlamydia trachomatis Infection.

The mechanism(s) by which -dominated cervicovaginal microbiota provide a barrier to infection remain(s) unknown. Here we evaluate the impact of different spp. identified via culture-independent metataxonomic analysis of -infected women on infection in a three-dimensional (3D) cervical epithelium model.

Comparative genomics of Bifidobacterium species isolated from marmosets and humans.

The genus Bifidobacterium is purported to have beneficial consequences for human health and is a major component of many gastrointestinal probiotics. Although species of Bifidobacterium are generally at low relative frequency in the adult human gastrointestinal tract, they can constitute high proportions of the gastrointestinal communities of adult marmosets. To identify genes that might be important for the maintenance of Bifidobacterium in adult marmosets, ten strains of Bifidobacterium were isolated from the feces of seven adult marmosets, and their genomes were sequenced.

The Relationship between Spatial Structure and the Maintenance of Diversity in Microbial Populations.

Spatial structure is pervasive in the microbial world, yet we know little about how it influences the evolution of microbial populations. It is thought that spatial structure limits the scale of competitive interactions and protracts selective sweeps. This may allow microbial populations to simultaneously explore multiple evolutionary paths.

Vaginal Glycogen, Not Estradiol, Is Associated With Vaginal Bacterial Community Composition in Black Adolescent Women.

Purpose: The purpose of this study was to characterize the composition of vaginal bacterial communities in a cohort of black adolescent women and to determine how the species composition of these communities correlates with levels of estradiol, glycogen, and stress.

Methods: Twenty-one black adolescent women were sampled longitudinally. The composition of their vaginal communities was determined by analyzing the sequences of the V1-V3 regions of 16S rRNA genes, and they were grouped based on patterns in species abundances.

Comparison of the Vaginal Microbiomes of Premenopausal and Postmenopausal Women.

For decades hormone therapy (HT) has been prescribed to treat the symptoms of menopause, such as vaginal dryness, itching and burning. Here we sought to compare the vaginal microbiomes of postmenopausal women who received low dose estrogen therapy to those of premenopausal and postmenopausal women, and to do so in conjunction with assessing the alleviation of symptoms associated with vaginal atrophy. In this study vaginal swab samples were obtained from 45 women who were classified as either premenopausal, postmenopausal, or postmenopausal and undergoing HT.