• Assessing the Concordance Between Urogenital and Vaginal Microbiota: Can Urine Specimens Be Used as a Proxy for Vaginal Samples?

      Brown, Sarah E; Robinson, Courtney K; Shardell, Michelle D; Holm, Johanna B; Ravel, Jacques; Ghanem, Khalil G; Brotman, Rebecca M (Frontiers Media S.A., 2021-06-29)
      Background: The vaginal microbiota play a key role in defense against reproductive tract infections; however, many population-based women’s health studies do not collect vaginal samples. Molecular examinations of urine samples have revealed common vaginal bacteria. We sought to assess the extent that community state type assignments of archived random-catch and clean-catch urine samples agreed with the paired vaginal samples in both reproductive-age and peri/post-menopausal women. Results: Using archived samples, we evaluated the microbiota concordance among women in three studies: two with paired mid-vaginal/random-catch urine (N=91 reproductive-age participants and N=13 peri/post-menopausal participants), and one with paired mid-vaginal/clean-catch urine (N=99 reproductive-age participants). Microbiota composition was characterized by sequencing amplicons of the 16S rRNA gene V3-V4 regions and assigned to community state types. Similarity of paired samples was gauged using agreement of community state types and Yue-Clayton θ indices. Analysis of Composition of Microbiomes II indicated which taxa were differently relatively abundant in paired vaginal and urine samples. In reproductive-age women, random-catch and clean-catch urines were 89.0% and 86.9% concordant on five community state types with paired mid-vaginal swabs, and Kappa statistics indicated almost perfect agreement (κrandom-catch=.85, κclean-catch=.81, p<0.0001). A small number of pairs of samples were discordant (23/190, 12%), and discordant pairs tended to be between samples classified to L. iners-dominated and/or low-Lactobacillus states. Concordance and agreement remained similar when dichotomizing the microbiota to Lactobacillus-dominated versus low-Lactobacillus microbiota, as well as when evaluating separately the three subtypes of the low-Lactobacillus community state type IV. Median similarity of paired urine/vaginal samples was high (θrandom-catch=.85, θclean-catch=.88), and a comparison of the random-catch and clean-catch similarity scores showed no significant difference (p=.80). Concordance and similarity were lower for peri/post-menopausal women, but agreement remained substantial (76.9% concordant, κrandom-catch= 0.64, θrandom-catch=.62). Taxonomic-level analysis confirmed these findings. Conclusions: Random-catch and clean-catch urine samples showed substantial agreement on bacterial composition to paired mid-vaginal samples, indicating that the genitourinary microbiota may be a reliable proxy for assessing the overall composition of the vaginal microbiota via community state types. This data suggests that urine samples can, with proper interpretation, be utilized as a surrogate for developing preliminary data and hypothesis-generating studies.
    • The vaginal metabolome and microbiota of cervical HPV-positive and HPV-negative women: a cross-sectional analysis

      Borgogna, J.C.; Shardell, M.D.; Santori, E.K.; Nelson, T.M.; Rath, J.M.; Glover, E.D.; Ravel, J.; Gravitt, P.E.; Yeoman, C.J.; Brotman, R.M. (Blackwell Publishing Ltd, 2019)
      Objective: Characterise the vaginal metabolome of cervical HPV-infected and uninfected women. Design: Cross-sectional. Setting: The Center for Health Behavior Research at the University of Maryland School of Public Health. Sample: Thirty-nine participants, 13 categorised as HPV-negative and 26 as HPV-positive (any genotype; HPV+), 14 of whom were positive with at least one high-risk HPV strain (hrHPV). Method: Self-collected mid-vaginal swabs were profiled for bacterial composition by 16S rRNA gene amplicon sequencing, metabolites by both gas and liquid chromatography mass spectrometry, and 37 types of HPV DNA. Main outcome measures: Metabolite abundances. Results: Vaginal microbiota clustered into Community State Type (CST) I (Lactobacillus crispatus-dominated), CST III (Lactobacillus iners-dominated), and CST IV (low-Lactobacillus, ‘molecular-BV’). HPV+ women had higher biogenic amine and phospholipid concentrations compared with HPV– women after adjustment for CST and cigarette smoking. Metabolomic profiles of HPV+ and HPV− women differed in strata of CST. In CST III, there were higher concentrations of biogenic amines and glycogen-related metabolites in HPV+ women than in HPV– women. In CST IV, there were lower concentrations of glutathione, glycogen, and phospholipid-related metabolites in HPV+ participants than in HPV–participants. Across all CSTs, women with hrHPV strains had lower concentrations of amino acids, lipids, and peptides compared with women who had only low-risk HPV (lrHPV). Conclusions: The vaginal metabolome of HPV+ women differed from HPV− women in terms of several metabolites, including biogenic amines, glutathione, and lipid-related metabolites. If the temporal relation between increased levels of reduced glutathione and oxidised glutathione and HPV incidence/persistence is confirmed in future studies, anti-oxidant therapies may be considered as a non-surgical HPV control intervention. Tweetable abstract: Metabolomics study: Vaginal microenvironment of HPV+ women may be informative for non-surgical interventions