title: Rapid fluctuation of the vaginal microbiota measured by Gram stain analysis.
abstract: BACKGROUND
  The aetiology of bacterial vaginosis (BV) remains unknown.
  
  
  OBJECTIVE
  To describe longitudinal changes in vaginal microbiota.
  
  
  METHODS
  Thirty-nine women (mean age 36.8 years; 22 (56.4%) African-American) self-collected vaginal specimens twice weekly for 16 weeks as part of a vaginal douching cessation study. In an analysis where each woman serves as her own control, conditional logistic regression was used to evaluate daily, time-varying factors associated with a woman's incident BV episode(s) as compared with her persistently BV-negative sample(s). BV was defined by a Nugent's Gram stain score >or=7.
  
  
  RESULTS
  46.2% of participants had BV in the first 4 weeks of observation. Rapid fluctuation of vaginal microbiota was observed in 226 transitions to BV or spontaneous remission. Duration of BV was often short: 51% of the episodes lasted for only one sample interval (3 days). Among women who had at least one BV episode, the median number of episodes per woman was 8.7 (SD 7.4, range 1-22). Lubricant use 1 day before specimen collection (adjusted OR (aOR)=11.75, 95% CI 1.96 to 70.27) and rectal sex 2 days before (aOR=4.48, 95% CI 2.79 to 7.17) were associated with BV onset.
  
  
  CONCLUSIONS
  Rapid fluctuation of the vaginal microbiota was seen. Longitudinal studies with long intervals between sampling are likely to miss episodes of BV. Recent report of lubricant use and rectal sex were associated with incident BV.
authors.affiliation: Department of Epidemiology and Preventive Medicine, Institute for Genome Sciences, University of Maryland School of Medicine, BioPark Building II, 801 West Baltimore Street, Baltimore, MD 21201, USA. rbrotman@som.umaryland.edu
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Brotman
authors.forename: Jacques
authors.initials: J
authors.lastname: Ravel
authors.forename: Richard A
authors.initials: RA
authors.lastname: Cone
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Zenilman
mesh_terms: D000328:Adult; D002690:Chlamydia Infections / Q000175:diagnosis; D002692:Chlamydia trachomatis / Q000302:isolation & purification; D004396:Coloring Agents; D018592:Cross-Over Studies; D005260:Female; D005840:Gentian Violet; D006069:Gonorrhea / Q000175:diagnosis; D006801:Humans; D008875:Middle Aged; D009344:Neisseria gonorrhoeae / Q000302:isolation & purification; D010619:Phenazines; D012307:Risk Factors; D013997:Time Factors; D014621:Vagina / Q000382:microbiology*; D044364:Vaginal Douching; D016585:Vaginosis, Bacterial / Q000175:diagnosis* / Q000382:microbiology; D055815:Young Adult
chemical_list: D004396:Coloring Agents; C035863:Gram's stain; D010619:Phenazines; D005840:Gentian Violet