title: The vaginal microbiota: what have we learned after a decade of molecular characterization?
abstract: We conducted a systematic review of the Medline database (U.S. National Library of Medicine, National Institutes of Health, Bethesda, MD, U.S.A) to determine if consistent molecular vaginal microbiota (VMB) composition patterns can be discerned after a decade of molecular testing, and to evaluate demographic, behavioral and clinical determinants of VMB compositions. Studies were eligible when published between 1 January 2008 and 15 November 2013, and if at least one molecular technique (sequencing, PCR, DNA fingerprinting, or DNA hybridization) was used to characterize the VMB. Sixty three eligible studies were identified. These studies have now conclusively shown that lactobacilli-dominated VMB are associated with a healthy vaginal micro-environment and that bacterial vaginosis (BV) is best described as a polybacterial dysbiosis. The extent of dysbiosis correlates well with Nugent score and vaginal pH but not with the other Amsel criteria. Lactobacillus crispatus is more beneficial than L. iners. Longitudinal studies have shown that a L. crispatus-dominated VMB is more likely to shift to a L. iners-dominated or mixed lactobacilli VMB than to full dysbiosis. Data on VMB determinants are scarce and inconsistent, but dysbiosis is consistently associated with HIV, human papillomavirus (HPV), and Trichomonas vaginalis infection. In contrast, vaginal colonization with Candida spp. is more common in women with a lactobacilli-dominated VMB than in women with dysbiosis. Cervicovaginal mucosal immune responses to molecular VMB compositions have not yet been properly characterized. Molecular techniques have now become more affordable, and we make a case for incorporating them into larger epidemiological studies to address knowledge gaps in etiology and pathogenesis of dysbiosis, associations of different dysbiotic states with clinical outcomes, and to evaluate interventions aimed at restoring and maintaining a lactobacilli-dominated VMB.
authors.affiliation: Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom.
authors.forename: Janneke H H M
authors.initials: JH
authors.lastname: van de Wijgert
authors.affiliation: Academic Medical Center and Amsterdam Institute of Global Health and Development, Amsterdam, The Netherlands.
authors.forename: Hanneke
authors.initials: H
authors.lastname: Borgdorff
authors.affiliation: International Centre for Reproductive Health, Ghent University Hospital, Ghent, Belgium.
authors.forename: Rita
authors.initials: R
authors.lastname: Verhelst
authors.affiliation: Prince Leopold Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Tania
authors.initials: T
authors.lastname: Crucitti
authors.affiliation: London School for Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Suzanna
authors.initials: S
authors.lastname: Francis
authors.affiliation: Department of Obstetrics and Gynecology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Hans
authors.initials: H
authors.lastname: Verstraelen
authors.affiliation: Prince Leopold Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: Vicky
authors.initials: V
authors.lastname: Jespers
mesh_terms: D000293:Adolescent; D000328:Adult; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D059013:Microbial Consortia; D064307:Microbiota; D011247:Pregnancy; D014621:Vagina / Q000382:microbiology*; D016585:Vaginosis, Bacterial / Q000175:diagnosis / Q000382:microbiology*