Browsing by Subject "Lactobacillus"

Now showing 1 - 5 of 5
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    A novel Gardnerella, Prevotella, and Lactobacillus standard that improves accuracy in quantifying bacterial burden in vaginal microbial communities
    (Frontiers Media, 2023-06-19) Elnaggar, Jacob H.; Ardizzone, Caleb M.; Cerca, Nuno; Toh, Evelyn; Łaniewski, Paweł; Lillis, Rebecca A.; Herbst-Kralovetz, Melissa M.; Quayle, Alison J.; Muzny, Christina A.; Taylor, Christopher M.; Microbiology and Immunology, School of Medicine
    Bacterial vaginosis (BV) is the most common vaginal dysbiosis. In this condition, a polymicrobial biofilm develops on vaginal epithelial cells. Accurately quantifying the bacterial burden of the BV biofilm is necessary to further our understanding of BV pathogenesis. Historically, the standard for calculating total bacterial burden of the BV biofilm has been based on quantifying Escherichia coli 16S rRNA gene copy number. However, E. coli is improper for measuring the bacterial burden of this unique micro-environment. Here, we propose a novel qPCR standard to quantify bacterial burden in vaginal microbial communities, from an optimal state to a mature BV biofilm. These standards consist of different combinations of vaginal bacteria including three common BV-associated bacteria (BVAB) Gardnerella spp. (G), Prevotella spp. (P), and Fannyhessea spp. (F) and commensal Lactobacillus spp. (L) using the 16S rRNA gene (G:P:F:L, G:P:F, G:P:L and 1G:9L). We compared these standards to the traditional E. coli (E) reference standard using known quantities of mock vaginal communities and 16 vaginal samples from women. The E standard significantly underestimated the copy numbers of the mock communities, and this underestimation was significantly greater at lower copy numbers of these communities. The G:P:L standard was the most accurate across all mock communities and when compared to other mixed vaginal standards. Mixed vaginal standards were further validated with vaginal samples. This new G:P:L standard can be used in BV pathogenesis research to enhance reproducibility and reliability in quantitative measurements of BVAB, spanning from the optimal to non-optimal (including BV) vaginal microbiota.
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    Association of Chlamydia trachomatis burden with the vaginal microbiota, bacterial vaginosis, and metronidazole treatment
    (Frontiers Media, 2023-12-12) Ardizzone, Caleb M.; Taylor, Christopher M.; Toh, Evelyn; Lillis, Rebecca A.; Elnaggar, Jacob H.; Lammons, John W.; Dehon Mott, Patricia; Duffy, Emily L.; Shen, Li; Quayle, Alison J.; Microbiology and Immunology, School of Medicine
    Bacterial vaginosis (BV), a dysbiosis of the vaginal microbiota, is a common coinfection with Chlamydia trachomatis (Ct), and BV-associated bacteria (BVAB) and their products have been implicated in aiding Ct evade natural immunity. Here, we determined if a non-optimal vaginal microbiota was associated with a higher genital Ct burden and if metronidazole, a standard treatment for BV, would reduce Ct burden or aid in natural clearance of Ct infection. Cervicovaginal samples were collected from women at enrollment and, if testing positive for Ct infection, at a follow-up visit approximately one week later. Cervical Ct burden was assessed by inclusion forming units (IFU) and Ct genome copy number (GCN), and 16S rRNA gene sequencing was used to determine the composition of the vaginal microbiota. We observed a six-log spectrum of IFU and an eight-log spectrum of GCN in our study participants at their enrollment visit, but BV, as indicated by Amsel’s criteria, Nugent scoring, or VALENCIA community state typing, did not predict infectious and total Ct burden, although IFU : GCN increased with Amsel and Nugent scores and in BV-like community state types. Ct burden was, however, associated with the abundance of bacterial species in the vaginal microbiota, negatively with Lactobacillus crispatus and positively with Prevotella bivia. Women diagnosed with BV were treated with metronidazole, and Ct burden was significantly reduced in those who resolved BV with treatment. A subset of women naturally cleared Ct infection in the interim, typified by low Ct burden at enrollment and resolution of BV. Abundance of many BVAB decreased, and Lactobacillus increased, in response to metronidazole treatment, but no changes in abundances of specific vaginal bacteria were unique to women who spontaneously cleared Ct infection.
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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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    Characterization of Vaginal Microbial Community Dynamics in the Pathogenesis of Incident Bacterial Vaginosis, a Pilot Study
    (Wolters Kluwer, 2023) Elnaggar, Jacob H.; Lammons, John W.; Taylor, Christopher M.; Toh, Evelyn; Ardizzone, Caleb M.; Dong, Amy; Aaron, Kristal J.; Luo, Meng; Tamhane, Ashutosh; Lefkowitz, Elliot J.; Quayle, Alison J.; Nelson, David E.; Muzny, Christina A.; Microbiology and Immunology, School of Medicine
    Background: Despite more than 60 years of research, the etiology of bacterial vaginosis (BV) remains controversial. In this pilot study, we used shotgun metagenomic sequencing to characterize vaginal microbial community changes before the development of incident BV (iBV). Methods: A cohort of African American women with a baseline healthy vaginal microbiome (no Amsel criteria, Nugent score 0-3 with no Gardnerella vaginalis morphotypes) were followed for 90 days with daily self-collected vaginal specimens for iBV (≥2 consecutive days of a Nugent score of 7-10). Shotgun metagenomic sequencing was performed on select vaginal specimens from 4 women, every other day for 12 days before iBV diagnosis. Sequencing data were analyzed through Kraken2 and bioBakery 3 workflows, and specimens were classified into community state types. Quantitative polymerase chain reaction was performed to compare the correlation of read counts with bacterial abundance. Results: Common BV-associated bacteria such as G. vaginalis , Prevotella bivia , and Fannyhessea vaginae were increasingly identified in the participants before iBV. Linear modeling indicated significant increases in G. vaginalis and F . vaginae relative abundance before iBV, whereas the relative abundance of Lactobacillus species declined over time. The Lactobacillus species decline correlated with the presence of Lactobacillus phages. We observed enrichment in bacterial adhesion factor genes on days before iBV. There were also significant correlations between bacterial read counts and abundances measured by quantitative polymerase chain reaction. Conclusions: This pilot study characterizes vaginal community dynamics before iBV and identifies key bacterial taxa and mechanisms potentially involved in the pathogenesis of iBV.
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    Exploring breast tissue microbial composition and the association with breast cancer risk factors
    (BMC, 2023-07-10) German, Rana; Marino, Natascia; Hemmerich, Chris; Podicheti, Ram; Rusch, Douglas B.; Stiemsma, Leah T.; Gao, Hongyu; Xuei, Xiaoling; Rockey, Pam; Storniolo, Anna Maria; Medicine, School of Medicine
    Background: Microbial dysbiosis has emerged as an important element in the development and progression of various cancers, including breast cancer. However, the microbial composition of the breast from healthy individuals, even relative to risk of developing breast cancer, remains unclear. Here, we performed a comprehensive analysis of the microbiota of the normal breast tissue, which was analyzed in relation to the microbial composition of the tumor and adjacent normal tissue. Methods: The study cohorts included 403 cancer-free women (who donated normal breast tissue cores) and 76 breast cancer patients (who donated tumor and/or adjacent normal tissue samples). Microbiome profiling was obtained by sequencing the nine hypervariable regions of the 16S rRNA gene (V1V2, V2V3, V3V4, V4V5, V5V7, and V7V9). Transcriptome analysis was also performed on 190 normal breast tissue samples. Breast cancer risk score was assessed using the Tyrer-Cuzick risk model. Results: The V1V2 amplicon sequencing resulted more suitable for the analysis of the normal breast microbiome and identified Lactobacillaceae (Firmicutes phylum), Acetobacterraceae, and Xanthomonadaceae (both Proteobacteria phylum) as the most abundant families in the normal breast. However, Ralstonia (Proteobacteria phylum) was more abundant in both breast tumors and histologically normal tissues adjacent to malignant tumors. We also conducted a correlation analysis between the microbiome and known breast cancer risk factors. Abundances of the bacterial taxa Acetotobacter aceti, Lactobacillus vini, Lactobacillus paracasei, and Xanthonomas sp. were associated with age (p < 0.0001), racial background (p < 0.0001), and parity (p < 0.0001). Finally, transcriptome analysis of normal breast tissues showed an enrichment in metabolism- and immune-related genes in the tissues with abundant Acetotobacter aceti, Lactobacillus vini, Lactobacillus paracasei, and Xanthonomas sp., whereas the presence of Ralstonia in the normal tissue was linked to dysregulation of genes involved in the carbohydrate metabolic pathway. Conclusions: This study defines the microbial features of normal breast tissue, thus providing a basis to understand cancer-related dysbiosis. Moreover, the findings reveal that lifestyle factors can significantly affect the normal breast microbial composition.