Browsing by Subject "vaginal microbiome"

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    Associations between the vaginal microbiome and Candida colonization in women of reproductive age
    (Elsevier, 2019) Tortelli, Brett A.; Lewis, Warren G.; Allsworth, Jenifer E.; Member-Meneh, Nadum; Foster, Lynne R.; Reno, Hilary E.; Peipert, Jeffrey F.; Fay, Justin C.; Lewis, Amanda L.; Medicine, School of Medicine
    Background The composition of bacteria within the vaginal microbiome has garnered a lot of recent attention and has been associated with reproductive health and disease. Despite the common occurrence of yeast (primarily Candida) within the vaginal microbiome, there is still an incomplete picture of relationships between yeast and bacteria (especially lactobacilli), as well as how such associations are governed. Such relationships could be important to a more holistic understanding of the vaginal microbiome and its connection to reproductive health. Objective To perform molecular characterization of clinical specimens to define associations between vaginal bacteria (especially Lactobacillus species) and Candida colonization. In vitro studies were conducted to test the two most common dominant Lactobacillus species (Lactobacillus crispatus and Lactobacillus iners) in their ability to inhibit Candida growth and to examine the basis for such inhibition. Study Design A nested cross-sectional study of reproductive age women from the Contraceptive CHOICE Project was conducted. Vaginal swabs from 299 women were selected to balance race and BV status, resulting in similar representation of black and white women in each of the three Nugent score categories [normal (0-3), intermediate (4-6), and bacterial vaginosis (7-10)]. Sequencing of the 16S ribosomal gene (V4 region) was used to determine the dominant Lactobacillus species present (primarily L. iners and L. crispatus), defined as >50% of the community. Subjects without dominance by a single Lactobacillus species were classified as Diverse. A Candida-specific qPCR targeting the internally transcribed spacer 1 (ITS1) was validated using vaginal samples collected from a second cohort of women and used to assess Candida colonization. 255 nonpregnant women with sufficient bacterial biomass for analysis were included in the final analysis. Generalized linear models were employed to evaluate associations between Lactobacillus dominance, sociodemographic and risk characteristics and vaginal Candida colonization. In separate in vitro studies, the potential of cell-free supernatants from L. crispatus and L. iners cultures to inhibit Candida growth was evaluated. Results Forty-two women (16%) were vaginally colonized with Candida. Microbiomes characterized as Diverse (38%), L. iners-dominant (39%), and L. crispatus-dominant (20%) were the most common. The microbiome, race and Candida colonization co-varied with a higher prevalence of Candida among black women and L. iners-dominant communities compared to white women and L. crispatus-dominant communities. L. iners-dominant communities were more likely to harbor Candida than L. crispatus-dominant communities (OR = 2.85, 95% CI: 1.03 to 7.21; Fisher’s Exact, p = 0.048). In vitro, L. crispatus produced greater concentrations of lactic acid and exhibited significantly more pH-dependent growth inhibition of C. albicans, suggesting a potential mechanism for the clinical observations. Conclusion In nonpregnant women, L. iners-dominant communities were significantly more likely to harbor Candida than L. crispatus-dominant communities, suggesting that Lactobacillus species have different relationships with Candida. In vitro experiments indicate that L. crispatus may impede Candida colonization more effectively than L. iners through a greater production of lactic acid.
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    Engaging Adolescent and Young Adults in Microbiome Sample Self-Collection: Strategies for Success
    (SAGE Journals, 2020) Chen, Chen X.; Carpenter, Janet S.; Murphy, Tabitha; Brooks, Patricia; Fortenberry, J. Dennis
    Human microbiome research provides rich opportunities to elucidate factors influencing health, uncover novel biomarkers, and expand disease treatment options. A well-conducted microbiome study depends not only on a rigorous design but also on successfully engaging participants in collecting quality samples. In this paper, we aim to describe (1) strategies our team used to engage adolescents and young adults in vaginal and gut microbiome sample self-collection and (2) their effectiveness. In our prospective, longitudinal, feasibility study of 20 female adolescents and young adults, research participants self-collected vaginal and gut microbiome samples at home. Using a participatory and iterative process, we developed strategies to engage participants in sample self-collection, including (1) providing clear instructions to ensure comprehension and buy-in, (2) providing a user-friendly take-home package, (3) minimizing disgust/embarrassment associated with sample collection, and (4) follow-up communications to facilitate sample collections and return. With these strategies, we achieved 100% participant retention and 100% sample return rates. All samples (n = 80, 100%) were usable for downstream 16s rRNA gene sequencing and analysis. All participants rated the study procedures as acceptable, and qualitative data showed that strategies were well received by participants. This study suggests that carefully planning and implementing strategies to engage participants in sample self-collection can result in high degrees of participant compliance, sample quality, and participant satisfaction in microbiome research.
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    Vaginal Glycogen, Not Estradiol, Is Associated With Vaginal Bacterial Community Composition in Black Adolescent Women
    (Elsevier, 2019-03-14) Nunn, Kenetta L.; Ridenhour, Benjamin J.; Chester, Emily M.; Vitzthum, Virginia J.; Fortenberry, J. Dennis; Forney, Larry J.; Pediatrics, School of Medicine
    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 correlate 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 Vl-V3 region of l6S rRNA genes and they were grouped based on patterns in species abundances. The relationships between estradiol, glycogen, psychosocial stress, and the composition of these communities were assessed. Results Vaginal communities could be distinguished and classified into three groups that differed in the abundances of Lactobacillus. Eighty-one percent of study participants had communities dominated by species of Lactobacillus. Glycogen levels were higher in communities dominated by one or multiple species of Lactobacillus as compared to those having low proportions of Lactobacillus. Estradiol and psychosocial stress measurements did not differ among the three groups, while estradiol and glycogen exhibited a weak positive relationship that was not statistically significant. Conclusions The findings of this pilot study suggest that glycogen levels are associated with vaginal community composition in young Black women; however, estradiol and psychosocial stress are not. Additionally, the results suggest there is no simple relationship between levels of estradiol and the production of vaginal glycogen.