Browsing by Author "Lewis, Warren G."

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    Association between obesity and bacterial vaginosis as assessed by Nugent score
    (Elsevier, 2019) Brookheart, Rita T.; Lewis, Warren G.; Peipert, Jeffrey F.; Lewis, Amanda L.; Allsworth, Jenifer E.; Obstetrics and Gynecology, School of Medicine
    Background Bacterial vaginosis is one of the most common vaginal conditions in the U.S. Recent studies have suggested obese women have an abnormal microbiota reminiscent of BV; however, few studies have investigated the prevalence of bacterial vaginosis in overweight and obese populations. Moreover, despite the increased prevalence of obesity and bacterial vaginosis in black women, it is not known whether racial disparities exist in the relationship between obesity and bacterial vaginosis. Objective The objective of this study was to examine the relationship between body mass index and bacterial vaginosis as determined by Nugent score and to determine the influence of race in this context. Study Design We performed a cross-sectional study using patient data and vaginal smears from 5,918 participants of the Contraceptive CHOICE Project. Gram stained vaginal smears were scored using the Nugent method and categorized as BV-negative (Nugent score 0-3), BV-intermediate (Nugent score 4-6), or BV-positive (Nugent score 7-10). Body mass index was determined using Centers for Disease Control and Prevention guidelines and obese individuals were categorized as Class I, II, or III obese based on NIH and World Health Organization body mass index parameters. Linear regression was used to model mean differences in Nugent scores and Poisson regression with robust error variance was used to model prevalence of bacterial vaginosis. Results In our cohort, 50.7% of participants were black, 41.5% were white, and 5.1% were of Hispanic ethnicity with an average age of 25.3 years old. Overall, 28.1% of participants were bacterial vaginosis-positive. Bacterial vaginosis was prevalent in 21.3% of lean, 30.4% of overweight, and 34.5% of obese women (p<0.001). The distribution of bacterial vaginosis-intermediate individuals was similar across all body mass index categories. Compared to lean women, Nugent scores were highest among overweight and obese Class I women (adjusted mean difference; overweight 0.33 [95% CI 0.14, 0.51] and Class I obese 0.51 [95% CI 0.29, 0.72]). Consistent with this, overweight and obese women had a higher frequency of bacterial vaginosis compared to lean women, even after adjusting for variables including race. Among white women, the prevalence of BV was higher for overweight and Class I and Class II/III obese white women compared to lean white women, a phenomenon not observed among black women, suggesting an effect modification. Conclusion Overweight and obese women have higher Nugent scores and a greater occurrence of bacterial vaginosis compared to lean women. Black women have a greater prevalence of bacterial vaginosis independent of their body mass index compared to white women.
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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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    Relationship between nugent score and vaginal epithelial exfoliation
    (PLoS, 2017-05-31) Amegashie, Courtney P.; Gilbert, Nicole M.; Peipert, Jeffrey F.; Allsworth, Jenifer E.; Lewis, Warren G.; Lewis, Amanda L.; Obstetrics and Gynecology, School of Medicine
    OBJECTIVE: Clue cells characteristic of bacterial vaginosis (BV) are thought to arise due to exfoliation of the vaginal epithelium; however, there is little published data connecting total numbers of epithelial cells to markers of BV. The purpose of this study was to enumerate exfoliated epithelial cells (independent of clue cells) and examine the relationship to Nugent score. STUDY DESIGN: We conducted a cross-sectional sub-study of the Contraceptive CHOICE Project cohort. Vaginal swabs were used to create vaginal smears for Gram staining and these smears were later scored using the Nugent method, and then two blinded observers used microscopy to enumerate exfoliated epithelial cells. The degree of epithelial cell exfoliation was compared between women diagnosed as BV-negative (Nugent score 0-3), BV-intermediate (Nugent score 4-6), and BV-positive (Nugent score 7-10). BV specimens (Nugent 7-10) were randomly matched to specimens in the two other groups (Nugent low and Nugent-intermediate), in order to avoid comparing groups of women with potentially confounding baseline demographics. RESULTS: Exfoliated epithelial cell counts were higher in the vaginal smears from BV-positive women compared with BV-negative women. Higher levels of epithelial exfoliation were also evident in BV-intermediate women compared to those with low Nugent scores. After adjustment for clustering introduced by matching, the incidence ratio of increased epithelial cell counts was 2.09 (95% CI 1.50-2.90) for the BV-intermediate women and 1.71 (95% CI 1.23-2.38) for the BV positive women. CONCLUSION: A vaginal epithelial exfoliation phenotype was measured in both Nugent-defined BV-positive and BV-intermediate women. Bacterial vaginosis and intermediate status (Nugent score >3) was associated with significantly more vaginal epithelial exfoliation compared to women with Lactobacillus-dominated microbiotas (Nugent 0-3).